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      1 /* png.h - header file for PNG reference library
      2  *
      3  * libpng version 1.2.46 - July 9, 2011
      4  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
      5  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
      6  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
      7  *
      8  * This code is released under the libpng license (See LICENSE, below)
      9  *
     10  * Authors and maintainers:
     11  *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
     12  *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
     13  *  libpng versions 0.97, January 1998, through 1.2.46 - July 9, 2011: Glenn
     14  *  See also "Contributing Authors", below.
     15  *
     16  * Note about libpng version numbers:
     17  *
     18  *    Due to various miscommunications, unforeseen code incompatibilities
     19  *    and occasional factors outside the authors' control, version numbering
     20  *    on the library has not always been consistent and straightforward.
     21  *    The following table summarizes matters since version 0.89c, which was
     22  *    the first widely used release:
     23  *
     24  *    source                 png.h  png.h  shared-lib
     25  *    version                string   int  version
     26  *    -------                ------ -----  ----------
     27  *    0.89c "1.0 beta 3"     0.89      89  1.0.89
     28  *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
     29  *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
     30  *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
     31  *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
     32  *    0.97c                  0.97      97  2.0.97
     33  *    0.98                   0.98      98  2.0.98
     34  *    0.99                   0.99      98  2.0.99
     35  *    0.99a-m                0.99      99  2.0.99
     36  *    1.00                   1.00     100  2.1.0 [100 should be 10000]
     37  *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
     38  *    1.0.1       png.h string is   10001  2.1.0
     39  *    1.0.1a-e    identical to the  10002  from here on, the shared library
     40  *    1.0.2       source version)   10002  is 2.V where V is the source code
     41  *    1.0.2a-b                      10003  version, except as noted.
     42  *    1.0.3                         10003
     43  *    1.0.3a-d                      10004
     44  *    1.0.4                         10004
     45  *    1.0.4a-f                      10005
     46  *    1.0.5 (+ 2 patches)           10005
     47  *    1.0.5a-d                      10006
     48  *    1.0.5e-r                      10100 (not source compatible)
     49  *    1.0.5s-v                      10006 (not binary compatible)
     50  *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
     51  *    1.0.6d-f                      10007 (still binary incompatible)
     52  *    1.0.6g                        10007
     53  *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
     54  *    1.0.6i                        10007  10.6i
     55  *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
     56  *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
     57  *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
     58  *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
     59  *    1.0.7                    1    10007  (still compatible)
     60  *    1.0.8beta1-4             1    10008  2.1.0.8beta1-4
     61  *    1.0.8rc1                 1    10008  2.1.0.8rc1
     62  *    1.0.8                    1    10008  2.1.0.8
     63  *    1.0.9beta1-6             1    10009  2.1.0.9beta1-6
     64  *    1.0.9rc1                 1    10009  2.1.0.9rc1
     65  *    1.0.9beta7-10            1    10009  2.1.0.9beta7-10
     66  *    1.0.9rc2                 1    10009  2.1.0.9rc2
     67  *    1.0.9                    1    10009  2.1.0.9
     68  *    1.0.10beta1              1    10010  2.1.0.10beta1
     69  *    1.0.10rc1                1    10010  2.1.0.10rc1
     70  *    1.0.10                   1    10010  2.1.0.10
     71  *    1.0.11beta1-3            1    10011  2.1.0.11beta1-3
     72  *    1.0.11rc1                1    10011  2.1.0.11rc1
     73  *    1.0.11                   1    10011  2.1.0.11
     74  *    1.0.12beta1-2            2    10012  2.1.0.12beta1-2
     75  *    1.0.12rc1                2    10012  2.1.0.12rc1
     76  *    1.0.12                   2    10012  2.1.0.12
     77  *    1.1.0a-f                 -    10100  2.1.1.0a-f (branch abandoned)
     78  *    1.2.0beta1-2             2    10200  2.1.2.0beta1-2
     79  *    1.2.0beta3-5             3    10200  3.1.2.0beta3-5
     80  *    1.2.0rc1                 3    10200  3.1.2.0rc1
     81  *    1.2.0                    3    10200  3.1.2.0
     82  *    1.2.1beta1-4             3    10201  3.1.2.1beta1-4
     83  *    1.2.1rc1-2               3    10201  3.1.2.1rc1-2
     84  *    1.2.1                    3    10201  3.1.2.1
     85  *    1.2.2beta1-6            12    10202  12.so.0.1.2.2beta1-6
     86  *    1.0.13beta1             10    10013  10.so.0.1.0.13beta1
     87  *    1.0.13rc1               10    10013  10.so.0.1.0.13rc1
     88  *    1.2.2rc1                12    10202  12.so.0.1.2.2rc1
     89  *    1.0.13                  10    10013  10.so.0.1.0.13
     90  *    1.2.2                   12    10202  12.so.0.1.2.2
     91  *    1.2.3rc1-6              12    10203  12.so.0.1.2.3rc1-6
     92  *    1.2.3                   12    10203  12.so.0.1.2.3
     93  *    1.2.4beta1-3            13    10204  12.so.0.1.2.4beta1-3
     94  *    1.0.14rc1               13    10014  10.so.0.1.0.14rc1
     95  *    1.2.4rc1                13    10204  12.so.0.1.2.4rc1
     96  *    1.0.14                  10    10014  10.so.0.1.0.14
     97  *    1.2.4                   13    10204  12.so.0.1.2.4
     98  *    1.2.5beta1-2            13    10205  12.so.0.1.2.5beta1-2
     99  *    1.0.15rc1-3             10    10015  10.so.0.1.0.15rc1-3
    100  *    1.2.5rc1-3              13    10205  12.so.0.1.2.5rc1-3
    101  *    1.0.15                  10    10015  10.so.0.1.0.15
    102  *    1.2.5                   13    10205  12.so.0.1.2.5
    103  *    1.2.6beta1-4            13    10206  12.so.0.1.2.6beta1-4
    104  *    1.0.16                  10    10016  10.so.0.1.0.16
    105  *    1.2.6                   13    10206  12.so.0.1.2.6
    106  *    1.2.7beta1-2            13    10207  12.so.0.1.2.7beta1-2
    107  *    1.0.17rc1               10    10017  10.so.0.1.0.17rc1
    108  *    1.2.7rc1                13    10207  12.so.0.1.2.7rc1
    109  *    1.0.17                  10    10017  10.so.0.1.0.17
    110  *    1.2.7                   13    10207  12.so.0.1.2.7
    111  *    1.2.8beta1-5            13    10208  12.so.0.1.2.8beta1-5
    112  *    1.0.18rc1-5             10    10018  10.so.0.1.0.18rc1-5
    113  *    1.2.8rc1-5              13    10208  12.so.0.1.2.8rc1-5
    114  *    1.0.18                  10    10018  10.so.0.1.0.18
    115  *    1.2.8                   13    10208  12.so.0.1.2.8
    116  *    1.2.9beta1-3            13    10209  12.so.0.1.2.9beta1-3
    117  *    1.2.9beta4-11           13    10209  12.so.0.9[.0]
    118  *    1.2.9rc1                13    10209  12.so.0.9[.0]
    119  *    1.2.9                   13    10209  12.so.0.9[.0]
    120  *    1.2.10beta1-8           13    10210  12.so.0.10[.0]
    121  *    1.2.10rc1-3             13    10210  12.so.0.10[.0]
    122  *    1.2.10                  13    10210  12.so.0.10[.0]
    123  *    1.2.11beta1-4           13    10211  12.so.0.11[.0]
    124  *    1.0.19rc1-5             10    10019  10.so.0.19[.0]
    125  *    1.2.11rc1-5             13    10211  12.so.0.11[.0]
    126  *    1.0.19                  10    10019  10.so.0.19[.0]
    127  *    1.2.11                  13    10211  12.so.0.11[.0]
    128  *    1.0.20                  10    10020  10.so.0.20[.0]
    129  *    1.2.12                  13    10212  12.so.0.12[.0]
    130  *    1.2.13beta1             13    10213  12.so.0.13[.0]
    131  *    1.0.21                  10    10021  10.so.0.21[.0]
    132  *    1.2.13                  13    10213  12.so.0.13[.0]
    133  *    1.2.14beta1-2           13    10214  12.so.0.14[.0]
    134  *    1.0.22rc1               10    10022  10.so.0.22[.0]
    135  *    1.2.14rc1               13    10214  12.so.0.14[.0]
    136  *    1.0.22                  10    10022  10.so.0.22[.0]
    137  *    1.2.14                  13    10214  12.so.0.14[.0]
    138  *    1.2.15beta1-6           13    10215  12.so.0.15[.0]
    139  *    1.0.23rc1-5             10    10023  10.so.0.23[.0]
    140  *    1.2.15rc1-5             13    10215  12.so.0.15[.0]
    141  *    1.0.23                  10    10023  10.so.0.23[.0]
    142  *    1.2.15                  13    10215  12.so.0.15[.0]
    143  *    1.2.16beta1-2           13    10216  12.so.0.16[.0]
    144  *    1.2.16rc1               13    10216  12.so.0.16[.0]
    145  *    1.0.24                  10    10024  10.so.0.24[.0]
    146  *    1.2.16                  13    10216  12.so.0.16[.0]
    147  *    1.2.17beta1-2           13    10217  12.so.0.17[.0]
    148  *    1.0.25rc1               10    10025  10.so.0.25[.0]
    149  *    1.2.17rc1-3             13    10217  12.so.0.17[.0]
    150  *    1.0.25                  10    10025  10.so.0.25[.0]
    151  *    1.2.17                  13    10217  12.so.0.17[.0]
    152  *    1.0.26                  10    10026  10.so.0.26[.0]
    153  *    1.2.18                  13    10218  12.so.0.18[.0]
    154  *    1.2.19beta1-31          13    10219  12.so.0.19[.0]
    155  *    1.0.27rc1-6             10    10027  10.so.0.27[.0]
    156  *    1.2.19rc1-6             13    10219  12.so.0.19[.0]
    157  *    1.0.27                  10    10027  10.so.0.27[.0]
    158  *    1.2.19                  13    10219  12.so.0.19[.0]
    159  *    1.2.20beta01-04         13    10220  12.so.0.20[.0]
    160  *    1.0.28rc1-6             10    10028  10.so.0.28[.0]
    161  *    1.2.20rc1-6             13    10220  12.so.0.20[.0]
    162  *    1.0.28                  10    10028  10.so.0.28[.0]
    163  *    1.2.20                  13    10220  12.so.0.20[.0]
    164  *    1.2.21beta1-2           13    10221  12.so.0.21[.0]
    165  *    1.2.21rc1-3             13    10221  12.so.0.21[.0]
    166  *    1.0.29                  10    10029  10.so.0.29[.0]
    167  *    1.2.21                  13    10221  12.so.0.21[.0]
    168  *    1.2.22beta1-4           13    10222  12.so.0.22[.0]
    169  *    1.0.30rc1               10    10030  10.so.0.30[.0]
    170  *    1.2.22rc1               13    10222  12.so.0.22[.0]
    171  *    1.0.30                  10    10030  10.so.0.30[.0]
    172  *    1.2.22                  13    10222  12.so.0.22[.0]
    173  *    1.2.23beta01-05         13    10223  12.so.0.23[.0]
    174  *    1.2.23rc01              13    10223  12.so.0.23[.0]
    175  *    1.2.23                  13    10223  12.so.0.23[.0]
    176  *    1.2.24beta01-02         13    10224  12.so.0.24[.0]
    177  *    1.2.24rc01              13    10224  12.so.0.24[.0]
    178  *    1.2.24                  13    10224  12.so.0.24[.0]
    179  *    1.2.25beta01-06         13    10225  12.so.0.25[.0]
    180  *    1.2.25rc01-02           13    10225  12.so.0.25[.0]
    181  *    1.0.31                  10    10031  10.so.0.31[.0]
    182  *    1.2.25                  13    10225  12.so.0.25[.0]
    183  *    1.2.26beta01-06         13    10226  12.so.0.26[.0]
    184  *    1.2.26rc01              13    10226  12.so.0.26[.0]
    185  *    1.2.26                  13    10226  12.so.0.26[.0]
    186  *    1.0.32                  10    10032  10.so.0.32[.0]
    187  *    1.2.27beta01-06         13    10227  12.so.0.27[.0]
    188  *    1.2.27rc01              13    10227  12.so.0.27[.0]
    189  *    1.0.33                  10    10033  10.so.0.33[.0]
    190  *    1.2.27                  13    10227  12.so.0.27[.0]
    191  *    1.0.34                  10    10034  10.so.0.34[.0]
    192  *    1.2.28                  13    10228  12.so.0.28[.0]
    193  *    1.2.29beta01-03         13    10229  12.so.0.29[.0]
    194  *    1.2.29rc01              13    10229  12.so.0.29[.0]
    195  *    1.0.35                  10    10035  10.so.0.35[.0]
    196  *    1.2.29                  13    10229  12.so.0.29[.0]
    197  *    1.0.37                  10    10037  10.so.0.37[.0]
    198  *    1.2.30beta01-04         13    10230  12.so.0.30[.0]
    199  *    1.0.38rc01-08           10    10038  10.so.0.38[.0]
    200  *    1.2.30rc01-08           13    10230  12.so.0.30[.0]
    201  *    1.0.38                  10    10038  10.so.0.38[.0]
    202  *    1.2.30                  13    10230  12.so.0.30[.0]
    203  *    1.0.39rc01-03           10    10039  10.so.0.39[.0]
    204  *    1.2.31rc01-03           13    10231  12.so.0.31[.0]
    205  *    1.0.39                  10    10039  10.so.0.39[.0]
    206  *    1.2.31                  13    10231  12.so.0.31[.0]
    207  *    1.2.32beta01-02         13    10232  12.so.0.32[.0]
    208  *    1.0.40rc01              10    10040  10.so.0.40[.0]
    209  *    1.2.32rc01              13    10232  12.so.0.32[.0]
    210  *    1.0.40                  10    10040  10.so.0.40[.0]
    211  *    1.2.32                  13    10232  12.so.0.32[.0]
    212  *    1.2.33beta01-02         13    10233  12.so.0.33[.0]
    213  *    1.2.33rc01-02           13    10233  12.so.0.33[.0]
    214  *    1.0.41rc01              10    10041  10.so.0.41[.0]
    215  *    1.2.33                  13    10233  12.so.0.33[.0]
    216  *    1.0.41                  10    10041  10.so.0.41[.0]
    217  *    1.2.34beta01-07         13    10234  12.so.0.34[.0]
    218  *    1.0.42rc01              10    10042  10.so.0.42[.0]
    219  *    1.2.34rc01              13    10234  12.so.0.34[.0]
    220  *    1.0.42                  10    10042  10.so.0.42[.0]
    221  *    1.2.34                  13    10234  12.so.0.34[.0]
    222  *    1.2.35beta01-03         13    10235  12.so.0.35[.0]
    223  *    1.0.43rc01-02           10    10043  10.so.0.43[.0]
    224  *    1.2.35rc01-02           13    10235  12.so.0.35[.0]
    225  *    1.0.43                  10    10043  10.so.0.43[.0]
    226  *    1.2.35                  13    10235  12.so.0.35[.0]
    227  *    1.2.36beta01-05         13    10236  12.so.0.36[.0]
    228  *    1.2.36rc01              13    10236  12.so.0.36[.0]
    229  *    1.0.44                  10    10044  10.so.0.44[.0]
    230  *    1.2.36                  13    10236  12.so.0.36[.0]
    231  *    1.2.37beta01-03         13    10237  12.so.0.37[.0]
    232  *    1.2.37rc01              13    10237  12.so.0.37[.0]
    233  *    1.2.37                  13    10237  12.so.0.37[.0]
    234  *    1.0.45                  10    10045  12.so.0.45[.0]
    235  *    1.0.46                  10    10046  10.so.0.46[.0]
    236  *    1.2.38beta01            13    10238  12.so.0.38[.0]
    237  *    1.2.38rc01-03           13    10238  12.so.0.38[.0]
    238  *    1.0.47                  10    10047  10.so.0.47[.0]
    239  *    1.2.38                  13    10238  12.so.0.38[.0]
    240  *    1.2.39beta01-05         13    10239  12.so.0.39[.0]
    241  *    1.2.39rc01              13    10239  12.so.0.39[.0]
    242  *    1.0.48                  10    10048  10.so.0.48[.0]
    243  *    1.2.39                  13    10239  12.so.0.39[.0]
    244  *    1.2.40beta01            13    10240  12.so.0.40[.0]
    245  *    1.2.40rc01              13    10240  12.so.0.40[.0]
    246  *    1.0.49                  10    10049  10.so.0.49[.0]
    247  *    1.2.40                  13    10240  12.so.0.40[.0]
    248  *    1.2.41beta01-18         13    10241  12.so.0.41[.0]
    249  *    1.0.51rc01              10    10051  10.so.0.51[.0]
    250  *    1.2.41rc01-03           13    10241  12.so.0.41[.0]
    251  *    1.0.51                  10    10051  10.so.0.51[.0]
    252  *    1.2.41                  13    10241  12.so.0.41[.0]
    253  *    1.2.42beta01-02         13    10242  12.so.0.42[.0]
    254  *    1.2.42rc01-05           13    10242  12.so.0.42[.0]
    255  *    1.0.52                  10    10052  10.so.0.52[.0]
    256  *    1.2.42                  13    10242  12.so.0.42[.0]
    257  *    1.2.43beta01-05         13    10243  12.so.0.43[.0]
    258  *    1.0.53rc01-02           10    10053  10.so.0.53[.0]
    259  *    1.2.43rc01-02           13    10243  12.so.0.43[.0]
    260  *    1.0.53                  10    10053  10.so.0.53[.0]
    261  *    1.2.43                  13    10243  12.so.0.43[.0]
    262  *    1.2.44beta01-03         13    10244  12.so.0.44[.0]
    263  *    1.2.44rc01-03           13    10244  12.so.0.44[.0]
    264  *    1.2.44                  13    10244  12.so.0.44[.0]
    265  *    1.2.45beta01-03         13    10245  12.so.0.45[.0]
    266  *    1.0.55rc01              10    10055  10.so.0.55[.0]
    267  *    1.2.45rc01              13    10245  12.so.0.45[.0]
    268  *    1.0.55                  10    10055  10.so.0.55[.0]
    269  *    1.2.45                  13    10245  12.so.0.45[.0]
    270  *    1.2.46rc01-02           13    10246  12.so.0.46[.0]
    271  *    1.0.56                  10    10056  10.so.0.56[.0]
    272  *    1.2.46                  13    10246  12.so.0.46[.0]
    273  *
    274  *    Henceforth the source version will match the shared-library major
    275  *    and minor numbers; the shared-library major version number will be
    276  *    used for changes in backward compatibility, as it is intended.  The
    277  *    PNG_LIBPNG_VER macro, which is not used within libpng but is available
    278  *    for applications, is an unsigned integer of the form xyyzz corresponding
    279  *    to the source version x.y.z (leading zeros in y and z).  Beta versions
    280  *    were given the previous public release number plus a letter, until
    281  *    version 1.0.6j; from then on they were given the upcoming public
    282  *    release number plus "betaNN" or "rcNN".
    283  *
    284  *    Binary incompatibility exists only when applications make direct access
    285  *    to the info_ptr or png_ptr members through png.h, and the compiled
    286  *    application is loaded with a different version of the library.
    287  *
    288  *    DLLNUM will change each time there are forward or backward changes
    289  *    in binary compatibility (e.g., when a new feature is added).
    290  *
    291  * See libpng.txt or libpng.3 for more information.  The PNG specification
    292  * is available as a W3C Recommendation and as an ISO Specification,
    293  * <http://www.w3.org/TR/2003/REC-PNG-20031110/
    294  */
    295 
    296 /*
    297  * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
    298  *
    299  * If you modify libpng you may insert additional notices immediately following
    300  * this sentence.
    301  *
    302  * This code is released under the libpng license.
    303  *
    304  * libpng versions 1.2.6, August 15, 2004, through 1.2.46, July 9, 2011, are
    305  * Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
    306  * distributed according to the same disclaimer and license as libpng-1.2.5
    307  * with the following individual added to the list of Contributing Authors:
    308  *
    309  *    Cosmin Truta
    310  *
    311  * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
    312  * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
    313  * distributed according to the same disclaimer and license as libpng-1.0.6
    314  * with the following individuals added to the list of Contributing Authors:
    315  *
    316  *    Simon-Pierre Cadieux
    317  *    Eric S. Raymond
    318  *    Gilles Vollant
    319  *
    320  * and with the following additions to the disclaimer:
    321  *
    322  *    There is no warranty against interference with your enjoyment of the
    323  *    library or against infringement.  There is no warranty that our
    324  *    efforts or the library will fulfill any of your particular purposes
    325  *    or needs.  This library is provided with all faults, and the entire
    326  *    risk of satisfactory quality, performance, accuracy, and effort is with
    327  *    the user.
    328  *
    329  * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
    330  * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
    331  * distributed according to the same disclaimer and license as libpng-0.96,
    332  * with the following individuals added to the list of Contributing Authors:
    333  *
    334  *    Tom Lane
    335  *    Glenn Randers-Pehrson
    336  *    Willem van Schaik
    337  *
    338  * libpng versions 0.89, June 1996, through 0.96, May 1997, are
    339  * Copyright (c) 1996, 1997 Andreas Dilger
    340  * Distributed according to the same disclaimer and license as libpng-0.88,
    341  * with the following individuals added to the list of Contributing Authors:
    342  *
    343  *    John Bowler
    344  *    Kevin Bracey
    345  *    Sam Bushell
    346  *    Magnus Holmgren
    347  *    Greg Roelofs
    348  *    Tom Tanner
    349  *
    350  * libpng versions 0.5, May 1995, through 0.88, January 1996, are
    351  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
    352  *
    353  * For the purposes of this copyright and license, "Contributing Authors"
    354  * is defined as the following set of individuals:
    355  *
    356  *    Andreas Dilger
    357  *    Dave Martindale
    358  *    Guy Eric Schalnat
    359  *    Paul Schmidt
    360  *    Tim Wegner
    361  *
    362  * The PNG Reference Library is supplied "AS IS".  The Contributing Authors
    363  * and Group 42, Inc. disclaim all warranties, expressed or implied,
    364  * including, without limitation, the warranties of merchantability and of
    365  * fitness for any purpose.  The Contributing Authors and Group 42, Inc.
    366  * assume no liability for direct, indirect, incidental, special, exemplary,
    367  * or consequential damages, which may result from the use of the PNG
    368  * Reference Library, even if advised of the possibility of such damage.
    369  *
    370  * Permission is hereby granted to use, copy, modify, and distribute this
    371  * source code, or portions hereof, for any purpose, without fee, subject
    372  * to the following restrictions:
    373  *
    374  * 1. The origin of this source code must not be misrepresented.
    375  *
    376  * 2. Altered versions must be plainly marked as such and
    377  * must not be misrepresented as being the original source.
    378  *
    379  * 3. This Copyright notice may not be removed or altered from
    380  *    any source or altered source distribution.
    381  *
    382  * The Contributing Authors and Group 42, Inc. specifically permit, without
    383  * fee, and encourage the use of this source code as a component to
    384  * supporting the PNG file format in commercial products.  If you use this
    385  * source code in a product, acknowledgment is not required but would be
    386  * appreciated.
    387  */
    388 
    389 /*
    390  * A "png_get_copyright" function is available, for convenient use in "about"
    391  * boxes and the like:
    392  *
    393  * printf("%s",png_get_copyright(NULL));
    394  *
    395  * Also, the PNG logo (in PNG format, of course) is supplied in the
    396  * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
    397  */
    398 
    399 /*
    400  * Libpng is OSI Certified Open Source Software.  OSI Certified is a
    401  * certification mark of the Open Source Initiative.
    402  */
    403 
    404 /*
    405  * The contributing authors would like to thank all those who helped
    406  * with testing, bug fixes, and patience.  This wouldn't have been
    407  * possible without all of you.
    408  *
    409  * Thanks to Frank J. T. Wojcik for helping with the documentation.
    410  */
    411 
    412 /*
    413  * Y2K compliance in libpng:
    414  * =========================
    415  *
    416  *    July 9, 2011
    417  *
    418  *    Since the PNG Development group is an ad-hoc body, we can't make
    419  *    an official declaration.
    420  *
    421  *    This is your unofficial assurance that libpng from version 0.71 and
    422  *    upward through 1.2.46 are Y2K compliant.  It is my belief that earlier
    423  *    versions were also Y2K compliant.
    424  *
    425  *    Libpng only has three year fields.  One is a 2-byte unsigned integer
    426  *    that will hold years up to 65535.  The other two hold the date in text
    427  *    format, and will hold years up to 9999.
    428  *
    429  *    The integer is
    430  *        "png_uint_16 year" in png_time_struct.
    431  *
    432  *    The strings are
    433  *        "png_charp time_buffer" in png_struct and
    434  *        "near_time_buffer", which is a local character string in png.c.
    435  *
    436  *    There are seven time-related functions:
    437  *        png.c: png_convert_to_rfc_1123() in png.c
    438  *          (formerly png_convert_to_rfc_1152() in error)
    439  *        png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
    440  *        png_convert_from_time_t() in pngwrite.c
    441  *        png_get_tIME() in pngget.c
    442  *        png_handle_tIME() in pngrutil.c, called in pngread.c
    443  *        png_set_tIME() in pngset.c
    444  *        png_write_tIME() in pngwutil.c, called in pngwrite.c
    445  *
    446  *    All handle dates properly in a Y2K environment.  The
    447  *    png_convert_from_time_t() function calls gmtime() to convert from system
    448  *    clock time, which returns (year - 1900), which we properly convert to
    449  *    the full 4-digit year.  There is a possibility that applications using
    450  *    libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
    451  *    function, or that they are incorrectly passing only a 2-digit year
    452  *    instead of "year - 1900" into the png_convert_from_struct_tm() function,
    453  *    but this is not under our control.  The libpng documentation has always
    454  *    stated that it works with 4-digit years, and the APIs have been
    455  *    documented as such.
    456  *
    457  *    The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
    458  *    integer to hold the year, and can hold years as large as 65535.
    459  *
    460  *    zlib, upon which libpng depends, is also Y2K compliant.  It contains
    461  *    no date-related code.
    462  *
    463  *       Glenn Randers-Pehrson
    464  *       libpng maintainer
    465  *       PNG Development Group
    466  */
    467 
    468 #ifndef PNG_H
    469 #define PNG_H
    470 
    471 /* This is not the place to learn how to use libpng.  The file libpng.txt
    472  * describes how to use libpng, and the file example.c summarizes it
    473  * with some code on which to build.  This file is useful for looking
    474  * at the actual function definitions and structure components.
    475  */
    476 
    477 /* Version information for png.h - this should match the version in png.c */
    478 #define PNG_LIBPNG_VER_STRING "1.2.46"
    479 #define PNG_HEADER_VERSION_STRING \
    480    " libpng version 1.2.46 - July 9, 2011\n"
    481 
    482 #define PNG_LIBPNG_VER_SONUM   0
    483 #define PNG_LIBPNG_VER_DLLNUM  13
    484 
    485 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
    486 #define PNG_LIBPNG_VER_MAJOR   1
    487 #define PNG_LIBPNG_VER_MINOR   2
    488 #define PNG_LIBPNG_VER_RELEASE 46
    489 /* This should match the numeric part of the final component of
    490  * PNG_LIBPNG_VER_STRING, omitting any leading zero:
    491  */
    492 
    493 #define PNG_LIBPNG_VER_BUILD  0
    494 
    495 /* Release Status */
    496 #define PNG_LIBPNG_BUILD_ALPHA    1
    497 #define PNG_LIBPNG_BUILD_BETA     2
    498 #define PNG_LIBPNG_BUILD_RC       3
    499 #define PNG_LIBPNG_BUILD_STABLE   4
    500 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
    501 
    502 /* Release-Specific Flags */
    503 #define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with
    504                                        PNG_LIBPNG_BUILD_STABLE only */
    505 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
    506                                        PNG_LIBPNG_BUILD_SPECIAL */
    507 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
    508                                        PNG_LIBPNG_BUILD_PRIVATE */
    509 
    510 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
    511 
    512 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
    513  * We must not include leading zeros.
    514  * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
    515  * version 1.0.0 was mis-numbered 100 instead of 10000).  From
    516  * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
    517  */
    518 #define PNG_LIBPNG_VER 10246 /* 1.2.46 */
    519 
    520 #ifndef PNG_VERSION_INFO_ONLY
    521 /* Include the compression library's header */
    522 #include "zlib.h"
    523 #endif
    524 
    525 /* Include all user configurable info, including optional assembler routines */
    526 #include "pngconf.h"
    527 
    528 /*
    529  * Added at libpng-1.2.8 */
    530 /* Ref MSDN: Private as priority over Special
    531  * VS_FF_PRIVATEBUILD File *was not* built using standard release
    532  * procedures. If this value is given, the StringFileInfo block must
    533  * contain a PrivateBuild string.
    534  *
    535  * VS_FF_SPECIALBUILD File *was* built by the original company using
    536  * standard release procedures but is a variation of the standard
    537  * file of the same version number. If this value is given, the
    538  * StringFileInfo block must contain a SpecialBuild string.
    539  */
    540 
    541 #ifdef PNG_USER_PRIVATEBUILD
    542 #  define PNG_LIBPNG_BUILD_TYPE \
    543           (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
    544 #else
    545 #  ifdef PNG_LIBPNG_SPECIALBUILD
    546 #    define PNG_LIBPNG_BUILD_TYPE \
    547             (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
    548 #  else
    549 #    define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
    550 #  endif
    551 #endif
    552 
    553 #ifndef PNG_VERSION_INFO_ONLY
    554 
    555 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
    556 #ifdef __cplusplus
    557 extern "C" {
    558 #endif /* __cplusplus */
    559 
    560 /* This file is arranged in several sections.  The first section contains
    561  * structure and type definitions.  The second section contains the external
    562  * library functions, while the third has the internal library functions,
    563  * which applications aren't expected to use directly.
    564  */
    565 
    566 #ifndef PNG_NO_TYPECAST_NULL
    567 #define int_p_NULL                (int *)NULL
    568 #define png_bytep_NULL            (png_bytep)NULL
    569 #define png_bytepp_NULL           (png_bytepp)NULL
    570 #define png_doublep_NULL          (png_doublep)NULL
    571 #define png_error_ptr_NULL        (png_error_ptr)NULL
    572 #define png_flush_ptr_NULL        (png_flush_ptr)NULL
    573 #define png_free_ptr_NULL         (png_free_ptr)NULL
    574 #define png_infopp_NULL           (png_infopp)NULL
    575 #define png_malloc_ptr_NULL       (png_malloc_ptr)NULL
    576 #define png_read_status_ptr_NULL  (png_read_status_ptr)NULL
    577 #define png_rw_ptr_NULL           (png_rw_ptr)NULL
    578 #define png_structp_NULL          (png_structp)NULL
    579 #define png_uint_16p_NULL         (png_uint_16p)NULL
    580 #define png_voidp_NULL            (png_voidp)NULL
    581 #define png_write_status_ptr_NULL (png_write_status_ptr)NULL
    582 #else
    583 #define int_p_NULL                NULL
    584 #define png_bytep_NULL            NULL
    585 #define png_bytepp_NULL           NULL
    586 #define png_doublep_NULL          NULL
    587 #define png_error_ptr_NULL        NULL
    588 #define png_flush_ptr_NULL        NULL
    589 #define png_free_ptr_NULL         NULL
    590 #define png_infopp_NULL           NULL
    591 #define png_malloc_ptr_NULL       NULL
    592 #define png_read_status_ptr_NULL  NULL
    593 #define png_rw_ptr_NULL           NULL
    594 #define png_structp_NULL          NULL
    595 #define png_uint_16p_NULL         NULL
    596 #define png_voidp_NULL            NULL
    597 #define png_write_status_ptr_NULL NULL
    598 #endif
    599 
    600 /* Variables declared in png.c - only it needs to define PNG_NO_EXTERN */
    601 #if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
    602 /* Version information for C files, stored in png.c.  This had better match
    603  * the version above.
    604  */
    605 #ifdef PNG_USE_GLOBAL_ARRAYS
    606 PNG_EXPORT_VAR (PNG_CONST char) png_libpng_ver[18];
    607   /* Need room for 99.99.99beta99z */
    608 #else
    609 #define png_libpng_ver png_get_header_ver(NULL)
    610 #endif
    611 
    612 #ifdef PNG_USE_GLOBAL_ARRAYS
    613 /* This was removed in version 1.0.5c */
    614 /* Structures to facilitate easy interlacing.  See png.c for more details */
    615 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_start[7];
    616 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_inc[7];
    617 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_ystart[7];
    618 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_yinc[7];
    619 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_mask[7];
    620 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_dsp_mask[7];
    621 /* This isn't currently used.  If you need it, see png.c for more details.
    622 PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_height[7];
    623 */
    624 #endif
    625 
    626 #endif /* PNG_NO_EXTERN */
    627 
    628 /* Three color definitions.  The order of the red, green, and blue, (and the
    629  * exact size) is not important, although the size of the fields need to
    630  * be png_byte or png_uint_16 (as defined below).
    631  */
    632 typedef struct png_color_struct
    633 {
    634    png_byte red;
    635    png_byte green;
    636    png_byte blue;
    637 } png_color;
    638 typedef png_color FAR * png_colorp;
    639 typedef png_color FAR * FAR * png_colorpp;
    640 
    641 typedef struct png_color_16_struct
    642 {
    643    png_byte index;    /* used for palette files */
    644    png_uint_16 red;   /* for use in red green blue files */
    645    png_uint_16 green;
    646    png_uint_16 blue;
    647    png_uint_16 gray;  /* for use in grayscale files */
    648 } png_color_16;
    649 typedef png_color_16 FAR * png_color_16p;
    650 typedef png_color_16 FAR * FAR * png_color_16pp;
    651 
    652 typedef struct png_color_8_struct
    653 {
    654    png_byte red;   /* for use in red green blue files */
    655    png_byte green;
    656    png_byte blue;
    657    png_byte gray;  /* for use in grayscale files */
    658    png_byte alpha; /* for alpha channel files */
    659 } png_color_8;
    660 typedef png_color_8 FAR * png_color_8p;
    661 typedef png_color_8 FAR * FAR * png_color_8pp;
    662 
    663 /*
    664  * The following two structures are used for the in-core representation
    665  * of sPLT chunks.
    666  */
    667 typedef struct png_sPLT_entry_struct
    668 {
    669    png_uint_16 red;
    670    png_uint_16 green;
    671    png_uint_16 blue;
    672    png_uint_16 alpha;
    673    png_uint_16 frequency;
    674 } png_sPLT_entry;
    675 typedef png_sPLT_entry FAR * png_sPLT_entryp;
    676 typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;
    677 
    678 /*  When the depth of the sPLT palette is 8 bits, the color and alpha samples
    679  *  occupy the LSB of their respective members, and the MSB of each member
    680  *  is zero-filled.  The frequency member always occupies the full 16 bits.
    681  */
    682 
    683 typedef struct png_sPLT_struct
    684 {
    685    png_charp name;           /* palette name */
    686    png_byte depth;           /* depth of palette samples */
    687    png_sPLT_entryp entries;  /* palette entries */
    688    png_int_32 nentries;      /* number of palette entries */
    689 } png_sPLT_t;
    690 typedef png_sPLT_t FAR * png_sPLT_tp;
    691 typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;
    692 
    693 #ifdef PNG_TEXT_SUPPORTED
    694 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
    695  * and whether that contents is compressed or not.  The "key" field
    696  * points to a regular zero-terminated C string.  The "text", "lang", and
    697  * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
    698  * However, the * structure returned by png_get_text() will always contain
    699  * regular zero-terminated C strings (possibly empty), never NULL pointers,
    700  * so they can be safely used in printf() and other string-handling functions.
    701  */
    702 typedef struct png_text_struct
    703 {
    704    int  compression;       /* compression value:
    705                              -1: tEXt, none
    706                               0: zTXt, deflate
    707                               1: iTXt, none
    708                               2: iTXt, deflate  */
    709    png_charp key;          /* keyword, 1-79 character description of "text" */
    710    png_charp text;         /* comment, may be an empty string (ie "")
    711                               or a NULL pointer */
    712    png_size_t text_length; /* length of the text string */
    713 #ifdef PNG_iTXt_SUPPORTED
    714    png_size_t itxt_length; /* length of the itxt string */
    715    png_charp lang;         /* language code, 0-79 characters
    716                               or a NULL pointer */
    717    png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
    718                               chars or a NULL pointer */
    719 #endif
    720 } png_text;
    721 typedef png_text FAR * png_textp;
    722 typedef png_text FAR * FAR * png_textpp;
    723 #endif
    724 
    725 /* Supported compression types for text in PNG files (tEXt, and zTXt).
    726  * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed.
    727  */
    728 #define PNG_TEXT_COMPRESSION_NONE_WR -3
    729 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
    730 #define PNG_TEXT_COMPRESSION_NONE    -1
    731 #define PNG_TEXT_COMPRESSION_zTXt     0
    732 #define PNG_ITXT_COMPRESSION_NONE     1
    733 #define PNG_ITXT_COMPRESSION_zTXt     2
    734 #define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */
    735 
    736 /* png_time is a way to hold the time in an machine independent way.
    737  * Two conversions are provided, both from time_t and struct tm.  There
    738  * is no portable way to convert to either of these structures, as far
    739  * as I know.  If you know of a portable way, send it to me.  As a side
    740  * note - PNG has always been Year 2000 compliant!
    741  */
    742 typedef struct png_time_struct
    743 {
    744    png_uint_16 year; /* full year, as in, 1995 */
    745    png_byte month;   /* month of year, 1 - 12 */
    746    png_byte day;     /* day of month, 1 - 31 */
    747    png_byte hour;    /* hour of day, 0 - 23 */
    748    png_byte minute;  /* minute of hour, 0 - 59 */
    749    png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */
    750 } png_time;
    751 typedef png_time FAR * png_timep;
    752 typedef png_time FAR * FAR * png_timepp;
    753 
    754 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) || \
    755  defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
    756 /* png_unknown_chunk is a structure to hold queued chunks for which there is
    757  * no specific support.  The idea is that we can use this to queue
    758  * up private chunks for output even though the library doesn't actually
    759  * know about their semantics.
    760  */
    761 #define PNG_CHUNK_NAME_LENGTH 5
    762 typedef struct png_unknown_chunk_t
    763 {
    764     png_byte name[PNG_CHUNK_NAME_LENGTH];
    765     png_byte *data;
    766     png_size_t size;
    767 
    768     /* libpng-using applications should NOT directly modify this byte. */
    769     png_byte location; /* mode of operation at read time */
    770 }
    771 png_unknown_chunk;
    772 typedef png_unknown_chunk FAR * png_unknown_chunkp;
    773 typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
    774 #endif
    775 
    776 #ifdef PNG_INDEX_SUPPORTED
    777 /* png_line_index_struct records an index point, where we impose an index point
    778  * to be located at the beginning of a line for simplifying the implementation.
    779  */
    780 typedef struct png_line_index_struct
    781 {
    782    // state of the lz decoder
    783    z_streamp   z_state;
    784 
    785    // the IDAT header position of the chunk, which the index point is in
    786    png_uint_32  stream_idat_position;
    787 
    788    // we intend to record the offset of the index point in the chunk,
    789    // but we record the number of remaining bytes in the chunk after the
    790    // index point. That's because PNG processes a chunk this way.
    791    png_uint_32  bytes_left_in_idat;
    792 
    793    // decompressed data of the previous row
    794    png_bytep   prev_row;
    795 } png_line_index;
    796 typedef png_line_index FAR * png_line_indexp;
    797 
    798 typedef struct png_index_struct
    799 {
    800    // A temporary variable used when we build the index. The variable records
    801    // the IDAT header position of the last chunk read in so far.
    802    png_uint_32  stream_idat_position;
    803 
    804    // line index information about each passes
    805 
    806    // the number of index points in each pass
    807    png_uint_32  size[7];
    808 
    809    // the line span of two index points of each pass
    810    png_uint_32  step[7];
    811 
    812    // the index points of each pass
    813    png_line_indexp  *pass_line_index[7];
    814 } png_index;
    815 typedef png_index FAR * png_indexp;
    816 
    817 #define INDEX_SAMPLE_SIZE 254
    818 #endif
    819 
    820 /* png_info is a structure that holds the information in a PNG file so
    821  * that the application can find out the characteristics of the image.
    822  * If you are reading the file, this structure will tell you what is
    823  * in the PNG file.  If you are writing the file, fill in the information
    824  * you want to put into the PNG file, then call png_write_info().
    825  * The names chosen should be very close to the PNG specification, so
    826  * consult that document for information about the meaning of each field.
    827  *
    828  * With libpng < 0.95, it was only possible to directly set and read the
    829  * the values in the png_info_struct, which meant that the contents and
    830  * order of the values had to remain fixed.  With libpng 0.95 and later,
    831  * however, there are now functions that abstract the contents of
    832  * png_info_struct from the application, so this makes it easier to use
    833  * libpng with dynamic libraries, and even makes it possible to use
    834  * libraries that don't have all of the libpng ancillary chunk-handing
    835  * functionality.
    836  *
    837  * In any case, the order of the parameters in png_info_struct should NOT
    838  * be changed for as long as possible to keep compatibility with applications
    839  * that use the old direct-access method with png_info_struct.
    840  *
    841  * The following members may have allocated storage attached that should be
    842  * cleaned up before the structure is discarded: palette, trans, text,
    843  * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
    844  * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
    845  * are automatically freed when the info structure is deallocated, if they were
    846  * allocated internally by libpng.  This behavior can be changed by means
    847  * of the png_data_freer() function.
    848  *
    849  * More allocation details: all the chunk-reading functions that
    850  * change these members go through the corresponding png_set_*
    851  * functions.  A function to clear these members is available: see
    852  * png_free_data().  The png_set_* functions do not depend on being
    853  * able to point info structure members to any of the storage they are
    854  * passed (they make their own copies), EXCEPT that the png_set_text
    855  * functions use the same storage passed to them in the text_ptr or
    856  * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
    857  * functions do not make their own copies.
    858  */
    859 typedef struct png_info_struct
    860 {
    861    /* The following are necessary for every PNG file */
    862    png_uint_32 width PNG_DEPSTRUCT;       /* width of image in pixels (from IHDR) */
    863    png_uint_32 height PNG_DEPSTRUCT;      /* height of image in pixels (from IHDR) */
    864    png_uint_32 valid PNG_DEPSTRUCT;       /* valid chunk data (see PNG_INFO_ below) */
    865    png_uint_32 rowbytes PNG_DEPSTRUCT;    /* bytes needed to hold an untransformed row */
    866    png_colorp palette PNG_DEPSTRUCT;      /* array of color values (valid & PNG_INFO_PLTE) */
    867    png_uint_16 num_palette PNG_DEPSTRUCT; /* number of color entries in "palette" (PLTE) */
    868    png_uint_16 num_trans PNG_DEPSTRUCT;   /* number of transparent palette color (tRNS) */
    869    png_byte bit_depth PNG_DEPSTRUCT;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
    870    png_byte color_type PNG_DEPSTRUCT;     /* see PNG_COLOR_TYPE_ below (from IHDR) */
    871    /* The following three should have been named *_method not *_type */
    872    png_byte compression_type PNG_DEPSTRUCT; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
    873    png_byte filter_type PNG_DEPSTRUCT;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
    874    png_byte interlace_type PNG_DEPSTRUCT; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
    875 
    876    /* The following is informational only on read, and not used on writes. */
    877    png_byte channels PNG_DEPSTRUCT;       /* number of data channels per pixel (1, 2, 3, 4) */
    878    png_byte pixel_depth PNG_DEPSTRUCT;    /* number of bits per pixel */
    879    png_byte spare_byte PNG_DEPSTRUCT;     /* to align the data, and for future use */
    880    png_byte signature[8] PNG_DEPSTRUCT;   /* magic bytes read by libpng from start of file */
    881 
    882    /* The rest of the data is optional.  If you are reading, check the
    883     * valid field to see if the information in these are valid.  If you
    884     * are writing, set the valid field to those chunks you want written,
    885     * and initialize the appropriate fields below.
    886     */
    887 
    888 #if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
    889    /* The gAMA chunk describes the gamma characteristics of the system
    890     * on which the image was created, normally in the range [1.0, 2.5].
    891     * Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
    892     */
    893    float gamma PNG_DEPSTRUCT; /* gamma value of image, if (valid & PNG_INFO_gAMA) */
    894 #endif
    895 
    896 #ifdef PNG_sRGB_SUPPORTED
    897     /* GR-P, 0.96a */
    898     /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
    899    png_byte srgb_intent PNG_DEPSTRUCT; /* sRGB rendering intent [0, 1, 2, or 3] */
    900 #endif
    901 
    902 #ifdef PNG_TEXT_SUPPORTED
    903    /* The tEXt, and zTXt chunks contain human-readable textual data in
    904     * uncompressed, compressed, and optionally compressed forms, respectively.
    905     * The data in "text" is an array of pointers to uncompressed,
    906     * null-terminated C strings. Each chunk has a keyword that describes the
    907     * textual data contained in that chunk.  Keywords are not required to be
    908     * unique, and the text string may be empty.  Any number of text chunks may
    909     * be in an image.
    910     */
    911    int num_text PNG_DEPSTRUCT; /* number of comments read/to write */
    912    int max_text PNG_DEPSTRUCT; /* current size of text array */
    913    png_textp text PNG_DEPSTRUCT; /* array of comments read/to write */
    914 #endif /* PNG_TEXT_SUPPORTED */
    915 
    916 #ifdef PNG_tIME_SUPPORTED
    917    /* The tIME chunk holds the last time the displayed image data was
    918     * modified.  See the png_time struct for the contents of this struct.
    919     */
    920    png_time mod_time PNG_DEPSTRUCT;
    921 #endif
    922 
    923 #ifdef PNG_sBIT_SUPPORTED
    924    /* The sBIT chunk specifies the number of significant high-order bits
    925     * in the pixel data.  Values are in the range [1, bit_depth], and are
    926     * only specified for the channels in the pixel data.  The contents of
    927     * the low-order bits is not specified.  Data is valid if
    928     * (valid & PNG_INFO_sBIT) is non-zero.
    929     */
    930    png_color_8 sig_bit PNG_DEPSTRUCT; /* significant bits in color channels */
    931 #endif
    932 
    933 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
    934 defined(PNG_READ_BACKGROUND_SUPPORTED)
    935    /* The tRNS chunk supplies transparency data for paletted images and
    936     * other image types that don't need a full alpha channel.  There are
    937     * "num_trans" transparency values for a paletted image, stored in the
    938     * same order as the palette colors, starting from index 0.  Values
    939     * for the data are in the range [0, 255], ranging from fully transparent
    940     * to fully opaque, respectively.  For non-paletted images, there is a
    941     * single color specified that should be treated as fully transparent.
    942     * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
    943     */
    944    png_bytep trans PNG_DEPSTRUCT; /* transparent values for paletted image */
    945    png_color_16 trans_values PNG_DEPSTRUCT; /* transparent color for non-palette image */
    946 #endif
    947 
    948 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
    949    /* The bKGD chunk gives the suggested image background color if the
    950     * display program does not have its own background color and the image
    951     * is needs to composited onto a background before display.  The colors
    952     * in "background" are normally in the same color space/depth as the
    953     * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
    954     */
    955    png_color_16 background PNG_DEPSTRUCT;
    956 #endif
    957 
    958 #ifdef PNG_oFFs_SUPPORTED
    959    /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
    960     * and downwards from the top-left corner of the display, page, or other
    961     * application-specific co-ordinate space.  See the PNG_OFFSET_ defines
    962     * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.
    963     */
    964    png_int_32 x_offset PNG_DEPSTRUCT; /* x offset on page */
    965    png_int_32 y_offset PNG_DEPSTRUCT; /* y offset on page */
    966    png_byte offset_unit_type PNG_DEPSTRUCT; /* offset units type */
    967 #endif
    968 
    969 #ifdef PNG_pHYs_SUPPORTED
    970    /* The pHYs chunk gives the physical pixel density of the image for
    971     * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
    972     * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
    973     */
    974    png_uint_32 x_pixels_per_unit PNG_DEPSTRUCT; /* horizontal pixel density */
    975    png_uint_32 y_pixels_per_unit PNG_DEPSTRUCT; /* vertical pixel density */
    976    png_byte phys_unit_type PNG_DEPSTRUCT; /* resolution type (see PNG_RESOLUTION_ below) */
    977 #endif
    978 
    979 #ifdef PNG_hIST_SUPPORTED
    980    /* The hIST chunk contains the relative frequency or importance of the
    981     * various palette entries, so that a viewer can intelligently select a
    982     * reduced-color palette, if required.  Data is an array of "num_palette"
    983     * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
    984     * is non-zero.
    985     */
    986    png_uint_16p hist PNG_DEPSTRUCT;
    987 #endif
    988 
    989 #ifdef PNG_cHRM_SUPPORTED
    990    /* The cHRM chunk describes the CIE color characteristics of the monitor
    991     * on which the PNG was created.  This data allows the viewer to do gamut
    992     * mapping of the input image to ensure that the viewer sees the same
    993     * colors in the image as the creator.  Values are in the range
    994     * [0.0, 0.8].  Data valid if (valid & PNG_INFO_cHRM) non-zero.
    995     */
    996 #ifdef PNG_FLOATING_POINT_SUPPORTED
    997    float x_white PNG_DEPSTRUCT;
    998    float y_white PNG_DEPSTRUCT;
    999    float x_red PNG_DEPSTRUCT;
   1000    float y_red PNG_DEPSTRUCT;
   1001    float x_green PNG_DEPSTRUCT;
   1002    float y_green PNG_DEPSTRUCT;
   1003    float x_blue PNG_DEPSTRUCT;
   1004    float y_blue PNG_DEPSTRUCT;
   1005 #endif
   1006 #endif
   1007 
   1008 #ifdef PNG_pCAL_SUPPORTED
   1009    /* The pCAL chunk describes a transformation between the stored pixel
   1010     * values and original physical data values used to create the image.
   1011     * The integer range [0, 2^bit_depth - 1] maps to the floating-point
   1012     * range given by [pcal_X0, pcal_X1], and are further transformed by a
   1013     * (possibly non-linear) transformation function given by "pcal_type"
   1014     * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_
   1015     * defines below, and the PNG-Group's PNG extensions document for a
   1016     * complete description of the transformations and how they should be
   1017     * implemented, and for a description of the ASCII parameter strings.
   1018     * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
   1019     */
   1020    png_charp pcal_purpose PNG_DEPSTRUCT;  /* pCAL chunk description string */
   1021    png_int_32 pcal_X0 PNG_DEPSTRUCT;      /* minimum value */
   1022    png_int_32 pcal_X1 PNG_DEPSTRUCT;      /* maximum value */
   1023    png_charp pcal_units PNG_DEPSTRUCT;    /* Latin-1 string giving physical units */
   1024    png_charpp pcal_params PNG_DEPSTRUCT;  /* ASCII strings containing parameter values */
   1025    png_byte pcal_type PNG_DEPSTRUCT;      /* equation type (see PNG_EQUATION_ below) */
   1026    png_byte pcal_nparams PNG_DEPSTRUCT;   /* number of parameters given in pcal_params */
   1027 #endif
   1028 
   1029 /* New members added in libpng-1.0.6 */
   1030 #ifdef PNG_FREE_ME_SUPPORTED
   1031    png_uint_32 free_me PNG_DEPSTRUCT;     /* flags items libpng is responsible for freeing */
   1032 #endif
   1033 
   1034 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) || \
   1035  defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
   1036    /* Storage for unknown chunks that the library doesn't recognize. */
   1037    png_unknown_chunkp unknown_chunks PNG_DEPSTRUCT;
   1038    png_size_t unknown_chunks_num PNG_DEPSTRUCT;
   1039 #endif
   1040 
   1041 #ifdef PNG_iCCP_SUPPORTED
   1042    /* iCCP chunk data. */
   1043    png_charp iccp_name PNG_DEPSTRUCT;     /* profile name */
   1044    png_charp iccp_profile PNG_DEPSTRUCT;  /* International Color Consortium profile data */
   1045                             /* Note to maintainer: should be png_bytep */
   1046    png_uint_32 iccp_proflen PNG_DEPSTRUCT;  /* ICC profile data length */
   1047    png_byte iccp_compression PNG_DEPSTRUCT; /* Always zero */
   1048 #endif
   1049 
   1050 #ifdef PNG_sPLT_SUPPORTED
   1051    /* Data on sPLT chunks (there may be more than one). */
   1052    png_sPLT_tp splt_palettes PNG_DEPSTRUCT;
   1053    png_uint_32 splt_palettes_num PNG_DEPSTRUCT;
   1054 #endif
   1055 
   1056 #ifdef PNG_sCAL_SUPPORTED
   1057    /* The sCAL chunk describes the actual physical dimensions of the
   1058     * subject matter of the graphic.  The chunk contains a unit specification
   1059     * a byte value, and two ASCII strings representing floating-point
   1060     * values.  The values are width and height corresponsing to one pixel
   1061     * in the image.  This external representation is converted to double
   1062     * here.  Data values are valid if (valid & PNG_INFO_sCAL) is non-zero.
   1063     */
   1064    png_byte scal_unit PNG_DEPSTRUCT;         /* unit of physical scale */
   1065 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1066    double scal_pixel_width PNG_DEPSTRUCT;    /* width of one pixel */
   1067    double scal_pixel_height PNG_DEPSTRUCT;   /* height of one pixel */
   1068 #endif
   1069 #ifdef PNG_FIXED_POINT_SUPPORTED
   1070    png_charp scal_s_width PNG_DEPSTRUCT;     /* string containing height */
   1071    png_charp scal_s_height PNG_DEPSTRUCT;    /* string containing width */
   1072 #endif
   1073 #endif
   1074 
   1075 #ifdef PNG_INFO_IMAGE_SUPPORTED
   1076    /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) non-zero */
   1077    /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
   1078    png_bytepp row_pointers PNG_DEPSTRUCT;        /* the image bits */
   1079 #endif
   1080 
   1081 #if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED)
   1082    png_fixed_point int_gamma PNG_DEPSTRUCT; /* gamma of image, if (valid & PNG_INFO_gAMA) */
   1083 #endif
   1084 
   1085 #if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED)
   1086    png_fixed_point int_x_white PNG_DEPSTRUCT;
   1087    png_fixed_point int_y_white PNG_DEPSTRUCT;
   1088    png_fixed_point int_x_red PNG_DEPSTRUCT;
   1089    png_fixed_point int_y_red PNG_DEPSTRUCT;
   1090    png_fixed_point int_x_green PNG_DEPSTRUCT;
   1091    png_fixed_point int_y_green PNG_DEPSTRUCT;
   1092    png_fixed_point int_x_blue PNG_DEPSTRUCT;
   1093    png_fixed_point int_y_blue PNG_DEPSTRUCT;
   1094 #endif
   1095 
   1096 } png_info;
   1097 
   1098 typedef png_info FAR * png_infop;
   1099 typedef png_info FAR * FAR * png_infopp;
   1100 
   1101 /* Maximum positive integer used in PNG is (2^31)-1 */
   1102 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
   1103 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
   1104 #define PNG_SIZE_MAX ((png_size_t)(-1))
   1105 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   1106 /* PNG_MAX_UINT is deprecated; use PNG_UINT_31_MAX instead. */
   1107 #define PNG_MAX_UINT PNG_UINT_31_MAX
   1108 #endif
   1109 
   1110 /* These describe the color_type field in png_info. */
   1111 /* color type masks */
   1112 #define PNG_COLOR_MASK_PALETTE    1
   1113 #define PNG_COLOR_MASK_COLOR      2
   1114 #define PNG_COLOR_MASK_ALPHA      4
   1115 
   1116 /* color types.  Note that not all combinations are legal */
   1117 #define PNG_COLOR_TYPE_GRAY 0
   1118 #define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
   1119 #define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
   1120 #define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
   1121 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
   1122 /* aliases */
   1123 #define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA
   1124 #define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA
   1125 
   1126 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
   1127 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
   1128 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
   1129 
   1130 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
   1131 #define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */
   1132 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
   1133 #define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE
   1134 
   1135 /* These are for the interlacing type.  These values should NOT be changed. */
   1136 #define PNG_INTERLACE_NONE        0 /* Non-interlaced image */
   1137 #define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */
   1138 #define PNG_INTERLACE_LAST        2 /* Not a valid value */
   1139 
   1140 /* These are for the oFFs chunk.  These values should NOT be changed. */
   1141 #define PNG_OFFSET_PIXEL          0 /* Offset in pixels */
   1142 #define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */
   1143 #define PNG_OFFSET_LAST           2 /* Not a valid value */
   1144 
   1145 /* These are for the pCAL chunk.  These values should NOT be changed. */
   1146 #define PNG_EQUATION_LINEAR       0 /* Linear transformation */
   1147 #define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */
   1148 #define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */
   1149 #define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */
   1150 #define PNG_EQUATION_LAST         4 /* Not a valid value */
   1151 
   1152 /* These are for the sCAL chunk.  These values should NOT be changed. */
   1153 #define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */
   1154 #define PNG_SCALE_METER           1 /* meters per pixel */
   1155 #define PNG_SCALE_RADIAN          2 /* radians per pixel */
   1156 #define PNG_SCALE_LAST            3 /* Not a valid value */
   1157 
   1158 /* These are for the pHYs chunk.  These values should NOT be changed. */
   1159 #define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */
   1160 #define PNG_RESOLUTION_METER      1 /* pixels/meter */
   1161 #define PNG_RESOLUTION_LAST       2 /* Not a valid value */
   1162 
   1163 /* These are for the sRGB chunk.  These values should NOT be changed. */
   1164 #define PNG_sRGB_INTENT_PERCEPTUAL 0
   1165 #define PNG_sRGB_INTENT_RELATIVE   1
   1166 #define PNG_sRGB_INTENT_SATURATION 2
   1167 #define PNG_sRGB_INTENT_ABSOLUTE   3
   1168 #define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */
   1169 
   1170 /* This is for text chunks */
   1171 #define PNG_KEYWORD_MAX_LENGTH     79
   1172 
   1173 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
   1174 #define PNG_MAX_PALETTE_LENGTH    256
   1175 
   1176 /* These determine if an ancillary chunk's data has been successfully read
   1177  * from the PNG header, or if the application has filled in the corresponding
   1178  * data in the info_struct to be written into the output file.  The values
   1179  * of the PNG_INFO_<chunk> defines should NOT be changed.
   1180  */
   1181 #define PNG_INFO_gAMA 0x0001
   1182 #define PNG_INFO_sBIT 0x0002
   1183 #define PNG_INFO_cHRM 0x0004
   1184 #define PNG_INFO_PLTE 0x0008
   1185 #define PNG_INFO_tRNS 0x0010
   1186 #define PNG_INFO_bKGD 0x0020
   1187 #define PNG_INFO_hIST 0x0040
   1188 #define PNG_INFO_pHYs 0x0080
   1189 #define PNG_INFO_oFFs 0x0100
   1190 #define PNG_INFO_tIME 0x0200
   1191 #define PNG_INFO_pCAL 0x0400
   1192 #define PNG_INFO_sRGB 0x0800   /* GR-P, 0.96a */
   1193 #define PNG_INFO_iCCP 0x1000   /* ESR, 1.0.6 */
   1194 #define PNG_INFO_sPLT 0x2000   /* ESR, 1.0.6 */
   1195 #define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */
   1196 #define PNG_INFO_IDAT 0x8000L  /* ESR, 1.0.6 */
   1197 
   1198 /* This is used for the transformation routines, as some of them
   1199  * change these values for the row.  It also should enable using
   1200  * the routines for other purposes.
   1201  */
   1202 typedef struct png_row_info_struct
   1203 {
   1204    png_uint_32 width; /* width of row */
   1205    png_uint_32 rowbytes; /* number of bytes in row */
   1206    png_byte color_type; /* color type of row */
   1207    png_byte bit_depth; /* bit depth of row */
   1208    png_byte channels; /* number of channels (1, 2, 3, or 4) */
   1209    png_byte pixel_depth; /* bits per pixel (depth * channels) */
   1210 } png_row_info;
   1211 
   1212 typedef png_row_info FAR * png_row_infop;
   1213 typedef png_row_info FAR * FAR * png_row_infopp;
   1214 
   1215 /* These are the function types for the I/O functions and for the functions
   1216  * that allow the user to override the default I/O functions with his or her
   1217  * own.  The png_error_ptr type should match that of user-supplied warning
   1218  * and error functions, while the png_rw_ptr type should match that of the
   1219  * user read/write data functions.
   1220  */
   1221 typedef struct png_struct_def png_struct;
   1222 typedef png_struct FAR * png_structp;
   1223 
   1224 typedef void (PNGAPI *png_error_ptr) PNGARG((png_structp, png_const_charp));
   1225 typedef void (PNGAPI *png_rw_ptr) PNGARG((png_structp, png_bytep, png_size_t));
   1226 #ifdef PNG_INDEX_SUPPORTED
   1227 typedef void (PNGAPI *png_seek_ptr) PNGARG((png_structp, png_uint_32));
   1228 #endif
   1229 typedef void (PNGAPI *png_flush_ptr) PNGARG((png_structp));
   1230 typedef void (PNGAPI *png_read_status_ptr) PNGARG((png_structp, png_uint_32,
   1231    int));
   1232 typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32,
   1233    int));
   1234 
   1235 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   1236 typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp, png_infop));
   1237 typedef void (PNGAPI *png_progressive_end_ptr) PNGARG((png_structp, png_infop));
   1238 typedef void (PNGAPI *png_progressive_row_ptr) PNGARG((png_structp, png_bytep,
   1239    png_uint_32, int));
   1240 #endif
   1241 
   1242 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   1243     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
   1244     defined(PNG_LEGACY_SUPPORTED)
   1245 typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp,
   1246     png_row_infop, png_bytep));
   1247 #endif
   1248 
   1249 #ifdef PNG_USER_CHUNKS_SUPPORTED
   1250 typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp, png_unknown_chunkp));
   1251 #endif
   1252 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
   1253 typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));
   1254 #endif
   1255 
   1256 /* Transform masks for the high-level interface */
   1257 #define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
   1258 #define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
   1259 #define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
   1260 #define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
   1261 #define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
   1262 #define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
   1263 #define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
   1264 #define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
   1265 #define PNG_TRANSFORM_BGR            0x0080    /* read and write */
   1266 #define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
   1267 #define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
   1268 #define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
   1269 #define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* write only, deprecated */
   1270 /* Added to libpng-1.2.34 */
   1271 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE 0x0800  /* write only */
   1272 #define PNG_TRANSFORM_STRIP_FILLER_AFTER  0x1000  /* write only */
   1273 /* Added to libpng-1.2.41 */
   1274 #define PNG_TRANSFORM_GRAY_TO_RGB   0x2000      /* read only */
   1275 
   1276 /* Flags for MNG supported features */
   1277 #define PNG_FLAG_MNG_EMPTY_PLTE     0x01
   1278 #define PNG_FLAG_MNG_FILTER_64      0x04
   1279 #define PNG_ALL_MNG_FEATURES        0x05
   1280 
   1281 typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_size_t));
   1282 typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp));
   1283 
   1284 /* The structure that holds the information to read and write PNG files.
   1285  * The only people who need to care about what is inside of this are the
   1286  * people who will be modifying the library for their own special needs.
   1287  * It should NOT be accessed directly by an application, except to store
   1288  * the jmp_buf.
   1289  */
   1290 
   1291 struct png_struct_def
   1292 {
   1293 #ifdef PNG_SETJMP_SUPPORTED
   1294    jmp_buf jmpbuf;            /* used in png_error */
   1295 #endif
   1296    png_error_ptr error_fn PNG_DEPSTRUCT;    /* function for printing errors and aborting */
   1297    png_error_ptr warning_fn PNG_DEPSTRUCT;  /* function for printing warnings */
   1298    png_voidp error_ptr PNG_DEPSTRUCT;       /* user supplied struct for error functions */
   1299    png_rw_ptr write_data_fn PNG_DEPSTRUCT;  /* function for writing output data */
   1300    png_rw_ptr read_data_fn PNG_DEPSTRUCT;   /* function for reading input data */
   1301 #ifdef PNG_INDEX_SUPPORTED
   1302    png_seek_ptr seek_data_fn PNG_DEPSTRUCT; /* function for seeking input data */
   1303 #endif
   1304    png_voidp io_ptr PNG_DEPSTRUCT;          /* ptr to application struct for I/O functions */
   1305 
   1306 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
   1307    png_user_transform_ptr read_user_transform_fn PNG_DEPSTRUCT; /* user read transform */
   1308 #endif
   1309 
   1310 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
   1311    png_user_transform_ptr write_user_transform_fn PNG_DEPSTRUCT; /* user write transform */
   1312 #endif
   1313 
   1314 /* These were added in libpng-1.0.2 */
   1315 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
   1316 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   1317     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
   1318    png_voidp user_transform_ptr PNG_DEPSTRUCT; /* user supplied struct for user transform */
   1319    png_byte user_transform_depth PNG_DEPSTRUCT;    /* bit depth of user transformed pixels */
   1320    png_byte user_transform_channels PNG_DEPSTRUCT; /* channels in user transformed pixels */
   1321 #endif
   1322 #endif
   1323 
   1324    png_uint_32 mode PNG_DEPSTRUCT;          /* tells us where we are in the PNG file */
   1325    png_uint_32 flags PNG_DEPSTRUCT;         /* flags indicating various things to libpng */
   1326    png_uint_32 transformations PNG_DEPSTRUCT; /* which transformations to perform */
   1327 
   1328    z_stream zstream PNG_DEPSTRUCT;          /* pointer to decompression structure (below) */
   1329    png_bytep zbuf PNG_DEPSTRUCT;            /* buffer for zlib */
   1330    png_size_t zbuf_size PNG_DEPSTRUCT;      /* size of zbuf */
   1331    int zlib_level PNG_DEPSTRUCT;            /* holds zlib compression level */
   1332    int zlib_method PNG_DEPSTRUCT;           /* holds zlib compression method */
   1333    int zlib_window_bits PNG_DEPSTRUCT;      /* holds zlib compression window bits */
   1334    int zlib_mem_level PNG_DEPSTRUCT;        /* holds zlib compression memory level */
   1335    int zlib_strategy PNG_DEPSTRUCT;         /* holds zlib compression strategy */
   1336 
   1337    png_uint_32 width PNG_DEPSTRUCT;         /* width of image in pixels */
   1338    png_uint_32 height PNG_DEPSTRUCT;        /* height of image in pixels */
   1339    png_uint_32 num_rows PNG_DEPSTRUCT;      /* number of rows in current pass */
   1340    png_uint_32 usr_width PNG_DEPSTRUCT;     /* width of row at start of write */
   1341    png_uint_32 rowbytes PNG_DEPSTRUCT;      /* size of row in bytes */
   1342 #if 0 /* Replaced with the following in libpng-1.2.43 */
   1343    png_size_t irowbytes PNG_DEPSTRUCT;
   1344 #endif
   1345 /* Added in libpng-1.2.43 */
   1346 #ifdef PNG_USER_LIMITS_SUPPORTED
   1347    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
   1348     * chunks that can be stored (0 means unlimited).
   1349     */
   1350    png_uint_32 user_chunk_cache_max PNG_DEPSTRUCT;
   1351 #endif
   1352    png_uint_32 iwidth PNG_DEPSTRUCT;        /* width of current interlaced row in pixels */
   1353    png_uint_32 row_number PNG_DEPSTRUCT;    /* current row in interlace pass */
   1354    png_bytep prev_row PNG_DEPSTRUCT;        /* buffer to save previous (unfiltered) row */
   1355    png_bytep row_buf PNG_DEPSTRUCT;         /* buffer to save current (unfiltered) row */
   1356 #ifndef PNG_NO_WRITE_FILTER
   1357    png_bytep sub_row PNG_DEPSTRUCT;         /* buffer to save "sub" row when filtering */
   1358    png_bytep up_row PNG_DEPSTRUCT;          /* buffer to save "up" row when filtering */
   1359    png_bytep avg_row PNG_DEPSTRUCT;         /* buffer to save "avg" row when filtering */
   1360    png_bytep paeth_row PNG_DEPSTRUCT;       /* buffer to save "Paeth" row when filtering */
   1361 #endif
   1362    png_row_info row_info PNG_DEPSTRUCT;     /* used for transformation routines */
   1363 
   1364    png_uint_32 idat_size PNG_DEPSTRUCT;     /* current IDAT size for read */
   1365    png_uint_32 crc PNG_DEPSTRUCT;           /* current chunk CRC value */
   1366    png_colorp palette PNG_DEPSTRUCT;        /* palette from the input file */
   1367    png_uint_16 num_palette PNG_DEPSTRUCT;   /* number of color entries in palette */
   1368    png_uint_16 num_trans PNG_DEPSTRUCT;     /* number of transparency values */
   1369    png_byte chunk_name[5] PNG_DEPSTRUCT;    /* null-terminated name of current chunk */
   1370    png_byte compression PNG_DEPSTRUCT;      /* file compression type (always 0) */
   1371    png_byte filter PNG_DEPSTRUCT;           /* file filter type (always 0) */
   1372    png_byte interlaced PNG_DEPSTRUCT;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
   1373    png_byte pass PNG_DEPSTRUCT;             /* current interlace pass (0 - 6) */
   1374    png_byte do_filter PNG_DEPSTRUCT;        /* row filter flags (see PNG_FILTER_ below ) */
   1375    png_byte color_type PNG_DEPSTRUCT;       /* color type of file */
   1376    png_byte bit_depth PNG_DEPSTRUCT;        /* bit depth of file */
   1377    png_byte usr_bit_depth PNG_DEPSTRUCT;    /* bit depth of users row */
   1378    png_byte pixel_depth PNG_DEPSTRUCT;      /* number of bits per pixel */
   1379    png_byte channels PNG_DEPSTRUCT;         /* number of channels in file */
   1380    png_byte usr_channels PNG_DEPSTRUCT;     /* channels at start of write */
   1381    png_byte sig_bytes PNG_DEPSTRUCT;        /* magic bytes read/written from start of file */
   1382 
   1383 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
   1384 #ifdef PNG_LEGACY_SUPPORTED
   1385    png_byte filler PNG_DEPSTRUCT;           /* filler byte for pixel expansion */
   1386 #else
   1387    png_uint_16 filler PNG_DEPSTRUCT;           /* filler bytes for pixel expansion */
   1388 #endif
   1389 #endif
   1390 
   1391 #ifdef PNG_bKGD_SUPPORTED
   1392    png_byte background_gamma_type PNG_DEPSTRUCT;
   1393 #  ifdef PNG_FLOATING_POINT_SUPPORTED
   1394    float background_gamma PNG_DEPSTRUCT;
   1395 #  endif
   1396    png_color_16 background PNG_DEPSTRUCT;   /* background color in screen gamma space */
   1397 #ifdef PNG_READ_GAMMA_SUPPORTED
   1398    png_color_16 background_1 PNG_DEPSTRUCT; /* background normalized to gamma 1.0 */
   1399 #endif
   1400 #endif /* PNG_bKGD_SUPPORTED */
   1401 
   1402 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   1403    png_flush_ptr output_flush_fn PNG_DEPSTRUCT; /* Function for flushing output */
   1404    png_uint_32 flush_dist PNG_DEPSTRUCT;    /* how many rows apart to flush, 0 - no flush */
   1405    png_uint_32 flush_rows PNG_DEPSTRUCT;    /* number of rows written since last flush */
   1406 #endif
   1407 
   1408 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1409    int gamma_shift PNG_DEPSTRUCT;      /* number of "insignificant" bits 16-bit gamma */
   1410 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1411    float gamma PNG_DEPSTRUCT;          /* file gamma value */
   1412    float screen_gamma PNG_DEPSTRUCT;   /* screen gamma value (display_exponent) */
   1413 #endif
   1414 #endif
   1415 
   1416 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1417    png_bytep gamma_table PNG_DEPSTRUCT;     /* gamma table for 8-bit depth files */
   1418    png_bytep gamma_from_1 PNG_DEPSTRUCT;    /* converts from 1.0 to screen */
   1419    png_bytep gamma_to_1 PNG_DEPSTRUCT;      /* converts from file to 1.0 */
   1420    png_uint_16pp gamma_16_table PNG_DEPSTRUCT; /* gamma table for 16-bit depth files */
   1421    png_uint_16pp gamma_16_from_1 PNG_DEPSTRUCT; /* converts from 1.0 to screen */
   1422    png_uint_16pp gamma_16_to_1 PNG_DEPSTRUCT; /* converts from file to 1.0 */
   1423 #endif
   1424 
   1425 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
   1426    png_color_8 sig_bit PNG_DEPSTRUCT;       /* significant bits in each available channel */
   1427 #endif
   1428 
   1429 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
   1430    png_color_8 shift PNG_DEPSTRUCT;         /* shift for significant bit tranformation */
   1431 #endif
   1432 
   1433 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
   1434  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1435    png_bytep trans PNG_DEPSTRUCT;           /* transparency values for paletted files */
   1436    png_color_16 trans_values PNG_DEPSTRUCT; /* transparency values for non-paletted files */
   1437 #endif
   1438 
   1439    png_read_status_ptr read_row_fn PNG_DEPSTRUCT;   /* called after each row is decoded */
   1440    png_write_status_ptr write_row_fn PNG_DEPSTRUCT; /* called after each row is encoded */
   1441 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   1442    png_progressive_info_ptr info_fn PNG_DEPSTRUCT; /* called after header data fully read */
   1443    png_progressive_row_ptr row_fn PNG_DEPSTRUCT;   /* called after each prog. row is decoded */
   1444    png_progressive_end_ptr end_fn PNG_DEPSTRUCT;   /* called after image is complete */
   1445    png_bytep save_buffer_ptr PNG_DEPSTRUCT;        /* current location in save_buffer */
   1446    png_bytep save_buffer PNG_DEPSTRUCT;            /* buffer for previously read data */
   1447    png_bytep current_buffer_ptr PNG_DEPSTRUCT;     /* current location in current_buffer */
   1448    png_bytep current_buffer PNG_DEPSTRUCT;         /* buffer for recently used data */
   1449    png_uint_32 push_length PNG_DEPSTRUCT;          /* size of current input chunk */
   1450    png_uint_32 skip_length PNG_DEPSTRUCT;          /* bytes to skip in input data */
   1451    png_size_t save_buffer_size PNG_DEPSTRUCT;      /* amount of data now in save_buffer */
   1452    png_size_t save_buffer_max PNG_DEPSTRUCT;       /* total size of save_buffer */
   1453    png_size_t buffer_size PNG_DEPSTRUCT;           /* total amount of available input data */
   1454    png_size_t current_buffer_size PNG_DEPSTRUCT;   /* amount of data now in current_buffer */
   1455    int process_mode PNG_DEPSTRUCT;                 /* what push library is currently doing */
   1456    int cur_palette PNG_DEPSTRUCT;                  /* current push library palette index */
   1457 
   1458 #  ifdef PNG_TEXT_SUPPORTED
   1459      png_size_t current_text_size PNG_DEPSTRUCT;   /* current size of text input data */
   1460      png_size_t current_text_left PNG_DEPSTRUCT;   /* how much text left to read in input */
   1461      png_charp current_text PNG_DEPSTRUCT;         /* current text chunk buffer */
   1462      png_charp current_text_ptr PNG_DEPSTRUCT;     /* current location in current_text */
   1463 #  endif /* PNG_TEXT_SUPPORTED */
   1464 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
   1465 
   1466 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
   1467 /* for the Borland special 64K segment handler */
   1468    png_bytepp offset_table_ptr PNG_DEPSTRUCT;
   1469    png_bytep offset_table PNG_DEPSTRUCT;
   1470    png_uint_16 offset_table_number PNG_DEPSTRUCT;
   1471    png_uint_16 offset_table_count PNG_DEPSTRUCT;
   1472    png_uint_16 offset_table_count_free PNG_DEPSTRUCT;
   1473 #endif
   1474 
   1475 #ifdef PNG_READ_DITHER_SUPPORTED
   1476    png_bytep palette_lookup PNG_DEPSTRUCT;         /* lookup table for dithering */
   1477    png_bytep dither_index PNG_DEPSTRUCT;           /* index translation for palette files */
   1478 #endif
   1479 
   1480 #if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
   1481    png_uint_16p hist PNG_DEPSTRUCT;                /* histogram */
   1482 #endif
   1483 
   1484 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
   1485    png_byte heuristic_method PNG_DEPSTRUCT;        /* heuristic for row filter selection */
   1486    png_byte num_prev_filters PNG_DEPSTRUCT;        /* number of weights for previous rows */
   1487    png_bytep prev_filters PNG_DEPSTRUCT;           /* filter type(s) of previous row(s) */
   1488    png_uint_16p filter_weights PNG_DEPSTRUCT;      /* weight(s) for previous line(s) */
   1489    png_uint_16p inv_filter_weights PNG_DEPSTRUCT;  /* 1/weight(s) for previous line(s) */
   1490    png_uint_16p filter_costs PNG_DEPSTRUCT;        /* relative filter calculation cost */
   1491    png_uint_16p inv_filter_costs PNG_DEPSTRUCT;    /* 1/relative filter calculation cost */
   1492 #endif
   1493 
   1494 #ifdef PNG_TIME_RFC1123_SUPPORTED
   1495    png_charp time_buffer PNG_DEPSTRUCT;            /* String to hold RFC 1123 time text */
   1496 #endif
   1497 
   1498 /* New members added in libpng-1.0.6 */
   1499 
   1500 #ifdef PNG_FREE_ME_SUPPORTED
   1501    png_uint_32 free_me PNG_DEPSTRUCT;   /* flags items libpng is responsible for freeing */
   1502 #endif
   1503 
   1504 #ifdef PNG_USER_CHUNKS_SUPPORTED
   1505    png_voidp user_chunk_ptr PNG_DEPSTRUCT;
   1506    png_user_chunk_ptr read_user_chunk_fn PNG_DEPSTRUCT; /* user read chunk handler */
   1507 #endif
   1508 
   1509 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   1510    int num_chunk_list PNG_DEPSTRUCT;
   1511    png_bytep chunk_list PNG_DEPSTRUCT;
   1512 #endif
   1513 
   1514 /* New members added in libpng-1.0.3 */
   1515 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
   1516    png_byte rgb_to_gray_status PNG_DEPSTRUCT;
   1517    /* These were changed from png_byte in libpng-1.0.6 */
   1518    png_uint_16 rgb_to_gray_red_coeff PNG_DEPSTRUCT;
   1519    png_uint_16 rgb_to_gray_green_coeff PNG_DEPSTRUCT;
   1520    png_uint_16 rgb_to_gray_blue_coeff PNG_DEPSTRUCT;
   1521 #endif
   1522 
   1523 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
   1524 #if defined(PNG_MNG_FEATURES_SUPPORTED) || \
   1525     defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
   1526     defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
   1527 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
   1528 #ifdef PNG_1_0_X
   1529    png_byte mng_features_permitted PNG_DEPSTRUCT;
   1530 #else
   1531    png_uint_32 mng_features_permitted PNG_DEPSTRUCT;
   1532 #endif /* PNG_1_0_X */
   1533 #endif
   1534 
   1535 /* New member added in libpng-1.0.7 */
   1536 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
   1537    png_fixed_point int_gamma PNG_DEPSTRUCT;
   1538 #endif
   1539 
   1540 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
   1541 #ifdef PNG_MNG_FEATURES_SUPPORTED
   1542    png_byte filter_type PNG_DEPSTRUCT;
   1543 #endif
   1544 
   1545 #ifdef PNG_1_0_X
   1546 /* New member added in libpng-1.0.10, ifdef'ed out in 1.2.0 */
   1547    png_uint_32 row_buf_size PNG_DEPSTRUCT;
   1548 #endif
   1549 
   1550 /* New members added in libpng-1.2.0 */
   1551 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
   1552 #  ifndef PNG_1_0_X
   1553 #    ifdef PNG_MMX_CODE_SUPPORTED
   1554    png_byte     mmx_bitdepth_threshold PNG_DEPSTRUCT;
   1555    png_uint_32  mmx_rowbytes_threshold PNG_DEPSTRUCT;
   1556 #    endif
   1557    png_uint_32  asm_flags PNG_DEPSTRUCT;
   1558 #  endif
   1559 #endif
   1560 
   1561 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
   1562 #ifdef PNG_USER_MEM_SUPPORTED
   1563    png_voidp mem_ptr PNG_DEPSTRUCT;            /* user supplied struct for mem functions */
   1564    png_malloc_ptr malloc_fn PNG_DEPSTRUCT;     /* function for allocating memory */
   1565    png_free_ptr free_fn PNG_DEPSTRUCT;         /* function for freeing memory */
   1566 #endif
   1567 
   1568 /* New member added in libpng-1.0.13 and 1.2.0 */
   1569    png_bytep big_row_buf PNG_DEPSTRUCT;        /* buffer to save current (unfiltered) row */
   1570 
   1571 #ifdef PNG_READ_DITHER_SUPPORTED
   1572 /* The following three members were added at version 1.0.14 and 1.2.4 */
   1573    png_bytep dither_sort PNG_DEPSTRUCT;        /* working sort array */
   1574    png_bytep index_to_palette PNG_DEPSTRUCT;   /* where the original index currently is */
   1575                                  /* in the palette */
   1576    png_bytep palette_to_index PNG_DEPSTRUCT;   /* which original index points to this */
   1577                                  /* palette color */
   1578 #endif
   1579 
   1580 /* New members added in libpng-1.0.16 and 1.2.6 */
   1581    png_byte compression_type PNG_DEPSTRUCT;
   1582 
   1583 #ifdef PNG_USER_LIMITS_SUPPORTED
   1584    png_uint_32 user_width_max PNG_DEPSTRUCT;
   1585    png_uint_32 user_height_max PNG_DEPSTRUCT;
   1586 #endif
   1587 
   1588 /* New member added in libpng-1.0.25 and 1.2.17 */
   1589 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
   1590    /* Storage for unknown chunk that the library doesn't recognize. */
   1591    png_unknown_chunk unknown_chunk PNG_DEPSTRUCT;
   1592 #endif
   1593 
   1594 #ifdef PNG_INDEX_SUPPORTED
   1595    png_indexp index PNG_DEPSTRUCT;
   1596    png_uint_32 total_data_read;
   1597 #endif
   1598 
   1599 /* New members added in libpng-1.2.26 */
   1600   png_uint_32 old_big_row_buf_size PNG_DEPSTRUCT;
   1601   png_uint_32 old_prev_row_size PNG_DEPSTRUCT;
   1602 
   1603 /* New member added in libpng-1.2.30 */
   1604   png_charp chunkdata PNG_DEPSTRUCT;  /* buffer for reading chunk data */
   1605 };
   1606 
   1607 
   1608 /* This triggers a compiler error in png.c, if png.c and png.h
   1609  * do not agree upon the version number.
   1610  */
   1611 typedef png_structp version_1_2_46;
   1612 
   1613 typedef png_struct FAR * FAR * png_structpp;
   1614 
   1615 /* Here are the function definitions most commonly used.  This is not
   1616  * the place to find out how to use libpng.  See libpng.txt for the
   1617  * full explanation, see example.c for the summary.  This just provides
   1618  * a simple one line description of the use of each function.
   1619  */
   1620 
   1621 /* Returns the version number of the library */
   1622 extern PNG_EXPORT(png_uint_32,png_access_version_number) PNGARG((void));
   1623 
   1624 /* Tell lib we have already handled the first <num_bytes> magic bytes.
   1625  * Handling more than 8 bytes from the beginning of the file is an error.
   1626  */
   1627 extern PNG_EXPORT(void,png_set_sig_bytes) PNGARG((png_structp png_ptr,
   1628    int num_bytes));
   1629 
   1630 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
   1631  * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG
   1632  * signature, and non-zero otherwise.  Having num_to_check == 0 or
   1633  * start > 7 will always fail (ie return non-zero).
   1634  */
   1635 extern PNG_EXPORT(int,png_sig_cmp) PNGARG((png_bytep sig, png_size_t start,
   1636    png_size_t num_to_check));
   1637 
   1638 /* Simple signature checking function.  This is the same as calling
   1639  * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
   1640  */
   1641 extern PNG_EXPORT(int,png_check_sig) PNGARG((png_bytep sig, int num)) PNG_DEPRECATED;
   1642 
   1643 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
   1644 extern PNG_EXPORT(png_structp,png_create_read_struct)
   1645    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1646    png_error_ptr error_fn, png_error_ptr warn_fn)) PNG_ALLOCATED;
   1647 
   1648 /* Allocate and initialize png_ptr struct for writing, and any other memory */
   1649 extern PNG_EXPORT(png_structp,png_create_write_struct)
   1650    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1651    png_error_ptr error_fn, png_error_ptr warn_fn)) PNG_ALLOCATED;
   1652 
   1653 #ifdef PNG_WRITE_SUPPORTED
   1654 extern PNG_EXPORT(png_uint_32,png_get_compression_buffer_size)
   1655    PNGARG((png_structp png_ptr));
   1656 #endif
   1657 
   1658 #ifdef PNG_WRITE_SUPPORTED
   1659 extern PNG_EXPORT(void,png_set_compression_buffer_size)
   1660    PNGARG((png_structp png_ptr, png_uint_32 size));
   1661 #endif
   1662 
   1663 /* Reset the compression stream */
   1664 extern PNG_EXPORT(int,png_reset_zstream) PNGARG((png_structp png_ptr));
   1665 
   1666 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
   1667 #ifdef PNG_USER_MEM_SUPPORTED
   1668 extern PNG_EXPORT(png_structp,png_create_read_struct_2)
   1669    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1670    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
   1671    png_malloc_ptr malloc_fn, png_free_ptr free_fn)) PNG_ALLOCATED;
   1672 extern PNG_EXPORT(png_structp,png_create_write_struct_2)
   1673    PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
   1674    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
   1675    png_malloc_ptr malloc_fn, png_free_ptr free_fn)) PNG_ALLOCATED;
   1676 #endif
   1677 
   1678 /* Write a PNG chunk - size, type, (optional) data, CRC. */
   1679 extern PNG_EXPORT(void,png_write_chunk) PNGARG((png_structp png_ptr,
   1680    png_bytep chunk_name, png_bytep data, png_size_t length));
   1681 
   1682 /* Write the start of a PNG chunk - length and chunk name. */
   1683 extern PNG_EXPORT(void,png_write_chunk_start) PNGARG((png_structp png_ptr,
   1684    png_bytep chunk_name, png_uint_32 length));
   1685 
   1686 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
   1687 extern PNG_EXPORT(void,png_write_chunk_data) PNGARG((png_structp png_ptr,
   1688    png_bytep data, png_size_t length));
   1689 
   1690 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
   1691 extern PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));
   1692 
   1693 /* Allocate and initialize the info structure */
   1694 extern PNG_EXPORT(png_infop,png_create_info_struct)
   1695    PNGARG((png_structp png_ptr)) PNG_ALLOCATED;
   1696 
   1697 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   1698 /* Initialize the info structure (old interface - DEPRECATED) */
   1699 extern PNG_EXPORT(void,png_info_init) PNGARG((png_infop info_ptr))
   1700     PNG_DEPRECATED;
   1701 #undef png_info_init
   1702 #define png_info_init(info_ptr) png_info_init_3(&info_ptr,\
   1703     png_sizeof(png_info));
   1704 #endif
   1705 
   1706 extern PNG_EXPORT(void,png_info_init_3) PNGARG((png_infopp info_ptr,
   1707     png_size_t png_info_struct_size));
   1708 
   1709 /* Writes all the PNG information before the image. */
   1710 extern PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,
   1711    png_infop info_ptr));
   1712 extern PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,
   1713    png_infop info_ptr));
   1714 
   1715 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
   1716 /* Read the information before the actual image data. */
   1717 extern PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,
   1718    png_infop info_ptr));
   1719 #endif
   1720 
   1721 #ifdef PNG_TIME_RFC1123_SUPPORTED
   1722 extern PNG_EXPORT(png_charp,png_convert_to_rfc1123)
   1723    PNGARG((png_structp png_ptr, png_timep ptime));
   1724 #endif
   1725 
   1726 #ifdef PNG_CONVERT_tIME_SUPPORTED
   1727 /* Convert from a struct tm to png_time */
   1728 extern PNG_EXPORT(void,png_convert_from_struct_tm) PNGARG((png_timep ptime,
   1729    struct tm FAR * ttime));
   1730 
   1731 /* Convert from time_t to png_time.  Uses gmtime() */
   1732 extern PNG_EXPORT(void,png_convert_from_time_t) PNGARG((png_timep ptime,
   1733    time_t ttime));
   1734 #endif /* PNG_CONVERT_tIME_SUPPORTED */
   1735 
   1736 #ifdef PNG_READ_EXPAND_SUPPORTED
   1737 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
   1738 extern PNG_EXPORT(void,png_set_expand) PNGARG((png_structp png_ptr));
   1739 #ifndef PNG_1_0_X
   1740 extern PNG_EXPORT(void,png_set_expand_gray_1_2_4_to_8) PNGARG((png_structp
   1741   png_ptr));
   1742 #endif
   1743 extern PNG_EXPORT(void,png_set_palette_to_rgb) PNGARG((png_structp png_ptr));
   1744 extern PNG_EXPORT(void,png_set_tRNS_to_alpha) PNGARG((png_structp png_ptr));
   1745 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   1746 /* Deprecated */
   1747 extern PNG_EXPORT(void,png_set_gray_1_2_4_to_8) PNGARG((png_structp
   1748     png_ptr)) PNG_DEPRECATED;
   1749 #endif
   1750 #endif
   1751 
   1752 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
   1753 /* Use blue, green, red order for pixels. */
   1754 extern PNG_EXPORT(void,png_set_bgr) PNGARG((png_structp png_ptr));
   1755 #endif
   1756 
   1757 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
   1758 /* Expand the grayscale to 24-bit RGB if necessary. */
   1759 extern PNG_EXPORT(void,png_set_gray_to_rgb) PNGARG((png_structp png_ptr));
   1760 #endif
   1761 
   1762 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
   1763 /* Reduce RGB to grayscale. */
   1764 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1765 extern PNG_EXPORT(void,png_set_rgb_to_gray) PNGARG((png_structp png_ptr,
   1766    int error_action, double red, double green ));
   1767 #endif
   1768 extern PNG_EXPORT(void,png_set_rgb_to_gray_fixed) PNGARG((png_structp png_ptr,
   1769    int error_action, png_fixed_point red, png_fixed_point green ));
   1770 extern PNG_EXPORT(png_byte,png_get_rgb_to_gray_status) PNGARG((png_structp
   1771    png_ptr));
   1772 #endif
   1773 
   1774 extern PNG_EXPORT(void,png_build_grayscale_palette) PNGARG((int bit_depth,
   1775    png_colorp palette));
   1776 
   1777 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
   1778 extern PNG_EXPORT(void,png_set_strip_alpha) PNGARG((png_structp png_ptr));
   1779 #endif
   1780 
   1781 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
   1782     defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
   1783 extern PNG_EXPORT(void,png_set_swap_alpha) PNGARG((png_structp png_ptr));
   1784 #endif
   1785 
   1786 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
   1787     defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
   1788 extern PNG_EXPORT(void,png_set_invert_alpha) PNGARG((png_structp png_ptr));
   1789 #endif
   1790 
   1791 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
   1792 /* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
   1793 extern PNG_EXPORT(void,png_set_filler) PNGARG((png_structp png_ptr,
   1794    png_uint_32 filler, int flags));
   1795 /* The values of the PNG_FILLER_ defines should NOT be changed */
   1796 #define PNG_FILLER_BEFORE 0
   1797 #define PNG_FILLER_AFTER 1
   1798 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
   1799 #ifndef PNG_1_0_X
   1800 extern PNG_EXPORT(void,png_set_add_alpha) PNGARG((png_structp png_ptr,
   1801    png_uint_32 filler, int flags));
   1802 #endif
   1803 #endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
   1804 
   1805 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
   1806 /* Swap bytes in 16-bit depth files. */
   1807 extern PNG_EXPORT(void,png_set_swap) PNGARG((png_structp png_ptr));
   1808 #endif
   1809 
   1810 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
   1811 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
   1812 extern PNG_EXPORT(void,png_set_packing) PNGARG((png_structp png_ptr));
   1813 #endif
   1814 
   1815 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)
   1816 /* Swap packing order of pixels in bytes. */
   1817 extern PNG_EXPORT(void,png_set_packswap) PNGARG((png_structp png_ptr));
   1818 #endif
   1819 
   1820 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
   1821 /* Converts files to legal bit depths. */
   1822 extern PNG_EXPORT(void,png_set_shift) PNGARG((png_structp png_ptr,
   1823    png_color_8p true_bits));
   1824 #endif
   1825 
   1826 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
   1827     defined(PNG_WRITE_INTERLACING_SUPPORTED)
   1828 /* Have the code handle the interlacing.  Returns the number of passes. */
   1829 extern PNG_EXPORT(int,png_set_interlace_handling) PNGARG((png_structp png_ptr));
   1830 #endif
   1831 
   1832 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
   1833 /* Invert monochrome files */
   1834 extern PNG_EXPORT(void,png_set_invert_mono) PNGARG((png_structp png_ptr));
   1835 #endif
   1836 
   1837 #ifdef PNG_READ_BACKGROUND_SUPPORTED
   1838 /* Handle alpha and tRNS by replacing with a background color. */
   1839 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1840 extern PNG_EXPORT(void,png_set_background) PNGARG((png_structp png_ptr,
   1841    png_color_16p background_color, int background_gamma_code,
   1842    int need_expand, double background_gamma));
   1843 #endif
   1844 #define PNG_BACKGROUND_GAMMA_UNKNOWN 0
   1845 #define PNG_BACKGROUND_GAMMA_SCREEN  1
   1846 #define PNG_BACKGROUND_GAMMA_FILE    2
   1847 #define PNG_BACKGROUND_GAMMA_UNIQUE  3
   1848 #endif
   1849 
   1850 #ifdef PNG_READ_16_TO_8_SUPPORTED
   1851 /* Strip the second byte of information from a 16-bit depth file. */
   1852 extern PNG_EXPORT(void,png_set_strip_16) PNGARG((png_structp png_ptr));
   1853 #endif
   1854 
   1855 #ifdef PNG_READ_DITHER_SUPPORTED
   1856 /* Turn on dithering, and reduce the palette to the number of colors available. */
   1857 extern PNG_EXPORT(void,png_set_dither) PNGARG((png_structp png_ptr,
   1858    png_colorp palette, int num_palette, int maximum_colors,
   1859    png_uint_16p histogram, int full_dither));
   1860 #endif
   1861 
   1862 #ifdef PNG_READ_GAMMA_SUPPORTED
   1863 /* Handle gamma correction. Screen_gamma=(display_exponent) */
   1864 #ifdef PNG_FLOATING_POINT_SUPPORTED
   1865 extern PNG_EXPORT(void,png_set_gamma) PNGARG((png_structp png_ptr,
   1866    double screen_gamma, double default_file_gamma));
   1867 #endif
   1868 #endif
   1869 
   1870 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   1871 #if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
   1872     defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
   1873 /* Permit or disallow empty PLTE (0: not permitted, 1: permitted) */
   1874 /* Deprecated and will be removed.  Use png_permit_mng_features() instead. */
   1875 extern PNG_EXPORT(void,png_permit_empty_plte) PNGARG((png_structp png_ptr,
   1876    int empty_plte_permitted)) PNG_DEPRECATED;
   1877 #endif
   1878 #endif
   1879 
   1880 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   1881 /* Set how many lines between output flushes - 0 for no flushing */
   1882 extern PNG_EXPORT(void,png_set_flush) PNGARG((png_structp png_ptr, int nrows));
   1883 /* Flush the current PNG output buffer */
   1884 extern PNG_EXPORT(void,png_write_flush) PNGARG((png_structp png_ptr));
   1885 #endif
   1886 
   1887 /* Optional update palette with requested transformations */
   1888 extern PNG_EXPORT(void,png_start_read_image) PNGARG((png_structp png_ptr));
   1889 
   1890 /* Optional call to update the users info structure */
   1891 extern PNG_EXPORT(void,png_read_update_info) PNGARG((png_structp png_ptr,
   1892    png_infop info_ptr));
   1893 
   1894 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1895 /* Read one or more rows of image data. */
   1896 extern PNG_EXPORT(void,png_read_rows) PNGARG((png_structp png_ptr,
   1897    png_bytepp row, png_bytepp display_row, png_uint_32 num_rows));
   1898 #endif
   1899 
   1900 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1901 /* Read a row of data. */
   1902 extern PNG_EXPORT(void,png_read_row) PNGARG((png_structp png_ptr,
   1903    png_bytep row,
   1904    png_bytep display_row));
   1905 #endif
   1906 
   1907 #ifdef PNG_INDEX_SUPPORTED
   1908 /* Build image index for partial image decoding. */
   1909 extern PNG_EXPORT(void,png_build_index) PNGARG((png_structp png_ptr));
   1910 extern PNG_EXPORT(void,png_configure_decoder)
   1911     PNGARG((png_structp png_ptr, int *row_offset, int pass));
   1912 #endif
   1913 
   1914 
   1915 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1916 /* Read the whole image into memory at once. */
   1917 extern PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,
   1918    png_bytepp image));
   1919 #endif
   1920 
   1921 /* Write a row of image data */
   1922 extern PNG_EXPORT(void,png_write_row) PNGARG((png_structp png_ptr,
   1923    png_bytep row));
   1924 
   1925 /* Write a few rows of image data */
   1926 extern PNG_EXPORT(void,png_write_rows) PNGARG((png_structp png_ptr,
   1927    png_bytepp row, png_uint_32 num_rows));
   1928 
   1929 /* Write the image data */
   1930 extern PNG_EXPORT(void,png_write_image) PNGARG((png_structp png_ptr,
   1931    png_bytepp image));
   1932 
   1933 /* Writes the end of the PNG file. */
   1934 extern PNG_EXPORT(void,png_write_end) PNGARG((png_structp png_ptr,
   1935    png_infop info_ptr));
   1936 
   1937 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
   1938 /* Read the end of the PNG file. */
   1939 extern PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,
   1940    png_infop info_ptr));
   1941 #endif
   1942 
   1943 /* Free any memory associated with the png_info_struct */
   1944 extern PNG_EXPORT(void,png_destroy_info_struct) PNGARG((png_structp png_ptr,
   1945    png_infopp info_ptr_ptr));
   1946 
   1947 /* Free any memory associated with the png_struct and the png_info_structs */
   1948 extern PNG_EXPORT(void,png_destroy_read_struct) PNGARG((png_structpp
   1949    png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
   1950 
   1951 /* Free all memory used by the read (old method - NOT DLL EXPORTED) */
   1952 extern void png_read_destroy PNGARG((png_structp png_ptr, png_infop info_ptr,
   1953    png_infop end_info_ptr)) PNG_DEPRECATED;
   1954 
   1955 /* Free any memory associated with the png_struct and the png_info_structs */
   1956 extern PNG_EXPORT(void,png_destroy_write_struct)
   1957    PNGARG((png_structpp png_ptr_ptr, png_infopp info_ptr_ptr));
   1958 
   1959 /* Free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
   1960 extern void png_write_destroy PNGARG((png_structp png_ptr)) PNG_DEPRECATED;
   1961 
   1962 /* Set the libpng method of handling chunk CRC errors */
   1963 extern PNG_EXPORT(void,png_set_crc_action) PNGARG((png_structp png_ptr,
   1964    int crit_action, int ancil_action));
   1965 
   1966 /* Values for png_set_crc_action() to say how to handle CRC errors in
   1967  * ancillary and critical chunks, and whether to use the data contained
   1968  * therein.  Note that it is impossible to "discard" data in a critical
   1969  * chunk.  For versions prior to 0.90, the action was always error/quit,
   1970  * whereas in version 0.90 and later, the action for CRC errors in ancillary
   1971  * chunks is warn/discard.  These values should NOT be changed.
   1972  *
   1973  *      value                       action:critical     action:ancillary
   1974  */
   1975 #define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */
   1976 #define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */
   1977 #define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */
   1978 #define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */
   1979 #define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
   1980 #define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */
   1981 
   1982 /* These functions give the user control over the scan-line filtering in
   1983  * libpng and the compression methods used by zlib.  These functions are
   1984  * mainly useful for testing, as the defaults should work with most users.
   1985  * Those users who are tight on memory or want faster performance at the
   1986  * expense of compression can modify them.  See the compression library
   1987  * header file (zlib.h) for an explination of the compression functions.
   1988  */
   1989 
   1990 /* Set the filtering method(s) used by libpng.  Currently, the only valid
   1991  * value for "method" is 0.
   1992  */
   1993 extern PNG_EXPORT(void,png_set_filter) PNGARG((png_structp png_ptr, int method,
   1994    int filters));
   1995 
   1996 /* Flags for png_set_filter() to say which filters to use.  The flags
   1997  * are chosen so that they don't conflict with real filter types
   1998  * below, in case they are supplied instead of the #defined constants.
   1999  * These values should NOT be changed.
   2000  */
   2001 #define PNG_NO_FILTERS     0x00
   2002 #define PNG_FILTER_NONE    0x08
   2003 #define PNG_FILTER_SUB     0x10
   2004 #define PNG_FILTER_UP      0x20
   2005 #define PNG_FILTER_AVG     0x40
   2006 #define PNG_FILTER_PAETH   0x80
   2007 #define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
   2008                          PNG_FILTER_AVG | PNG_FILTER_PAETH)
   2009 
   2010 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
   2011  * These defines should NOT be changed.
   2012  */
   2013 #define PNG_FILTER_VALUE_NONE  0
   2014 #define PNG_FILTER_VALUE_SUB   1
   2015 #define PNG_FILTER_VALUE_UP    2
   2016 #define PNG_FILTER_VALUE_AVG   3
   2017 #define PNG_FILTER_VALUE_PAETH 4
   2018 #define PNG_FILTER_VALUE_LAST  5
   2019 
   2020 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* EXPERIMENTAL */
   2021 /* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
   2022  * defines, either the default (minimum-sum-of-absolute-differences), or
   2023  * the experimental method (weighted-minimum-sum-of-absolute-differences).
   2024  *
   2025  * Weights are factors >= 1.0, indicating how important it is to keep the
   2026  * filter type consistent between rows.  Larger numbers mean the current
   2027  * filter is that many times as likely to be the same as the "num_weights"
   2028  * previous filters.  This is cumulative for each previous row with a weight.
   2029  * There needs to be "num_weights" values in "filter_weights", or it can be
   2030  * NULL if the weights aren't being specified.  Weights have no influence on
   2031  * the selection of the first row filter.  Well chosen weights can (in theory)
   2032  * improve the compression for a given image.
   2033  *
   2034  * Costs are factors >= 1.0 indicating the relative decoding costs of a
   2035  * filter type.  Higher costs indicate more decoding expense, and are
   2036  * therefore less likely to be selected over a filter with lower computational
   2037  * costs.  There needs to be a value in "filter_costs" for each valid filter
   2038  * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
   2039  * setting the costs.  Costs try to improve the speed of decompression without
   2040  * unduly increasing the compressed image size.
   2041  *
   2042  * A negative weight or cost indicates the default value is to be used, and
   2043  * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
   2044  * The default values for both weights and costs are currently 1.0, but may
   2045  * change if good general weighting/cost heuristics can be found.  If both
   2046  * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
   2047  * to the UNWEIGHTED method, but with added encoding time/computation.
   2048  */
   2049 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2050 extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,
   2051    int heuristic_method, int num_weights, png_doublep filter_weights,
   2052    png_doublep filter_costs));
   2053 #endif
   2054 #endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
   2055 
   2056 /* Heuristic used for row filter selection.  These defines should NOT be
   2057  * changed.
   2058  */
   2059 #define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
   2060 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
   2061 #define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
   2062 #define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
   2063 
   2064 /* Set the library compression level.  Currently, valid values range from
   2065  * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
   2066  * (0 - no compression, 9 - "maximal" compression).  Note that tests have
   2067  * shown that zlib compression levels 3-6 usually perform as well as level 9
   2068  * for PNG images, and do considerably fewer caclulations.  In the future,
   2069  * these values may not correspond directly to the zlib compression levels.
   2070  */
   2071 extern PNG_EXPORT(void,png_set_compression_level) PNGARG((png_structp png_ptr,
   2072    int level));
   2073 
   2074 extern PNG_EXPORT(void,png_set_compression_mem_level)
   2075    PNGARG((png_structp png_ptr, int mem_level));
   2076 
   2077 extern PNG_EXPORT(void,png_set_compression_strategy)
   2078    PNGARG((png_structp png_ptr, int strategy));
   2079 
   2080 extern PNG_EXPORT(void,png_set_compression_window_bits)
   2081    PNGARG((png_structp png_ptr, int window_bits));
   2082 
   2083 extern PNG_EXPORT(void,png_set_compression_method) PNGARG((png_structp png_ptr,
   2084    int method));
   2085 
   2086 /* These next functions are called for input/output, memory, and error
   2087  * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
   2088  * and call standard C I/O routines such as fread(), fwrite(), and
   2089  * fprintf().  These functions can be made to use other I/O routines
   2090  * at run time for those applications that need to handle I/O in a
   2091  * different manner by calling png_set_???_fn().  See libpng.txt for
   2092  * more information.
   2093  */
   2094 
   2095 #ifdef PNG_STDIO_SUPPORTED
   2096 /* Initialize the input/output for the PNG file to the default functions. */
   2097 extern PNG_EXPORT(void,png_init_io) PNGARG((png_structp png_ptr, png_FILE_p fp));
   2098 #endif
   2099 
   2100 /* Replace the (error and abort), and warning functions with user
   2101  * supplied functions.  If no messages are to be printed you must still
   2102  * write and use replacement functions. The replacement error_fn should
   2103  * still do a longjmp to the last setjmp location if you are using this
   2104  * method of error handling.  If error_fn or warning_fn is NULL, the
   2105  * default function will be used.
   2106  */
   2107 
   2108 extern PNG_EXPORT(void,png_set_error_fn) PNGARG((png_structp png_ptr,
   2109    png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
   2110 
   2111 /* Return the user pointer associated with the error functions */
   2112 extern PNG_EXPORT(png_voidp,png_get_error_ptr) PNGARG((png_structp png_ptr));
   2113 
   2114 /* Replace the default data output functions with a user supplied one(s).
   2115  * If buffered output is not used, then output_flush_fn can be set to NULL.
   2116  * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
   2117  * output_flush_fn will be ignored (and thus can be NULL).
   2118  * It is probably a mistake to use NULL for output_flush_fn if
   2119  * write_data_fn is not also NULL unless you have built libpng with
   2120  * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
   2121  * default flush function, which uses the standard *FILE structure, will
   2122  * be used.
   2123  */
   2124 extern PNG_EXPORT(void,png_set_write_fn) PNGARG((png_structp png_ptr,
   2125    png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
   2126 
   2127 /* Replace the default data input function with a user supplied one. */
   2128 extern PNG_EXPORT(void,png_set_read_fn) PNGARG((png_structp png_ptr,
   2129    png_voidp io_ptr, png_rw_ptr read_data_fn));
   2130 
   2131 #ifdef PNG_INDEX_SUPPORTED
   2132 /* Set the data seek function with a user supplied one.
   2133  * REQUIRED by partial image decode.
   2134  */
   2135 extern PNG_EXPORT(void,png_set_seek_fn) PNGARG((png_structp png_ptr,
   2136    png_seek_ptr seek_data_fn));
   2137 #endif
   2138 
   2139 /* Return the user pointer associated with the I/O functions */
   2140 extern PNG_EXPORT(png_voidp,png_get_io_ptr) PNGARG((png_structp png_ptr));
   2141 
   2142 extern PNG_EXPORT(void,png_set_read_status_fn) PNGARG((png_structp png_ptr,
   2143    png_read_status_ptr read_row_fn));
   2144 
   2145 extern PNG_EXPORT(void,png_set_write_status_fn) PNGARG((png_structp png_ptr,
   2146    png_write_status_ptr write_row_fn));
   2147 
   2148 #ifdef PNG_USER_MEM_SUPPORTED
   2149 /* Replace the default memory allocation functions with user supplied one(s). */
   2150 extern PNG_EXPORT(void,png_set_mem_fn) PNGARG((png_structp png_ptr,
   2151    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn));
   2152 /* Return the user pointer associated with the memory functions */
   2153 extern PNG_EXPORT(png_voidp,png_get_mem_ptr) PNGARG((png_structp png_ptr));
   2154 #endif
   2155 
   2156 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   2157     defined(PNG_LEGACY_SUPPORTED)
   2158 extern PNG_EXPORT(void,png_set_read_user_transform_fn) PNGARG((png_structp
   2159    png_ptr, png_user_transform_ptr read_user_transform_fn));
   2160 #endif
   2161 
   2162 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
   2163     defined(PNG_LEGACY_SUPPORTED)
   2164 extern PNG_EXPORT(void,png_set_write_user_transform_fn) PNGARG((png_structp
   2165    png_ptr, png_user_transform_ptr write_user_transform_fn));
   2166 #endif
   2167 
   2168 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
   2169     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
   2170     defined(PNG_LEGACY_SUPPORTED)
   2171 extern PNG_EXPORT(void,png_set_user_transform_info) PNGARG((png_structp
   2172    png_ptr, png_voidp user_transform_ptr, int user_transform_depth,
   2173    int user_transform_channels));
   2174 /* Return the user pointer associated with the user transform functions */
   2175 extern PNG_EXPORT(png_voidp,png_get_user_transform_ptr)
   2176    PNGARG((png_structp png_ptr));
   2177 #endif
   2178 
   2179 #ifdef PNG_USER_CHUNKS_SUPPORTED
   2180 extern PNG_EXPORT(void,png_set_read_user_chunk_fn) PNGARG((png_structp png_ptr,
   2181    png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
   2182 extern PNG_EXPORT(png_voidp,png_get_user_chunk_ptr) PNGARG((png_structp
   2183    png_ptr));
   2184 #endif
   2185 
   2186 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   2187 /* Sets the function callbacks for the push reader, and a pointer to a
   2188  * user-defined structure available to the callback functions.
   2189  */
   2190 extern PNG_EXPORT(void,png_set_progressive_read_fn) PNGARG((png_structp png_ptr,
   2191    png_voidp progressive_ptr,
   2192    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
   2193    png_progressive_end_ptr end_fn));
   2194 
   2195 /* Returns the user pointer associated with the push read functions */
   2196 extern PNG_EXPORT(png_voidp,png_get_progressive_ptr)
   2197    PNGARG((png_structp png_ptr));
   2198 
   2199 /* Function to be called when data becomes available */
   2200 extern PNG_EXPORT(void,png_process_data) PNGARG((png_structp png_ptr,
   2201    png_infop info_ptr, png_bytep buffer, png_size_t buffer_size));
   2202 
   2203 /* Function that combines rows.  Not very much different than the
   2204  * png_combine_row() call.  Is this even used?????
   2205  */
   2206 extern PNG_EXPORT(void,png_progressive_combine_row) PNGARG((png_structp png_ptr,
   2207    png_bytep old_row, png_bytep new_row));
   2208 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
   2209 
   2210 extern PNG_EXPORT(png_voidp,png_malloc) PNGARG((png_structp png_ptr,
   2211    png_uint_32 size)) PNG_ALLOCATED;
   2212 
   2213 #ifdef PNG_1_0_X
   2214 #  define png_malloc_warn png_malloc
   2215 #else
   2216 /* Added at libpng version 1.2.4 */
   2217 extern PNG_EXPORT(png_voidp,png_malloc_warn) PNGARG((png_structp png_ptr,
   2218    png_uint_32 size)) PNG_ALLOCATED;
   2219 #endif
   2220 
   2221 /* Frees a pointer allocated by png_malloc() */
   2222 extern PNG_EXPORT(void,png_free) PNGARG((png_structp png_ptr, png_voidp ptr));
   2223 
   2224 #ifdef PNG_1_0_X
   2225 /* Function to allocate memory for zlib. */
   2226 extern PNG_EXPORT(voidpf,png_zalloc) PNGARG((voidpf png_ptr, uInt items,
   2227    uInt size));
   2228 
   2229 /* Function to free memory for zlib */
   2230 extern PNG_EXPORT(void,png_zfree) PNGARG((voidpf png_ptr, voidpf ptr));
   2231 #endif
   2232 
   2233 /* Free data that was allocated internally */
   2234 extern PNG_EXPORT(void,png_free_data) PNGARG((png_structp png_ptr,
   2235    png_infop info_ptr, png_uint_32 free_me, int num));
   2236 #ifdef PNG_FREE_ME_SUPPORTED
   2237 /* Reassign responsibility for freeing existing data, whether allocated
   2238  * by libpng or by the application
   2239  */
   2240 extern PNG_EXPORT(void,png_data_freer) PNGARG((png_structp png_ptr,
   2241    png_infop info_ptr, int freer, png_uint_32 mask));
   2242 #endif
   2243 /* Assignments for png_data_freer */
   2244 #define PNG_DESTROY_WILL_FREE_DATA 1
   2245 #define PNG_SET_WILL_FREE_DATA 1
   2246 #define PNG_USER_WILL_FREE_DATA 2
   2247 /* Flags for png_ptr->free_me and info_ptr->free_me */
   2248 #define PNG_FREE_HIST 0x0008
   2249 #define PNG_FREE_ICCP 0x0010
   2250 #define PNG_FREE_SPLT 0x0020
   2251 #define PNG_FREE_ROWS 0x0040
   2252 #define PNG_FREE_PCAL 0x0080
   2253 #define PNG_FREE_SCAL 0x0100
   2254 #define PNG_FREE_UNKN 0x0200
   2255 #define PNG_FREE_LIST 0x0400
   2256 #define PNG_FREE_PLTE 0x1000
   2257 #define PNG_FREE_TRNS 0x2000
   2258 #define PNG_FREE_TEXT 0x4000
   2259 #define PNG_FREE_ALL  0x7fff
   2260 #define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
   2261 
   2262 #ifdef PNG_USER_MEM_SUPPORTED
   2263 extern PNG_EXPORT(png_voidp,png_malloc_default) PNGARG((png_structp png_ptr,
   2264    png_uint_32 size)) PNG_ALLOCATED;
   2265 extern PNG_EXPORT(void,png_free_default) PNGARG((png_structp png_ptr,
   2266    png_voidp ptr));
   2267 #endif
   2268 
   2269 extern PNG_EXPORT(png_voidp,png_memcpy_check) PNGARG((png_structp png_ptr,
   2270    png_voidp s1, png_voidp s2, png_uint_32 size)) PNG_DEPRECATED;
   2271 
   2272 extern PNG_EXPORT(png_voidp,png_memset_check) PNGARG((png_structp png_ptr,
   2273    png_voidp s1, int value, png_uint_32 size)) PNG_DEPRECATED;
   2274 
   2275 #if defined(USE_FAR_KEYWORD)  /* memory model conversion function */
   2276 extern void *png_far_to_near PNGARG((png_structp png_ptr,png_voidp ptr,
   2277    int check));
   2278 #endif /* USE_FAR_KEYWORD */
   2279 
   2280 #ifndef PNG_NO_ERROR_TEXT
   2281 /* Fatal error in PNG image of libpng - can't continue */
   2282 extern PNG_EXPORT(void,png_error) PNGARG((png_structp png_ptr,
   2283    png_const_charp error_message)) PNG_NORETURN;
   2284 
   2285 /* The same, but the chunk name is prepended to the error string. */
   2286 extern PNG_EXPORT(void,png_chunk_error) PNGARG((png_structp png_ptr,
   2287    png_const_charp error_message)) PNG_NORETURN;
   2288 #else
   2289 /* Fatal error in PNG image of libpng - can't continue */
   2290 extern PNG_EXPORT(void,png_err) PNGARG((png_structp png_ptr)) PNG_NORETURN;
   2291 #endif
   2292 
   2293 #ifndef PNG_NO_WARNINGS
   2294 /* Non-fatal error in libpng.  Can continue, but may have a problem. */
   2295 extern PNG_EXPORT(void,png_warning) PNGARG((png_structp png_ptr,
   2296    png_const_charp warning_message));
   2297 
   2298 #ifdef PNG_READ_SUPPORTED
   2299 /* Non-fatal error in libpng, chunk name is prepended to message. */
   2300 extern PNG_EXPORT(void,png_chunk_warning) PNGARG((png_structp png_ptr,
   2301    png_const_charp warning_message));
   2302 #endif /* PNG_READ_SUPPORTED */
   2303 #endif /* PNG_NO_WARNINGS */
   2304 
   2305 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
   2306  * Similarly, the png_get_<chunk> calls are used to read values from the
   2307  * png_info_struct, either storing the parameters in the passed variables, or
   2308  * setting pointers into the png_info_struct where the data is stored.  The
   2309  * png_get_<chunk> functions return a non-zero value if the data was available
   2310  * in info_ptr, or return zero and do not change any of the parameters if the
   2311  * data was not available.
   2312  *
   2313  * These functions should be used instead of directly accessing png_info
   2314  * to avoid problems with future changes in the size and internal layout of
   2315  * png_info_struct.
   2316  */
   2317 /* Returns "flag" if chunk data is valid in info_ptr. */
   2318 extern PNG_EXPORT(png_uint_32,png_get_valid) PNGARG((png_structp png_ptr,
   2319 png_infop info_ptr, png_uint_32 flag));
   2320 
   2321 /* Returns number of bytes needed to hold a transformed row. */
   2322 extern PNG_EXPORT(png_uint_32,png_get_rowbytes) PNGARG((png_structp png_ptr,
   2323 png_infop info_ptr));
   2324 
   2325 #ifdef PNG_INFO_IMAGE_SUPPORTED
   2326 /* Returns row_pointers, which is an array of pointers to scanlines that was
   2327  * returned from png_read_png().
   2328  */
   2329 extern PNG_EXPORT(png_bytepp,png_get_rows) PNGARG((png_structp png_ptr,
   2330 png_infop info_ptr));
   2331 /* Set row_pointers, which is an array of pointers to scanlines for use
   2332  * by png_write_png().
   2333  */
   2334 extern PNG_EXPORT(void,png_set_rows) PNGARG((png_structp png_ptr,
   2335    png_infop info_ptr, png_bytepp row_pointers));
   2336 #endif
   2337 
   2338 /* Returns number of color channels in image. */
   2339 extern PNG_EXPORT(png_byte,png_get_channels) PNGARG((png_structp png_ptr,
   2340 png_infop info_ptr));
   2341 
   2342 #ifdef PNG_EASY_ACCESS_SUPPORTED
   2343 /* Returns image width in pixels. */
   2344 extern PNG_EXPORT(png_uint_32, png_get_image_width) PNGARG((png_structp
   2345 png_ptr, png_infop info_ptr));
   2346 
   2347 /* Returns image height in pixels. */
   2348 extern PNG_EXPORT(png_uint_32, png_get_image_height) PNGARG((png_structp
   2349 png_ptr, png_infop info_ptr));
   2350 
   2351 /* Returns image bit_depth. */
   2352 extern PNG_EXPORT(png_byte, png_get_bit_depth) PNGARG((png_structp
   2353 png_ptr, png_infop info_ptr));
   2354 
   2355 /* Returns image color_type. */
   2356 extern PNG_EXPORT(png_byte, png_get_color_type) PNGARG((png_structp
   2357 png_ptr, png_infop info_ptr));
   2358 
   2359 /* Returns image filter_type. */
   2360 extern PNG_EXPORT(png_byte, png_get_filter_type) PNGARG((png_structp
   2361 png_ptr, png_infop info_ptr));
   2362 
   2363 /* Returns image interlace_type. */
   2364 extern PNG_EXPORT(png_byte, png_get_interlace_type) PNGARG((png_structp
   2365 png_ptr, png_infop info_ptr));
   2366 
   2367 /* Returns image compression_type. */
   2368 extern PNG_EXPORT(png_byte, png_get_compression_type) PNGARG((png_structp
   2369 png_ptr, png_infop info_ptr));
   2370 
   2371 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
   2372 extern PNG_EXPORT(png_uint_32, png_get_pixels_per_meter) PNGARG((png_structp
   2373 png_ptr, png_infop info_ptr));
   2374 extern PNG_EXPORT(png_uint_32, png_get_x_pixels_per_meter) PNGARG((png_structp
   2375 png_ptr, png_infop info_ptr));
   2376 extern PNG_EXPORT(png_uint_32, png_get_y_pixels_per_meter) PNGARG((png_structp
   2377 png_ptr, png_infop info_ptr));
   2378 
   2379 /* Returns pixel aspect ratio, computed from pHYs chunk data.  */
   2380 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2381 extern PNG_EXPORT(float, png_get_pixel_aspect_ratio) PNGARG((png_structp
   2382 png_ptr, png_infop info_ptr));
   2383 #endif
   2384 
   2385 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
   2386 extern PNG_EXPORT(png_int_32, png_get_x_offset_pixels) PNGARG((png_structp
   2387 png_ptr, png_infop info_ptr));
   2388 extern PNG_EXPORT(png_int_32, png_get_y_offset_pixels) PNGARG((png_structp
   2389 png_ptr, png_infop info_ptr));
   2390 extern PNG_EXPORT(png_int_32, png_get_x_offset_microns) PNGARG((png_structp
   2391 png_ptr, png_infop info_ptr));
   2392 extern PNG_EXPORT(png_int_32, png_get_y_offset_microns) PNGARG((png_structp
   2393 png_ptr, png_infop info_ptr));
   2394 
   2395 #endif /* PNG_EASY_ACCESS_SUPPORTED */
   2396 
   2397 /* Returns pointer to signature string read from PNG header */
   2398 extern PNG_EXPORT(png_bytep,png_get_signature) PNGARG((png_structp png_ptr,
   2399 png_infop info_ptr));
   2400 
   2401 #ifdef PNG_bKGD_SUPPORTED
   2402 extern PNG_EXPORT(png_uint_32,png_get_bKGD) PNGARG((png_structp png_ptr,
   2403    png_infop info_ptr, png_color_16p *background));
   2404 #endif
   2405 
   2406 #ifdef PNG_bKGD_SUPPORTED
   2407 extern PNG_EXPORT(void,png_set_bKGD) PNGARG((png_structp png_ptr,
   2408    png_infop info_ptr, png_color_16p background));
   2409 #endif
   2410 
   2411 #ifdef PNG_cHRM_SUPPORTED
   2412 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2413 extern PNG_EXPORT(png_uint_32,png_get_cHRM) PNGARG((png_structp png_ptr,
   2414    png_infop info_ptr, double *white_x, double *white_y, double *red_x,
   2415    double *red_y, double *green_x, double *green_y, double *blue_x,
   2416    double *blue_y));
   2417 #endif
   2418 #ifdef PNG_FIXED_POINT_SUPPORTED
   2419 extern PNG_EXPORT(png_uint_32,png_get_cHRM_fixed) PNGARG((png_structp png_ptr,
   2420    png_infop info_ptr, png_fixed_point *int_white_x, png_fixed_point
   2421    *int_white_y, png_fixed_point *int_red_x, png_fixed_point *int_red_y,
   2422    png_fixed_point *int_green_x, png_fixed_point *int_green_y, png_fixed_point
   2423    *int_blue_x, png_fixed_point *int_blue_y));
   2424 #endif
   2425 #endif
   2426 
   2427 #ifdef PNG_cHRM_SUPPORTED
   2428 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2429 extern PNG_EXPORT(void,png_set_cHRM) PNGARG((png_structp png_ptr,
   2430    png_infop info_ptr, double white_x, double white_y, double red_x,
   2431    double red_y, double green_x, double green_y, double blue_x, double blue_y));
   2432 #endif
   2433 #ifdef PNG_FIXED_POINT_SUPPORTED
   2434 extern PNG_EXPORT(void,png_set_cHRM_fixed) PNGARG((png_structp png_ptr,
   2435    png_infop info_ptr, png_fixed_point int_white_x, png_fixed_point int_white_y,
   2436    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
   2437    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
   2438    png_fixed_point int_blue_y));
   2439 #endif
   2440 #endif
   2441 
   2442 #ifdef PNG_gAMA_SUPPORTED
   2443 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2444 extern PNG_EXPORT(png_uint_32,png_get_gAMA) PNGARG((png_structp png_ptr,
   2445    png_infop info_ptr, double *file_gamma));
   2446 #endif
   2447 extern PNG_EXPORT(png_uint_32,png_get_gAMA_fixed) PNGARG((png_structp png_ptr,
   2448    png_infop info_ptr, png_fixed_point *int_file_gamma));
   2449 #endif
   2450 
   2451 #ifdef PNG_gAMA_SUPPORTED
   2452 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2453 extern PNG_EXPORT(void,png_set_gAMA) PNGARG((png_structp png_ptr,
   2454    png_infop info_ptr, double file_gamma));
   2455 #endif
   2456 extern PNG_EXPORT(void,png_set_gAMA_fixed) PNGARG((png_structp png_ptr,
   2457    png_infop info_ptr, png_fixed_point int_file_gamma));
   2458 #endif
   2459 
   2460 #ifdef PNG_hIST_SUPPORTED
   2461 extern PNG_EXPORT(png_uint_32,png_get_hIST) PNGARG((png_structp png_ptr,
   2462    png_infop info_ptr, png_uint_16p *hist));
   2463 #endif
   2464 
   2465 #ifdef PNG_hIST_SUPPORTED
   2466 extern PNG_EXPORT(void,png_set_hIST) PNGARG((png_structp png_ptr,
   2467    png_infop info_ptr, png_uint_16p hist));
   2468 #endif
   2469 
   2470 extern PNG_EXPORT(png_uint_32,png_get_IHDR) PNGARG((png_structp png_ptr,
   2471    png_infop info_ptr, png_uint_32 *width, png_uint_32 *height,
   2472    int *bit_depth, int *color_type, int *interlace_method,
   2473    int *compression_method, int *filter_method));
   2474 
   2475 extern PNG_EXPORT(void,png_set_IHDR) PNGARG((png_structp png_ptr,
   2476    png_infop info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
   2477    int color_type, int interlace_method, int compression_method,
   2478    int filter_method));
   2479 
   2480 #ifdef PNG_oFFs_SUPPORTED
   2481 extern PNG_EXPORT(png_uint_32,png_get_oFFs) PNGARG((png_structp png_ptr,
   2482    png_infop info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
   2483    int *unit_type));
   2484 #endif
   2485 
   2486 #ifdef PNG_oFFs_SUPPORTED
   2487 extern PNG_EXPORT(void,png_set_oFFs) PNGARG((png_structp png_ptr,
   2488    png_infop info_ptr, png_int_32 offset_x, png_int_32 offset_y,
   2489    int unit_type));
   2490 #endif
   2491 
   2492 #ifdef PNG_pCAL_SUPPORTED
   2493 extern PNG_EXPORT(png_uint_32,png_get_pCAL) PNGARG((png_structp png_ptr,
   2494    png_infop info_ptr, png_charp *purpose, png_int_32 *X0, png_int_32 *X1,
   2495    int *type, int *nparams, png_charp *units, png_charpp *params));
   2496 #endif
   2497 
   2498 #ifdef PNG_pCAL_SUPPORTED
   2499 extern PNG_EXPORT(void,png_set_pCAL) PNGARG((png_structp png_ptr,
   2500    png_infop info_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1,
   2501    int type, int nparams, png_charp units, png_charpp params));
   2502 #endif
   2503 
   2504 #ifdef PNG_pHYs_SUPPORTED
   2505 extern PNG_EXPORT(png_uint_32,png_get_pHYs) PNGARG((png_structp png_ptr,
   2506    png_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
   2507 #endif
   2508 
   2509 #ifdef PNG_pHYs_SUPPORTED
   2510 extern PNG_EXPORT(void,png_set_pHYs) PNGARG((png_structp png_ptr,
   2511    png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
   2512 #endif
   2513 
   2514 extern PNG_EXPORT(png_uint_32,png_get_PLTE) PNGARG((png_structp png_ptr,
   2515    png_infop info_ptr, png_colorp *palette, int *num_palette));
   2516 
   2517 extern PNG_EXPORT(void,png_set_PLTE) PNGARG((png_structp png_ptr,
   2518    png_infop info_ptr, png_colorp palette, int num_palette));
   2519 
   2520 #ifdef PNG_sBIT_SUPPORTED
   2521 extern PNG_EXPORT(png_uint_32,png_get_sBIT) PNGARG((png_structp png_ptr,
   2522    png_infop info_ptr, png_color_8p *sig_bit));
   2523 #endif
   2524 
   2525 #ifdef PNG_sBIT_SUPPORTED
   2526 extern PNG_EXPORT(void,png_set_sBIT) PNGARG((png_structp png_ptr,
   2527    png_infop info_ptr, png_color_8p sig_bit));
   2528 #endif
   2529 
   2530 #ifdef PNG_sRGB_SUPPORTED
   2531 extern PNG_EXPORT(png_uint_32,png_get_sRGB) PNGARG((png_structp png_ptr,
   2532    png_infop info_ptr, int *intent));
   2533 #endif
   2534 
   2535 #ifdef PNG_sRGB_SUPPORTED
   2536 extern PNG_EXPORT(void,png_set_sRGB) PNGARG((png_structp png_ptr,
   2537    png_infop info_ptr, int intent));
   2538 extern PNG_EXPORT(void,png_set_sRGB_gAMA_and_cHRM) PNGARG((png_structp png_ptr,
   2539    png_infop info_ptr, int intent));
   2540 #endif
   2541 
   2542 #ifdef PNG_iCCP_SUPPORTED
   2543 extern PNG_EXPORT(png_uint_32,png_get_iCCP) PNGARG((png_structp png_ptr,
   2544    png_infop info_ptr, png_charpp name, int *compression_type,
   2545    png_charpp profile, png_uint_32 *proflen));
   2546    /* Note to maintainer: profile should be png_bytepp */
   2547 #endif
   2548 
   2549 #ifdef PNG_iCCP_SUPPORTED
   2550 extern PNG_EXPORT(void,png_set_iCCP) PNGARG((png_structp png_ptr,
   2551    png_infop info_ptr, png_charp name, int compression_type,
   2552    png_charp profile, png_uint_32 proflen));
   2553    /* Note to maintainer: profile should be png_bytep */
   2554 #endif
   2555 
   2556 #ifdef PNG_sPLT_SUPPORTED
   2557 extern PNG_EXPORT(png_uint_32,png_get_sPLT) PNGARG((png_structp png_ptr,
   2558    png_infop info_ptr, png_sPLT_tpp entries));
   2559 #endif
   2560 
   2561 #ifdef PNG_sPLT_SUPPORTED
   2562 extern PNG_EXPORT(void,png_set_sPLT) PNGARG((png_structp png_ptr,
   2563    png_infop info_ptr, png_sPLT_tp entries, int nentries));
   2564 #endif
   2565 
   2566 #ifdef PNG_TEXT_SUPPORTED
   2567 /* png_get_text also returns the number of text chunks in *num_text */
   2568 extern PNG_EXPORT(png_uint_32,png_get_text) PNGARG((png_structp png_ptr,
   2569    png_infop info_ptr, png_textp *text_ptr, int *num_text));
   2570 #endif
   2571 
   2572 /*
   2573  *  Note while png_set_text() will accept a structure whose text,
   2574  *  language, and  translated keywords are NULL pointers, the structure
   2575  *  returned by png_get_text will always contain regular
   2576  *  zero-terminated C strings.  They might be empty strings but
   2577  *  they will never be NULL pointers.
   2578  */
   2579 
   2580 #ifdef PNG_TEXT_SUPPORTED
   2581 extern PNG_EXPORT(void,png_set_text) PNGARG((png_structp png_ptr,
   2582    png_infop info_ptr, png_textp text_ptr, int num_text));
   2583 #endif
   2584 
   2585 #ifdef PNG_tIME_SUPPORTED
   2586 extern PNG_EXPORT(png_uint_32,png_get_tIME) PNGARG((png_structp png_ptr,
   2587    png_infop info_ptr, png_timep *mod_time));
   2588 #endif
   2589 
   2590 #ifdef PNG_tIME_SUPPORTED
   2591 extern PNG_EXPORT(void,png_set_tIME) PNGARG((png_structp png_ptr,
   2592    png_infop info_ptr, png_timep mod_time));
   2593 #endif
   2594 
   2595 #ifdef PNG_tRNS_SUPPORTED
   2596 extern PNG_EXPORT(png_uint_32,png_get_tRNS) PNGARG((png_structp png_ptr,
   2597    png_infop info_ptr, png_bytep *trans, int *num_trans,
   2598    png_color_16p *trans_values));
   2599 #endif
   2600 
   2601 #ifdef PNG_tRNS_SUPPORTED
   2602 extern PNG_EXPORT(void,png_set_tRNS) PNGARG((png_structp png_ptr,
   2603    png_infop info_ptr, png_bytep trans, int num_trans,
   2604    png_color_16p trans_values));
   2605 #endif
   2606 
   2607 #ifdef PNG_tRNS_SUPPORTED
   2608 #endif
   2609 
   2610 #ifdef PNG_sCAL_SUPPORTED
   2611 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2612 extern PNG_EXPORT(png_uint_32,png_get_sCAL) PNGARG((png_structp png_ptr,
   2613    png_infop info_ptr, int *unit, double *width, double *height));
   2614 #else
   2615 #ifdef PNG_FIXED_POINT_SUPPORTED
   2616 extern PNG_EXPORT(png_uint_32,png_get_sCAL_s) PNGARG((png_structp png_ptr,
   2617    png_infop info_ptr, int *unit, png_charpp swidth, png_charpp sheight));
   2618 #endif
   2619 #endif
   2620 #endif /* PNG_sCAL_SUPPORTED */
   2621 
   2622 #ifdef PNG_sCAL_SUPPORTED
   2623 #ifdef PNG_FLOATING_POINT_SUPPORTED
   2624 extern PNG_EXPORT(void,png_set_sCAL) PNGARG((png_structp png_ptr,
   2625    png_infop info_ptr, int unit, double width, double height));
   2626 #else
   2627 #ifdef PNG_FIXED_POINT_SUPPORTED
   2628 extern PNG_EXPORT(void,png_set_sCAL_s) PNGARG((png_structp png_ptr,
   2629    png_infop info_ptr, int unit, png_charp swidth, png_charp sheight));
   2630 #endif
   2631 #endif
   2632 #endif /* PNG_sCAL_SUPPORTED || PNG_WRITE_sCAL_SUPPORTED */
   2633 
   2634 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
   2635 /* Provide a list of chunks and how they are to be handled, if the built-in
   2636    handling or default unknown chunk handling is not desired.  Any chunks not
   2637    listed will be handled in the default manner.  The IHDR and IEND chunks
   2638    must not be listed.
   2639       keep = 0: follow default behaviour
   2640            = 1: do not keep
   2641            = 2: keep only if safe-to-copy
   2642            = 3: keep even if unsafe-to-copy
   2643 */
   2644 extern PNG_EXPORT(void, png_set_keep_unknown_chunks) PNGARG((png_structp
   2645    png_ptr, int keep, png_bytep chunk_list, int num_chunks));
   2646 PNG_EXPORT(int,png_handle_as_unknown) PNGARG((png_structp png_ptr, png_bytep
   2647    chunk_name));
   2648 #endif
   2649 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
   2650 extern PNG_EXPORT(void, png_set_unknown_chunks) PNGARG((png_structp png_ptr,
   2651    png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));
   2652 extern PNG_EXPORT(void, png_set_unknown_chunk_location)
   2653    PNGARG((png_structp png_ptr, png_infop info_ptr, int chunk, int location));
   2654 extern PNG_EXPORT(png_uint_32,png_get_unknown_chunks) PNGARG((png_structp
   2655    png_ptr, png_infop info_ptr, png_unknown_chunkpp entries));
   2656 #endif
   2657 
   2658 /* Png_free_data() will turn off the "valid" flag for anything it frees.
   2659  * If you need to turn it off for a chunk that your application has freed,
   2660  * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
   2661  */
   2662 extern PNG_EXPORT(void, png_set_invalid) PNGARG((png_structp png_ptr,
   2663    png_infop info_ptr, int mask));
   2664 
   2665 #ifdef PNG_INFO_IMAGE_SUPPORTED
   2666 /* The "params" pointer is currently not used and is for future expansion. */
   2667 extern PNG_EXPORT(void, png_read_png) PNGARG((png_structp png_ptr,
   2668                         png_infop info_ptr,
   2669                         int transforms,
   2670                         png_voidp params));
   2671 extern PNG_EXPORT(void, png_write_png) PNGARG((png_structp png_ptr,
   2672                         png_infop info_ptr,
   2673                         int transforms,
   2674                         png_voidp params));
   2675 #endif
   2676 
   2677 /* Define PNG_DEBUG at compile time for debugging information.  Higher
   2678  * numbers for PNG_DEBUG mean more debugging information.  This has
   2679  * only been added since version 0.95 so it is not implemented throughout
   2680  * libpng yet, but more support will be added as needed.
   2681  */
   2682 #ifdef PNG_DEBUG
   2683 #if (PNG_DEBUG > 0)
   2684 #if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
   2685 #include <crtdbg.h>
   2686 #if (PNG_DEBUG > 1)
   2687 #ifndef _DEBUG
   2688 #  define _DEBUG
   2689 #endif
   2690 #ifndef png_debug
   2691 #define png_debug(l,m)  _RPT0(_CRT_WARN,m PNG_STRING_NEWLINE)
   2692 #endif
   2693 #ifndef png_debug1
   2694 #define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m PNG_STRING_NEWLINE,p1)
   2695 #endif
   2696 #ifndef png_debug2
   2697 #define png_debug2(l,m,p1,p2) _RPT2(_CRT_WARN,m PNG_STRING_NEWLINE,p1,p2)
   2698 #endif
   2699 #endif
   2700 #else /* PNG_DEBUG_FILE || !_MSC_VER */
   2701 #ifndef PNG_DEBUG_FILE
   2702 #define PNG_DEBUG_FILE stderr
   2703 #endif /* PNG_DEBUG_FILE */
   2704 
   2705 #if (PNG_DEBUG > 1)
   2706 /* Note: ["%s"m PNG_STRING_NEWLINE] probably does not work on non-ISO
   2707  * compilers.
   2708  */
   2709 #  ifdef __STDC__
   2710 #    ifndef png_debug
   2711 #      define png_debug(l,m) \
   2712        { \
   2713        int num_tabs=l; \
   2714        fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
   2715          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
   2716        }
   2717 #    endif
   2718 #    ifndef png_debug1
   2719 #      define png_debug1(l,m,p1) \
   2720        { \
   2721        int num_tabs=l; \
   2722        fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
   2723          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
   2724        }
   2725 #    endif
   2726 #    ifndef png_debug2
   2727 #      define png_debug2(l,m,p1,p2) \
   2728        { \
   2729        int num_tabs=l; \
   2730        fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
   2731          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
   2732        }
   2733 #    endif
   2734 #  else /* __STDC __ */
   2735 #    ifndef png_debug
   2736 #      define png_debug(l,m) \
   2737        { \
   2738        int num_tabs=l; \
   2739        char format[256]; \
   2740        snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
   2741          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
   2742          m,PNG_STRING_NEWLINE); \
   2743        fprintf(PNG_DEBUG_FILE,format); \
   2744        }
   2745 #    endif
   2746 #    ifndef png_debug1
   2747 #      define png_debug1(l,m,p1) \
   2748        { \
   2749        int num_tabs=l; \
   2750        char format[256]; \
   2751        snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
   2752          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
   2753          m,PNG_STRING_NEWLINE); \
   2754        fprintf(PNG_DEBUG_FILE,format,p1); \
   2755        }
   2756 #    endif
   2757 #    ifndef png_debug2
   2758 #      define png_debug2(l,m,p1,p2) \
   2759        { \
   2760        int num_tabs=l; \
   2761        char format[256]; \
   2762        snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
   2763          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
   2764          m,PNG_STRING_NEWLINE); \
   2765        fprintf(PNG_DEBUG_FILE,format,p1,p2); \
   2766        }
   2767 #    endif
   2768 #  endif /* __STDC __ */
   2769 #endif /* (PNG_DEBUG > 1) */
   2770 
   2771 #endif /* _MSC_VER */
   2772 #endif /* (PNG_DEBUG > 0) */
   2773 #endif /* PNG_DEBUG */
   2774 #ifndef png_debug
   2775 #define png_debug(l, m)
   2776 #endif
   2777 #ifndef png_debug1
   2778 #define png_debug1(l, m, p1)
   2779 #endif
   2780 #ifndef png_debug2
   2781 #define png_debug2(l, m, p1, p2)
   2782 #endif
   2783 
   2784 extern PNG_EXPORT(png_charp,png_get_copyright) PNGARG((png_structp png_ptr));
   2785 extern PNG_EXPORT(png_charp,png_get_header_ver) PNGARG((png_structp png_ptr));
   2786 extern PNG_EXPORT(png_charp,png_get_header_version) PNGARG((png_structp png_ptr));
   2787 extern PNG_EXPORT(png_charp,png_get_libpng_ver) PNGARG((png_structp png_ptr));
   2788 
   2789 #ifdef PNG_MNG_FEATURES_SUPPORTED
   2790 extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
   2791    png_ptr, png_uint_32 mng_features_permitted));
   2792 #endif
   2793 
   2794 /* For use in png_set_keep_unknown, added to version 1.2.6 */
   2795 #define PNG_HANDLE_CHUNK_AS_DEFAULT   0
   2796 #define PNG_HANDLE_CHUNK_NEVER        1
   2797 #define PNG_HANDLE_CHUNK_IF_SAFE      2
   2798 #define PNG_HANDLE_CHUNK_ALWAYS       3
   2799 
   2800 /* Added to version 1.2.0 */
   2801 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
   2802 #ifdef PNG_MMX_CODE_SUPPORTED
   2803 #define PNG_ASM_FLAG_MMX_SUPPORT_COMPILED  0x01  /* not user-settable */
   2804 #define PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU    0x02  /* not user-settable */
   2805 #define PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  0x04
   2806 #define PNG_ASM_FLAG_MMX_READ_INTERLACE    0x08
   2807 #define PNG_ASM_FLAG_MMX_READ_FILTER_SUB   0x10
   2808 #define PNG_ASM_FLAG_MMX_READ_FILTER_UP    0x20
   2809 #define PNG_ASM_FLAG_MMX_READ_FILTER_AVG   0x40
   2810 #define PNG_ASM_FLAG_MMX_READ_FILTER_PAETH 0x80
   2811 #define PNG_ASM_FLAGS_INITIALIZED          0x80000000  /* not user-settable */
   2812 
   2813 #define PNG_MMX_READ_FLAGS ( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  \
   2814                            | PNG_ASM_FLAG_MMX_READ_INTERLACE    \
   2815                            | PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \
   2816                            | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \
   2817                            | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \
   2818                            | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH )
   2819 #define PNG_MMX_WRITE_FLAGS ( 0 )
   2820 
   2821 #define PNG_MMX_FLAGS ( PNG_ASM_FLAG_MMX_SUPPORT_COMPILED \
   2822                       | PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU   \
   2823                       | PNG_MMX_READ_FLAGS                \
   2824                       | PNG_MMX_WRITE_FLAGS )
   2825 
   2826 #define PNG_SELECT_READ   1
   2827 #define PNG_SELECT_WRITE  2
   2828 #endif /* PNG_MMX_CODE_SUPPORTED */
   2829 
   2830 #ifndef PNG_1_0_X
   2831 /* pngget.c */
   2832 extern PNG_EXPORT(png_uint_32,png_get_mmx_flagmask)
   2833    PNGARG((int flag_select, int *compilerID));
   2834 
   2835 /* pngget.c */
   2836 extern PNG_EXPORT(png_uint_32,png_get_asm_flagmask)
   2837    PNGARG((int flag_select));
   2838 
   2839 /* pngget.c */
   2840 extern PNG_EXPORT(png_uint_32,png_get_asm_flags)
   2841    PNGARG((png_structp png_ptr));
   2842 
   2843 /* pngget.c */
   2844 extern PNG_EXPORT(png_byte,png_get_mmx_bitdepth_threshold)
   2845    PNGARG((png_structp png_ptr));
   2846 
   2847 /* pngget.c */
   2848 extern PNG_EXPORT(png_uint_32,png_get_mmx_rowbytes_threshold)
   2849    PNGARG((png_structp png_ptr));
   2850 
   2851 /* pngset.c */
   2852 extern PNG_EXPORT(void,png_set_asm_flags)
   2853    PNGARG((png_structp png_ptr, png_uint_32 asm_flags));
   2854 
   2855 /* pngset.c */
   2856 extern PNG_EXPORT(void,png_set_mmx_thresholds)
   2857    PNGARG((png_structp png_ptr, png_byte mmx_bitdepth_threshold,
   2858    png_uint_32 mmx_rowbytes_threshold));
   2859 
   2860 #endif /* PNG_1_0_X */
   2861 
   2862 #ifndef PNG_1_0_X
   2863 /* png.c, pnggccrd.c, or pngvcrd.c */
   2864 extern PNG_EXPORT(int,png_mmx_support) PNGARG((void));
   2865 #endif /* PNG_1_0_X */
   2866 #endif /* PNG_ASSEMBLER_CODE_SUPPORTED */
   2867 
   2868 /* Strip the prepended error numbers ("#nnn ") from error and warning
   2869  * messages before passing them to the error or warning handler.
   2870  */
   2871 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
   2872 extern PNG_EXPORT(void,png_set_strip_error_numbers) PNGARG((png_structp
   2873    png_ptr, png_uint_32 strip_mode));
   2874 #endif
   2875 
   2876 /* Added at libpng-1.2.6 */
   2877 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
   2878 extern PNG_EXPORT(void,png_set_user_limits) PNGARG((png_structp
   2879    png_ptr, png_uint_32 user_width_max, png_uint_32 user_height_max));
   2880 extern PNG_EXPORT(png_uint_32,png_get_user_width_max) PNGARG((png_structp
   2881    png_ptr));
   2882 extern PNG_EXPORT(png_uint_32,png_get_user_height_max) PNGARG((png_structp
   2883    png_ptr));
   2884 #endif
   2885 /* Maintainer: Put new public prototypes here ^, in libpng.3, and in
   2886  * project defs
   2887  */
   2888 
   2889 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
   2890 /* With these routines we avoid an integer divide, which will be slower on
   2891  * most machines.  However, it does take more operations than the corresponding
   2892  * divide method, so it may be slower on a few RISC systems.  There are two
   2893  * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
   2894  *
   2895  * Note that the rounding factors are NOT supposed to be the same!  128 and
   2896  * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
   2897  * standard method.
   2898  *
   2899  * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
   2900  */
   2901 
   2902  /* fg and bg should be in `gamma 1.0' space; alpha is the opacity          */
   2903 
   2904 #  define png_composite(composite, fg, alpha, bg)                            \
   2905      { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) * (png_uint_16)(alpha) \
   2906                         +        (png_uint_16)(bg)*(png_uint_16)(255 -       \
   2907                         (png_uint_16)(alpha)) + (png_uint_16)128);           \
   2908        (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
   2909 
   2910 #  define png_composite_16(composite, fg, alpha, bg)                         \
   2911      { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) * (png_uint_32)(alpha) \
   2912                         + (png_uint_32)(bg)*(png_uint_32)(65535L -           \
   2913                         (png_uint_32)(alpha)) + (png_uint_32)32768L);        \
   2914        (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
   2915 
   2916 #else  /* Standard method using integer division */
   2917 
   2918 #  define png_composite(composite, fg, alpha, bg)                            \
   2919      (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +    \
   2920        (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \
   2921        (png_uint_16)127) / 255)
   2922 
   2923 #  define png_composite_16(composite, fg, alpha, bg)                         \
   2924      (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
   2925        (png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) +      \
   2926        (png_uint_32)32767) / (png_uint_32)65535L)
   2927 
   2928 #endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
   2929 
   2930 /* Inline macros to do direct reads of bytes from the input buffer.  These
   2931  * require that you are using an architecture that uses PNG byte ordering
   2932  * (MSB first) and supports unaligned data storage.  I think that PowerPC
   2933  * in big-endian mode and 680x0 are the only ones that will support this.
   2934  * The x86 line of processors definitely do not.  The png_get_int_32()
   2935  * routine also assumes we are using two's complement format for negative
   2936  * values, which is almost certainly true.
   2937  */
   2938 #ifdef PNG_READ_BIG_ENDIAN_SUPPORTED
   2939 #  define png_get_uint_32(buf) ( *((png_uint_32p) (buf)))
   2940 #  define png_get_uint_16(buf) ( *((png_uint_16p) (buf)))
   2941 #  define png_get_int_32(buf)  ( *((png_int_32p)  (buf)))
   2942 #else
   2943 extern PNG_EXPORT(png_uint_32,png_get_uint_32) PNGARG((png_bytep buf));
   2944 extern PNG_EXPORT(png_uint_16,png_get_uint_16) PNGARG((png_bytep buf));
   2945 extern PNG_EXPORT(png_int_32,png_get_int_32) PNGARG((png_bytep buf));
   2946 #endif /* !PNG_READ_BIG_ENDIAN_SUPPORTED */
   2947 extern PNG_EXPORT(png_uint_32,png_get_uint_31)
   2948   PNGARG((png_structp png_ptr, png_bytep buf));
   2949 /* No png_get_int_16 -- may be added if there's a real need for it. */
   2950 
   2951 /* Place a 32-bit number into a buffer in PNG byte order (big-endian).
   2952  */
   2953 extern PNG_EXPORT(void,png_save_uint_32)
   2954    PNGARG((png_bytep buf, png_uint_32 i));
   2955 extern PNG_EXPORT(void,png_save_int_32)
   2956    PNGARG((png_bytep buf, png_int_32 i));
   2957 
   2958 /* Place a 16-bit number into a buffer in PNG byte order.
   2959  * The parameter is declared unsigned int, not png_uint_16,
   2960  * just to avoid potential problems on pre-ANSI C compilers.
   2961  */
   2962 extern PNG_EXPORT(void,png_save_uint_16)
   2963    PNGARG((png_bytep buf, unsigned int i));
   2964 /* No png_save_int_16 -- may be added if there's a real need for it. */
   2965 
   2966 /* ************************************************************************* */
   2967 
   2968 /* These next functions are used internally in the code.  They generally
   2969  * shouldn't be used unless you are writing code to add or replace some
   2970  * functionality in libpng.  More information about most functions can
   2971  * be found in the files where the functions are located.
   2972  */
   2973 
   2974 
   2975 /* Various modes of operation, that are visible to applications because
   2976  * they are used for unknown chunk location.
   2977  */
   2978 #define PNG_HAVE_IHDR               0x01
   2979 #define PNG_HAVE_PLTE               0x02
   2980 #define PNG_HAVE_IDAT               0x04
   2981 #define PNG_AFTER_IDAT              0x08 /* Have complete zlib datastream */
   2982 #define PNG_HAVE_IEND               0x10
   2983 
   2984 #ifdef PNG_INTERNAL
   2985 
   2986 /* More modes of operation.  Note that after an init, mode is set to
   2987  * zero automatically when the structure is created.
   2988  */
   2989 #define PNG_HAVE_gAMA               0x20
   2990 #define PNG_HAVE_cHRM               0x40
   2991 #define PNG_HAVE_sRGB               0x80
   2992 #define PNG_HAVE_CHUNK_HEADER      0x100
   2993 #define PNG_WROTE_tIME             0x200
   2994 #define PNG_WROTE_INFO_BEFORE_PLTE 0x400
   2995 #define PNG_BACKGROUND_IS_GRAY     0x800
   2996 #define PNG_HAVE_PNG_SIGNATURE    0x1000
   2997 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
   2998 
   2999 /* Flags for the transformations the PNG library does on the image data */
   3000 #define PNG_BGR                0x0001
   3001 #define PNG_INTERLACE          0x0002
   3002 #define PNG_PACK               0x0004
   3003 #define PNG_SHIFT              0x0008
   3004 #define PNG_SWAP_BYTES         0x0010
   3005 #define PNG_INVERT_MONO        0x0020
   3006 #define PNG_DITHER             0x0040
   3007 #define PNG_BACKGROUND         0x0080
   3008 #define PNG_BACKGROUND_EXPAND  0x0100
   3009                           /*   0x0200 unused */
   3010 #define PNG_16_TO_8            0x0400
   3011 #define PNG_RGBA               0x0800
   3012 #define PNG_EXPAND             0x1000
   3013 #define PNG_GAMMA              0x2000
   3014 #define PNG_GRAY_TO_RGB        0x4000
   3015 #define PNG_FILLER             0x8000L
   3016 #define PNG_PACKSWAP          0x10000L
   3017 #define PNG_SWAP_ALPHA        0x20000L
   3018 #define PNG_STRIP_ALPHA       0x40000L
   3019 #define PNG_INVERT_ALPHA      0x80000L
   3020 #define PNG_USER_TRANSFORM   0x100000L
   3021 #define PNG_RGB_TO_GRAY_ERR  0x200000L
   3022 #define PNG_RGB_TO_GRAY_WARN 0x400000L
   3023 #define PNG_RGB_TO_GRAY      0x600000L  /* two bits, RGB_TO_GRAY_ERR|WARN */
   3024                        /*    0x800000L     Unused */
   3025 #define PNG_ADD_ALPHA       0x1000000L  /* Added to libpng-1.2.7 */
   3026 #define PNG_EXPAND_tRNS     0x2000000L  /* Added to libpng-1.2.9 */
   3027 #define PNG_PREMULTIPLY_ALPHA 0x4000000L  /* Added to libpng-1.2.41 */
   3028                                           /* by volker */
   3029                        /*   0x8000000L  unused */
   3030                        /*  0x10000000L  unused */
   3031                        /*  0x20000000L  unused */
   3032                        /*  0x40000000L  unused */
   3033 
   3034 /* Flags for png_create_struct */
   3035 #define PNG_STRUCT_PNG   0x0001
   3036 #define PNG_STRUCT_INFO  0x0002
   3037 
   3038 /* Scaling factor for filter heuristic weighting calculations */
   3039 #define PNG_WEIGHT_SHIFT 8
   3040 #define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
   3041 #define PNG_COST_SHIFT 3
   3042 #define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
   3043 
   3044 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
   3045 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
   3046 #define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002
   3047 #define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004
   3048 #define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008
   3049 #define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010
   3050 #define PNG_FLAG_ZLIB_FINISHED            0x0020
   3051 #define PNG_FLAG_ROW_INIT                 0x0040
   3052 #define PNG_FLAG_FILLER_AFTER             0x0080
   3053 #define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
   3054 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
   3055 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400
   3056 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
   3057 #define PNG_FLAG_FREE_PLTE                0x1000
   3058 #define PNG_FLAG_FREE_TRNS                0x2000
   3059 #define PNG_FLAG_FREE_HIST                0x4000
   3060 #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000L
   3061 #define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000L
   3062 #define PNG_FLAG_LIBRARY_MISMATCH         0x20000L
   3063 #define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000L
   3064 #define PNG_FLAG_STRIP_ERROR_TEXT         0x80000L
   3065 #define PNG_FLAG_MALLOC_NULL_MEM_OK       0x100000L
   3066 #define PNG_FLAG_ADD_ALPHA                0x200000L  /* Added to libpng-1.2.8 */
   3067 #define PNG_FLAG_STRIP_ALPHA              0x400000L  /* Added to libpng-1.2.8 */
   3068                                   /*      0x800000L  unused */
   3069                                   /*     0x1000000L  unused */
   3070                                   /*     0x2000000L  unused */
   3071                                   /*     0x4000000L  unused */
   3072                                   /*     0x8000000L  unused */
   3073                                   /*    0x10000000L  unused */
   3074                                   /*    0x20000000L  unused */
   3075                                   /*    0x40000000L  unused */
   3076 
   3077 #define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
   3078                                      PNG_FLAG_CRC_ANCILLARY_NOWARN)
   3079 
   3080 #define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
   3081                                      PNG_FLAG_CRC_CRITICAL_IGNORE)
   3082 
   3083 #define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
   3084                                      PNG_FLAG_CRC_CRITICAL_MASK)
   3085 
   3086 /* Save typing and make code easier to understand */
   3087 
   3088 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
   3089    abs((int)((c1).green) - (int)((c2).green)) + \
   3090    abs((int)((c1).blue) - (int)((c2).blue)))
   3091 
   3092 /* Added to libpng-1.2.6 JB */
   3093 #define PNG_ROWBYTES(pixel_bits, width) \
   3094     ((pixel_bits) >= 8 ? \
   3095     ((width) * (((png_uint_32)(pixel_bits)) >> 3)) : \
   3096     (( ((width) * ((png_uint_32)(pixel_bits))) + 7) >> 3) )
   3097 
   3098 /* PNG_OUT_OF_RANGE returns true if value is outside the range
   3099  * ideal-delta..ideal+delta.  Each argument is evaluated twice.
   3100  * "ideal" and "delta" should be constants, normally simple
   3101  * integers, "value" a variable. Added to libpng-1.2.6 JB
   3102  */
   3103 #define PNG_OUT_OF_RANGE(value, ideal, delta) \
   3104         ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
   3105 
   3106 /* Variables declared in png.c - only it needs to define PNG_NO_EXTERN */
   3107 #if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
   3108 /* Place to hold the signature string for a PNG file. */
   3109 #ifdef PNG_USE_GLOBAL_ARRAYS
   3110    PNG_EXPORT_VAR (PNG_CONST png_byte FARDATA) png_sig[8];
   3111 #else
   3112 #endif
   3113 #endif /* PNG_NO_EXTERN */
   3114 
   3115 /* Constant strings for known chunk types.  If you need to add a chunk,
   3116  * define the name here, and add an invocation of the macro in png.c and
   3117  * wherever it's needed.
   3118  */
   3119 #define PNG_IHDR png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}
   3120 #define PNG_IDAT png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}
   3121 #define PNG_IEND png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}
   3122 #define PNG_PLTE png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}
   3123 #define PNG_bKGD png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}
   3124 #define PNG_cHRM png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}
   3125 #define PNG_gAMA png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}
   3126 #define PNG_hIST png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}
   3127 #define PNG_iCCP png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}
   3128 #define PNG_iTXt png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}
   3129 #define PNG_oFFs png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}
   3130 #define PNG_pCAL png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}
   3131 #define PNG_sCAL png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}
   3132 #define PNG_pHYs png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}
   3133 #define PNG_sBIT png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}
   3134 #define PNG_sPLT png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}
   3135 #define PNG_sRGB png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}
   3136 #define PNG_tEXt png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}
   3137 #define PNG_tIME png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}
   3138 #define PNG_tRNS png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
   3139 #define PNG_zTXt png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}
   3140 
   3141 #ifdef PNG_USE_GLOBAL_ARRAYS
   3142 PNG_EXPORT_VAR (png_byte FARDATA) png_IHDR[5];
   3143 PNG_EXPORT_VAR (png_byte FARDATA) png_IDAT[5];
   3144 PNG_EXPORT_VAR (png_byte FARDATA) png_IEND[5];
   3145 PNG_EXPORT_VAR (png_byte FARDATA) png_PLTE[5];
   3146 PNG_EXPORT_VAR (png_byte FARDATA) png_bKGD[5];
   3147 PNG_EXPORT_VAR (png_byte FARDATA) png_cHRM[5];
   3148 PNG_EXPORT_VAR (png_byte FARDATA) png_gAMA[5];
   3149 PNG_EXPORT_VAR (png_byte FARDATA) png_hIST[5];
   3150 PNG_EXPORT_VAR (png_byte FARDATA) png_iCCP[5];
   3151 PNG_EXPORT_VAR (png_byte FARDATA) png_iTXt[5];
   3152 PNG_EXPORT_VAR (png_byte FARDATA) png_oFFs[5];
   3153 PNG_EXPORT_VAR (png_byte FARDATA) png_pCAL[5];
   3154 PNG_EXPORT_VAR (png_byte FARDATA) png_sCAL[5];
   3155 PNG_EXPORT_VAR (png_byte FARDATA) png_pHYs[5];
   3156 PNG_EXPORT_VAR (png_byte FARDATA) png_sBIT[5];
   3157 PNG_EXPORT_VAR (png_byte FARDATA) png_sPLT[5];
   3158 PNG_EXPORT_VAR (png_byte FARDATA) png_sRGB[5];
   3159 PNG_EXPORT_VAR (png_byte FARDATA) png_tEXt[5];
   3160 PNG_EXPORT_VAR (png_byte FARDATA) png_tIME[5];
   3161 PNG_EXPORT_VAR (png_byte FARDATA) png_tRNS[5];
   3162 PNG_EXPORT_VAR (png_byte FARDATA) png_zTXt[5];
   3163 #endif /* PNG_USE_GLOBAL_ARRAYS */
   3164 
   3165 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   3166 /* Initialize png_ptr struct for reading, and allocate any other memory.
   3167  * (old interface - DEPRECATED - use png_create_read_struct instead).
   3168  */
   3169 extern PNG_EXPORT(void,png_read_init) PNGARG((png_structp png_ptr))
   3170     PNG_DEPRECATED;
   3171 #undef png_read_init
   3172 #define png_read_init(png_ptr) png_read_init_3(&png_ptr, \
   3173     PNG_LIBPNG_VER_STRING,  png_sizeof(png_struct));
   3174 #endif
   3175 
   3176 extern PNG_EXPORT(void,png_read_init_3) PNGARG((png_structpp ptr_ptr,
   3177     png_const_charp user_png_ver, png_size_t png_struct_size));
   3178 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   3179 extern PNG_EXPORT(void,png_read_init_2) PNGARG((png_structp png_ptr,
   3180     png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t
   3181     png_info_size));
   3182 #endif
   3183 
   3184 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
   3185 /* Initialize png_ptr struct for writing, and allocate any other memory.
   3186  * (old interface - DEPRECATED - use png_create_write_struct instead).
   3187  */
   3188 extern PNG_EXPORT(void,png_write_init) PNGARG((png_structp png_ptr))
   3189     PNG_DEPRECATED;
   3190 #undef png_write_init
   3191 #define png_write_init(png_ptr) png_write_init_3(&png_ptr, \
   3192     PNG_LIBPNG_VER_STRING, png_sizeof(png_struct));
   3193 #endif
   3194 
   3195 extern PNG_EXPORT(void,png_write_init_3) PNGARG((png_structpp ptr_ptr,
   3196     png_const_charp user_png_ver, png_size_t png_struct_size));
   3197 extern PNG_EXPORT(void,png_write_init_2) PNGARG((png_structp png_ptr,
   3198     png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t
   3199     png_info_size));
   3200 
   3201 /* Allocate memory for an internal libpng struct */
   3202 PNG_EXTERN png_voidp png_create_struct PNGARG((int type)) PNG_PRIVATE;
   3203 
   3204 /* Free memory from internal libpng struct */
   3205 PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr)) PNG_PRIVATE;
   3206 
   3207 PNG_EXTERN png_voidp png_create_struct_2 PNGARG((int type, png_malloc_ptr
   3208   malloc_fn, png_voidp mem_ptr)) PNG_PRIVATE;
   3209 PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,
   3210    png_free_ptr free_fn, png_voidp mem_ptr)) PNG_PRIVATE;
   3211 
   3212 /* Free any memory that info_ptr points to and reset struct. */
   3213 PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,
   3214    png_infop info_ptr)) PNG_PRIVATE;
   3215 
   3216 #ifndef PNG_1_0_X
   3217 /* Function to allocate memory for zlib. */
   3218 PNG_EXTERN voidpf png_zalloc PNGARG((voidpf png_ptr, uInt items,
   3219    uInt size)) PNG_PRIVATE;
   3220 
   3221 /* Function to free memory for zlib */
   3222 PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr)) PNG_PRIVATE;
   3223 
   3224 #ifdef PNG_SIZE_T
   3225 /* Function to convert a sizeof an item to png_sizeof item */
   3226    PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size))
   3227       PNG_PRIVATE;
   3228 #endif
   3229 
   3230 /* Next four functions are used internally as callbacks.  PNGAPI is required
   3231  * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3.
   3232  */
   3233 
   3234 PNG_EXTERN void PNGAPI png_default_read_data PNGARG((png_structp png_ptr,
   3235    png_bytep data, png_size_t length)) PNG_PRIVATE;
   3236 
   3237 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   3238 PNG_EXTERN void PNGAPI png_push_fill_buffer PNGARG((png_structp png_ptr,
   3239    png_bytep buffer, png_size_t length)) PNG_PRIVATE;
   3240 #endif
   3241 
   3242 PNG_EXTERN void PNGAPI png_default_write_data PNGARG((png_structp png_ptr,
   3243    png_bytep data, png_size_t length)) PNG_PRIVATE;
   3244 
   3245 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   3246 #ifdef PNG_STDIO_SUPPORTED
   3247 PNG_EXTERN void PNGAPI png_default_flush PNGARG((png_structp png_ptr))
   3248    PNG_PRIVATE;
   3249 #endif
   3250 #endif
   3251 #else /* PNG_1_0_X */
   3252 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   3253 PNG_EXTERN void png_push_fill_buffer PNGARG((png_structp png_ptr,
   3254    png_bytep buffer, png_size_t length)) PNG_PRIVATE;
   3255 #endif
   3256 #endif /* PNG_1_0_X */
   3257 
   3258 /* Reset the CRC variable */
   3259 PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3260 
   3261 /* Write the "data" buffer to whatever output you are using. */
   3262 PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr, png_bytep data,
   3263    png_size_t length)) PNG_PRIVATE;
   3264 
   3265 /* Read data from whatever input you are using into the "data" buffer */
   3266 PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,
   3267    png_size_t length)) PNG_PRIVATE;
   3268 
   3269 #ifdef PNG_INDEX_SUPPORTED
   3270 PNG_EXTERN void png_seek_data PNGARG((png_structp png_ptr,
   3271    png_uint_32 length)) PNG_PRIVATE;
   3272 #endif
   3273 
   3274 /* Read bytes into buf, and update png_ptr->crc */
   3275 PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,
   3276    png_size_t length)) PNG_PRIVATE;
   3277 
   3278 /* Decompress data in a chunk that uses compression */
   3279 #if defined(PNG_zTXt_SUPPORTED) || defined(PNG_iTXt_SUPPORTED) || \
   3280     defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)
   3281 PNG_EXTERN void png_decompress_chunk PNGARG((png_structp png_ptr,
   3282    int comp_type, png_size_t chunklength,
   3283    png_size_t prefix_length, png_size_t *data_length)) PNG_PRIVATE;
   3284 #endif
   3285 
   3286 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
   3287 PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip)
   3288    PNG_PRIVATE);
   3289 
   3290 #ifdef PNG_INDEX_SUPPORTED
   3291 /* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
   3292 PNG_EXTERN int png_opt_crc_finish PNGARG((png_structp png_ptr,
   3293    png_uint_32 skip, int check_crc)
   3294    PNG_PRIVATE);
   3295 #endif
   3296 
   3297 /* Read the CRC from the file and compare it to the libpng calculated CRC */
   3298 PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3299 
   3300 /* Calculate the CRC over a section of data.  Note that we are only
   3301  * passing a maximum of 64K on systems that have this as a memory limit,
   3302  * since this is the maximum buffer size we can specify.
   3303  */
   3304 PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr, png_bytep ptr,
   3305    png_size_t length)) PNG_PRIVATE;
   3306 
   3307 #ifdef PNG_WRITE_FLUSH_SUPPORTED
   3308 PNG_EXTERN void png_flush PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3309 #endif
   3310 
   3311 /* Simple function to write the signature */
   3312 PNG_EXTERN void png_write_sig PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3313 
   3314 /* Write various chunks */
   3315 
   3316 /* Write the IHDR chunk, and update the png_struct with the necessary
   3317  * information.
   3318  */
   3319 PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,
   3320    png_uint_32 height,
   3321    int bit_depth, int color_type, int compression_method, int filter_method,
   3322    int interlace_method)) PNG_PRIVATE;
   3323 
   3324 PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr, png_colorp palette,
   3325    png_uint_32 num_pal)) PNG_PRIVATE;
   3326 
   3327 PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,
   3328    png_size_t length)) PNG_PRIVATE;
   3329 
   3330 PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3331 
   3332 #ifdef PNG_WRITE_gAMA_SUPPORTED
   3333 #ifdef PNG_FLOATING_POINT_SUPPORTED
   3334 PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma))
   3335     PNG_PRIVATE;
   3336 #endif
   3337 #ifdef PNG_FIXED_POINT_SUPPORTED
   3338 PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr,
   3339     png_fixed_point file_gamma)) PNG_PRIVATE;
   3340 #endif
   3341 #endif
   3342 
   3343 #ifdef PNG_WRITE_sBIT_SUPPORTED
   3344 PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr, png_color_8p sbit,
   3345    int color_type)) PNG_PRIVATE;
   3346 #endif
   3347 
   3348 #ifdef PNG_WRITE_cHRM_SUPPORTED
   3349 #ifdef PNG_FLOATING_POINT_SUPPORTED
   3350 PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,
   3351    double white_x, double white_y,
   3352    double red_x, double red_y, double green_x, double green_y,
   3353    double blue_x, double blue_y)) PNG_PRIVATE;
   3354 #endif
   3355 #ifdef PNG_FIXED_POINT_SUPPORTED
   3356 PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,
   3357    png_fixed_point int_white_x, png_fixed_point int_white_y,
   3358    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
   3359    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
   3360    png_fixed_point int_blue_y)) PNG_PRIVATE;
   3361 #endif
   3362 #endif
   3363 
   3364 #ifdef PNG_WRITE_sRGB_SUPPORTED
   3365 PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,
   3366    int intent)) PNG_PRIVATE;
   3367 #endif
   3368 
   3369 #ifdef PNG_WRITE_iCCP_SUPPORTED
   3370 PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,
   3371    png_charp name, int compression_type,
   3372    png_charp profile, int proflen)) PNG_PRIVATE;
   3373    /* Note to maintainer: profile should be png_bytep */
   3374 #endif
   3375 
   3376 #ifdef PNG_WRITE_sPLT_SUPPORTED
   3377 PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,
   3378    png_sPLT_tp palette)) PNG_PRIVATE;
   3379 #endif
   3380 
   3381 #ifdef PNG_WRITE_tRNS_SUPPORTED
   3382 PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr, png_bytep trans,
   3383    png_color_16p values, int number, int color_type)) PNG_PRIVATE;
   3384 #endif
   3385 
   3386 #ifdef PNG_WRITE_bKGD_SUPPORTED
   3387 PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,
   3388    png_color_16p values, int color_type)) PNG_PRIVATE;
   3389 #endif
   3390 
   3391 #ifdef PNG_WRITE_hIST_SUPPORTED
   3392 PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr, png_uint_16p hist,
   3393    int num_hist)) PNG_PRIVATE;
   3394 #endif
   3395 
   3396 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
   3397     defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
   3398 PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
   3399    png_charp key, png_charpp new_key)) PNG_PRIVATE;
   3400 #endif
   3401 
   3402 #ifdef PNG_WRITE_tEXt_SUPPORTED
   3403 PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_charp key,
   3404    png_charp text, png_size_t text_len)) PNG_PRIVATE;
   3405 #endif
   3406 
   3407 #ifdef PNG_WRITE_zTXt_SUPPORTED
   3408 PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_charp key,
   3409    png_charp text, png_size_t text_len, int compression)) PNG_PRIVATE;
   3410 #endif
   3411 
   3412 #ifdef PNG_WRITE_iTXt_SUPPORTED
   3413 PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,
   3414    int compression, png_charp key, png_charp lang, png_charp lang_key,
   3415    png_charp text)) PNG_PRIVATE;
   3416 #endif
   3417 
   3418 #ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
   3419 PNG_EXTERN int png_set_text_2 PNGARG((png_structp png_ptr,
   3420    png_infop info_ptr, png_textp text_ptr, int num_text)) PNG_PRIVATE;
   3421 #endif
   3422 
   3423 #ifdef PNG_WRITE_oFFs_SUPPORTED
   3424 PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,
   3425    png_int_32 x_offset, png_int_32 y_offset, int unit_type)) PNG_PRIVATE;
   3426 #endif
   3427 
   3428 #ifdef PNG_WRITE_pCAL_SUPPORTED
   3429 PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,
   3430    png_int_32 X0, png_int_32 X1, int type, int nparams,
   3431    png_charp units, png_charpp params)) PNG_PRIVATE;
   3432 #endif
   3433 
   3434 #ifdef PNG_WRITE_pHYs_SUPPORTED
   3435 PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,
   3436    png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
   3437    int unit_type)) PNG_PRIVATE;
   3438 #endif
   3439 
   3440 #ifdef PNG_WRITE_tIME_SUPPORTED
   3441 PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,
   3442    png_timep mod_time)) PNG_PRIVATE;
   3443 #endif
   3444 
   3445 #ifdef PNG_WRITE_sCAL_SUPPORTED
   3446 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
   3447 PNG_EXTERN void png_write_sCAL PNGARG((png_structp png_ptr,
   3448    int unit, double width, double height)) PNG_PRIVATE;
   3449 #else
   3450 #ifdef PNG_FIXED_POINT_SUPPORTED
   3451 PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,
   3452    int unit, png_charp width, png_charp height)) PNG_PRIVATE;
   3453 #endif
   3454 #endif
   3455 #endif
   3456 
   3457 /* Called when finished processing a row of data */
   3458 PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3459 
   3460 /* Internal use only.   Called before first row of data */
   3461 PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3462 
   3463 #ifdef PNG_READ_GAMMA_SUPPORTED
   3464 PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3465 #endif
   3466 
   3467 /* Combine a row of data, dealing with alpha, etc. if requested */
   3468 PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
   3469    int mask)) PNG_PRIVATE;
   3470 
   3471 #ifdef PNG_READ_INTERLACING_SUPPORTED
   3472 /* Expand an interlaced row */
   3473 /* OLD pre-1.0.9 interface:
   3474 PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
   3475    png_bytep row, int pass, png_uint_32 transformations)) PNG_PRIVATE;
   3476  */
   3477 PNG_EXTERN void png_do_read_interlace PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3478 #endif
   3479 
   3480 /* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
   3481 
   3482 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
   3483 /* Grab pixels out of a row for an interlaced pass */
   3484 PNG_EXTERN void png_do_write_interlace PNGARG((png_row_infop row_info,
   3485    png_bytep row, int pass)) PNG_PRIVATE;
   3486 #endif
   3487 
   3488 /* Unfilter a row */
   3489 PNG_EXTERN void png_read_filter_row PNGARG((png_structp png_ptr,
   3490    png_row_infop row_info, png_bytep row, png_bytep prev_row,
   3491    int filter)) PNG_PRIVATE;
   3492 
   3493 /* Choose the best filter to use and filter the row data */
   3494 PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
   3495    png_row_infop row_info)) PNG_PRIVATE;
   3496 
   3497 /* Write out the filtered row. */
   3498 PNG_EXTERN void png_write_filtered_row PNGARG((png_structp png_ptr,
   3499    png_bytep filtered_row)) PNG_PRIVATE;
   3500 /* Finish a row while reading, dealing with interlacing passes, etc. */
   3501 PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));
   3502 
   3503 #ifdef PNG_INDEX_SUPPORTED
   3504 /* Update the decoder status to the given pass */
   3505 PNG_EXTERN void png_set_interlaced_pass PNGARG((png_structp png_ptr, int pass));
   3506 #endif
   3507 
   3508 /* Initialize the row buffers, etc. */
   3509 PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3510 /* Optional call to update the users info structure */
   3511 PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
   3512    png_infop info_ptr)) PNG_PRIVATE;
   3513 
   3514 /* These are the functions that do the transformations */
   3515 #ifdef PNG_READ_FILLER_SUPPORTED
   3516 PNG_EXTERN void png_do_read_filler PNGARG((png_row_infop row_info,
   3517    png_bytep row, png_uint_32 filler, png_uint_32 flags)) PNG_PRIVATE;
   3518 #endif
   3519 
   3520 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
   3521 PNG_EXTERN void png_do_read_swap_alpha PNGARG((png_row_infop row_info,
   3522    png_bytep row)) PNG_PRIVATE;
   3523 #endif
   3524 
   3525 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
   3526 PNG_EXTERN void png_do_write_swap_alpha PNGARG((png_row_infop row_info,
   3527    png_bytep row)) PNG_PRIVATE;
   3528 #endif
   3529 
   3530 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
   3531 PNG_EXTERN void png_do_read_invert_alpha PNGARG((png_row_infop row_info,
   3532    png_bytep row)) PNG_PRIVATE;
   3533 #endif
   3534 
   3535 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
   3536 PNG_EXTERN void png_do_write_invert_alpha PNGARG((png_row_infop row_info,
   3537    png_bytep row)) PNG_PRIVATE;
   3538 #endif
   3539 
   3540 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
   3541     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
   3542 PNG_EXTERN void png_do_strip_filler PNGARG((png_row_infop row_info,
   3543    png_bytep row, png_uint_32 flags)) PNG_PRIVATE;
   3544 #endif
   3545 
   3546 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
   3547 PNG_EXTERN void png_do_swap PNGARG((png_row_infop row_info,
   3548     png_bytep row)) PNG_PRIVATE;
   3549 #endif
   3550 
   3551 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)
   3552 PNG_EXTERN void png_do_packswap PNGARG((png_row_infop row_info,
   3553     png_bytep row)) PNG_PRIVATE;
   3554 #endif
   3555 
   3556 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
   3557 PNG_EXTERN int png_do_rgb_to_gray PNGARG((png_structp png_ptr, png_row_infop
   3558    row_info, png_bytep row)) PNG_PRIVATE;
   3559 #endif
   3560 
   3561 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
   3562 PNG_EXTERN void png_do_gray_to_rgb PNGARG((png_row_infop row_info,
   3563    png_bytep row)) PNG_PRIVATE;
   3564 #endif
   3565 
   3566 #ifdef PNG_READ_PACK_SUPPORTED
   3567 PNG_EXTERN void png_do_unpack PNGARG((png_row_infop row_info,
   3568     png_bytep row)) PNG_PRIVATE;
   3569 #endif
   3570 
   3571 #ifdef PNG_READ_SHIFT_SUPPORTED
   3572 PNG_EXTERN void png_do_unshift PNGARG((png_row_infop row_info, png_bytep row,
   3573    png_color_8p sig_bits)) PNG_PRIVATE;
   3574 #endif
   3575 
   3576 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
   3577 PNG_EXTERN void png_do_invert PNGARG((png_row_infop row_info,
   3578     png_bytep row)) PNG_PRIVATE;
   3579 #endif
   3580 
   3581 #ifdef PNG_READ_16_TO_8_SUPPORTED
   3582 PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info,
   3583     png_bytep row)) PNG_PRIVATE;
   3584 #endif
   3585 
   3586 #ifdef PNG_READ_DITHER_SUPPORTED
   3587 PNG_EXTERN void png_do_dither PNGARG((png_row_infop row_info,
   3588    png_bytep row, png_bytep palette_lookup,
   3589     png_bytep dither_lookup)) PNG_PRIVATE;
   3590 
   3591 #  ifdef PNG_CORRECT_PALETTE_SUPPORTED
   3592 PNG_EXTERN void png_correct_palette PNGARG((png_structp png_ptr,
   3593    png_colorp palette, int num_palette)) PNG_PRIVATE;
   3594 #  endif
   3595 #endif
   3596 
   3597 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
   3598 PNG_EXTERN void png_do_bgr PNGARG((png_row_infop row_info,
   3599     png_bytep row)) PNG_PRIVATE;
   3600 #endif
   3601 
   3602 #ifdef PNG_WRITE_PACK_SUPPORTED
   3603 PNG_EXTERN void png_do_pack PNGARG((png_row_infop row_info,
   3604    png_bytep row, png_uint_32 bit_depth)) PNG_PRIVATE;
   3605 #endif
   3606 
   3607 #ifdef PNG_WRITE_SHIFT_SUPPORTED
   3608 PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info, png_bytep row,
   3609    png_color_8p bit_depth)) PNG_PRIVATE;
   3610 #endif
   3611 
   3612 #ifdef PNG_READ_BACKGROUND_SUPPORTED
   3613 #ifdef PNG_READ_GAMMA_SUPPORTED
   3614 PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,
   3615    png_color_16p trans_values, png_color_16p background,
   3616    png_color_16p background_1,
   3617    png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
   3618    png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
   3619    png_uint_16pp gamma_16_to_1, int gamma_shift)) PNG_PRIVATE;
   3620 #else
   3621 PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,
   3622    png_color_16p trans_values, png_color_16p background)) PNG_PRIVATE;
   3623 #endif
   3624 #endif
   3625 
   3626 #ifdef PNG_READ_GAMMA_SUPPORTED
   3627 PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info, png_bytep row,
   3628    png_bytep gamma_table, png_uint_16pp gamma_16_table,
   3629    int gamma_shift)) PNG_PRIVATE;
   3630 #endif
   3631 
   3632 #ifdef PNG_READ_EXPAND_SUPPORTED
   3633 PNG_EXTERN void png_do_expand_palette PNGARG((png_row_infop row_info,
   3634    png_bytep row, png_colorp palette, png_bytep trans,
   3635    int num_trans)) PNG_PRIVATE;
   3636 PNG_EXTERN void png_do_expand PNGARG((png_row_infop row_info,
   3637    png_bytep row, png_color_16p trans_value)) PNG_PRIVATE;
   3638 #endif
   3639 
   3640 /* The following decodes the appropriate chunks, and does error correction,
   3641  * then calls the appropriate callback for the chunk if it is valid.
   3642  */
   3643 
   3644 /* Decode the IHDR chunk */
   3645 PNG_EXTERN void png_handle_IHDR PNGARG((png_structp png_ptr, png_infop info_ptr,
   3646    png_uint_32 length)) PNG_PRIVATE;
   3647 PNG_EXTERN void png_handle_PLTE PNGARG((png_structp png_ptr, png_infop info_ptr,
   3648    png_uint_32 length));
   3649 PNG_EXTERN void png_handle_IEND PNGARG((png_structp png_ptr, png_infop info_ptr,
   3650    png_uint_32 length));
   3651 
   3652 #ifdef PNG_READ_bKGD_SUPPORTED
   3653 PNG_EXTERN void png_handle_bKGD PNGARG((png_structp png_ptr, png_infop info_ptr,
   3654    png_uint_32 length)) PNG_PRIVATE;
   3655 #endif
   3656 
   3657 #ifdef PNG_READ_cHRM_SUPPORTED
   3658 PNG_EXTERN void png_handle_cHRM PNGARG((png_structp png_ptr, png_infop info_ptr,
   3659    png_uint_32 length)) PNG_PRIVATE;
   3660 #endif
   3661 
   3662 #ifdef PNG_READ_gAMA_SUPPORTED
   3663 PNG_EXTERN void png_handle_gAMA PNGARG((png_structp png_ptr, png_infop info_ptr,
   3664    png_uint_32 length)) PNG_PRIVATE;
   3665 #endif
   3666 
   3667 #ifdef PNG_READ_hIST_SUPPORTED
   3668 PNG_EXTERN void png_handle_hIST PNGARG((png_structp png_ptr, png_infop info_ptr,
   3669    png_uint_32 length)) PNG_PRIVATE;
   3670 #endif
   3671 
   3672 #ifdef PNG_READ_iCCP_SUPPORTED
   3673 extern void png_handle_iCCP PNGARG((png_structp png_ptr, png_infop info_ptr,
   3674    png_uint_32 length));
   3675 #endif /* PNG_READ_iCCP_SUPPORTED */
   3676 
   3677 #ifdef PNG_READ_iTXt_SUPPORTED
   3678 PNG_EXTERN void png_handle_iTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
   3679    png_uint_32 length)) PNG_PRIVATE;
   3680 #endif
   3681 
   3682 #ifdef PNG_READ_oFFs_SUPPORTED
   3683 PNG_EXTERN void png_handle_oFFs PNGARG((png_structp png_ptr, png_infop info_ptr,
   3684    png_uint_32 length)) PNG_PRIVATE;
   3685 #endif
   3686 
   3687 #ifdef PNG_READ_pCAL_SUPPORTED
   3688 PNG_EXTERN void png_handle_pCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
   3689    png_uint_32 length)) PNG_PRIVATE;
   3690 #endif
   3691 
   3692 #ifdef PNG_READ_pHYs_SUPPORTED
   3693 PNG_EXTERN void png_handle_pHYs PNGARG((png_structp png_ptr, png_infop info_ptr,
   3694    png_uint_32 length)) PNG_PRIVATE;
   3695 #endif
   3696 
   3697 #ifdef PNG_READ_sBIT_SUPPORTED
   3698 PNG_EXTERN void png_handle_sBIT PNGARG((png_structp png_ptr, png_infop info_ptr,
   3699    png_uint_32 length)) PNG_PRIVATE;
   3700 #endif
   3701 
   3702 #ifdef PNG_READ_sCAL_SUPPORTED
   3703 PNG_EXTERN void png_handle_sCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
   3704    png_uint_32 length)) PNG_PRIVATE;
   3705 #endif
   3706 
   3707 #ifdef PNG_READ_sPLT_SUPPORTED
   3708 extern void png_handle_sPLT PNGARG((png_structp png_ptr, png_infop info_ptr,
   3709    png_uint_32 length)) PNG_PRIVATE;
   3710 #endif /* PNG_READ_sPLT_SUPPORTED */
   3711 
   3712 #ifdef PNG_READ_sRGB_SUPPORTED
   3713 PNG_EXTERN void png_handle_sRGB PNGARG((png_structp png_ptr, png_infop info_ptr,
   3714    png_uint_32 length)) PNG_PRIVATE;
   3715 #endif
   3716 
   3717 #ifdef PNG_READ_tEXt_SUPPORTED
   3718 PNG_EXTERN void png_handle_tEXt PNGARG((png_structp png_ptr, png_infop info_ptr,
   3719    png_uint_32 length)) PNG_PRIVATE;
   3720 #endif
   3721 
   3722 #ifdef PNG_READ_tIME_SUPPORTED
   3723 PNG_EXTERN void png_handle_tIME PNGARG((png_structp png_ptr, png_infop info_ptr,
   3724    png_uint_32 length)) PNG_PRIVATE;
   3725 #endif
   3726 
   3727 #ifdef PNG_READ_tRNS_SUPPORTED
   3728 PNG_EXTERN void png_handle_tRNS PNGARG((png_structp png_ptr, png_infop info_ptr,
   3729    png_uint_32 length)) PNG_PRIVATE;
   3730 #endif
   3731 
   3732 #ifdef PNG_READ_zTXt_SUPPORTED
   3733 PNG_EXTERN void png_handle_zTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
   3734    png_uint_32 length)) PNG_PRIVATE;
   3735 #endif
   3736 
   3737 PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,
   3738    png_infop info_ptr, png_uint_32 length)) PNG_PRIVATE;
   3739 
   3740 PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
   3741    png_bytep chunk_name)) PNG_PRIVATE;
   3742 
   3743 /* Handle the transformations for reading and writing */
   3744 PNG_EXTERN void png_do_read_transformations
   3745    PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3746 PNG_EXTERN void png_do_write_transformations
   3747    PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3748 
   3749 PNG_EXTERN void png_init_read_transformations
   3750    PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3751 
   3752 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
   3753 PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
   3754    png_infop info_ptr)) PNG_PRIVATE;
   3755 PNG_EXTERN void png_push_read_sig PNGARG((png_structp png_ptr,
   3756    png_infop info_ptr)) PNG_PRIVATE;
   3757 PNG_EXTERN void png_push_check_crc PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3758 PNG_EXTERN void png_push_crc_skip PNGARG((png_structp png_ptr,
   3759    png_uint_32 length)) PNG_PRIVATE;
   3760 PNG_EXTERN void png_push_crc_finish PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3761 PNG_EXTERN void png_push_save_buffer PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3762 PNG_EXTERN void png_push_restore_buffer PNGARG((png_structp png_ptr,
   3763    png_bytep buffer, png_size_t buffer_length)) PNG_PRIVATE;
   3764 PNG_EXTERN void png_push_read_IDAT PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3765 PNG_EXTERN void png_process_IDAT_data PNGARG((png_structp png_ptr,
   3766    png_bytep buffer, png_size_t buffer_length)) PNG_PRIVATE;
   3767 PNG_EXTERN void png_push_process_row PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3768 PNG_EXTERN void png_push_handle_unknown PNGARG((png_structp png_ptr,
   3769    png_infop info_ptr, png_uint_32 length)) PNG_PRIVATE;
   3770 PNG_EXTERN void png_push_have_info PNGARG((png_structp png_ptr,
   3771    png_infop info_ptr)) PNG_PRIVATE;
   3772 PNG_EXTERN void png_push_have_end PNGARG((png_structp png_ptr,
   3773    png_infop info_ptr)) PNG_PRIVATE;
   3774 PNG_EXTERN void png_push_have_row PNGARG((png_structp png_ptr,
   3775    png_bytep row)) PNG_PRIVATE;
   3776 PNG_EXTERN void png_push_read_end PNGARG((png_structp png_ptr,
   3777    png_infop info_ptr)) PNG_PRIVATE;
   3778 PNG_EXTERN void png_process_some_data PNGARG((png_structp png_ptr,
   3779    png_infop info_ptr)) PNG_PRIVATE;
   3780 PNG_EXTERN void png_read_push_finish_row
   3781    PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3782 #ifdef PNG_READ_tEXt_SUPPORTED
   3783 PNG_EXTERN void png_push_handle_tEXt PNGARG((png_structp png_ptr,
   3784    png_infop info_ptr, png_uint_32 length)) PNG_PRIVATE;
   3785 PNG_EXTERN void png_push_read_tEXt PNGARG((png_structp png_ptr,
   3786    png_infop info_ptr)) PNG_PRIVATE;
   3787 #endif
   3788 #ifdef PNG_READ_zTXt_SUPPORTED
   3789 PNG_EXTERN void png_push_handle_zTXt PNGARG((png_structp png_ptr,
   3790    png_infop info_ptr, png_uint_32 length)) PNG_PRIVATE;
   3791 PNG_EXTERN void png_push_read_zTXt PNGARG((png_structp png_ptr,
   3792    png_infop info_ptr)) PNG_PRIVATE;
   3793 #endif
   3794 #ifdef PNG_READ_iTXt_SUPPORTED
   3795 PNG_EXTERN void png_push_handle_iTXt PNGARG((png_structp png_ptr,
   3796    png_infop info_ptr, png_uint_32 length)) PNG_PRIVATE;
   3797 PNG_EXTERN void png_push_read_iTXt PNGARG((png_structp png_ptr,
   3798    png_infop info_ptr)) PNG_PRIVATE;
   3799 #endif
   3800 
   3801 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
   3802 
   3803 #ifdef PNG_MNG_FEATURES_SUPPORTED
   3804 PNG_EXTERN void png_do_read_intrapixel PNGARG((png_row_infop row_info,
   3805    png_bytep row)) PNG_PRIVATE;
   3806 PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,
   3807    png_bytep row)) PNG_PRIVATE;
   3808 #endif
   3809 
   3810 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
   3811 #ifdef PNG_MMX_CODE_SUPPORTED
   3812 /* png.c */ /* PRIVATE */
   3813 PNG_EXTERN void png_init_mmx_flags PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3814 #endif
   3815 #endif
   3816 
   3817 
   3818 /* The following six functions will be exported in libpng-1.4.0. */
   3819 #if defined(PNG_INCH_CONVERSIONS) && defined(PNG_FLOATING_POINT_SUPPORTED)
   3820 PNG_EXTERN png_uint_32 png_get_pixels_per_inch PNGARG((png_structp png_ptr,
   3821 png_infop info_ptr));
   3822 
   3823 PNG_EXTERN png_uint_32 png_get_x_pixels_per_inch PNGARG((png_structp png_ptr,
   3824 png_infop info_ptr));
   3825 
   3826 PNG_EXTERN png_uint_32 png_get_y_pixels_per_inch PNGARG((png_structp png_ptr,
   3827 png_infop info_ptr));
   3828 
   3829 PNG_EXTERN float png_get_x_offset_inches PNGARG((png_structp png_ptr,
   3830 png_infop info_ptr));
   3831 
   3832 PNG_EXTERN float png_get_y_offset_inches PNGARG((png_structp png_ptr,
   3833 png_infop info_ptr));
   3834 
   3835 #ifdef PNG_pHYs_SUPPORTED
   3836 PNG_EXTERN png_uint_32 png_get_pHYs_dpi PNGARG((png_structp png_ptr,
   3837 png_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
   3838 #endif /* PNG_pHYs_SUPPORTED */
   3839 #endif  /* PNG_INCH_CONVERSIONS && PNG_FLOATING_POINT_SUPPORTED */
   3840 
   3841 /* Read the chunk header (length + type name) */
   3842 PNG_EXTERN png_uint_32 png_read_chunk_header
   3843    PNGARG((png_structp png_ptr)) PNG_PRIVATE;
   3844 
   3845 /* Added at libpng version 1.2.34 */
   3846 #ifdef PNG_cHRM_SUPPORTED
   3847 PNG_EXTERN int png_check_cHRM_fixed PNGARG((png_structp png_ptr,
   3848    png_fixed_point int_white_x, png_fixed_point int_white_y,
   3849    png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
   3850    int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
   3851    png_fixed_point int_blue_y)) PNG_PRIVATE;
   3852 #endif
   3853 
   3854 #ifdef PNG_cHRM_SUPPORTED
   3855 #ifdef PNG_CHECK_cHRM_SUPPORTED
   3856 /* Added at libpng version 1.2.34 */
   3857 PNG_EXTERN void png_64bit_product PNGARG((long v1, long v2,
   3858    unsigned long *hi_product, unsigned long *lo_product)) PNG_PRIVATE;
   3859 #endif
   3860 #endif
   3861 
   3862 /* Added at libpng version 1.2.41 */
   3863 PNG_EXTERN void png_check_IHDR PNGARG((png_structp png_ptr,
   3864    png_uint_32 width, png_uint_32 height, int bit_depth,
   3865    int color_type, int interlace_type, int compression_type,
   3866    int filter_type)) PNG_PRIVATE;
   3867 
   3868 /* Added at libpng version 1.2.41 */
   3869 PNG_EXTERN png_voidp png_calloc PNGARG((png_structp png_ptr,
   3870    png_uint_32 size));
   3871 
   3872 /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
   3873 
   3874 #endif /* PNG_INTERNAL */
   3875 
   3876 #ifdef __cplusplus
   3877 }
   3878 #endif
   3879 
   3880 #endif /* PNG_VERSION_INFO_ONLY */
   3881 /* Do not put anything past this line */
   3882 #endif /* PNG_H */
   3883