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      1 /***************************************************************************/
      2 /*                                                                         */
      3 /*  ftimage.h                                                              */
      4 /*                                                                         */
      5 /*    FreeType glyph image formats and default raster interface            */
      6 /*    (specification).                                                     */
      7 /*                                                                         */
      8 /*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,   */
      9 /*            2010 by                                                      */
     10 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
     11 /*                                                                         */
     12 /*  This file is part of the FreeType project, and may only be used,       */
     13 /*  modified, and distributed under the terms of the FreeType project      */
     14 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
     15 /*  this file you indicate that you have read the license and              */
     16 /*  understand and accept it fully.                                        */
     17 /*                                                                         */
     18 /***************************************************************************/
     19 
     20   /*************************************************************************/
     21   /*                                                                       */
     22   /* Note: A `raster' is simply a scan-line converter, used to render      */
     23   /*       FT_Outlines into FT_Bitmaps.                                    */
     24   /*                                                                       */
     25   /*************************************************************************/
     26 
     27 
     28 #ifndef __FTIMAGE_H__
     29 #define __FTIMAGE_H__
     30 
     31 
     32   /* _STANDALONE_ is from ftgrays.c */
     33 #ifndef _STANDALONE_
     34 #include <ft2build.h>
     35 #endif
     36 
     37 
     38 FT_BEGIN_HEADER
     39 
     40 
     41   /*************************************************************************/
     42   /*                                                                       */
     43   /* <Section>                                                             */
     44   /*    basic_types                                                        */
     45   /*                                                                       */
     46   /*************************************************************************/
     47 
     48 
     49   /*************************************************************************/
     50   /*                                                                       */
     51   /* <Type>                                                                */
     52   /*    FT_Pos                                                             */
     53   /*                                                                       */
     54   /* <Description>                                                         */
     55   /*    The type FT_Pos is used to store vectorial coordinates.  Depending */
     56   /*    on the context, these can represent distances in integer font      */
     57   /*    units, or 16.16, or 26.6 fixed float pixel coordinates.            */
     58   /*                                                                       */
     59   typedef signed long  FT_Pos;
     60 
     61 
     62   /*************************************************************************/
     63   /*                                                                       */
     64   /* <Struct>                                                              */
     65   /*    FT_Vector                                                          */
     66   /*                                                                       */
     67   /* <Description>                                                         */
     68   /*    A simple structure used to store a 2D vector; coordinates are of   */
     69   /*    the FT_Pos type.                                                   */
     70   /*                                                                       */
     71   /* <Fields>                                                              */
     72   /*    x :: The horizontal coordinate.                                    */
     73   /*    y :: The vertical coordinate.                                      */
     74   /*                                                                       */
     75   typedef struct  FT_Vector_
     76   {
     77     FT_Pos  x;
     78     FT_Pos  y;
     79 
     80   } FT_Vector;
     81 
     82 
     83   /*************************************************************************/
     84   /*                                                                       */
     85   /* <Struct>                                                              */
     86   /*    FT_BBox                                                            */
     87   /*                                                                       */
     88   /* <Description>                                                         */
     89   /*    A structure used to hold an outline's bounding box, i.e., the      */
     90   /*    coordinates of its extrema in the horizontal and vertical          */
     91   /*    directions.                                                        */
     92   /*                                                                       */
     93   /* <Fields>                                                              */
     94   /*    xMin :: The horizontal minimum (left-most).                        */
     95   /*                                                                       */
     96   /*    yMin :: The vertical minimum (bottom-most).                        */
     97   /*                                                                       */
     98   /*    xMax :: The horizontal maximum (right-most).                       */
     99   /*                                                                       */
    100   /*    yMax :: The vertical maximum (top-most).                           */
    101   /*                                                                       */
    102   /* <Note>                                                                */
    103   /*    The bounding box is specified with the coordinates of the lower    */
    104   /*    left and the upper right corner.  In PostScript, those values are  */
    105   /*    often called (llx,lly) and (urx,ury), respectively.                */
    106   /*                                                                       */
    107   /*    If `yMin' is negative, this value gives the glyph's descender.     */
    108   /*    Otherwise, the glyph doesn't descend below the baseline.           */
    109   /*    Similarly, if `ymax' is positive, this value gives the glyph's     */
    110   /*    ascender.                                                          */
    111   /*                                                                       */
    112   /*    `xMin' gives the horizontal distance from the glyph's origin to    */
    113   /*    the left edge of the glyph's bounding box.  If `xMin' is negative, */
    114   /*    the glyph extends to the left of the origin.                       */
    115   /*                                                                       */
    116   typedef struct  FT_BBox_
    117   {
    118     FT_Pos  xMin, yMin;
    119     FT_Pos  xMax, yMax;
    120 
    121   } FT_BBox;
    122 
    123 
    124   /*************************************************************************/
    125   /*                                                                       */
    126   /* <Enum>                                                                */
    127   /*    FT_Pixel_Mode                                                      */
    128   /*                                                                       */
    129   /* <Description>                                                         */
    130   /*    An enumeration type used to describe the format of pixels in a     */
    131   /*    given bitmap.  Note that additional formats may be added in the    */
    132   /*    future.                                                            */
    133   /*                                                                       */
    134   /* <Values>                                                              */
    135   /*    FT_PIXEL_MODE_NONE ::                                              */
    136   /*      Value~0 is reserved.                                             */
    137   /*                                                                       */
    138   /*    FT_PIXEL_MODE_MONO ::                                              */
    139   /*      A monochrome bitmap, using 1~bit per pixel.  Note that pixels    */
    140   /*      are stored in most-significant order (MSB), which means that     */
    141   /*      the left-most pixel in a byte has value 128.                     */
    142   /*                                                                       */
    143   /*    FT_PIXEL_MODE_GRAY ::                                              */
    144   /*      An 8-bit bitmap, generally used to represent anti-aliased glyph  */
    145   /*      images.  Each pixel is stored in one byte.  Note that the number */
    146   /*      of `gray' levels is stored in the `num_grays' field of the       */
    147   /*      @FT_Bitmap structure (it generally is 256).                      */
    148   /*                                                                       */
    149   /*    FT_PIXEL_MODE_GRAY2 ::                                             */
    150   /*      A 2-bit per pixel bitmap, used to represent embedded             */
    151   /*      anti-aliased bitmaps in font files according to the OpenType     */
    152   /*      specification.  We haven't found a single font using this        */
    153   /*      format, however.                                                 */
    154   /*                                                                       */
    155   /*    FT_PIXEL_MODE_GRAY4 ::                                             */
    156   /*      A 4-bit per pixel bitmap, representing embedded anti-aliased     */
    157   /*      bitmaps in font files according to the OpenType specification.   */
    158   /*      We haven't found a single font using this format, however.       */
    159   /*                                                                       */
    160   /*    FT_PIXEL_MODE_LCD ::                                               */
    161   /*      An 8-bit bitmap, representing RGB or BGR decimated glyph images  */
    162   /*      used for display on LCD displays; the bitmap is three times      */
    163   /*      wider than the original glyph image.  See also                   */
    164   /*      @FT_RENDER_MODE_LCD.                                             */
    165   /*                                                                       */
    166   /*    FT_PIXEL_MODE_LCD_V ::                                             */
    167   /*      An 8-bit bitmap, representing RGB or BGR decimated glyph images  */
    168   /*      used for display on rotated LCD displays; the bitmap is three    */
    169   /*      times taller than the original glyph image.  See also            */
    170   /*      @FT_RENDER_MODE_LCD_V.                                           */
    171   /*                                                                       */
    172   typedef enum  FT_Pixel_Mode_
    173   {
    174     FT_PIXEL_MODE_NONE = 0,
    175     FT_PIXEL_MODE_MONO,
    176     FT_PIXEL_MODE_GRAY,
    177     FT_PIXEL_MODE_GRAY2,
    178     FT_PIXEL_MODE_GRAY4,
    179     FT_PIXEL_MODE_LCD,
    180     FT_PIXEL_MODE_LCD_V,
    181 
    182     FT_PIXEL_MODE_MAX      /* do not remove */
    183 
    184   } FT_Pixel_Mode;
    185 
    186 
    187   /*************************************************************************/
    188   /*                                                                       */
    189   /* <Enum>                                                                */
    190   /*    ft_pixel_mode_xxx                                                  */
    191   /*                                                                       */
    192   /* <Description>                                                         */
    193   /*    A list of deprecated constants.  Use the corresponding             */
    194   /*    @FT_Pixel_Mode values instead.                                     */
    195   /*                                                                       */
    196   /* <Values>                                                              */
    197   /*    ft_pixel_mode_none  :: See @FT_PIXEL_MODE_NONE.                    */
    198   /*    ft_pixel_mode_mono  :: See @FT_PIXEL_MODE_MONO.                    */
    199   /*    ft_pixel_mode_grays :: See @FT_PIXEL_MODE_GRAY.                    */
    200   /*    ft_pixel_mode_pal2  :: See @FT_PIXEL_MODE_GRAY2.                   */
    201   /*    ft_pixel_mode_pal4  :: See @FT_PIXEL_MODE_GRAY4.                   */
    202   /*                                                                       */
    203 #define ft_pixel_mode_none   FT_PIXEL_MODE_NONE
    204 #define ft_pixel_mode_mono   FT_PIXEL_MODE_MONO
    205 #define ft_pixel_mode_grays  FT_PIXEL_MODE_GRAY
    206 #define ft_pixel_mode_pal2   FT_PIXEL_MODE_GRAY2
    207 #define ft_pixel_mode_pal4   FT_PIXEL_MODE_GRAY4
    208 
    209  /* */
    210 
    211 #if 0
    212 
    213   /*************************************************************************/
    214   /*                                                                       */
    215   /* <Enum>                                                                */
    216   /*    FT_Palette_Mode                                                    */
    217   /*                                                                       */
    218   /* <Description>                                                         */
    219   /*    THIS TYPE IS DEPRECATED.  DO NOT USE IT!                           */
    220   /*                                                                       */
    221   /*    An enumeration type to describe the format of a bitmap palette,    */
    222   /*    used with ft_pixel_mode_pal4 and ft_pixel_mode_pal8.               */
    223   /*                                                                       */
    224   /* <Values>                                                              */
    225   /*    ft_palette_mode_rgb  :: The palette is an array of 3-byte RGB      */
    226   /*                            records.                                   */
    227   /*                                                                       */
    228   /*    ft_palette_mode_rgba :: The palette is an array of 4-byte RGBA     */
    229   /*                            records.                                   */
    230   /*                                                                       */
    231   /* <Note>                                                                */
    232   /*    As ft_pixel_mode_pal2, pal4 and pal8 are currently unused by       */
    233   /*    FreeType, these types are not handled by the library itself.       */
    234   /*                                                                       */
    235   typedef enum  FT_Palette_Mode_
    236   {
    237     ft_palette_mode_rgb = 0,
    238     ft_palette_mode_rgba,
    239 
    240     ft_palette_mode_max   /* do not remove */
    241 
    242   } FT_Palette_Mode;
    243 
    244   /* */
    245 
    246 #endif
    247 
    248 
    249   /*************************************************************************/
    250   /*                                                                       */
    251   /* <Struct>                                                              */
    252   /*    FT_Bitmap                                                          */
    253   /*                                                                       */
    254   /* <Description>                                                         */
    255   /*    A structure used to describe a bitmap or pixmap to the raster.     */
    256   /*    Note that we now manage pixmaps of various depths through the      */
    257   /*    `pixel_mode' field.                                                */
    258   /*                                                                       */
    259   /* <Fields>                                                              */
    260   /*    rows         :: The number of bitmap rows.                         */
    261   /*                                                                       */
    262   /*    width        :: The number of pixels in bitmap row.                */
    263   /*                                                                       */
    264   /*    pitch        :: The pitch's absolute value is the number of bytes  */
    265   /*                    taken by one bitmap row, including padding.        */
    266   /*                    However, the pitch is positive when the bitmap has */
    267   /*                    a `down' flow, and negative when it has an `up'    */
    268   /*                    flow.  In all cases, the pitch is an offset to add */
    269   /*                    to a bitmap pointer in order to go down one row.   */
    270   /*                                                                       */
    271   /*                    For the B/W rasterizer, `pitch' is always an even  */
    272   /*                    number.                                            */
    273   /*                                                                       */
    274   /*    buffer       :: A typeless pointer to the bitmap buffer.  This     */
    275   /*                    value should be aligned on 32-bit boundaries in    */
    276   /*                    most cases.                                        */
    277   /*                                                                       */
    278   /*    num_grays    :: This field is only used with                       */
    279   /*                    @FT_PIXEL_MODE_GRAY; it gives the number of gray   */
    280   /*                    levels used in the bitmap.                         */
    281   /*                                                                       */
    282   /*    pixel_mode   :: The pixel mode, i.e., how pixel bits are stored.   */
    283   /*                    See @FT_Pixel_Mode for possible values.            */
    284   /*                                                                       */
    285   /*    palette_mode :: This field is intended for paletted pixel modes;   */
    286   /*                    it indicates how the palette is stored.  Not       */
    287   /*                    used currently.                                    */
    288   /*                                                                       */
    289   /*    palette      :: A typeless pointer to the bitmap palette; this     */
    290   /*                    field is intended for paletted pixel modes.  Not   */
    291   /*                    used currently.                                    */
    292   /*                                                                       */
    293   /* <Note>                                                                */
    294   /*   For now, the only pixel modes supported by FreeType are mono and    */
    295   /*   grays.  However, drivers might be added in the future to support    */
    296   /*   more `colorful' options.                                            */
    297   /*                                                                       */
    298   typedef struct  FT_Bitmap_
    299   {
    300     int             rows;
    301     int             width;
    302     int             pitch;
    303     unsigned char*  buffer;
    304     short           num_grays;
    305     char            pixel_mode;
    306     char            palette_mode;
    307     void*           palette;
    308 
    309   } FT_Bitmap;
    310 
    311 
    312   /*************************************************************************/
    313   /*                                                                       */
    314   /* <Section>                                                             */
    315   /*    outline_processing                                                 */
    316   /*                                                                       */
    317   /*************************************************************************/
    318 
    319 
    320   /*************************************************************************/
    321   /*                                                                       */
    322   /* <Struct>                                                              */
    323   /*    FT_Outline                                                         */
    324   /*                                                                       */
    325   /* <Description>                                                         */
    326   /*    This structure is used to describe an outline to the scan-line     */
    327   /*    converter.                                                         */
    328   /*                                                                       */
    329   /* <Fields>                                                              */
    330   /*    n_contours :: The number of contours in the outline.               */
    331   /*                                                                       */
    332   /*    n_points   :: The number of points in the outline.                 */
    333   /*                                                                       */
    334   /*    points     :: A pointer to an array of `n_points' @FT_Vector       */
    335   /*                  elements, giving the outline's point coordinates.    */
    336   /*                                                                       */
    337   /*    tags       :: A pointer to an array of `n_points' chars, giving    */
    338   /*                  each outline point's type.                           */
    339   /*                                                                       */
    340   /*                  If bit~0 is unset, the point is `off' the curve,     */
    341   /*                  i.e., a Bzier control point, while it is `on' if    */
    342   /*                  set.                                                 */
    343   /*                                                                       */
    344   /*                  Bit~1 is meaningful for `off' points only.  If set,  */
    345   /*                  it indicates a third-order Bzier arc control point; */
    346   /*                  and a second-order control point if unset.           */
    347   /*                                                                       */
    348   /*                  If bit~2 is set, bits 5-7 contain the drop-out mode  */
    349   /*                  (as defined in the OpenType specification; the value */
    350   /*                  is the same as the argument to the SCANMODE          */
    351   /*                  instruction).                                        */
    352   /*                                                                       */
    353   /*                  Bits 3 and~4 are reserved for internal purposes.     */
    354   /*                                                                       */
    355   /*    contours   :: An array of `n_contours' shorts, giving the end      */
    356   /*                  point of each contour within the outline.  For       */
    357   /*                  example, the first contour is defined by the points  */
    358   /*                  `0' to `contours[0]', the second one is defined by   */
    359   /*                  the points `contours[0]+1' to `contours[1]', etc.    */
    360   /*                                                                       */
    361   /*    flags      :: A set of bit flags used to characterize the outline  */
    362   /*                  and give hints to the scan-converter and hinter on   */
    363   /*                  how to convert/grid-fit it.  See @FT_OUTLINE_FLAGS.  */
    364   /*                                                                       */
    365   /* <Note>                                                                */
    366   /*    The B/W rasterizer only checks bit~2 in the `tags' array for the   */
    367   /*    first point of each contour.  The drop-out mode as given with      */
    368   /*    @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and       */
    369   /*    @FT_OUTLINE_INCLUDE_STUBS in `flags' is then overridden.           */
    370   /*                                                                       */
    371   typedef struct  FT_Outline_
    372   {
    373     short       n_contours;      /* number of contours in glyph        */
    374     short       n_points;        /* number of points in the glyph      */
    375 
    376     FT_Vector*  points;          /* the outline's points               */
    377     char*       tags;            /* the points flags                   */
    378     short*      contours;        /* the contour end points             */
    379 
    380     int         flags;           /* outline masks                      */
    381 
    382   } FT_Outline;
    383 
    384   /* Following limits must be consistent with */
    385   /* FT_Outline.{n_contours,n_points}         */
    386 #define FT_OUTLINE_CONTOURS_MAX  SHRT_MAX
    387 #define FT_OUTLINE_POINTS_MAX    SHRT_MAX
    388 
    389 
    390   /*************************************************************************/
    391   /*                                                                       */
    392   /* <Enum>                                                                */
    393   /*    FT_OUTLINE_FLAGS                                                   */
    394   /*                                                                       */
    395   /* <Description>                                                         */
    396   /*    A list of bit-field constants use for the flags in an outline's    */
    397   /*    `flags' field.                                                     */
    398   /*                                                                       */
    399   /* <Values>                                                              */
    400   /*    FT_OUTLINE_NONE ::                                                 */
    401   /*      Value~0 is reserved.                                             */
    402   /*                                                                       */
    403   /*    FT_OUTLINE_OWNER ::                                                */
    404   /*      If set, this flag indicates that the outline's field arrays      */
    405   /*      (i.e., `points', `flags', and `contours') are `owned' by the     */
    406   /*      outline object, and should thus be freed when it is destroyed.   */
    407   /*                                                                       */
    408   /*    FT_OUTLINE_EVEN_ODD_FILL ::                                        */
    409   /*      By default, outlines are filled using the non-zero winding rule. */
    410   /*      If set to 1, the outline will be filled using the even-odd fill  */
    411   /*      rule (only works with the smooth rasterizer).                    */
    412   /*                                                                       */
    413   /*    FT_OUTLINE_REVERSE_FILL ::                                         */
    414   /*      By default, outside contours of an outline are oriented in       */
    415   /*      clock-wise direction, as defined in the TrueType specification.  */
    416   /*      This flag is set if the outline uses the opposite direction      */
    417   /*      (typically for Type~1 fonts).  This flag is ignored by the scan  */
    418   /*      converter.                                                       */
    419   /*                                                                       */
    420   /*    FT_OUTLINE_IGNORE_DROPOUTS ::                                      */
    421   /*      By default, the scan converter will try to detect drop-outs in   */
    422   /*      an outline and correct the glyph bitmap to ensure consistent     */
    423   /*      shape continuity.  If set, this flag hints the scan-line         */
    424   /*      converter to ignore such cases.  See below for more information. */
    425   /*                                                                       */
    426   /*    FT_OUTLINE_SMART_DROPOUTS ::                                       */
    427   /*      Select smart dropout control.  If unset, use simple dropout      */
    428   /*      control.  Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set.  See    */
    429   /*      below for more information.                                      */
    430   /*                                                                       */
    431   /*    FT_OUTLINE_INCLUDE_STUBS ::                                        */
    432   /*      If set, turn pixels on for `stubs', otherwise exclude them.      */
    433   /*      Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set.  See below for    */
    434   /*      more information.                                                */
    435   /*                                                                       */
    436   /*    FT_OUTLINE_HIGH_PRECISION ::                                       */
    437   /*      This flag indicates that the scan-line converter should try to   */
    438   /*      convert this outline to bitmaps with the highest possible        */
    439   /*      quality.  It is typically set for small character sizes.  Note   */
    440   /*      that this is only a hint that might be completely ignored by a   */
    441   /*      given scan-converter.                                            */
    442   /*                                                                       */
    443   /*    FT_OUTLINE_SINGLE_PASS ::                                          */
    444   /*      This flag is set to force a given scan-converter to only use a   */
    445   /*      single pass over the outline to render a bitmap glyph image.     */
    446   /*      Normally, it is set for very large character sizes.  It is only  */
    447   /*      a hint that might be completely ignored by a given               */
    448   /*      scan-converter.                                                  */
    449   /*                                                                       */
    450   /* <Note>                                                                */
    451   /*    The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, */
    452   /*    and @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth            */
    453   /*    rasterizer.                                                        */
    454   /*                                                                       */
    455   /*    There exists a second mechanism to pass the drop-out mode to the   */
    456   /*    B/W rasterizer; see the `tags' field in @FT_Outline.               */
    457   /*                                                                       */
    458   /*    Please refer to the description of the `SCANTYPE' instruction in   */
    459   /*    the OpenType specification (in file `ttinst1.doc') how simple      */
    460   /*    drop-outs, smart drop-outs, and stubs are defined.                 */
    461   /*                                                                       */
    462 #define FT_OUTLINE_NONE             0x0
    463 #define FT_OUTLINE_OWNER            0x1
    464 #define FT_OUTLINE_EVEN_ODD_FILL    0x2
    465 #define FT_OUTLINE_REVERSE_FILL     0x4
    466 #define FT_OUTLINE_IGNORE_DROPOUTS  0x8
    467 #define FT_OUTLINE_SMART_DROPOUTS   0x10
    468 #define FT_OUTLINE_INCLUDE_STUBS    0x20
    469 
    470 #define FT_OUTLINE_HIGH_PRECISION   0x100
    471 #define FT_OUTLINE_SINGLE_PASS      0x200
    472 
    473 
    474  /*************************************************************************
    475   *
    476   * @enum:
    477   *   ft_outline_flags
    478   *
    479   * @description:
    480   *   These constants are deprecated.  Please use the corresponding
    481   *   @FT_OUTLINE_FLAGS values.
    482   *
    483   * @values:
    484   *   ft_outline_none            :: See @FT_OUTLINE_NONE.
    485   *   ft_outline_owner           :: See @FT_OUTLINE_OWNER.
    486   *   ft_outline_even_odd_fill   :: See @FT_OUTLINE_EVEN_ODD_FILL.
    487   *   ft_outline_reverse_fill    :: See @FT_OUTLINE_REVERSE_FILL.
    488   *   ft_outline_ignore_dropouts :: See @FT_OUTLINE_IGNORE_DROPOUTS.
    489   *   ft_outline_high_precision  :: See @FT_OUTLINE_HIGH_PRECISION.
    490   *   ft_outline_single_pass     :: See @FT_OUTLINE_SINGLE_PASS.
    491   */
    492 #define ft_outline_none             FT_OUTLINE_NONE
    493 #define ft_outline_owner            FT_OUTLINE_OWNER
    494 #define ft_outline_even_odd_fill    FT_OUTLINE_EVEN_ODD_FILL
    495 #define ft_outline_reverse_fill     FT_OUTLINE_REVERSE_FILL
    496 #define ft_outline_ignore_dropouts  FT_OUTLINE_IGNORE_DROPOUTS
    497 #define ft_outline_high_precision   FT_OUTLINE_HIGH_PRECISION
    498 #define ft_outline_single_pass      FT_OUTLINE_SINGLE_PASS
    499 
    500   /* */
    501 
    502 #define FT_CURVE_TAG( flag )  ( flag & 3 )
    503 
    504 #define FT_CURVE_TAG_ON            1
    505 #define FT_CURVE_TAG_CONIC         0
    506 #define FT_CURVE_TAG_CUBIC         2
    507 
    508 #define FT_CURVE_TAG_HAS_SCANMODE  4
    509 
    510 #define FT_CURVE_TAG_TOUCH_X       8  /* reserved for the TrueType hinter */
    511 #define FT_CURVE_TAG_TOUCH_Y      16  /* reserved for the TrueType hinter */
    512 
    513 #define FT_CURVE_TAG_TOUCH_BOTH    ( FT_CURVE_TAG_TOUCH_X | \
    514                                      FT_CURVE_TAG_TOUCH_Y )
    515 
    516 #define FT_Curve_Tag_On       FT_CURVE_TAG_ON
    517 #define FT_Curve_Tag_Conic    FT_CURVE_TAG_CONIC
    518 #define FT_Curve_Tag_Cubic    FT_CURVE_TAG_CUBIC
    519 #define FT_Curve_Tag_Touch_X  FT_CURVE_TAG_TOUCH_X
    520 #define FT_Curve_Tag_Touch_Y  FT_CURVE_TAG_TOUCH_Y
    521 
    522 
    523   /*************************************************************************/
    524   /*                                                                       */
    525   /* <FuncType>                                                            */
    526   /*    FT_Outline_MoveToFunc                                              */
    527   /*                                                                       */
    528   /* <Description>                                                         */
    529   /*    A function pointer type used to describe the signature of a `move  */
    530   /*    to' function during outline walking/decomposition.                 */
    531   /*                                                                       */
    532   /*    A `move to' is emitted to start a new contour in an outline.       */
    533   /*                                                                       */
    534   /* <Input>                                                               */
    535   /*    to   :: A pointer to the target point of the `move to'.            */
    536   /*                                                                       */
    537   /*    user :: A typeless pointer which is passed from the caller of the  */
    538   /*            decomposition function.                                    */
    539   /*                                                                       */
    540   /* <Return>                                                              */
    541   /*    Error code.  0~means success.                                      */
    542   /*                                                                       */
    543   typedef int
    544   (*FT_Outline_MoveToFunc)( const FT_Vector*  to,
    545                             void*             user );
    546 
    547 #define FT_Outline_MoveTo_Func  FT_Outline_MoveToFunc
    548 
    549 
    550   /*************************************************************************/
    551   /*                                                                       */
    552   /* <FuncType>                                                            */
    553   /*    FT_Outline_LineToFunc                                              */
    554   /*                                                                       */
    555   /* <Description>                                                         */
    556   /*    A function pointer type used to describe the signature of a `line  */
    557   /*    to' function during outline walking/decomposition.                 */
    558   /*                                                                       */
    559   /*    A `line to' is emitted to indicate a segment in the outline.       */
    560   /*                                                                       */
    561   /* <Input>                                                               */
    562   /*    to   :: A pointer to the target point of the `line to'.            */
    563   /*                                                                       */
    564   /*    user :: A typeless pointer which is passed from the caller of the  */
    565   /*            decomposition function.                                    */
    566   /*                                                                       */
    567   /* <Return>                                                              */
    568   /*    Error code.  0~means success.                                      */
    569   /*                                                                       */
    570   typedef int
    571   (*FT_Outline_LineToFunc)( const FT_Vector*  to,
    572                             void*             user );
    573 
    574 #define FT_Outline_LineTo_Func  FT_Outline_LineToFunc
    575 
    576 
    577   /*************************************************************************/
    578   /*                                                                       */
    579   /* <FuncType>                                                            */
    580   /*    FT_Outline_ConicToFunc                                             */
    581   /*                                                                       */
    582   /* <Description>                                                         */
    583   /*    A function pointer type used to describe the signature of a `conic */
    584   /*    to' function during outline walking or decomposition.              */
    585   /*                                                                       */
    586   /*    A `conic to' is emitted to indicate a second-order Bzier arc in   */
    587   /*    the outline.                                                       */
    588   /*                                                                       */
    589   /* <Input>                                                               */
    590   /*    control :: An intermediate control point between the last position */
    591   /*               and the new target in `to'.                             */
    592   /*                                                                       */
    593   /*    to      :: A pointer to the target end point of the conic arc.     */
    594   /*                                                                       */
    595   /*    user    :: A typeless pointer which is passed from the caller of   */
    596   /*               the decomposition function.                             */
    597   /*                                                                       */
    598   /* <Return>                                                              */
    599   /*    Error code.  0~means success.                                      */
    600   /*                                                                       */
    601   typedef int
    602   (*FT_Outline_ConicToFunc)( const FT_Vector*  control,
    603                              const FT_Vector*  to,
    604                              void*             user );
    605 
    606 #define FT_Outline_ConicTo_Func  FT_Outline_ConicToFunc
    607 
    608 
    609   /*************************************************************************/
    610   /*                                                                       */
    611   /* <FuncType>                                                            */
    612   /*    FT_Outline_CubicToFunc                                             */
    613   /*                                                                       */
    614   /* <Description>                                                         */
    615   /*    A function pointer type used to describe the signature of a `cubic */
    616   /*    to' function during outline walking or decomposition.              */
    617   /*                                                                       */
    618   /*    A `cubic to' is emitted to indicate a third-order Bzier arc.      */
    619   /*                                                                       */
    620   /* <Input>                                                               */
    621   /*    control1 :: A pointer to the first Bzier control point.           */
    622   /*                                                                       */
    623   /*    control2 :: A pointer to the second Bzier control point.          */
    624   /*                                                                       */
    625   /*    to       :: A pointer to the target end point.                     */
    626   /*                                                                       */
    627   /*    user     :: A typeless pointer which is passed from the caller of  */
    628   /*                the decomposition function.                            */
    629   /*                                                                       */
    630   /* <Return>                                                              */
    631   /*    Error code.  0~means success.                                      */
    632   /*                                                                       */
    633   typedef int
    634   (*FT_Outline_CubicToFunc)( const FT_Vector*  control1,
    635                              const FT_Vector*  control2,
    636                              const FT_Vector*  to,
    637                              void*             user );
    638 
    639 #define FT_Outline_CubicTo_Func  FT_Outline_CubicToFunc
    640 
    641 
    642   /*************************************************************************/
    643   /*                                                                       */
    644   /* <Struct>                                                              */
    645   /*    FT_Outline_Funcs                                                   */
    646   /*                                                                       */
    647   /* <Description>                                                         */
    648   /*    A structure to hold various function pointers used during outline  */
    649   /*    decomposition in order to emit segments, conic, and cubic Bziers. */
    650   /*                                                                       */
    651   /* <Fields>                                                              */
    652   /*    move_to  :: The `move to' emitter.                                 */
    653   /*                                                                       */
    654   /*    line_to  :: The segment emitter.                                   */
    655   /*                                                                       */
    656   /*    conic_to :: The second-order Bzier arc emitter.                   */
    657   /*                                                                       */
    658   /*    cubic_to :: The third-order Bzier arc emitter.                    */
    659   /*                                                                       */
    660   /*    shift    :: The shift that is applied to coordinates before they   */
    661   /*                are sent to the emitter.                               */
    662   /*                                                                       */
    663   /*    delta    :: The delta that is applied to coordinates before they   */
    664   /*                are sent to the emitter, but after the shift.          */
    665   /*                                                                       */
    666   /* <Note>                                                                */
    667   /*    The point coordinates sent to the emitters are the transformed     */
    668   /*    version of the original coordinates (this is important for high    */
    669   /*    accuracy during scan-conversion).  The transformation is simple:   */
    670   /*                                                                       */
    671   /*    {                                                                  */
    672   /*      x' = (x << shift) - delta                                        */
    673   /*      y' = (x << shift) - delta                                        */
    674   /*    }                                                                  */
    675   /*                                                                       */
    676   /*    Set the values of `shift' and `delta' to~0 to get the original     */
    677   /*    point coordinates.                                                 */
    678   /*                                                                       */
    679   typedef struct  FT_Outline_Funcs_
    680   {
    681     FT_Outline_MoveToFunc   move_to;
    682     FT_Outline_LineToFunc   line_to;
    683     FT_Outline_ConicToFunc  conic_to;
    684     FT_Outline_CubicToFunc  cubic_to;
    685 
    686     int                     shift;
    687     FT_Pos                  delta;
    688 
    689   } FT_Outline_Funcs;
    690 
    691 
    692   /*************************************************************************/
    693   /*                                                                       */
    694   /* <Section>                                                             */
    695   /*    basic_types                                                        */
    696   /*                                                                       */
    697   /*************************************************************************/
    698 
    699 
    700   /*************************************************************************/
    701   /*                                                                       */
    702   /* <Macro>                                                               */
    703   /*    FT_IMAGE_TAG                                                       */
    704   /*                                                                       */
    705   /* <Description>                                                         */
    706   /*    This macro converts four-letter tags to an unsigned long type.     */
    707   /*                                                                       */
    708   /* <Note>                                                                */
    709   /*    Since many 16-bit compilers don't like 32-bit enumerations, you    */
    710   /*    should redefine this macro in case of problems to something like   */
    711   /*    this:                                                              */
    712   /*                                                                       */
    713   /*    {                                                                  */
    714   /*      #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 )  value         */
    715   /*    }                                                                  */
    716   /*                                                                       */
    717   /*    to get a simple enumeration without assigning special numbers.     */
    718   /*                                                                       */
    719 #ifndef FT_IMAGE_TAG
    720 #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 )  \
    721           value = ( ( (unsigned long)_x1 << 24 ) | \
    722                     ( (unsigned long)_x2 << 16 ) | \
    723                     ( (unsigned long)_x3 << 8  ) | \
    724                       (unsigned long)_x4         )
    725 #endif /* FT_IMAGE_TAG */
    726 
    727 
    728   /*************************************************************************/
    729   /*                                                                       */
    730   /* <Enum>                                                                */
    731   /*    FT_Glyph_Format                                                    */
    732   /*                                                                       */
    733   /* <Description>                                                         */
    734   /*    An enumeration type used to describe the format of a given glyph   */
    735   /*    image.  Note that this version of FreeType only supports two image */
    736   /*    formats, even though future font drivers will be able to register  */
    737   /*    their own format.                                                  */
    738   /*                                                                       */
    739   /* <Values>                                                              */
    740   /*    FT_GLYPH_FORMAT_NONE ::                                            */
    741   /*      The value~0 is reserved.                                         */
    742   /*                                                                       */
    743   /*    FT_GLYPH_FORMAT_COMPOSITE ::                                       */
    744   /*      The glyph image is a composite of several other images.  This    */
    745   /*      format is _only_ used with @FT_LOAD_NO_RECURSE, and is used to   */
    746   /*      report compound glyphs (like accented characters).               */
    747   /*                                                                       */
    748   /*    FT_GLYPH_FORMAT_BITMAP ::                                          */
    749   /*      The glyph image is a bitmap, and can be described as an          */
    750   /*      @FT_Bitmap.  You generally need to access the `bitmap' field of  */
    751   /*      the @FT_GlyphSlotRec structure to read it.                       */
    752   /*                                                                       */
    753   /*    FT_GLYPH_FORMAT_OUTLINE ::                                         */
    754   /*      The glyph image is a vectorial outline made of line segments     */
    755   /*      and Bzier arcs; it can be described as an @FT_Outline; you      */
    756   /*      generally want to access the `outline' field of the              */
    757   /*      @FT_GlyphSlotRec structure to read it.                           */
    758   /*                                                                       */
    759   /*    FT_GLYPH_FORMAT_PLOTTER ::                                         */
    760   /*      The glyph image is a vectorial path with no inside and outside   */
    761   /*      contours.  Some Type~1 fonts, like those in the Hershey family,  */
    762   /*      contain glyphs in this format.  These are described as           */
    763   /*      @FT_Outline, but FreeType isn't currently capable of rendering   */
    764   /*      them correctly.                                                  */
    765   /*                                                                       */
    766   typedef enum  FT_Glyph_Format_
    767   {
    768     FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ),
    769 
    770     FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
    771     FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP,    'b', 'i', 't', 's' ),
    772     FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE,   'o', 'u', 't', 'l' ),
    773     FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER,   'p', 'l', 'o', 't' )
    774 
    775   } FT_Glyph_Format;
    776 
    777 
    778   /*************************************************************************/
    779   /*                                                                       */
    780   /* <Enum>                                                                */
    781   /*    ft_glyph_format_xxx                                                */
    782   /*                                                                       */
    783   /* <Description>                                                         */
    784   /*    A list of deprecated constants.  Use the corresponding             */
    785   /*    @FT_Glyph_Format values instead.                                   */
    786   /*                                                                       */
    787   /* <Values>                                                              */
    788   /*    ft_glyph_format_none      :: See @FT_GLYPH_FORMAT_NONE.            */
    789   /*    ft_glyph_format_composite :: See @FT_GLYPH_FORMAT_COMPOSITE.       */
    790   /*    ft_glyph_format_bitmap    :: See @FT_GLYPH_FORMAT_BITMAP.          */
    791   /*    ft_glyph_format_outline   :: See @FT_GLYPH_FORMAT_OUTLINE.         */
    792   /*    ft_glyph_format_plotter   :: See @FT_GLYPH_FORMAT_PLOTTER.         */
    793   /*                                                                       */
    794 #define ft_glyph_format_none       FT_GLYPH_FORMAT_NONE
    795 #define ft_glyph_format_composite  FT_GLYPH_FORMAT_COMPOSITE
    796 #define ft_glyph_format_bitmap     FT_GLYPH_FORMAT_BITMAP
    797 #define ft_glyph_format_outline    FT_GLYPH_FORMAT_OUTLINE
    798 #define ft_glyph_format_plotter    FT_GLYPH_FORMAT_PLOTTER
    799 
    800 
    801   /*************************************************************************/
    802   /*************************************************************************/
    803   /*************************************************************************/
    804   /*****                                                               *****/
    805   /*****            R A S T E R   D E F I N I T I O N S                *****/
    806   /*****                                                               *****/
    807   /*************************************************************************/
    808   /*************************************************************************/
    809   /*************************************************************************/
    810 
    811 
    812   /*************************************************************************/
    813   /*                                                                       */
    814   /* A raster is a scan converter, in charge of rendering an outline into  */
    815   /* a a bitmap.  This section contains the public API for rasters.        */
    816   /*                                                                       */
    817   /* Note that in FreeType 2, all rasters are now encapsulated within      */
    818   /* specific modules called `renderers'.  See `freetype/ftrender.h' for   */
    819   /* more details on renderers.                                            */
    820   /*                                                                       */
    821   /*************************************************************************/
    822 
    823 
    824   /*************************************************************************/
    825   /*                                                                       */
    826   /* <Section>                                                             */
    827   /*    raster                                                             */
    828   /*                                                                       */
    829   /* <Title>                                                               */
    830   /*    Scanline Converter                                                 */
    831   /*                                                                       */
    832   /* <Abstract>                                                            */
    833   /*    How vectorial outlines are converted into bitmaps and pixmaps.     */
    834   /*                                                                       */
    835   /* <Description>                                                         */
    836   /*    This section contains technical definitions.                       */
    837   /*                                                                       */
    838   /*************************************************************************/
    839 
    840 
    841   /*************************************************************************/
    842   /*                                                                       */
    843   /* <Type>                                                                */
    844   /*    FT_Raster                                                          */
    845   /*                                                                       */
    846   /* <Description>                                                         */
    847   /*    A handle (pointer) to a raster object.  Each object can be used    */
    848   /*    independently to convert an outline into a bitmap or pixmap.       */
    849   /*                                                                       */
    850   typedef struct FT_RasterRec_*  FT_Raster;
    851 
    852 
    853   /*************************************************************************/
    854   /*                                                                       */
    855   /* <Struct>                                                              */
    856   /*    FT_Span                                                            */
    857   /*                                                                       */
    858   /* <Description>                                                         */
    859   /*    A structure used to model a single span of gray (or black) pixels  */
    860   /*    when rendering a monochrome or anti-aliased bitmap.                */
    861   /*                                                                       */
    862   /* <Fields>                                                              */
    863   /*    x        :: The span's horizontal start position.                  */
    864   /*                                                                       */
    865   /*    len      :: The span's length in pixels.                           */
    866   /*                                                                       */
    867   /*    coverage :: The span color/coverage, ranging from 0 (background)   */
    868   /*                to 255 (foreground).  Only used for anti-aliased       */
    869   /*                rendering.                                             */
    870   /*                                                                       */
    871   /* <Note>                                                                */
    872   /*    This structure is used by the span drawing callback type named     */
    873   /*    @FT_SpanFunc which takes the y~coordinate of the span as a         */
    874   /*    a parameter.                                                       */
    875   /*                                                                       */
    876   /*    The coverage value is always between 0 and 255.  If you want less  */
    877   /*    gray values, the callback function has to reduce them.             */
    878   /*                                                                       */
    879   typedef struct  FT_Span_
    880   {
    881     short           x;
    882     unsigned short  len;
    883     unsigned char   coverage;
    884 
    885   } FT_Span;
    886 
    887 
    888   /*************************************************************************/
    889   /*                                                                       */
    890   /* <FuncType>                                                            */
    891   /*    FT_SpanFunc                                                        */
    892   /*                                                                       */
    893   /* <Description>                                                         */
    894   /*    A function used as a call-back by the anti-aliased renderer in     */
    895   /*    order to let client applications draw themselves the gray pixel    */
    896   /*    spans on each scan line.                                           */
    897   /*                                                                       */
    898   /* <Input>                                                               */
    899   /*    y     :: The scanline's y~coordinate.                              */
    900   /*                                                                       */
    901   /*    count :: The number of spans to draw on this scanline.             */
    902   /*                                                                       */
    903   /*    spans :: A table of `count' spans to draw on the scanline.         */
    904   /*                                                                       */
    905   /*    user  :: User-supplied data that is passed to the callback.        */
    906   /*                                                                       */
    907   /* <Note>                                                                */
    908   /*    This callback allows client applications to directly render the    */
    909   /*    gray spans of the anti-aliased bitmap to any kind of surfaces.     */
    910   /*                                                                       */
    911   /*    This can be used to write anti-aliased outlines directly to a      */
    912   /*    given background bitmap, and even perform translucency.            */
    913   /*                                                                       */
    914   /*    Note that the `count' field cannot be greater than a fixed value   */
    915   /*    defined by the `FT_MAX_GRAY_SPANS' configuration macro in          */
    916   /*    `ftoption.h'.  By default, this value is set to~32, which means    */
    917   /*    that if there are more than 32~spans on a given scanline, the      */
    918   /*    callback is called several times with the same `y' parameter in    */
    919   /*    order to draw all callbacks.                                       */
    920   /*                                                                       */
    921   /*    Otherwise, the callback is only called once per scan-line, and     */
    922   /*    only for those scanlines that do have `gray' pixels on them.       */
    923   /*                                                                       */
    924   typedef void
    925   (*FT_SpanFunc)( int             y,
    926                   int             count,
    927                   const FT_Span*  spans,
    928                   void*           user );
    929 
    930 #define FT_Raster_Span_Func  FT_SpanFunc
    931 
    932 
    933   /*************************************************************************/
    934   /*                                                                       */
    935   /* <FuncType>                                                            */
    936   /*    FT_Raster_BitTest_Func                                             */
    937   /*                                                                       */
    938   /* <Description>                                                         */
    939   /*    THIS TYPE IS DEPRECATED.  DO NOT USE IT.                           */
    940   /*                                                                       */
    941   /*    A function used as a call-back by the monochrome scan-converter    */
    942   /*    to test whether a given target pixel is already set to the drawing */
    943   /*    `color'.  These tests are crucial to implement drop-out control    */
    944   /*    per-se the TrueType spec.                                          */
    945   /*                                                                       */
    946   /* <Input>                                                               */
    947   /*    y     :: The pixel's y~coordinate.                                 */
    948   /*                                                                       */
    949   /*    x     :: The pixel's x~coordinate.                                 */
    950   /*                                                                       */
    951   /*    user  :: User-supplied data that is passed to the callback.        */
    952   /*                                                                       */
    953   /* <Return>                                                              */
    954   /*   1~if the pixel is `set', 0~otherwise.                               */
    955   /*                                                                       */
    956   typedef int
    957   (*FT_Raster_BitTest_Func)( int    y,
    958                              int    x,
    959                              void*  user );
    960 
    961 
    962   /*************************************************************************/
    963   /*                                                                       */
    964   /* <FuncType>                                                            */
    965   /*    FT_Raster_BitSet_Func                                              */
    966   /*                                                                       */
    967   /* <Description>                                                         */
    968   /*    THIS TYPE IS DEPRECATED.  DO NOT USE IT.                           */
    969   /*                                                                       */
    970   /*    A function used as a call-back by the monochrome scan-converter    */
    971   /*    to set an individual target pixel.  This is crucial to implement   */
    972   /*    drop-out control according to the TrueType specification.          */
    973   /*                                                                       */
    974   /* <Input>                                                               */
    975   /*    y     :: The pixel's y~coordinate.                                 */
    976   /*                                                                       */
    977   /*    x     :: The pixel's x~coordinate.                                 */
    978   /*                                                                       */
    979   /*    user  :: User-supplied data that is passed to the callback.        */
    980   /*                                                                       */
    981   /* <Return>                                                              */
    982   /*    1~if the pixel is `set', 0~otherwise.                              */
    983   /*                                                                       */
    984   typedef void
    985   (*FT_Raster_BitSet_Func)( int    y,
    986                             int    x,
    987                             void*  user );
    988 
    989 
    990   /*************************************************************************/
    991   /*                                                                       */
    992   /* <Enum>                                                                */
    993   /*    FT_RASTER_FLAG_XXX                                                 */
    994   /*                                                                       */
    995   /* <Description>                                                         */
    996   /*    A list of bit flag constants as used in the `flags' field of a     */
    997   /*    @FT_Raster_Params structure.                                       */
    998   /*                                                                       */
    999   /* <Values>                                                              */
   1000   /*    FT_RASTER_FLAG_DEFAULT :: This value is 0.                         */
   1001   /*                                                                       */
   1002   /*    FT_RASTER_FLAG_AA      :: This flag is set to indicate that an     */
   1003   /*                              anti-aliased glyph image should be       */
   1004   /*                              generated.  Otherwise, it will be        */
   1005   /*                              monochrome (1-bit).                      */
   1006   /*                                                                       */
   1007   /*    FT_RASTER_FLAG_DIRECT  :: This flag is set to indicate direct      */
   1008   /*                              rendering.  In this mode, client         */
   1009   /*                              applications must provide their own span */
   1010   /*                              callback.  This lets them directly       */
   1011   /*                              draw or compose over an existing bitmap. */
   1012   /*                              If this bit is not set, the target       */
   1013   /*                              pixmap's buffer _must_ be zeroed before  */
   1014   /*                              rendering.                               */
   1015   /*                                                                       */
   1016   /*                              Note that for now, direct rendering is   */
   1017   /*                              only possible with anti-aliased glyphs.  */
   1018   /*                                                                       */
   1019   /*    FT_RASTER_FLAG_CLIP    :: This flag is only used in direct         */
   1020   /*                              rendering mode.  If set, the output will */
   1021   /*                              be clipped to a box specified in the     */
   1022   /*                              `clip_box' field of the                  */
   1023   /*                              @FT_Raster_Params structure.             */
   1024   /*                                                                       */
   1025   /*                              Note that by default, the glyph bitmap   */
   1026   /*                              is clipped to the target pixmap, except  */
   1027   /*                              in direct rendering mode where all spans */
   1028   /*                              are generated if no clipping box is set. */
   1029   /*                                                                       */
   1030 #define FT_RASTER_FLAG_DEFAULT  0x0
   1031 #define FT_RASTER_FLAG_AA       0x1
   1032 #define FT_RASTER_FLAG_DIRECT   0x2
   1033 #define FT_RASTER_FLAG_CLIP     0x4
   1034 
   1035   /* deprecated */
   1036 #define ft_raster_flag_default  FT_RASTER_FLAG_DEFAULT
   1037 #define ft_raster_flag_aa       FT_RASTER_FLAG_AA
   1038 #define ft_raster_flag_direct   FT_RASTER_FLAG_DIRECT
   1039 #define ft_raster_flag_clip     FT_RASTER_FLAG_CLIP
   1040 
   1041 
   1042   /*************************************************************************/
   1043   /*                                                                       */
   1044   /* <Struct>                                                              */
   1045   /*    FT_Raster_Params                                                   */
   1046   /*                                                                       */
   1047   /* <Description>                                                         */
   1048   /*    A structure to hold the arguments used by a raster's render        */
   1049   /*    function.                                                          */
   1050   /*                                                                       */
   1051   /* <Fields>                                                              */
   1052   /*    target      :: The target bitmap.                                  */
   1053   /*                                                                       */
   1054   /*    source      :: A pointer to the source glyph image (e.g., an       */
   1055   /*                   @FT_Outline).                                       */
   1056   /*                                                                       */
   1057   /*    flags       :: The rendering flags.                                */
   1058   /*                                                                       */
   1059   /*    gray_spans  :: The gray span drawing callback.                     */
   1060   /*                                                                       */
   1061   /*    black_spans :: The black span drawing callback.  UNIMPLEMENTED!    */
   1062   /*                                                                       */
   1063   /*    bit_test    :: The bit test callback.  UNIMPLEMENTED!              */
   1064   /*                                                                       */
   1065   /*    bit_set     :: The bit set callback.  UNIMPLEMENTED!               */
   1066   /*                                                                       */
   1067   /*    user        :: User-supplied data that is passed to each drawing   */
   1068   /*                   callback.                                           */
   1069   /*                                                                       */
   1070   /*    clip_box    :: An optional clipping box.  It is only used in       */
   1071   /*                   direct rendering mode.  Note that coordinates here  */
   1072   /*                   should be expressed in _integer_ pixels (and not in */
   1073   /*                   26.6 fixed-point units).                            */
   1074   /*                                                                       */
   1075   /* <Note>                                                                */
   1076   /*    An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA    */
   1077   /*    bit flag is set in the `flags' field, otherwise a monochrome       */
   1078   /*    bitmap is generated.                                               */
   1079   /*                                                                       */
   1080   /*    If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the      */
   1081   /*    raster will call the `gray_spans' callback to draw gray pixel      */
   1082   /*    spans, in the case of an aa glyph bitmap, it will call             */
   1083   /*    `black_spans', and `bit_test' and `bit_set' in the case of a       */
   1084   /*    monochrome bitmap.  This allows direct composition over a          */
   1085   /*    pre-existing bitmap through user-provided callbacks to perform the */
   1086   /*    span drawing/composition.                                          */
   1087   /*                                                                       */
   1088   /*    Note that the `bit_test' and `bit_set' callbacks are required when */
   1089   /*    rendering a monochrome bitmap, as they are crucial to implement    */
   1090   /*    correct drop-out control as defined in the TrueType specification. */
   1091   /*                                                                       */
   1092   typedef struct  FT_Raster_Params_
   1093   {
   1094     const FT_Bitmap*        target;
   1095     const void*             source;
   1096     int                     flags;
   1097     FT_SpanFunc             gray_spans;
   1098     FT_SpanFunc             black_spans;  /* doesn't work! */
   1099     FT_Raster_BitTest_Func  bit_test;     /* doesn't work! */
   1100     FT_Raster_BitSet_Func   bit_set;      /* doesn't work! */
   1101     void*                   user;
   1102     FT_BBox                 clip_box;
   1103 
   1104   } FT_Raster_Params;
   1105 
   1106 
   1107   /*************************************************************************/
   1108   /*                                                                       */
   1109   /* <FuncType>                                                            */
   1110   /*    FT_Raster_NewFunc                                                  */
   1111   /*                                                                       */
   1112   /* <Description>                                                         */
   1113   /*    A function used to create a new raster object.                     */
   1114   /*                                                                       */
   1115   /* <Input>                                                               */
   1116   /*    memory :: A handle to the memory allocator.                        */
   1117   /*                                                                       */
   1118   /* <Output>                                                              */
   1119   /*    raster :: A handle to the new raster object.                       */
   1120   /*                                                                       */
   1121   /* <Return>                                                              */
   1122   /*    Error code.  0~means success.                                      */
   1123   /*                                                                       */
   1124   /* <Note>                                                                */
   1125   /*    The `memory' parameter is a typeless pointer in order to avoid     */
   1126   /*    un-wanted dependencies on the rest of the FreeType code.  In       */
   1127   /*    practice, it is an @FT_Memory object, i.e., a handle to the        */
   1128   /*    standard FreeType memory allocator.  However, this field can be    */
   1129   /*    completely ignored by a given raster implementation.               */
   1130   /*                                                                       */
   1131   typedef int
   1132   (*FT_Raster_NewFunc)( void*       memory,
   1133                         FT_Raster*  raster );
   1134 
   1135 #define FT_Raster_New_Func  FT_Raster_NewFunc
   1136 
   1137 
   1138   /*************************************************************************/
   1139   /*                                                                       */
   1140   /* <FuncType>                                                            */
   1141   /*    FT_Raster_DoneFunc                                                 */
   1142   /*                                                                       */
   1143   /* <Description>                                                         */
   1144   /*    A function used to destroy a given raster object.                  */
   1145   /*                                                                       */
   1146   /* <Input>                                                               */
   1147   /*    raster :: A handle to the raster object.                           */
   1148   /*                                                                       */
   1149   typedef void
   1150   (*FT_Raster_DoneFunc)( FT_Raster  raster );
   1151 
   1152 #define FT_Raster_Done_Func  FT_Raster_DoneFunc
   1153 
   1154 
   1155   /*************************************************************************/
   1156   /*                                                                       */
   1157   /* <FuncType>                                                            */
   1158   /*    FT_Raster_ResetFunc                                                */
   1159   /*                                                                       */
   1160   /* <Description>                                                         */
   1161   /*    FreeType provides an area of memory called the `render pool',      */
   1162   /*    available to all registered rasters.  This pool can be freely used */
   1163   /*    during a given scan-conversion but is shared by all rasters.  Its  */
   1164   /*    content is thus transient.                                         */
   1165   /*                                                                       */
   1166   /*    This function is called each time the render pool changes, or just */
   1167   /*    after a new raster object is created.                              */
   1168   /*                                                                       */
   1169   /* <Input>                                                               */
   1170   /*    raster    :: A handle to the new raster object.                    */
   1171   /*                                                                       */
   1172   /*    pool_base :: The address in memory of the render pool.             */
   1173   /*                                                                       */
   1174   /*    pool_size :: The size in bytes of the render pool.                 */
   1175   /*                                                                       */
   1176   /* <Note>                                                                */
   1177   /*    Rasters can ignore the render pool and rely on dynamic memory      */
   1178   /*    allocation if they want to (a handle to the memory allocator is    */
   1179   /*    passed to the raster constructor).  However, this is not           */
   1180   /*    recommended for efficiency purposes.                               */
   1181   /*                                                                       */
   1182   typedef void
   1183   (*FT_Raster_ResetFunc)( FT_Raster       raster,
   1184                           unsigned char*  pool_base,
   1185                           unsigned long   pool_size );
   1186 
   1187 #define FT_Raster_Reset_Func  FT_Raster_ResetFunc
   1188 
   1189 
   1190   /*************************************************************************/
   1191   /*                                                                       */
   1192   /* <FuncType>                                                            */
   1193   /*    FT_Raster_SetModeFunc                                              */
   1194   /*                                                                       */
   1195   /* <Description>                                                         */
   1196   /*    This function is a generic facility to change modes or attributes  */
   1197   /*    in a given raster.  This can be used for debugging purposes, or    */
   1198   /*    simply to allow implementation-specific `features' in a given      */
   1199   /*    raster module.                                                     */
   1200   /*                                                                       */
   1201   /* <Input>                                                               */
   1202   /*    raster :: A handle to the new raster object.                       */
   1203   /*                                                                       */
   1204   /*    mode   :: A 4-byte tag used to name the mode or property.          */
   1205   /*                                                                       */
   1206   /*    args   :: A pointer to the new mode/property to use.               */
   1207   /*                                                                       */
   1208   typedef int
   1209   (*FT_Raster_SetModeFunc)( FT_Raster      raster,
   1210                             unsigned long  mode,
   1211                             void*          args );
   1212 
   1213 #define FT_Raster_Set_Mode_Func  FT_Raster_SetModeFunc
   1214 
   1215 
   1216   /*************************************************************************/
   1217   /*                                                                       */
   1218   /* <FuncType>                                                            */
   1219   /*    FT_Raster_RenderFunc                                               */
   1220   /*                                                                       */
   1221   /* <Description>                                                         */
   1222   /*    Invoke a given raster to scan-convert a given glyph image into a   */
   1223   /*    target bitmap.                                                     */
   1224   /*                                                                       */
   1225   /* <Input>                                                               */
   1226   /*    raster :: A handle to the raster object.                           */
   1227   /*                                                                       */
   1228   /*    params :: A pointer to an @FT_Raster_Params structure used to      */
   1229   /*              store the rendering parameters.                          */
   1230   /*                                                                       */
   1231   /* <Return>                                                              */
   1232   /*    Error code.  0~means success.                                      */
   1233   /*                                                                       */
   1234   /* <Note>                                                                */
   1235   /*    The exact format of the source image depends on the raster's glyph */
   1236   /*    format defined in its @FT_Raster_Funcs structure.  It can be an    */
   1237   /*    @FT_Outline or anything else in order to support a large array of  */
   1238   /*    glyph formats.                                                     */
   1239   /*                                                                       */
   1240   /*    Note also that the render function can fail and return a           */
   1241   /*    `FT_Err_Unimplemented_Feature' error code if the raster used does  */
   1242   /*    not support direct composition.                                    */
   1243   /*                                                                       */
   1244   /*    XXX: For now, the standard raster doesn't support direct           */
   1245   /*         composition but this should change for the final release (see */
   1246   /*         the files `demos/src/ftgrays.c' and `demos/src/ftgrays2.c'    */
   1247   /*         for examples of distinct implementations which support direct */
   1248   /*         composition).                                                 */
   1249   /*                                                                       */
   1250   typedef int
   1251   (*FT_Raster_RenderFunc)( FT_Raster                raster,
   1252                            const FT_Raster_Params*  params );
   1253 
   1254 #define FT_Raster_Render_Func  FT_Raster_RenderFunc
   1255 
   1256 
   1257   /*************************************************************************/
   1258   /*                                                                       */
   1259   /* <Struct>                                                              */
   1260   /*    FT_Raster_Funcs                                                    */
   1261   /*                                                                       */
   1262   /* <Description>                                                         */
   1263   /*   A structure used to describe a given raster class to the library.   */
   1264   /*                                                                       */
   1265   /* <Fields>                                                              */
   1266   /*    glyph_format  :: The supported glyph format for this raster.       */
   1267   /*                                                                       */
   1268   /*    raster_new    :: The raster constructor.                           */
   1269   /*                                                                       */
   1270   /*    raster_reset  :: Used to reset the render pool within the raster.  */
   1271   /*                                                                       */
   1272   /*    raster_render :: A function to render a glyph into a given bitmap. */
   1273   /*                                                                       */
   1274   /*    raster_done   :: The raster destructor.                            */
   1275   /*                                                                       */
   1276   typedef struct  FT_Raster_Funcs_
   1277   {
   1278     FT_Glyph_Format        glyph_format;
   1279     FT_Raster_NewFunc      raster_new;
   1280     FT_Raster_ResetFunc    raster_reset;
   1281     FT_Raster_SetModeFunc  raster_set_mode;
   1282     FT_Raster_RenderFunc   raster_render;
   1283     FT_Raster_DoneFunc     raster_done;
   1284 
   1285   } FT_Raster_Funcs;
   1286 
   1287 
   1288   /* */
   1289 
   1290 
   1291 FT_END_HEADER
   1292 
   1293 #endif /* __FTIMAGE_H__ */
   1294 
   1295 
   1296 /* END */
   1297 
   1298 
   1299 /* Local Variables: */
   1300 /* coding: utf-8    */
   1301 /* End:             */
   1302