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      1 /***************************************************************************/
      2 /*                                                                         */
      3 /*  ttgload.c                                                              */
      4 /*                                                                         */
      5 /*    TrueType Glyph Loader (body).                                        */
      6 /*                                                                         */
      7 /*  Copyright 1996-2017 by                                                 */
      8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
      9 /*                                                                         */
     10 /*  This file is part of the FreeType project, and may only be used,       */
     11 /*  modified, and distributed under the terms of the FreeType project      */
     12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
     13 /*  this file you indicate that you have read the license and              */
     14 /*  understand and accept it fully.                                        */
     15 /*                                                                         */
     16 /***************************************************************************/
     17 
     18 
     19 #include <ft2build.h>
     20 #include FT_INTERNAL_DEBUG_H
     21 #include FT_INTERNAL_CALC_H
     22 #include FT_INTERNAL_STREAM_H
     23 #include FT_INTERNAL_SFNT_H
     24 #include FT_TRUETYPE_TAGS_H
     25 #include FT_OUTLINE_H
     26 #include FT_TRUETYPE_DRIVER_H
     27 #include FT_LIST_H
     28 
     29 #include "ttgload.h"
     30 #include "ttpload.h"
     31 
     32 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
     33 #include "ttgxvar.h"
     34 #endif
     35 
     36 #include "tterrors.h"
     37 #include "ttsubpix.h"
     38 
     39 
     40   /*************************************************************************/
     41   /*                                                                       */
     42   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
     43   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
     44   /* messages during execution.                                            */
     45   /*                                                                       */
     46 #undef  FT_COMPONENT
     47 #define FT_COMPONENT  trace_ttgload
     48 
     49 
     50   /*************************************************************************/
     51   /*                                                                       */
     52   /* Composite glyph flags.                                                */
     53   /*                                                                       */
     54 #define ARGS_ARE_WORDS             0x0001
     55 #define ARGS_ARE_XY_VALUES         0x0002
     56 #define ROUND_XY_TO_GRID           0x0004
     57 #define WE_HAVE_A_SCALE            0x0008
     58 /* reserved                        0x0010 */
     59 #define MORE_COMPONENTS            0x0020
     60 #define WE_HAVE_AN_XY_SCALE        0x0040
     61 #define WE_HAVE_A_2X2              0x0080
     62 #define WE_HAVE_INSTR              0x0100
     63 #define USE_MY_METRICS             0x0200
     64 #define OVERLAP_COMPOUND           0x0400
     65 #define SCALED_COMPONENT_OFFSET    0x0800
     66 #define UNSCALED_COMPONENT_OFFSET  0x1000
     67 
     68 
     69   /*************************************************************************/
     70   /*                                                                       */
     71   /* Return the horizontal metrics in font units for a given glyph.        */
     72   /*                                                                       */
     73   FT_LOCAL_DEF( void )
     74   TT_Get_HMetrics( TT_Face     face,
     75                    FT_UInt     idx,
     76                    FT_Short*   lsb,
     77                    FT_UShort*  aw )
     78   {
     79     ( (SFNT_Service)face->sfnt )->get_metrics( face, 0, idx, lsb, aw );
     80 
     81     FT_TRACE5(( "  advance width (font units): %d\n", *aw ));
     82     FT_TRACE5(( "  left side bearing (font units): %d\n", *lsb ));
     83   }
     84 
     85 
     86   /*************************************************************************/
     87   /*                                                                       */
     88   /* Return the vertical metrics in font units for a given glyph.          */
     89   /* See macro `TT_LOADER_SET_PP' below for explanations.                  */
     90   /*                                                                       */
     91   FT_LOCAL_DEF( void )
     92   TT_Get_VMetrics( TT_Face     face,
     93                    FT_UInt     idx,
     94                    FT_Pos      yMax,
     95                    FT_Short*   tsb,
     96                    FT_UShort*  ah )
     97   {
     98     if ( face->vertical_info )
     99       ( (SFNT_Service)face->sfnt )->get_metrics( face, 1, idx, tsb, ah );
    100 
    101     else if ( face->os2.version != 0xFFFFU )
    102     {
    103       *tsb = (FT_Short)( face->os2.sTypoAscender - yMax );
    104       *ah  = (FT_UShort)FT_ABS( face->os2.sTypoAscender -
    105                                 face->os2.sTypoDescender );
    106     }
    107 
    108     else
    109     {
    110       *tsb = (FT_Short)( face->horizontal.Ascender - yMax );
    111       *ah  = (FT_UShort)FT_ABS( face->horizontal.Ascender -
    112                                 face->horizontal.Descender );
    113     }
    114 
    115     FT_TRACE5(( "  advance height (font units): %d\n", *ah ));
    116     FT_TRACE5(( "  top side bearing (font units): %d\n", *tsb ));
    117   }
    118 
    119 
    120   static FT_Error
    121   tt_get_metrics( TT_Loader  loader,
    122                   FT_UInt    glyph_index )
    123   {
    124     TT_Face    face   = loader->face;
    125 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
    126     TT_Driver  driver = (TT_Driver)FT_FACE_DRIVER( face );
    127 #endif
    128 
    129     FT_Error   error;
    130     FT_Stream  stream = loader->stream;
    131 
    132     FT_Short   left_bearing = 0, top_bearing = 0;
    133     FT_UShort  advance_width = 0, advance_height = 0;
    134 
    135     /* we must preserve the stream position          */
    136     /* (which gets altered by the metrics functions) */
    137     FT_ULong  pos = FT_STREAM_POS();
    138 
    139 
    140     TT_Get_HMetrics( face, glyph_index,
    141                      &left_bearing,
    142                      &advance_width );
    143     TT_Get_VMetrics( face, glyph_index,
    144                      loader->bbox.yMax,
    145                      &top_bearing,
    146                      &advance_height );
    147 
    148     if ( FT_STREAM_SEEK( pos ) )
    149       return error;
    150 
    151     loader->left_bearing = left_bearing;
    152     loader->advance      = advance_width;
    153     loader->top_bearing  = top_bearing;
    154     loader->vadvance     = advance_height;
    155 
    156 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
    157     if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 &&
    158          loader->exec                                             )
    159     {
    160       loader->exec->sph_tweak_flags = 0;
    161 
    162       /* This may not be the right place for this, but it works...  */
    163       /* Note that we have to unconditionally load the tweaks since */
    164       /* it is possible that glyphs individually switch ClearType's */
    165       /* backwards compatibility mode on and off.                   */
    166       sph_set_tweaks( loader, glyph_index );
    167     }
    168 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
    169 
    170     if ( !loader->linear_def )
    171     {
    172       loader->linear_def = 1;
    173       loader->linear     = advance_width;
    174     }
    175 
    176     return FT_Err_Ok;
    177   }
    178 
    179 
    180 #ifdef FT_CONFIG_OPTION_INCREMENTAL
    181 
    182   static void
    183   tt_get_metrics_incr_overrides( TT_Loader  loader,
    184                                  FT_UInt    glyph_index )
    185   {
    186     TT_Face  face = loader->face;
    187 
    188     FT_Short   left_bearing = 0, top_bearing = 0;
    189     FT_UShort  advance_width = 0, advance_height = 0;
    190 
    191 
    192     /* If this is an incrementally loaded font check whether there are */
    193     /* overriding metrics for this glyph.                              */
    194     if ( face->root.internal->incremental_interface                           &&
    195          face->root.internal->incremental_interface->funcs->get_glyph_metrics )
    196     {
    197       FT_Incremental_MetricsRec  metrics;
    198       FT_Error                   error;
    199 
    200 
    201       metrics.bearing_x = loader->left_bearing;
    202       metrics.bearing_y = 0;
    203       metrics.advance   = loader->advance;
    204       metrics.advance_v = 0;
    205 
    206       error = face->root.internal->incremental_interface->funcs->get_glyph_metrics(
    207                 face->root.internal->incremental_interface->object,
    208                 glyph_index, FALSE, &metrics );
    209       if ( error )
    210         goto Exit;
    211 
    212       left_bearing  = (FT_Short)metrics.bearing_x;
    213       advance_width = (FT_UShort)metrics.advance;
    214 
    215 #if 0
    216 
    217       /* GWW: Do I do the same for vertical metrics? */
    218       metrics.bearing_x = 0;
    219       metrics.bearing_y = loader->top_bearing;
    220       metrics.advance   = loader->vadvance;
    221 
    222       error = face->root.internal->incremental_interface->funcs->get_glyph_metrics(
    223                 face->root.internal->incremental_interface->object,
    224                 glyph_index, TRUE, &metrics );
    225       if ( error )
    226         goto Exit;
    227 
    228       top_bearing    = (FT_Short)metrics.bearing_y;
    229       advance_height = (FT_UShort)metrics.advance;
    230 
    231 #endif /* 0 */
    232 
    233       loader->left_bearing = left_bearing;
    234       loader->advance      = advance_width;
    235       loader->top_bearing  = top_bearing;
    236       loader->vadvance     = advance_height;
    237 
    238       if ( !loader->linear_def )
    239       {
    240         loader->linear_def = 1;
    241         loader->linear     = advance_width;
    242       }
    243     }
    244 
    245   Exit:
    246     return;
    247   }
    248 
    249 #endif /* FT_CONFIG_OPTION_INCREMENTAL */
    250 
    251 
    252   /*************************************************************************/
    253   /*                                                                       */
    254   /* The following functions are used by default with TrueType fonts.      */
    255   /* However, they can be replaced by alternatives if we need to support   */
    256   /* TrueType-compressed formats (like MicroType) in the future.           */
    257   /*                                                                       */
    258   /*************************************************************************/
    259 
    260   FT_CALLBACK_DEF( FT_Error )
    261   TT_Access_Glyph_Frame( TT_Loader  loader,
    262                          FT_UInt    glyph_index,
    263                          FT_ULong   offset,
    264                          FT_UInt    byte_count )
    265   {
    266     FT_Error   error;
    267     FT_Stream  stream = loader->stream;
    268 
    269     /* for non-debug mode */
    270     FT_UNUSED( glyph_index );
    271 
    272 
    273     FT_TRACE4(( "Glyph %ld\n", glyph_index ));
    274 
    275     /* the following line sets the `error' variable through macros! */
    276     if ( FT_STREAM_SEEK( offset ) || FT_FRAME_ENTER( byte_count ) )
    277       return error;
    278 
    279     loader->cursor = stream->cursor;
    280     loader->limit  = stream->limit;
    281 
    282     return FT_Err_Ok;
    283   }
    284 
    285 
    286   FT_CALLBACK_DEF( void )
    287   TT_Forget_Glyph_Frame( TT_Loader  loader )
    288   {
    289     FT_Stream  stream = loader->stream;
    290 
    291 
    292     FT_FRAME_EXIT();
    293   }
    294 
    295 
    296   FT_CALLBACK_DEF( FT_Error )
    297   TT_Load_Glyph_Header( TT_Loader  loader )
    298   {
    299     FT_Byte*  p     = loader->cursor;
    300     FT_Byte*  limit = loader->limit;
    301 
    302 
    303     if ( p + 10 > limit )
    304       return FT_THROW( Invalid_Outline );
    305 
    306     loader->n_contours = FT_NEXT_SHORT( p );
    307 
    308     loader->bbox.xMin = FT_NEXT_SHORT( p );
    309     loader->bbox.yMin = FT_NEXT_SHORT( p );
    310     loader->bbox.xMax = FT_NEXT_SHORT( p );
    311     loader->bbox.yMax = FT_NEXT_SHORT( p );
    312 
    313     FT_TRACE5(( "  # of contours: %d\n", loader->n_contours ));
    314     FT_TRACE5(( "  xMin: %4d  xMax: %4d\n", loader->bbox.xMin,
    315                                             loader->bbox.xMax ));
    316     FT_TRACE5(( "  yMin: %4d  yMax: %4d\n", loader->bbox.yMin,
    317                                             loader->bbox.yMax ));
    318     loader->cursor = p;
    319 
    320     return FT_Err_Ok;
    321   }
    322 
    323 
    324   FT_CALLBACK_DEF( FT_Error )
    325   TT_Load_Simple_Glyph( TT_Loader  load )
    326   {
    327     FT_Error        error;
    328     FT_Byte*        p          = load->cursor;
    329     FT_Byte*        limit      = load->limit;
    330     FT_GlyphLoader  gloader    = load->gloader;
    331     FT_Int          n_contours = load->n_contours;
    332     FT_Outline*     outline;
    333     FT_UShort       n_ins;
    334     FT_Int          n_points;
    335     FT_ULong        tmp;
    336 
    337     FT_Byte         *flag, *flag_limit;
    338     FT_Byte         c, count;
    339     FT_Vector       *vec, *vec_limit;
    340     FT_Pos          x;
    341     FT_Short        *cont, *cont_limit, prev_cont;
    342     FT_Int          xy_size = 0;
    343 
    344 
    345     /* check that we can add the contours to the glyph */
    346     error = FT_GLYPHLOADER_CHECK_POINTS( gloader, 0, n_contours );
    347     if ( error )
    348       goto Fail;
    349 
    350     /* reading the contours' endpoints & number of points */
    351     cont       = gloader->current.outline.contours;
    352     cont_limit = cont + n_contours;
    353 
    354     /* check space for contours array + instructions count */
    355     if ( n_contours >= 0xFFF || p + ( n_contours + 1 ) * 2 > limit )
    356       goto Invalid_Outline;
    357 
    358     prev_cont = FT_NEXT_SHORT( p );
    359 
    360     if ( n_contours > 0 )
    361       cont[0] = prev_cont;
    362 
    363     if ( prev_cont < 0 )
    364       goto Invalid_Outline;
    365 
    366     for ( cont++; cont < cont_limit; cont++ )
    367     {
    368       cont[0] = FT_NEXT_SHORT( p );
    369       if ( cont[0] <= prev_cont )
    370       {
    371         /* unordered contours: this is invalid */
    372         goto Invalid_Outline;
    373       }
    374       prev_cont = cont[0];
    375     }
    376 
    377     n_points = 0;
    378     if ( n_contours > 0 )
    379     {
    380       n_points = cont[-1] + 1;
    381       if ( n_points < 0 )
    382         goto Invalid_Outline;
    383     }
    384 
    385     /* note that we will add four phantom points later */
    386     error = FT_GLYPHLOADER_CHECK_POINTS( gloader, n_points + 4, 0 );
    387     if ( error )
    388       goto Fail;
    389 
    390     /* reading the bytecode instructions */
    391     load->glyph->control_len  = 0;
    392     load->glyph->control_data = NULL;
    393 
    394     if ( p + 2 > limit )
    395       goto Invalid_Outline;
    396 
    397     n_ins = FT_NEXT_USHORT( p );
    398 
    399     FT_TRACE5(( "  Instructions size: %u\n", n_ins ));
    400 
    401 #ifdef TT_USE_BYTECODE_INTERPRETER
    402 
    403     if ( IS_HINTED( load->load_flags ) )
    404     {
    405       /* check instructions size */
    406       if ( ( limit - p ) < n_ins )
    407       {
    408         FT_TRACE1(( "TT_Load_Simple_Glyph: instruction count mismatch\n" ));
    409         error = FT_THROW( Too_Many_Hints );
    410         goto Fail;
    411       }
    412 
    413       /* we don't trust `maxSizeOfInstructions' in the `maxp' table */
    414       /* and thus update the bytecode array size by ourselves       */
    415 
    416       tmp   = load->exec->glyphSize;
    417       error = Update_Max( load->exec->memory,
    418                           &tmp,
    419                           sizeof ( FT_Byte ),
    420                           (void*)&load->exec->glyphIns,
    421                           n_ins );
    422 
    423       load->exec->glyphSize = (FT_UShort)tmp;
    424       if ( error )
    425         return error;
    426 
    427       load->glyph->control_len  = n_ins;
    428       load->glyph->control_data = load->exec->glyphIns;
    429 
    430       if ( n_ins )
    431         FT_MEM_COPY( load->exec->glyphIns, p, (FT_Long)n_ins );
    432     }
    433 
    434 #endif /* TT_USE_BYTECODE_INTERPRETER */
    435 
    436     p += n_ins;
    437 
    438     outline = &gloader->current.outline;
    439 
    440     /* reading the point tags */
    441     flag       = (FT_Byte*)outline->tags;
    442     flag_limit = flag + n_points;
    443 
    444     FT_ASSERT( flag );
    445 
    446     while ( flag < flag_limit )
    447     {
    448       if ( p + 1 > limit )
    449         goto Invalid_Outline;
    450 
    451       *flag++ = c = FT_NEXT_BYTE( p );
    452       if ( c & 8 )
    453       {
    454         if ( p + 1 > limit )
    455           goto Invalid_Outline;
    456 
    457         count = FT_NEXT_BYTE( p );
    458         if ( flag + (FT_Int)count > flag_limit )
    459           goto Invalid_Outline;
    460 
    461         for ( ; count > 0; count-- )
    462           *flag++ = c;
    463       }
    464     }
    465 
    466     /* reading the X coordinates */
    467 
    468     vec       = outline->points;
    469     vec_limit = vec + n_points;
    470     flag      = (FT_Byte*)outline->tags;
    471     x         = 0;
    472 
    473     if ( p + xy_size > limit )
    474       goto Invalid_Outline;
    475 
    476     for ( ; vec < vec_limit; vec++, flag++ )
    477     {
    478       FT_Pos   y = 0;
    479       FT_Byte  f = *flag;
    480 
    481 
    482       if ( f & 2 )
    483       {
    484         if ( p + 1 > limit )
    485           goto Invalid_Outline;
    486 
    487         y = (FT_Pos)FT_NEXT_BYTE( p );
    488         if ( ( f & 16 ) == 0 )
    489           y = -y;
    490       }
    491       else if ( ( f & 16 ) == 0 )
    492       {
    493         if ( p + 2 > limit )
    494           goto Invalid_Outline;
    495 
    496         y = (FT_Pos)FT_NEXT_SHORT( p );
    497       }
    498 
    499       x     += y;
    500       vec->x = x;
    501       /* the cast is for stupid compilers */
    502       *flag  = (FT_Byte)( f & ~( 2 | 16 ) );
    503     }
    504 
    505     /* reading the Y coordinates */
    506 
    507     vec       = gloader->current.outline.points;
    508     vec_limit = vec + n_points;
    509     flag      = (FT_Byte*)outline->tags;
    510     x         = 0;
    511 
    512     for ( ; vec < vec_limit; vec++, flag++ )
    513     {
    514       FT_Pos   y = 0;
    515       FT_Byte  f = *flag;
    516 
    517 
    518       if ( f & 4 )
    519       {
    520         if ( p + 1 > limit )
    521           goto Invalid_Outline;
    522 
    523         y = (FT_Pos)FT_NEXT_BYTE( p );
    524         if ( ( f & 32 ) == 0 )
    525           y = -y;
    526       }
    527       else if ( ( f & 32 ) == 0 )
    528       {
    529         if ( p + 2 > limit )
    530           goto Invalid_Outline;
    531 
    532         y = (FT_Pos)FT_NEXT_SHORT( p );
    533       }
    534 
    535       x     += y;
    536       vec->y = x;
    537       /* the cast is for stupid compilers */
    538       *flag  = (FT_Byte)( f & FT_CURVE_TAG_ON );
    539     }
    540 
    541     outline->n_points   = (FT_Short)n_points;
    542     outline->n_contours = (FT_Short)n_contours;
    543 
    544     load->cursor = p;
    545 
    546   Fail:
    547     return error;
    548 
    549   Invalid_Outline:
    550     error = FT_THROW( Invalid_Outline );
    551     goto Fail;
    552   }
    553 
    554 
    555   FT_CALLBACK_DEF( FT_Error )
    556   TT_Load_Composite_Glyph( TT_Loader  loader )
    557   {
    558     FT_Error        error;
    559     FT_Byte*        p       = loader->cursor;
    560     FT_Byte*        limit   = loader->limit;
    561     FT_GlyphLoader  gloader = loader->gloader;
    562     FT_SubGlyph     subglyph;
    563     FT_UInt         num_subglyphs;
    564 
    565 
    566     num_subglyphs = 0;
    567 
    568     do
    569     {
    570       FT_Fixed  xx, xy, yy, yx;
    571       FT_UInt   count;
    572 
    573 
    574       /* check that we can load a new subglyph */
    575       error = FT_GlyphLoader_CheckSubGlyphs( gloader, num_subglyphs + 1 );
    576       if ( error )
    577         goto Fail;
    578 
    579       /* check space */
    580       if ( p + 4 > limit )
    581         goto Invalid_Composite;
    582 
    583       subglyph = gloader->current.subglyphs + num_subglyphs;
    584 
    585       subglyph->arg1 = subglyph->arg2 = 0;
    586 
    587       subglyph->flags = FT_NEXT_USHORT( p );
    588       subglyph->index = FT_NEXT_USHORT( p );
    589 
    590       /* check space */
    591       count = 2;
    592       if ( subglyph->flags & ARGS_ARE_WORDS )
    593         count += 2;
    594       if ( subglyph->flags & WE_HAVE_A_SCALE )
    595         count += 2;
    596       else if ( subglyph->flags & WE_HAVE_AN_XY_SCALE )
    597         count += 4;
    598       else if ( subglyph->flags & WE_HAVE_A_2X2 )
    599         count += 8;
    600 
    601       if ( p + count > limit )
    602         goto Invalid_Composite;
    603 
    604       /* read arguments */
    605       if ( subglyph->flags & ARGS_ARE_XY_VALUES )
    606       {
    607         if ( subglyph->flags & ARGS_ARE_WORDS )
    608         {
    609           subglyph->arg1 = FT_NEXT_SHORT( p );
    610           subglyph->arg2 = FT_NEXT_SHORT( p );
    611         }
    612         else
    613         {
    614           subglyph->arg1 = FT_NEXT_CHAR( p );
    615           subglyph->arg2 = FT_NEXT_CHAR( p );
    616         }
    617       }
    618       else
    619       {
    620         if ( subglyph->flags & ARGS_ARE_WORDS )
    621         {
    622           subglyph->arg1 = (FT_Int)FT_NEXT_USHORT( p );
    623           subglyph->arg2 = (FT_Int)FT_NEXT_USHORT( p );
    624         }
    625         else
    626         {
    627           subglyph->arg1 = (FT_Int)FT_NEXT_BYTE( p );
    628           subglyph->arg2 = (FT_Int)FT_NEXT_BYTE( p );
    629         }
    630       }
    631 
    632       /* read transform */
    633       xx = yy = 0x10000L;
    634       xy = yx = 0;
    635 
    636       if ( subglyph->flags & WE_HAVE_A_SCALE )
    637       {
    638         xx = (FT_Fixed)FT_NEXT_SHORT( p ) * 4;
    639         yy = xx;
    640       }
    641       else if ( subglyph->flags & WE_HAVE_AN_XY_SCALE )
    642       {
    643         xx = (FT_Fixed)FT_NEXT_SHORT( p ) * 4;
    644         yy = (FT_Fixed)FT_NEXT_SHORT( p ) * 4;
    645       }
    646       else if ( subglyph->flags & WE_HAVE_A_2X2 )
    647       {
    648         xx = (FT_Fixed)FT_NEXT_SHORT( p ) * 4;
    649         yx = (FT_Fixed)FT_NEXT_SHORT( p ) * 4;
    650         xy = (FT_Fixed)FT_NEXT_SHORT( p ) * 4;
    651         yy = (FT_Fixed)FT_NEXT_SHORT( p ) * 4;
    652       }
    653 
    654       subglyph->transform.xx = xx;
    655       subglyph->transform.xy = xy;
    656       subglyph->transform.yx = yx;
    657       subglyph->transform.yy = yy;
    658 
    659       num_subglyphs++;
    660 
    661     } while ( subglyph->flags & MORE_COMPONENTS );
    662 
    663     gloader->current.num_subglyphs = num_subglyphs;
    664     FT_TRACE5(( "  %d components\n", num_subglyphs ));
    665 
    666 #ifdef TT_USE_BYTECODE_INTERPRETER
    667 
    668     {
    669       FT_Stream  stream = loader->stream;
    670 
    671 
    672       /* we must undo the FT_FRAME_ENTER in order to point */
    673       /* to the composite instructions, if we find some.   */
    674       /* We will process them later.                       */
    675       /*                                                   */
    676       loader->ins_pos = (FT_ULong)( FT_STREAM_POS() +
    677                                     p - limit );
    678     }
    679 
    680 #endif
    681 
    682     loader->cursor = p;
    683 
    684   Fail:
    685     return error;
    686 
    687   Invalid_Composite:
    688     error = FT_THROW( Invalid_Composite );
    689     goto Fail;
    690   }
    691 
    692 
    693   FT_LOCAL_DEF( void )
    694   TT_Init_Glyph_Loading( TT_Face  face )
    695   {
    696     face->access_glyph_frame   = TT_Access_Glyph_Frame;
    697     face->read_glyph_header    = TT_Load_Glyph_Header;
    698     face->read_simple_glyph    = TT_Load_Simple_Glyph;
    699     face->read_composite_glyph = TT_Load_Composite_Glyph;
    700     face->forget_glyph_frame   = TT_Forget_Glyph_Frame;
    701   }
    702 
    703 
    704   static void
    705   tt_prepare_zone( TT_GlyphZone  zone,
    706                    FT_GlyphLoad  load,
    707                    FT_UInt       start_point,
    708                    FT_UInt       start_contour )
    709   {
    710     zone->n_points    = (FT_UShort)load->outline.n_points -
    711                           (FT_UShort)start_point;
    712     zone->n_contours  = load->outline.n_contours -
    713                           (FT_Short)start_contour;
    714     zone->org         = load->extra_points + start_point;
    715     zone->cur         = load->outline.points + start_point;
    716     zone->orus        = load->extra_points2 + start_point;
    717     zone->tags        = (FT_Byte*)load->outline.tags + start_point;
    718     zone->contours    = (FT_UShort*)load->outline.contours + start_contour;
    719     zone->first_point = (FT_UShort)start_point;
    720   }
    721 
    722 
    723   /*************************************************************************/
    724   /*                                                                       */
    725   /* <Function>                                                            */
    726   /*    TT_Hint_Glyph                                                      */
    727   /*                                                                       */
    728   /* <Description>                                                         */
    729   /*    Hint the glyph using the zone prepared by the caller.  Note that   */
    730   /*    the zone is supposed to include four phantom points.               */
    731   /*                                                                       */
    732   static FT_Error
    733   TT_Hint_Glyph( TT_Loader  loader,
    734                  FT_Bool    is_composite )
    735   {
    736 #if defined TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY || \
    737     defined TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
    738     TT_Face    face   = loader->face;
    739     TT_Driver  driver = (TT_Driver)FT_FACE_DRIVER( face );
    740 #endif
    741 
    742     TT_GlyphZone  zone = &loader->zone;
    743 
    744 #ifdef TT_USE_BYTECODE_INTERPRETER
    745     FT_Long       n_ins;
    746 #else
    747     FT_UNUSED( is_composite );
    748 #endif
    749 
    750 
    751 #ifdef TT_USE_BYTECODE_INTERPRETER
    752     if ( loader->glyph->control_len > 0xFFFFL )
    753     {
    754       FT_TRACE1(( "TT_Hint_Glyph: too long instructions" ));
    755       FT_TRACE1(( " (0x%lx byte) is truncated\n",
    756                  loader->glyph->control_len ));
    757     }
    758     n_ins = loader->glyph->control_len;
    759 
    760     /* save original point position in org */
    761     if ( n_ins > 0 )
    762       FT_ARRAY_COPY( zone->org, zone->cur, zone->n_points );
    763 
    764     /* Reset graphics state. */
    765     loader->exec->GS = loader->size->GS;
    766 
    767     /* XXX: UNDOCUMENTED! Hinting instructions of a composite glyph */
    768     /*      completely refer to the (already) hinted subglyphs.     */
    769     if ( is_composite )
    770     {
    771       loader->exec->metrics.x_scale = 1 << 16;
    772       loader->exec->metrics.y_scale = 1 << 16;
    773 
    774       FT_ARRAY_COPY( zone->orus, zone->cur, zone->n_points );
    775     }
    776     else
    777     {
    778       loader->exec->metrics.x_scale = loader->size->metrics.x_scale;
    779       loader->exec->metrics.y_scale = loader->size->metrics.y_scale;
    780     }
    781 #endif
    782 
    783     /* round phantom points */
    784     zone->cur[zone->n_points - 4].x =
    785       FT_PIX_ROUND( zone->cur[zone->n_points - 4].x );
    786     zone->cur[zone->n_points - 3].x =
    787       FT_PIX_ROUND( zone->cur[zone->n_points - 3].x );
    788     zone->cur[zone->n_points - 2].y =
    789       FT_PIX_ROUND( zone->cur[zone->n_points - 2].y );
    790     zone->cur[zone->n_points - 1].y =
    791       FT_PIX_ROUND( zone->cur[zone->n_points - 1].y );
    792 
    793 #ifdef TT_USE_BYTECODE_INTERPRETER
    794 
    795     if ( n_ins > 0 )
    796     {
    797       FT_Error  error;
    798 
    799       FT_GlyphLoader  gloader         = loader->gloader;
    800       FT_Outline      current_outline = gloader->current.outline;
    801 
    802 
    803       TT_Set_CodeRange( loader->exec, tt_coderange_glyph,
    804                         loader->exec->glyphIns, n_ins );
    805 
    806       loader->exec->is_composite = is_composite;
    807       loader->exec->pts          = *zone;
    808 
    809       error = TT_Run_Context( loader->exec );
    810       if ( error && loader->exec->pedantic_hinting )
    811         return error;
    812 
    813       /* store drop-out mode in bits 5-7; set bit 2 also as a marker */
    814       current_outline.tags[0] |=
    815         ( loader->exec->GS.scan_type << 5 ) | FT_CURVE_TAG_HAS_SCANMODE;
    816     }
    817 
    818 #endif
    819 
    820 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
    821     /* Save possibly modified glyph phantom points unless in v40 backwards */
    822     /* compatibility mode, where no movement on the x axis means no reason */
    823     /* to change bearings or advance widths.                               */
    824     if ( !( driver->interpreter_version == TT_INTERPRETER_VERSION_40 &&
    825             !loader->exec->backwards_compatibility ) )
    826     {
    827 #endif
    828       loader->pp1 = zone->cur[zone->n_points - 4];
    829       loader->pp2 = zone->cur[zone->n_points - 3];
    830       loader->pp3 = zone->cur[zone->n_points - 2];
    831       loader->pp4 = zone->cur[zone->n_points - 1];
    832 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
    833     }
    834 #endif
    835 
    836 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
    837     if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 )
    838     {
    839       if ( loader->exec->sph_tweak_flags & SPH_TWEAK_DEEMBOLDEN )
    840         FT_Outline_EmboldenXY( &loader->gloader->current.outline, -24, 0 );
    841 
    842       else if ( loader->exec->sph_tweak_flags & SPH_TWEAK_EMBOLDEN )
    843         FT_Outline_EmboldenXY( &loader->gloader->current.outline, 24, 0 );
    844     }
    845 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
    846 
    847     return FT_Err_Ok;
    848   }
    849 
    850 
    851   /*************************************************************************/
    852   /*                                                                       */
    853   /* <Function>                                                            */
    854   /*    TT_Process_Simple_Glyph                                            */
    855   /*                                                                       */
    856   /* <Description>                                                         */
    857   /*    Once a simple glyph has been loaded, it needs to be processed.     */
    858   /*    Usually, this means scaling and hinting through bytecode           */
    859   /*    interpretation.                                                    */
    860   /*                                                                       */
    861   static FT_Error
    862   TT_Process_Simple_Glyph( TT_Loader  loader )
    863   {
    864     FT_GlyphLoader  gloader = loader->gloader;
    865     FT_Error        error   = FT_Err_Ok;
    866     FT_Outline*     outline;
    867     FT_Int          n_points;
    868 
    869 
    870     outline  = &gloader->current.outline;
    871     n_points = outline->n_points;
    872 
    873     /* set phantom points */
    874 
    875     outline->points[n_points    ] = loader->pp1;
    876     outline->points[n_points + 1] = loader->pp2;
    877     outline->points[n_points + 2] = loader->pp3;
    878     outline->points[n_points + 3] = loader->pp4;
    879 
    880     outline->tags[n_points    ] = 0;
    881     outline->tags[n_points + 1] = 0;
    882     outline->tags[n_points + 2] = 0;
    883     outline->tags[n_points + 3] = 0;
    884 
    885     n_points += 4;
    886 
    887 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
    888 
    889     if ( loader->face->doblend && !loader->face->is_default_instance )
    890     {
    891       /* Deltas apply to the unscaled data. */
    892       error = TT_Vary_Apply_Glyph_Deltas( loader->face,
    893                                           loader->glyph_index,
    894                                           outline,
    895                                           (FT_UInt)n_points );
    896 
    897       /* recalculate linear horizontal and vertical advances */
    898       /* if we don't have HVAR and VVAR, respectively        */
    899       if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_HADVANCE ) )
    900         loader->linear = outline->points[n_points - 3].x -
    901                          outline->points[n_points - 4].x;
    902       if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_VADVANCE ) )
    903         loader->vadvance = outline->points[n_points - 1].x -
    904                            outline->points[n_points - 2].x;
    905 
    906       if ( error )
    907         return error;
    908     }
    909 
    910 #endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
    911 
    912     if ( IS_HINTED( loader->load_flags ) )
    913     {
    914       tt_prepare_zone( &loader->zone, &gloader->current, 0, 0 );
    915 
    916       FT_ARRAY_COPY( loader->zone.orus, loader->zone.cur,
    917                      loader->zone.n_points + 4 );
    918     }
    919 
    920     {
    921 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
    922       TT_Face    face   = loader->face;
    923       TT_Driver  driver = (TT_Driver)FT_FACE_DRIVER( face );
    924 
    925       FT_String*  family         = face->root.family_name;
    926       FT_UInt     ppem           = loader->size->metrics.x_ppem;
    927       FT_String*  style          = face->root.style_name;
    928       FT_UInt     x_scale_factor = 1000;
    929 #endif
    930 
    931       FT_Vector*  vec   = outline->points;
    932       FT_Vector*  limit = outline->points + n_points;
    933 
    934       FT_Fixed  x_scale = 0; /* pacify compiler */
    935       FT_Fixed  y_scale = 0;
    936 
    937       FT_Bool  do_scale = FALSE;
    938 
    939 
    940 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
    941 
    942       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 )
    943       {
    944         /* scale, but only if enabled and only if TT hinting is being used */
    945         if ( IS_HINTED( loader->load_flags ) )
    946           x_scale_factor = sph_test_tweak_x_scaling( face,
    947                                                      family,
    948                                                      ppem,
    949                                                      style,
    950                                                      loader->glyph_index );
    951         /* scale the glyph */
    952         if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 ||
    953              x_scale_factor != 1000                         )
    954         {
    955           x_scale = FT_MulDiv( loader->size->metrics.x_scale,
    956                                (FT_Long)x_scale_factor, 1000 );
    957           y_scale = loader->size->metrics.y_scale;
    958 
    959           /* compensate for any scaling by de/emboldening; */
    960           /* the amount was determined via experimentation */
    961           if ( x_scale_factor != 1000 && ppem > 11 )
    962             FT_Outline_EmboldenXY( outline,
    963                                    FT_MulFix( 1280 * ppem,
    964                                               1000 - x_scale_factor ),
    965                                    0 );
    966           do_scale = TRUE;
    967         }
    968       }
    969       else
    970 
    971 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
    972 
    973       {
    974         /* scale the glyph */
    975         if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
    976         {
    977           x_scale = loader->size->metrics.x_scale;
    978           y_scale = loader->size->metrics.y_scale;
    979 
    980           do_scale = TRUE;
    981         }
    982       }
    983 
    984       if ( do_scale )
    985       {
    986         for ( ; vec < limit; vec++ )
    987         {
    988           vec->x = FT_MulFix( vec->x, x_scale );
    989           vec->y = FT_MulFix( vec->y, y_scale );
    990         }
    991 
    992         loader->pp1 = outline->points[n_points - 4];
    993         loader->pp2 = outline->points[n_points - 3];
    994         loader->pp3 = outline->points[n_points - 2];
    995         loader->pp4 = outline->points[n_points - 1];
    996       }
    997     }
    998 
    999     if ( IS_HINTED( loader->load_flags ) )
   1000     {
   1001       loader->zone.n_points += 4;
   1002 
   1003       error = TT_Hint_Glyph( loader, 0 );
   1004     }
   1005 
   1006     return error;
   1007   }
   1008 
   1009 
   1010   /*************************************************************************/
   1011   /*                                                                       */
   1012   /* <Function>                                                            */
   1013   /*    TT_Process_Composite_Component                                     */
   1014   /*                                                                       */
   1015   /* <Description>                                                         */
   1016   /*    Once a composite component has been loaded, it needs to be         */
   1017   /*    processed.  Usually, this means transforming and translating.      */
   1018   /*                                                                       */
   1019   static FT_Error
   1020   TT_Process_Composite_Component( TT_Loader    loader,
   1021                                   FT_SubGlyph  subglyph,
   1022                                   FT_UInt      start_point,
   1023                                   FT_UInt      num_base_points )
   1024   {
   1025     FT_GlyphLoader  gloader = loader->gloader;
   1026     FT_Outline      current;
   1027     FT_Bool         have_scale;
   1028     FT_Pos          x, y;
   1029 
   1030 
   1031     current.points   = gloader->base.outline.points +
   1032                          num_base_points;
   1033     current.n_points = gloader->base.outline.n_points -
   1034                          (short)num_base_points;
   1035 
   1036     have_scale = FT_BOOL( subglyph->flags & ( WE_HAVE_A_SCALE     |
   1037                                               WE_HAVE_AN_XY_SCALE |
   1038                                               WE_HAVE_A_2X2       ) );
   1039 
   1040     /* perform the transform required for this subglyph */
   1041     if ( have_scale )
   1042       FT_Outline_Transform( &current, &subglyph->transform );
   1043 
   1044     /* get offset */
   1045     if ( !( subglyph->flags & ARGS_ARE_XY_VALUES ) )
   1046     {
   1047       FT_UInt     num_points = (FT_UInt)gloader->base.outline.n_points;
   1048       FT_UInt     k = (FT_UInt)subglyph->arg1;
   1049       FT_UInt     l = (FT_UInt)subglyph->arg2;
   1050       FT_Vector*  p1;
   1051       FT_Vector*  p2;
   1052 
   1053 
   1054       /* match l-th point of the newly loaded component to the k-th point */
   1055       /* of the previously loaded components.                             */
   1056 
   1057       /* change to the point numbers used by our outline */
   1058       k += start_point;
   1059       l += num_base_points;
   1060       if ( k >= num_base_points ||
   1061            l >= num_points      )
   1062         return FT_THROW( Invalid_Composite );
   1063 
   1064       p1 = gloader->base.outline.points + k;
   1065       p2 = gloader->base.outline.points + l;
   1066 
   1067       x = p1->x - p2->x;
   1068       y = p1->y - p2->y;
   1069     }
   1070     else
   1071     {
   1072       x = subglyph->arg1;
   1073       y = subglyph->arg2;
   1074 
   1075       if ( !x && !y )
   1076         return FT_Err_Ok;
   1077 
   1078       /* Use a default value dependent on                                  */
   1079       /* TT_CONFIG_OPTION_COMPONENT_OFFSET_SCALED.  This is useful for old */
   1080       /* TT fonts which don't set the xxx_COMPONENT_OFFSET bit.            */
   1081 
   1082       if ( have_scale &&
   1083 #ifdef TT_CONFIG_OPTION_COMPONENT_OFFSET_SCALED
   1084            !( subglyph->flags & UNSCALED_COMPONENT_OFFSET ) )
   1085 #else
   1086             ( subglyph->flags & SCALED_COMPONENT_OFFSET ) )
   1087 #endif
   1088       {
   1089 
   1090 #if 0
   1091 
   1092         /*******************************************************************/
   1093         /*                                                                 */
   1094         /* This algorithm is what Apple documents.  But it doesn't work.   */
   1095         /*                                                                 */
   1096         int  a = subglyph->transform.xx > 0 ?  subglyph->transform.xx
   1097                                             : -subglyph->transform.xx;
   1098         int  b = subglyph->transform.yx > 0 ?  subglyph->transform.yx
   1099                                             : -subglyph->transform.yx;
   1100         int  c = subglyph->transform.xy > 0 ?  subglyph->transform.xy
   1101                                             : -subglyph->transform.xy;
   1102         int  d = subglyph->transform.yy > 0 ?  subglyph->transform.yy
   1103                                             : -subglyph->transform.yy;
   1104         int  m = a > b ? a : b;
   1105         int  n = c > d ? c : d;
   1106 
   1107 
   1108         if ( a - b <= 33 && a - b >= -33 )
   1109           m *= 2;
   1110         if ( c - d <= 33 && c - d >= -33 )
   1111           n *= 2;
   1112         x = FT_MulFix( x, m );
   1113         y = FT_MulFix( y, n );
   1114 
   1115 #else /* 1 */
   1116 
   1117         /*******************************************************************/
   1118         /*                                                                 */
   1119         /* This algorithm is a guess and works much better than the above. */
   1120         /*                                                                 */
   1121         FT_Fixed  mac_xscale = FT_Hypot( subglyph->transform.xx,
   1122                                          subglyph->transform.xy );
   1123         FT_Fixed  mac_yscale = FT_Hypot( subglyph->transform.yy,
   1124                                          subglyph->transform.yx );
   1125 
   1126 
   1127         x = FT_MulFix( x, mac_xscale );
   1128         y = FT_MulFix( y, mac_yscale );
   1129 
   1130 #endif /* 1 */
   1131 
   1132       }
   1133 
   1134       if ( !( loader->load_flags & FT_LOAD_NO_SCALE ) )
   1135       {
   1136         FT_Fixed  x_scale = loader->size->metrics.x_scale;
   1137         FT_Fixed  y_scale = loader->size->metrics.y_scale;
   1138 
   1139 
   1140         x = FT_MulFix( x, x_scale );
   1141         y = FT_MulFix( y, y_scale );
   1142 
   1143         if ( subglyph->flags & ROUND_XY_TO_GRID )
   1144         {
   1145           x = FT_PIX_ROUND( x );
   1146           y = FT_PIX_ROUND( y );
   1147         }
   1148       }
   1149     }
   1150 
   1151     if ( x || y )
   1152       FT_Outline_Translate( &current, x, y );
   1153 
   1154     return FT_Err_Ok;
   1155   }
   1156 
   1157 
   1158   /*************************************************************************/
   1159   /*                                                                       */
   1160   /* <Function>                                                            */
   1161   /*    TT_Process_Composite_Glyph                                         */
   1162   /*                                                                       */
   1163   /* <Description>                                                         */
   1164   /*    This is slightly different from TT_Process_Simple_Glyph, in that   */
   1165   /*    its sole purpose is to hint the glyph.  Thus this function is      */
   1166   /*    only available when bytecode interpreter is enabled.               */
   1167   /*                                                                       */
   1168   static FT_Error
   1169   TT_Process_Composite_Glyph( TT_Loader  loader,
   1170                               FT_UInt    start_point,
   1171                               FT_UInt    start_contour )
   1172   {
   1173     FT_Error     error;
   1174     FT_Outline*  outline;
   1175     FT_UInt      i;
   1176 
   1177 
   1178     outline = &loader->gloader->base.outline;
   1179 
   1180     /* make room for phantom points */
   1181     error = FT_GLYPHLOADER_CHECK_POINTS( loader->gloader,
   1182                                          outline->n_points + 4,
   1183                                          0 );
   1184     if ( error )
   1185       return error;
   1186 
   1187     outline->points[outline->n_points    ] = loader->pp1;
   1188     outline->points[outline->n_points + 1] = loader->pp2;
   1189     outline->points[outline->n_points + 2] = loader->pp3;
   1190     outline->points[outline->n_points + 3] = loader->pp4;
   1191 
   1192     outline->tags[outline->n_points    ] = 0;
   1193     outline->tags[outline->n_points + 1] = 0;
   1194     outline->tags[outline->n_points + 2] = 0;
   1195     outline->tags[outline->n_points + 3] = 0;
   1196 
   1197 #ifdef TT_USE_BYTECODE_INTERPRETER
   1198 
   1199     {
   1200       FT_Stream  stream = loader->stream;
   1201       FT_UShort  n_ins, max_ins;
   1202       FT_ULong   tmp;
   1203 
   1204 
   1205       /* TT_Load_Composite_Glyph only gives us the offset of instructions */
   1206       /* so we read them here                                             */
   1207       if ( FT_STREAM_SEEK( loader->ins_pos ) ||
   1208            FT_READ_USHORT( n_ins )           )
   1209         return error;
   1210 
   1211       FT_TRACE5(( "  Instructions size = %d\n", n_ins ));
   1212 
   1213       /* check it */
   1214       max_ins = loader->face->max_profile.maxSizeOfInstructions;
   1215       if ( n_ins > max_ins )
   1216       {
   1217         /* don't trust `maxSizeOfInstructions'; */
   1218         /* only do a rough safety check         */
   1219         if ( (FT_Int)n_ins > loader->byte_len )
   1220         {
   1221           FT_TRACE1(( "TT_Process_Composite_Glyph:"
   1222                       " too many instructions (%d) for glyph with length %d\n",
   1223                       n_ins, loader->byte_len ));
   1224           return FT_THROW( Too_Many_Hints );
   1225         }
   1226 
   1227         tmp   = loader->exec->glyphSize;
   1228         error = Update_Max( loader->exec->memory,
   1229                             &tmp,
   1230                             sizeof ( FT_Byte ),
   1231                             (void*)&loader->exec->glyphIns,
   1232                             n_ins );
   1233 
   1234         loader->exec->glyphSize = (FT_UShort)tmp;
   1235         if ( error )
   1236           return error;
   1237       }
   1238       else if ( n_ins == 0 )
   1239         return FT_Err_Ok;
   1240 
   1241       if ( FT_STREAM_READ( loader->exec->glyphIns, n_ins ) )
   1242         return error;
   1243 
   1244       loader->glyph->control_data = loader->exec->glyphIns;
   1245       loader->glyph->control_len  = n_ins;
   1246     }
   1247 
   1248 #endif
   1249 
   1250     tt_prepare_zone( &loader->zone, &loader->gloader->base,
   1251                      start_point, start_contour );
   1252 
   1253     /* Some points are likely touched during execution of  */
   1254     /* instructions on components.  So let's untouch them. */
   1255     for ( i = 0; i < loader->zone.n_points; i++ )
   1256       loader->zone.tags[i] &= ~FT_CURVE_TAG_TOUCH_BOTH;
   1257 
   1258     loader->zone.n_points += 4;
   1259 
   1260     return TT_Hint_Glyph( loader, 1 );
   1261   }
   1262 
   1263 
   1264   /*
   1265    * Calculate the phantom points
   1266    *
   1267    * Defining the right side bearing (rsb) as
   1268    *
   1269    *   rsb = aw - (lsb + xmax - xmin)
   1270    *
   1271    * (with `aw' the advance width, `lsb' the left side bearing, and `xmin'
   1272    * and `xmax' the glyph's minimum and maximum x value), the OpenType
   1273    * specification defines the initial position of horizontal phantom points
   1274    * as
   1275    *
   1276    *   pp1 = (round(xmin - lsb), 0)      ,
   1277    *   pp2 = (round(pp1 + aw), 0)        .
   1278    *
   1279    * Note that the rounding to the grid (in the device space) is not
   1280    * documented currently in the specification.
   1281    *
   1282    * However, the specification lacks the precise definition of vertical
   1283    * phantom points.  Greg Hitchcock provided the following explanation.
   1284    *
   1285    * - a `vmtx' table is present
   1286    *
   1287    *   For any glyph, the minimum and maximum y values (`ymin' and `ymax')
   1288    *   are given in the `glyf' table, the top side bearing (tsb) and advance
   1289    *   height (ah) are given in the `vmtx' table.  The bottom side bearing
   1290    *   (bsb) is then calculated as
   1291    *
   1292    *     bsb = ah - (tsb + ymax - ymin)       ,
   1293    *
   1294    *   and the initial position of vertical phantom points is
   1295    *
   1296    *     pp3 = (x, round(ymax + tsb))       ,
   1297    *     pp4 = (x, round(pp3 - ah))         .
   1298    *
   1299    *   See below for value `x'.
   1300    *
   1301    * - no `vmtx' table in the font
   1302    *
   1303    *   If there is an `OS/2' table, we set
   1304    *
   1305    *     DefaultAscender = sTypoAscender       ,
   1306    *     DefaultDescender = sTypoDescender     ,
   1307    *
   1308    *   otherwise we use data from the `hhea' table:
   1309    *
   1310    *     DefaultAscender = Ascender         ,
   1311    *     DefaultDescender = Descender       .
   1312    *
   1313    *   With these two variables we can now set
   1314    *
   1315    *     ah = DefaultAscender - sDefaultDescender    ,
   1316    *     tsb = DefaultAscender - yMax                ,
   1317    *
   1318    *   and proceed as if a `vmtx' table was present.
   1319    *
   1320    * Usually we have
   1321    *
   1322    *   x = aw / 2      ,                                                (1)
   1323    *
   1324    * but there is one compatibility case where it can be set to
   1325    *
   1326    *   x = -DefaultDescender -
   1327    *         ((DefaultAscender - DefaultDescender - aw) / 2)     .      (2)
   1328    *
   1329    * and another one with
   1330    *
   1331    *   x = 0     .                                                      (3)
   1332    *
   1333    * In Windows, the history of those values is quite complicated,
   1334    * depending on the hinting engine (that is, the graphics framework).
   1335    *
   1336    *   framework        from                 to       formula
   1337    *  ----------------------------------------------------------
   1338    *    GDI       Windows 98               current      (1)
   1339    *              (Windows 2000 for NT)
   1340    *    GDI+      Windows XP               Windows 7    (2)
   1341    *    GDI+      Windows 8                current      (3)
   1342    *    DWrite    Windows 7                current      (3)
   1343    *
   1344    * For simplicity, FreeType uses (1) for grayscale subpixel hinting and
   1345    * (3) for everything else.
   1346    *
   1347    */
   1348   static void
   1349   tt_loader_set_pp( TT_Loader  loader )
   1350   {
   1351     FT_Bool  subpixel_hinting = 0;
   1352     FT_Bool  grayscale        = 0;
   1353     FT_Bool  use_aw_2         = 0;
   1354 
   1355 #ifdef TT_CONFIG_OPTION_SUBPIXEL_HINTING
   1356     TT_Driver driver = (TT_Driver)FT_FACE_DRIVER( loader->face );
   1357 #endif
   1358 
   1359 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
   1360     if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 )
   1361     {
   1362       subpixel_hinting = loader->exec ? loader->exec->subpixel_hinting
   1363                                       : 0;
   1364       grayscale        = loader->exec ? loader->exec->grayscale
   1365                                       : 0;
   1366     }
   1367 #endif
   1368 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   1369     if ( driver->interpreter_version == TT_INTERPRETER_VERSION_40 )
   1370     {
   1371       subpixel_hinting = loader->exec ? loader->exec->subpixel_hinting_lean
   1372                                       : 0;
   1373       grayscale        = loader->exec ? loader->exec->grayscale_cleartype
   1374                                       : 0;
   1375     }
   1376 #endif
   1377 
   1378     use_aw_2 = (FT_Bool)( subpixel_hinting && grayscale );
   1379 
   1380     loader->pp1.x = loader->bbox.xMin - loader->left_bearing;
   1381     loader->pp1.y = 0;
   1382     loader->pp2.x = loader->pp1.x + loader->advance;
   1383     loader->pp2.y = 0;
   1384 
   1385     loader->pp3.x = use_aw_2 ? loader->advance / 2 : 0;
   1386     loader->pp3.y = loader->bbox.yMax + loader->top_bearing;
   1387     loader->pp4.x = use_aw_2 ? loader->advance / 2 : 0;
   1388     loader->pp4.y = loader->pp3.y - loader->vadvance;
   1389   }
   1390 
   1391 
   1392   /* a utility function to retrieve i-th node from given FT_List */
   1393   static FT_ListNode
   1394   ft_list_get_node_at( FT_List  list,
   1395                        FT_UInt  index )
   1396   {
   1397     FT_ListNode  cur;
   1398 
   1399 
   1400     if ( !list )
   1401       return NULL;
   1402 
   1403     for ( cur = list->head; cur; cur = cur->next )
   1404     {
   1405       if ( !index )
   1406         return cur;
   1407 
   1408       index--;
   1409     }
   1410 
   1411     return NULL;
   1412   }
   1413 
   1414 
   1415   /*************************************************************************/
   1416   /*                                                                       */
   1417   /* <Function>                                                            */
   1418   /*    load_truetype_glyph                                                */
   1419   /*                                                                       */
   1420   /* <Description>                                                         */
   1421   /*    Loads a given truetype glyph.  Handles composites and uses a       */
   1422   /*    TT_Loader object.                                                  */
   1423   /*                                                                       */
   1424   static FT_Error
   1425   load_truetype_glyph( TT_Loader  loader,
   1426                        FT_UInt    glyph_index,
   1427                        FT_UInt    recurse_count,
   1428                        FT_Bool    header_only )
   1429   {
   1430     FT_Error        error        = FT_Err_Ok;
   1431     FT_Fixed        x_scale, y_scale;
   1432     FT_ULong        offset;
   1433     TT_Face         face         = loader->face;
   1434     FT_GlyphLoader  gloader      = loader->gloader;
   1435     FT_Bool         opened_frame = 0;
   1436 
   1437 #ifdef FT_CONFIG_OPTION_INCREMENTAL
   1438     FT_StreamRec    inc_stream;
   1439     FT_Data         glyph_data;
   1440     FT_Bool         glyph_data_loaded = 0;
   1441 #endif
   1442 
   1443 
   1444 #ifdef FT_DEBUG_LEVEL_TRACE
   1445     if ( recurse_count )
   1446       FT_TRACE5(( "  nesting level: %d\n", recurse_count ));
   1447 #endif
   1448 
   1449     /* some fonts have an incorrect value of `maxComponentDepth' */
   1450     if ( recurse_count > face->max_profile.maxComponentDepth )
   1451     {
   1452       FT_TRACE1(( "load_truetype_glyph: maxComponentDepth set to %d\n",
   1453                   recurse_count ));
   1454       face->max_profile.maxComponentDepth = (FT_UShort)recurse_count;
   1455     }
   1456 
   1457 #ifndef FT_CONFIG_OPTION_INCREMENTAL
   1458     /* check glyph index */
   1459     if ( glyph_index >= (FT_UInt)face->root.num_glyphs )
   1460     {
   1461       error = FT_THROW( Invalid_Glyph_Index );
   1462       goto Exit;
   1463     }
   1464 #endif
   1465 
   1466     loader->glyph_index = glyph_index;
   1467 
   1468     if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
   1469     {
   1470       x_scale = loader->size->metrics.x_scale;
   1471       y_scale = loader->size->metrics.y_scale;
   1472     }
   1473     else
   1474     {
   1475       x_scale = 0x10000L;
   1476       y_scale = 0x10000L;
   1477     }
   1478 
   1479     /* Set `offset' to the start of the glyph relative to the start of */
   1480     /* the `glyf' table, and `byte_len' to the length of the glyph in  */
   1481     /* bytes.                                                          */
   1482 
   1483 #ifdef FT_CONFIG_OPTION_INCREMENTAL
   1484 
   1485     /* If we are loading glyph data via the incremental interface, set */
   1486     /* the loader stream to a memory stream reading the data returned  */
   1487     /* by the interface.                                               */
   1488     if ( face->root.internal->incremental_interface )
   1489     {
   1490       error = face->root.internal->incremental_interface->funcs->get_glyph_data(
   1491                 face->root.internal->incremental_interface->object,
   1492                 glyph_index, &glyph_data );
   1493       if ( error )
   1494         goto Exit;
   1495 
   1496       glyph_data_loaded = 1;
   1497       offset            = 0;
   1498       loader->byte_len  = glyph_data.length;
   1499 
   1500       FT_ZERO( &inc_stream );
   1501       FT_Stream_OpenMemory( &inc_stream,
   1502                             glyph_data.pointer,
   1503                             (FT_ULong)glyph_data.length );
   1504 
   1505       loader->stream = &inc_stream;
   1506     }
   1507     else
   1508 
   1509 #endif /* FT_CONFIG_OPTION_INCREMENTAL */
   1510 
   1511       offset = tt_face_get_location( face, glyph_index,
   1512                                      (FT_UInt*)&loader->byte_len );
   1513 
   1514     if ( loader->byte_len > 0 )
   1515     {
   1516 #ifdef FT_CONFIG_OPTION_INCREMENTAL
   1517       /* for the incremental interface, `glyf_offset' is always zero */
   1518       if ( !face->glyf_offset                          &&
   1519            !face->root.internal->incremental_interface )
   1520 #else
   1521       if ( !face->glyf_offset )
   1522 #endif /* FT_CONFIG_OPTION_INCREMENTAL */
   1523       {
   1524         FT_TRACE2(( "no `glyf' table but non-zero `loca' entry\n" ));
   1525         error = FT_THROW( Invalid_Table );
   1526         goto Exit;
   1527       }
   1528 
   1529       error = face->access_glyph_frame( loader, glyph_index,
   1530                                         face->glyf_offset + offset,
   1531                                         (FT_UInt)loader->byte_len );
   1532       if ( error )
   1533         goto Exit;
   1534 
   1535       opened_frame = 1;
   1536 
   1537       /* read glyph header first */
   1538       error = face->read_glyph_header( loader );
   1539       if ( error )
   1540         goto Exit;
   1541 
   1542       /* the metrics must be computed after loading the glyph header */
   1543       /* since we need the glyph's `yMax' value in case the vertical */
   1544       /* metrics must be emulated                                    */
   1545       error = tt_get_metrics( loader, glyph_index );
   1546       if ( error )
   1547         goto Exit;
   1548 
   1549       if ( header_only )
   1550         goto Exit;
   1551     }
   1552 
   1553     if ( loader->byte_len == 0 || loader->n_contours == 0 )
   1554     {
   1555       loader->bbox.xMin = 0;
   1556       loader->bbox.xMax = 0;
   1557       loader->bbox.yMin = 0;
   1558       loader->bbox.yMax = 0;
   1559 
   1560       error = tt_get_metrics( loader, glyph_index );
   1561       if ( error )
   1562         goto Exit;
   1563 
   1564       if ( header_only )
   1565         goto Exit;
   1566 
   1567       /* must initialize points before (possibly) overriding */
   1568       /* glyph metrics from the incremental interface        */
   1569       tt_loader_set_pp( loader );
   1570 
   1571 #ifdef FT_CONFIG_OPTION_INCREMENTAL
   1572       tt_get_metrics_incr_overrides( loader, glyph_index );
   1573 #endif
   1574 
   1575 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
   1576 
   1577       if ( loader->face->doblend && !loader->face->is_default_instance )
   1578       {
   1579         /* a small outline structure with four elements for */
   1580         /* communication with `TT_Vary_Apply_Glyph_Deltas'  */
   1581         FT_Vector   points[4];
   1582         char        tags[4]     = { 1, 1, 1, 1 };
   1583         short       contours[4] = { 0, 1, 2, 3 };
   1584         FT_Outline  outline;
   1585 
   1586 
   1587         points[0].x = loader->pp1.x;
   1588         points[0].y = loader->pp1.y;
   1589         points[1].x = loader->pp2.x;
   1590         points[1].y = loader->pp2.y;
   1591 
   1592         points[2].x = loader->pp3.x;
   1593         points[2].y = loader->pp3.y;
   1594         points[3].x = loader->pp4.x;
   1595         points[3].y = loader->pp4.y;
   1596 
   1597         outline.n_points   = 4;
   1598         outline.n_contours = 4;
   1599         outline.points     = points;
   1600         outline.tags       = tags;
   1601         outline.contours   = contours;
   1602 
   1603         /* this must be done before scaling */
   1604         error = TT_Vary_Apply_Glyph_Deltas( loader->face,
   1605                                             glyph_index,
   1606                                             &outline,
   1607                                             (FT_UInt)outline.n_points );
   1608         if ( error )
   1609           goto Exit;
   1610 
   1611         loader->pp1.x = points[0].x;
   1612         loader->pp1.y = points[0].y;
   1613         loader->pp2.x = points[1].x;
   1614         loader->pp2.y = points[1].y;
   1615 
   1616         loader->pp3.x = points[2].x;
   1617         loader->pp3.y = points[2].y;
   1618         loader->pp4.x = points[3].x;
   1619         loader->pp4.y = points[3].y;
   1620 
   1621 
   1622         /* recalculate linear horizontal and vertical advances */
   1623         /* if we don't have HVAR and VVAR, respectively        */
   1624         if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_HADVANCE ) )
   1625           loader->linear = loader->pp2.x - loader->pp1.x;
   1626         if ( !( loader->face->variation_support & TT_FACE_FLAG_VAR_VADVANCE ) )
   1627           loader->vadvance = loader->pp4.x - loader->pp3.x;
   1628       }
   1629 
   1630 #endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
   1631 
   1632       /* scale phantom points, if necessary; */
   1633       /* they get rounded in `TT_Hint_Glyph' */
   1634       if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
   1635       {
   1636         loader->pp1.x = FT_MulFix( loader->pp1.x, x_scale );
   1637         loader->pp2.x = FT_MulFix( loader->pp2.x, x_scale );
   1638         /* pp1.y and pp2.y are always zero */
   1639 
   1640         loader->pp3.x = FT_MulFix( loader->pp3.x, x_scale );
   1641         loader->pp3.y = FT_MulFix( loader->pp3.y, y_scale );
   1642         loader->pp4.x = FT_MulFix( loader->pp4.x, x_scale );
   1643         loader->pp4.y = FT_MulFix( loader->pp4.y, y_scale );
   1644       }
   1645 
   1646       error = FT_Err_Ok;
   1647       goto Exit;
   1648     }
   1649 
   1650     /* must initialize phantom points before (possibly) overriding */
   1651     /* glyph metrics from the incremental interface                */
   1652     tt_loader_set_pp( loader );
   1653 
   1654 #ifdef FT_CONFIG_OPTION_INCREMENTAL
   1655     tt_get_metrics_incr_overrides( loader, glyph_index );
   1656 #endif
   1657 
   1658     /***********************************************************************/
   1659     /***********************************************************************/
   1660     /***********************************************************************/
   1661 
   1662     /* if it is a simple glyph, load it */
   1663 
   1664     if ( loader->n_contours > 0 )
   1665     {
   1666       error = face->read_simple_glyph( loader );
   1667       if ( error )
   1668         goto Exit;
   1669 
   1670       /* all data have been read */
   1671       face->forget_glyph_frame( loader );
   1672       opened_frame = 0;
   1673 
   1674       error = TT_Process_Simple_Glyph( loader );
   1675       if ( error )
   1676         goto Exit;
   1677 
   1678       FT_GlyphLoader_Add( gloader );
   1679     }
   1680 
   1681     /***********************************************************************/
   1682     /***********************************************************************/
   1683     /***********************************************************************/
   1684 
   1685     /* otherwise, load a composite! */
   1686     else if ( loader->n_contours == -1 )
   1687     {
   1688       FT_Memory  memory = face->root.memory;
   1689 
   1690       FT_UInt   start_point;
   1691       FT_UInt   start_contour;
   1692       FT_ULong  ins_pos;  /* position of composite instructions, if any */
   1693 
   1694       FT_ListNode  node, node2;
   1695 
   1696 
   1697       /*
   1698        * We store the glyph index directly in the `node->data' pointer,
   1699        * following the glib solution (cf. macro `GUINT_TO_POINTER') with a
   1700        * double cast to make this portable.  Note, however, that this needs
   1701        * pointers with a width of at least 32 bits.
   1702        */
   1703 
   1704 
   1705       /* clear the nodes filled by sibling chains */
   1706       node = ft_list_get_node_at( &loader->composites, recurse_count );
   1707       for ( node2 = node; node2; node2 = node2->next )
   1708         node2->data = (void*)ULONG_MAX;
   1709 
   1710       /* check whether we already have a composite glyph with this index */
   1711       if ( FT_List_Find( &loader->composites,
   1712                          (void*)(unsigned long)glyph_index ) )
   1713       {
   1714         FT_TRACE1(( "TT_Load_Composite_Glyph:"
   1715                     " infinite recursion detected\n" ));
   1716         error = FT_THROW( Invalid_Composite );
   1717         goto Exit;
   1718       }
   1719 
   1720       else if ( node )
   1721         node->data = (void*)(unsigned long)glyph_index;
   1722 
   1723       else
   1724       {
   1725         if ( FT_NEW( node ) )
   1726           goto Exit;
   1727         node->data = (void*)(unsigned long)glyph_index;
   1728         FT_List_Add( &loader->composites, node );
   1729       }
   1730 
   1731       start_point   = (FT_UInt)gloader->base.outline.n_points;
   1732       start_contour = (FT_UInt)gloader->base.outline.n_contours;
   1733 
   1734       /* for each subglyph, read composite header */
   1735       error = face->read_composite_glyph( loader );
   1736       if ( error )
   1737         goto Exit;
   1738 
   1739       /* store the offset of instructions */
   1740       ins_pos = loader->ins_pos;
   1741 
   1742       /* all data we need are read */
   1743       face->forget_glyph_frame( loader );
   1744       opened_frame = 0;
   1745 
   1746 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
   1747 
   1748       if ( face->doblend && !face->is_default_instance )
   1749       {
   1750         short        i, limit;
   1751         FT_SubGlyph  subglyph;
   1752 
   1753         FT_Outline  outline;
   1754         FT_Vector*  points   = NULL;
   1755         char*       tags     = NULL;
   1756         short*      contours = NULL;
   1757 
   1758 
   1759         limit = (short)gloader->current.num_subglyphs;
   1760 
   1761         /* construct an outline structure for              */
   1762         /* communication with `TT_Vary_Apply_Glyph_Deltas' */
   1763         outline.n_points   = (short)( gloader->current.num_subglyphs + 4 );
   1764         outline.n_contours = outline.n_points;
   1765 
   1766         outline.points   = NULL;
   1767         outline.tags     = NULL;
   1768         outline.contours = NULL;
   1769 
   1770         if ( FT_NEW_ARRAY( points, outline.n_points )   ||
   1771              FT_NEW_ARRAY( tags, outline.n_points )     ||
   1772              FT_NEW_ARRAY( contours, outline.n_points ) )
   1773           goto Exit1;
   1774 
   1775         subglyph = gloader->current.subglyphs;
   1776 
   1777         for ( i = 0; i < limit; i++, subglyph++ )
   1778         {
   1779           /* applying deltas for anchor points doesn't make sense, */
   1780           /* but we don't have to specially check this since       */
   1781           /* unused delta values are zero anyways                  */
   1782           points[i].x = subglyph->arg1;
   1783           points[i].y = subglyph->arg2;
   1784           tags[i]     = 1;
   1785           contours[i] = i;
   1786         }
   1787 
   1788         points[i].x = loader->pp1.x;
   1789         points[i].y = loader->pp1.y;
   1790         tags[i]     = 1;
   1791         contours[i] = i;
   1792 
   1793         i++;
   1794         points[i].x = loader->pp2.x;
   1795         points[i].y = loader->pp2.y;
   1796         tags[i]     = 1;
   1797         contours[i] = i;
   1798 
   1799         i++;
   1800         points[i].x = loader->pp3.x;
   1801         points[i].y = loader->pp3.y;
   1802         tags[i]     = 1;
   1803         contours[i] = i;
   1804 
   1805         i++;
   1806         points[i].x = loader->pp4.x;
   1807         points[i].y = loader->pp4.y;
   1808         tags[i]     = 1;
   1809         contours[i] = i;
   1810 
   1811         outline.points   = points;
   1812         outline.tags     = tags;
   1813         outline.contours = contours;
   1814 
   1815         /* this call provides additional offsets */
   1816         /* for each component's translation      */
   1817         if ( FT_SET_ERROR( TT_Vary_Apply_Glyph_Deltas(
   1818                              face,
   1819                              glyph_index,
   1820                              &outline,
   1821                              (FT_UInt)outline.n_points ) ) )
   1822           goto Exit1;
   1823 
   1824         subglyph = gloader->current.subglyphs;
   1825 
   1826         for ( i = 0; i < limit; i++, subglyph++ )
   1827         {
   1828           if ( subglyph->flags & ARGS_ARE_XY_VALUES )
   1829           {
   1830             subglyph->arg1 = (FT_Int16)points[i].x;
   1831             subglyph->arg2 = (FT_Int16)points[i].y;
   1832           }
   1833         }
   1834 
   1835         loader->pp1.x = points[i + 0].x;
   1836         loader->pp1.y = points[i + 0].y;
   1837         loader->pp2.x = points[i + 1].x;
   1838         loader->pp2.y = points[i + 1].y;
   1839 
   1840         loader->pp3.x = points[i + 2].x;
   1841         loader->pp3.y = points[i + 2].y;
   1842         loader->pp4.x = points[i + 3].x;
   1843         loader->pp4.y = points[i + 3].y;
   1844 
   1845         /* recalculate linear horizontal and vertical advances */
   1846         /* if we don't have HVAR and VVAR, respectively        */
   1847         if ( !( face->variation_support & TT_FACE_FLAG_VAR_HADVANCE ) )
   1848           loader->linear = loader->pp2.x - loader->pp1.x;
   1849         if ( !( face->variation_support & TT_FACE_FLAG_VAR_VADVANCE ) )
   1850           loader->vadvance = loader->pp4.x - loader->pp3.x;
   1851 
   1852       Exit1:
   1853         FT_FREE( outline.points );
   1854         FT_FREE( outline.tags );
   1855         FT_FREE( outline.contours );
   1856 
   1857         if ( error )
   1858           goto Exit;
   1859       }
   1860 
   1861 #endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
   1862 
   1863       /* scale phantom points, if necessary; */
   1864       /* they get rounded in `TT_Hint_Glyph' */
   1865       if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
   1866       {
   1867         loader->pp1.x = FT_MulFix( loader->pp1.x, x_scale );
   1868         loader->pp2.x = FT_MulFix( loader->pp2.x, x_scale );
   1869         /* pp1.y and pp2.y are always zero */
   1870 
   1871         loader->pp3.x = FT_MulFix( loader->pp3.x, x_scale );
   1872         loader->pp3.y = FT_MulFix( loader->pp3.y, y_scale );
   1873         loader->pp4.x = FT_MulFix( loader->pp4.x, x_scale );
   1874         loader->pp4.y = FT_MulFix( loader->pp4.y, y_scale );
   1875       }
   1876 
   1877       /* if the flag FT_LOAD_NO_RECURSE is set, we return the subglyph */
   1878       /* `as is' in the glyph slot (the client application will be     */
   1879       /* responsible for interpreting these data)...                   */
   1880       if ( loader->load_flags & FT_LOAD_NO_RECURSE )
   1881       {
   1882         FT_GlyphLoader_Add( gloader );
   1883         loader->glyph->format = FT_GLYPH_FORMAT_COMPOSITE;
   1884 
   1885         goto Exit;
   1886       }
   1887 
   1888       /*********************************************************************/
   1889       /*********************************************************************/
   1890       /*********************************************************************/
   1891 
   1892       {
   1893         FT_UInt      n, num_base_points;
   1894         FT_SubGlyph  subglyph       = NULL;
   1895 
   1896         FT_UInt      num_points     = start_point;
   1897         FT_UInt      num_subglyphs  = gloader->current.num_subglyphs;
   1898         FT_UInt      num_base_subgs = gloader->base.num_subglyphs;
   1899 
   1900         FT_Stream    old_stream     = loader->stream;
   1901         FT_Int       old_byte_len   = loader->byte_len;
   1902 
   1903 
   1904         FT_GlyphLoader_Add( gloader );
   1905 
   1906         /* read each subglyph independently */
   1907         for ( n = 0; n < num_subglyphs; n++ )
   1908         {
   1909           FT_Vector  pp[4];
   1910 
   1911           FT_Int  linear_hadvance;
   1912           FT_Int  linear_vadvance;
   1913 
   1914 
   1915           /* Each time we call load_truetype_glyph in this loop, the   */
   1916           /* value of `gloader.base.subglyphs' can change due to table */
   1917           /* reallocations.  We thus need to recompute the subglyph    */
   1918           /* pointer on each iteration.                                */
   1919           subglyph = gloader->base.subglyphs + num_base_subgs + n;
   1920 
   1921           pp[0] = loader->pp1;
   1922           pp[1] = loader->pp2;
   1923           pp[2] = loader->pp3;
   1924           pp[3] = loader->pp4;
   1925 
   1926           linear_hadvance = loader->linear;
   1927           linear_vadvance = loader->vadvance;
   1928 
   1929           num_base_points = (FT_UInt)gloader->base.outline.n_points;
   1930 
   1931           error = load_truetype_glyph( loader,
   1932                                        (FT_UInt)subglyph->index,
   1933                                        recurse_count + 1,
   1934                                        FALSE );
   1935           if ( error )
   1936             goto Exit;
   1937 
   1938           /* restore subglyph pointer */
   1939           subglyph = gloader->base.subglyphs + num_base_subgs + n;
   1940 
   1941           /* restore phantom points if necessary */
   1942           if ( !( subglyph->flags & USE_MY_METRICS ) )
   1943           {
   1944             loader->pp1 = pp[0];
   1945             loader->pp2 = pp[1];
   1946             loader->pp3 = pp[2];
   1947             loader->pp4 = pp[3];
   1948 
   1949             loader->linear   = linear_hadvance;
   1950             loader->vadvance = linear_vadvance;
   1951           }
   1952 
   1953           num_points = (FT_UInt)gloader->base.outline.n_points;
   1954 
   1955           if ( num_points == num_base_points )
   1956             continue;
   1957 
   1958           /* gloader->base.outline consists of three parts:               */
   1959           /* 0 -(1)-> start_point -(2)-> num_base_points -(3)-> n_points. */
   1960           /*                                                              */
   1961           /* (1): exists from the beginning                               */
   1962           /* (2): components that have been loaded so far                 */
   1963           /* (3): the newly loaded component                              */
   1964           error = TT_Process_Composite_Component( loader,
   1965                                                   subglyph,
   1966                                                   start_point,
   1967                                                   num_base_points );
   1968           if ( error )
   1969             goto Exit;
   1970         }
   1971 
   1972         loader->stream   = old_stream;
   1973         loader->byte_len = old_byte_len;
   1974 
   1975         /* process the glyph */
   1976         loader->ins_pos = ins_pos;
   1977         if ( IS_HINTED( loader->load_flags ) &&
   1978 #ifdef TT_USE_BYTECODE_INTERPRETER
   1979              subglyph->flags & WE_HAVE_INSTR &&
   1980 #endif
   1981              num_points > start_point )
   1982         {
   1983           error = TT_Process_Composite_Glyph( loader,
   1984                                               start_point,
   1985                                               start_contour );
   1986           if ( error )
   1987             goto Exit;
   1988         }
   1989       }
   1990     }
   1991     else
   1992     {
   1993       /* invalid composite count (negative but not -1) */
   1994       error = FT_THROW( Invalid_Outline );
   1995       goto Exit;
   1996     }
   1997 
   1998     /***********************************************************************/
   1999     /***********************************************************************/
   2000     /***********************************************************************/
   2001 
   2002   Exit:
   2003 
   2004     if ( opened_frame )
   2005       face->forget_glyph_frame( loader );
   2006 
   2007 #ifdef FT_CONFIG_OPTION_INCREMENTAL
   2008 
   2009     if ( glyph_data_loaded )
   2010       face->root.internal->incremental_interface->funcs->free_glyph_data(
   2011         face->root.internal->incremental_interface->object,
   2012         &glyph_data );
   2013 
   2014 #endif
   2015 
   2016     return error;
   2017   }
   2018 
   2019 
   2020   static FT_Error
   2021   compute_glyph_metrics( TT_Loader  loader,
   2022                          FT_UInt    glyph_index )
   2023   {
   2024     TT_Face    face   = loader->face;
   2025 #if defined TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY || \
   2026     defined TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   2027     TT_Driver  driver = (TT_Driver)FT_FACE_DRIVER( face );
   2028 #endif
   2029 
   2030     FT_BBox       bbox;
   2031     FT_Fixed      y_scale;
   2032     TT_GlyphSlot  glyph = loader->glyph;
   2033     TT_Size       size  = loader->size;
   2034 
   2035 
   2036     y_scale = 0x10000L;
   2037     if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
   2038       y_scale = size->root.metrics.y_scale;
   2039 
   2040     if ( glyph->format != FT_GLYPH_FORMAT_COMPOSITE )
   2041       FT_Outline_Get_CBox( &glyph->outline, &bbox );
   2042     else
   2043       bbox = loader->bbox;
   2044 
   2045     /* get the device-independent horizontal advance; it is scaled later */
   2046     /* by the base layer.                                                */
   2047     glyph->linearHoriAdvance = loader->linear;
   2048 
   2049     glyph->metrics.horiBearingX = bbox.xMin;
   2050     glyph->metrics.horiBearingY = bbox.yMax;
   2051     glyph->metrics.horiAdvance  = loader->pp2.x - loader->pp1.x;
   2052 
   2053     /* Adjust advance width to the value contained in the hdmx table    */
   2054     /* unless FT_LOAD_COMPUTE_METRICS is set or backwards compatibility */
   2055     /* mode of the v40 interpreter is active.  See `ttinterp.h' for     */
   2056     /* details on backwards compatibility mode.                         */
   2057     if (
   2058 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   2059          !( driver->interpreter_version == TT_INTERPRETER_VERSION_40 &&
   2060             ( loader->exec && loader->exec->backwards_compatibility  ) ) &&
   2061 #endif
   2062          !face->postscript.isFixedPitch                                  &&
   2063          IS_HINTED( loader->load_flags )                                 &&
   2064          !( loader->load_flags & FT_LOAD_COMPUTE_METRICS )               )
   2065     {
   2066       FT_Byte*  widthp;
   2067 
   2068 
   2069       widthp = tt_face_get_device_metrics( face,
   2070                                            size->root.metrics.x_ppem,
   2071                                            glyph_index );
   2072 
   2073 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
   2074 
   2075       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 )
   2076       {
   2077         FT_Bool  ignore_x_mode;
   2078 
   2079 
   2080         ignore_x_mode = FT_BOOL( FT_LOAD_TARGET_MODE( loader->load_flags ) !=
   2081                                  FT_RENDER_MODE_MONO );
   2082 
   2083         if ( widthp                                                   &&
   2084              ( ( ignore_x_mode && loader->exec->compatible_widths ) ||
   2085                 !ignore_x_mode                                      ||
   2086                 SPH_OPTION_BITMAP_WIDTHS                            ) )
   2087           glyph->metrics.horiAdvance = *widthp * 64;
   2088       }
   2089       else
   2090 
   2091 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
   2092 
   2093       {
   2094         if ( widthp )
   2095           glyph->metrics.horiAdvance = *widthp * 64;
   2096       }
   2097     }
   2098 
   2099     /* set glyph dimensions */
   2100     glyph->metrics.width  = bbox.xMax - bbox.xMin;
   2101     glyph->metrics.height = bbox.yMax - bbox.yMin;
   2102 
   2103     /* Now take care of vertical metrics.  In the case where there is */
   2104     /* no vertical information within the font (relatively common),   */
   2105     /* create some metrics manually                                   */
   2106     {
   2107       FT_Pos  top;      /* scaled vertical top side bearing  */
   2108       FT_Pos  advance;  /* scaled vertical advance height    */
   2109 
   2110 
   2111       /* Get the unscaled top bearing and advance height. */
   2112       if ( face->vertical_info                   &&
   2113            face->vertical.number_Of_VMetrics > 0 )
   2114       {
   2115         top = (FT_Short)FT_DivFix( loader->pp3.y - bbox.yMax,
   2116                                    y_scale );
   2117 
   2118         if ( loader->pp3.y <= loader->pp4.y )
   2119           advance = 0;
   2120         else
   2121           advance = (FT_UShort)FT_DivFix( loader->pp3.y - loader->pp4.y,
   2122                                           y_scale );
   2123       }
   2124       else
   2125       {
   2126         FT_Pos  height;
   2127 
   2128 
   2129         /* XXX Compute top side bearing and advance height in  */
   2130         /*     Get_VMetrics instead of here.                   */
   2131 
   2132         /* NOTE: The OS/2 values are the only `portable' ones, */
   2133         /*       which is why we use them, if there is an OS/2 */
   2134         /*       table in the font.  Otherwise, we use the     */
   2135         /*       values defined in the horizontal header.      */
   2136 
   2137         height = (FT_Short)FT_DivFix( bbox.yMax - bbox.yMin,
   2138                                       y_scale );
   2139         if ( face->os2.version != 0xFFFFU )
   2140           advance = (FT_Pos)( face->os2.sTypoAscender -
   2141                               face->os2.sTypoDescender );
   2142         else
   2143           advance = (FT_Pos)( face->horizontal.Ascender -
   2144                               face->horizontal.Descender );
   2145 
   2146         top = ( advance - height ) / 2;
   2147       }
   2148 
   2149 #ifdef FT_CONFIG_OPTION_INCREMENTAL
   2150       {
   2151         FT_Incremental_InterfaceRec*  incr;
   2152         FT_Incremental_MetricsRec     metrics;
   2153         FT_Error                      error;
   2154 
   2155 
   2156         incr = face->root.internal->incremental_interface;
   2157 
   2158         /* If this is an incrementally loaded font see if there are */
   2159         /* overriding metrics for this glyph.                       */
   2160         if ( incr && incr->funcs->get_glyph_metrics )
   2161         {
   2162           metrics.bearing_x = 0;
   2163           metrics.bearing_y = top;
   2164           metrics.advance   = advance;
   2165 
   2166           error = incr->funcs->get_glyph_metrics( incr->object,
   2167                                                   glyph_index,
   2168                                                   TRUE,
   2169                                                   &metrics );
   2170           if ( error )
   2171             return error;
   2172 
   2173           top     = metrics.bearing_y;
   2174           advance = metrics.advance;
   2175         }
   2176       }
   2177 
   2178       /* GWW: Do vertical metrics get loaded incrementally too? */
   2179 
   2180 #endif /* FT_CONFIG_OPTION_INCREMENTAL */
   2181 
   2182       glyph->linearVertAdvance = advance;
   2183 
   2184       /* scale the metrics */
   2185       if ( !( loader->load_flags & FT_LOAD_NO_SCALE ) )
   2186       {
   2187         top     = FT_MulFix( top,     y_scale );
   2188         advance = FT_MulFix( advance, y_scale );
   2189       }
   2190 
   2191       /* XXX: for now, we have no better algorithm for the lsb, but it */
   2192       /*      should work fine.                                        */
   2193       /*                                                               */
   2194       glyph->metrics.vertBearingX = glyph->metrics.horiBearingX -
   2195                                       glyph->metrics.horiAdvance / 2;
   2196       glyph->metrics.vertBearingY = top;
   2197       glyph->metrics.vertAdvance  = advance;
   2198     }
   2199 
   2200     return 0;
   2201   }
   2202 
   2203 
   2204 #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
   2205 
   2206   static FT_Error
   2207   load_sbit_image( TT_Size       size,
   2208                    TT_GlyphSlot  glyph,
   2209                    FT_UInt       glyph_index,
   2210                    FT_Int32      load_flags )
   2211   {
   2212     TT_Face             face;
   2213     SFNT_Service        sfnt;
   2214     FT_Stream           stream;
   2215     FT_Error            error;
   2216     TT_SBit_MetricsRec  metrics;
   2217 
   2218 
   2219     face   = (TT_Face)glyph->face;
   2220     sfnt   = (SFNT_Service)face->sfnt;
   2221     stream = face->root.stream;
   2222 
   2223     error = sfnt->load_sbit_image( face,
   2224                                    size->strike_index,
   2225                                    glyph_index,
   2226                                    (FT_UInt)load_flags,
   2227                                    stream,
   2228                                    &glyph->bitmap,
   2229                                    &metrics );
   2230     if ( !error )
   2231     {
   2232       glyph->outline.n_points   = 0;
   2233       glyph->outline.n_contours = 0;
   2234 
   2235       glyph->metrics.width  = (FT_Pos)metrics.width  * 64;
   2236       glyph->metrics.height = (FT_Pos)metrics.height * 64;
   2237 
   2238       glyph->metrics.horiBearingX = (FT_Pos)metrics.horiBearingX * 64;
   2239       glyph->metrics.horiBearingY = (FT_Pos)metrics.horiBearingY * 64;
   2240       glyph->metrics.horiAdvance  = (FT_Pos)metrics.horiAdvance  * 64;
   2241 
   2242       glyph->metrics.vertBearingX = (FT_Pos)metrics.vertBearingX * 64;
   2243       glyph->metrics.vertBearingY = (FT_Pos)metrics.vertBearingY * 64;
   2244       glyph->metrics.vertAdvance  = (FT_Pos)metrics.vertAdvance  * 64;
   2245 
   2246       glyph->format = FT_GLYPH_FORMAT_BITMAP;
   2247 
   2248       if ( load_flags & FT_LOAD_VERTICAL_LAYOUT )
   2249       {
   2250         glyph->bitmap_left = metrics.vertBearingX;
   2251         glyph->bitmap_top  = metrics.vertBearingY;
   2252       }
   2253       else
   2254       {
   2255         glyph->bitmap_left = metrics.horiBearingX;
   2256         glyph->bitmap_top  = metrics.horiBearingY;
   2257       }
   2258     }
   2259 
   2260     return error;
   2261   }
   2262 
   2263 #endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */
   2264 
   2265 
   2266   static FT_Error
   2267   tt_loader_init( TT_Loader     loader,
   2268                   TT_Size       size,
   2269                   TT_GlyphSlot  glyph,
   2270                   FT_Int32      load_flags,
   2271                   FT_Bool       glyf_table_only )
   2272   {
   2273     FT_Error  error;
   2274 
   2275     TT_Face    face;
   2276     FT_Stream  stream;
   2277 #ifdef TT_USE_BYTECODE_INTERPRETER
   2278     FT_Bool    pedantic = FT_BOOL( load_flags & FT_LOAD_PEDANTIC );
   2279 #endif
   2280 #if defined TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY || \
   2281     defined TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   2282     TT_Driver  driver = (TT_Driver)FT_FACE_DRIVER( (TT_Face)glyph->face );
   2283 #endif
   2284 
   2285 
   2286     face   = (TT_Face)glyph->face;
   2287     stream = face->root.stream;
   2288 
   2289     FT_ZERO( loader );
   2290 
   2291 #ifdef TT_USE_BYTECODE_INTERPRETER
   2292 
   2293     /* load execution context */
   2294     if ( IS_HINTED( load_flags ) && !glyf_table_only )
   2295     {
   2296       TT_ExecContext  exec;
   2297       FT_Bool         grayscale = TRUE;
   2298 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   2299       FT_Bool         subpixel_hinting_lean;
   2300       FT_Bool         grayscale_cleartype;
   2301 #endif
   2302 
   2303 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
   2304       FT_Bool  subpixel_hinting = FALSE;
   2305 
   2306 #if 0
   2307       /* not used yet */
   2308       FT_Bool  compatible_widths;
   2309       FT_Bool  symmetrical_smoothing;
   2310       FT_Bool  bgr;
   2311       FT_Bool  vertical_lcd;
   2312       FT_Bool  subpixel_positioned;
   2313       FT_Bool  gray_cleartype;
   2314 #endif
   2315 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
   2316 
   2317       FT_Bool  reexecute = FALSE;
   2318 
   2319 
   2320       if ( size->bytecode_ready < 0 || size->cvt_ready < 0 )
   2321       {
   2322         error = tt_size_ready_bytecode( size, pedantic );
   2323         if ( error )
   2324           return error;
   2325       }
   2326       else if ( size->bytecode_ready )
   2327         return size->bytecode_ready;
   2328       else if ( size->cvt_ready )
   2329         return size->cvt_ready;
   2330 
   2331       /* query new execution context */
   2332       exec = size->context;
   2333       if ( !exec )
   2334         return FT_THROW( Could_Not_Find_Context );
   2335 
   2336 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   2337       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_40 )
   2338       {
   2339         subpixel_hinting_lean   = TRUE;
   2340         grayscale_cleartype     = !FT_BOOL( load_flags         &
   2341                                             FT_LOAD_TARGET_LCD     ||
   2342                                             load_flags           &
   2343                                             FT_LOAD_TARGET_LCD_V   );
   2344         exec->vertical_lcd_lean = FT_BOOL( load_flags           &
   2345                                            FT_LOAD_TARGET_LCD_V );
   2346       }
   2347       else
   2348       {
   2349         subpixel_hinting_lean   = FALSE;
   2350         grayscale_cleartype     = FALSE;
   2351         exec->vertical_lcd_lean = FALSE;
   2352       }
   2353 #endif
   2354 
   2355 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
   2356 
   2357       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 )
   2358       {
   2359         subpixel_hinting = FT_BOOL( ( FT_LOAD_TARGET_MODE( load_flags ) !=
   2360                                       FT_RENDER_MODE_MONO               )  &&
   2361                                     SPH_OPTION_SET_SUBPIXEL                );
   2362 
   2363         if ( subpixel_hinting )
   2364           grayscale = FALSE;
   2365         else if ( SPH_OPTION_SET_GRAYSCALE )
   2366         {
   2367           grayscale        = TRUE;
   2368           subpixel_hinting = FALSE;
   2369         }
   2370         else
   2371           grayscale = FALSE;
   2372 
   2373         if ( FT_IS_TRICKY( glyph->face ) )
   2374           subpixel_hinting = FALSE;
   2375 
   2376         exec->ignore_x_mode      = subpixel_hinting || grayscale;
   2377         exec->rasterizer_version = SPH_OPTION_SET_RASTERIZER_VERSION;
   2378         if ( exec->sph_tweak_flags & SPH_TWEAK_RASTERIZER_35 )
   2379           exec->rasterizer_version = TT_INTERPRETER_VERSION_35;
   2380 
   2381 #if 1
   2382         exec->compatible_widths     = SPH_OPTION_SET_COMPATIBLE_WIDTHS;
   2383         exec->symmetrical_smoothing = TRUE;
   2384         exec->bgr                   = FALSE;
   2385         exec->vertical_lcd          = FALSE;
   2386         exec->subpixel_positioned   = TRUE;
   2387         exec->gray_cleartype        = FALSE;
   2388 #else /* 0 */
   2389         exec->compatible_widths =
   2390           FT_BOOL( FT_LOAD_TARGET_MODE( load_flags ) !=
   2391                    TT_LOAD_COMPATIBLE_WIDTHS );
   2392         exec->symmetrical_smoothing =
   2393           FT_BOOL( FT_LOAD_TARGET_MODE( load_flags ) !=
   2394                    TT_LOAD_SYMMETRICAL_SMOOTHING );
   2395         exec->bgr =
   2396           FT_BOOL( FT_LOAD_TARGET_MODE( load_flags ) !=
   2397                    TT_LOAD_BGR );
   2398         exec->vertical_lcd =
   2399           FT_BOOL( FT_LOAD_TARGET_MODE( load_flags ) !=
   2400                    TT_LOAD_VERTICAL_LCD );
   2401         exec->subpixel_positioned =
   2402           FT_BOOL( FT_LOAD_TARGET_MODE( load_flags ) !=
   2403                    TT_LOAD_SUBPIXEL_POSITIONED );
   2404         exec->gray_cleartype =
   2405           FT_BOOL( FT_LOAD_TARGET_MODE( load_flags ) !=
   2406                    TT_LOAD_GRAY_CLEARTYPE );
   2407 #endif /* 0 */
   2408 
   2409       }
   2410       else
   2411 
   2412 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
   2413 
   2414 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   2415       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_40 )
   2416         grayscale = FT_BOOL( !subpixel_hinting_lean               &&
   2417                              FT_LOAD_TARGET_MODE( load_flags ) !=
   2418                                FT_RENDER_MODE_MONO                );
   2419       else
   2420 #endif
   2421         grayscale = FT_BOOL( FT_LOAD_TARGET_MODE( load_flags ) !=
   2422                                FT_RENDER_MODE_MONO             );
   2423 
   2424       error = TT_Load_Context( exec, face, size );
   2425       if ( error )
   2426         return error;
   2427 
   2428 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
   2429 
   2430       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 )
   2431       {
   2432         /* a change from mono to subpixel rendering (and vice versa) */
   2433         /* requires a re-execution of the CVT program                */
   2434         if ( subpixel_hinting != exec->subpixel_hinting )
   2435         {
   2436           FT_TRACE4(( "tt_loader_init: subpixel hinting change,"
   2437                       " re-executing `prep' table\n" ));
   2438 
   2439           exec->subpixel_hinting = subpixel_hinting;
   2440           reexecute              = TRUE;
   2441         }
   2442 
   2443         /* a change from mono to grayscale rendering (and vice versa) */
   2444         /* requires a re-execution of the CVT program                 */
   2445         if ( grayscale != exec->grayscale )
   2446         {
   2447           FT_TRACE4(( "tt_loader_init: grayscale hinting change,"
   2448                       " re-executing `prep' table\n" ));
   2449 
   2450           exec->grayscale = grayscale;
   2451           reexecute       = TRUE;
   2452         }
   2453       }
   2454       else
   2455 
   2456 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
   2457 
   2458       {
   2459 
   2460 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
   2461         if ( driver->interpreter_version == TT_INTERPRETER_VERSION_40 )
   2462         {
   2463           /* a change from mono to subpixel rendering (and vice versa) */
   2464           /* requires a re-execution of the CVT program                */
   2465           if ( subpixel_hinting_lean != exec->subpixel_hinting_lean )
   2466           {
   2467             FT_TRACE4(( "tt_loader_init: subpixel hinting change,"
   2468                         " re-executing `prep' table\n" ));
   2469 
   2470             exec->subpixel_hinting_lean = subpixel_hinting_lean;
   2471             reexecute                   = TRUE;
   2472           }
   2473 
   2474           /* a change from colored to grayscale subpixel rendering (and */
   2475           /* vice versa) requires a re-execution of the CVT program     */
   2476           if ( grayscale_cleartype != exec->grayscale_cleartype )
   2477           {
   2478             FT_TRACE4(( "tt_loader_init: grayscale subpixel hinting change,"
   2479                         " re-executing `prep' table\n" ));
   2480 
   2481             exec->grayscale_cleartype = grayscale_cleartype;
   2482             reexecute                 = TRUE;
   2483           }
   2484         }
   2485 #endif
   2486 
   2487         /* a change from mono to grayscale rendering (and vice versa) */
   2488         /* requires a re-execution of the CVT program                 */
   2489         if ( grayscale != exec->grayscale )
   2490         {
   2491           FT_TRACE4(( "tt_loader_init: grayscale hinting change,"
   2492                       " re-executing `prep' table\n" ));
   2493 
   2494           exec->grayscale = grayscale;
   2495           reexecute       = TRUE;
   2496         }
   2497       }
   2498 
   2499       if ( reexecute )
   2500       {
   2501         FT_UInt  i;
   2502 
   2503 
   2504         for ( i = 0; i < size->cvt_size; i++ )
   2505           size->cvt[i] = FT_MulFix( face->cvt[i], size->ttmetrics.scale );
   2506         error = tt_size_run_prep( size, pedantic );
   2507         if ( error )
   2508           return error;
   2509       }
   2510 
   2511       /* check whether the cvt program has disabled hinting */
   2512       if ( exec->GS.instruct_control & 1 )
   2513         load_flags |= FT_LOAD_NO_HINTING;
   2514 
   2515       /* load default graphics state -- if needed */
   2516       if ( exec->GS.instruct_control & 2 )
   2517         exec->GS = tt_default_graphics_state;
   2518 
   2519 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
   2520       /* check whether we have a font hinted for ClearType --           */
   2521       /* note that this flag can also be modified in a glyph's bytecode */
   2522       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 &&
   2523            exec->GS.instruct_control & 4                            )
   2524         exec->ignore_x_mode = 0;
   2525 #endif
   2526 
   2527       exec->pedantic_hinting = FT_BOOL( load_flags & FT_LOAD_PEDANTIC );
   2528       loader->exec = exec;
   2529       loader->instructions = exec->glyphIns;
   2530     }
   2531 
   2532 #endif /* TT_USE_BYTECODE_INTERPRETER */
   2533 
   2534     /* get face's glyph loader */
   2535     if ( !glyf_table_only )
   2536     {
   2537       FT_GlyphLoader  gloader = glyph->internal->loader;
   2538 
   2539 
   2540       FT_GlyphLoader_Rewind( gloader );
   2541       loader->gloader = gloader;
   2542     }
   2543 
   2544     loader->load_flags = (FT_ULong)load_flags;
   2545 
   2546     loader->face   = face;
   2547     loader->size   = size;
   2548     loader->glyph  = (FT_GlyphSlot)glyph;
   2549     loader->stream = stream;
   2550 
   2551     loader->composites.head = NULL;
   2552     loader->composites.tail = NULL;
   2553 
   2554     return FT_Err_Ok;
   2555   }
   2556 
   2557 
   2558   static void
   2559   tt_loader_done( TT_Loader  loader )
   2560   {
   2561     FT_List_Finalize( &loader->composites,
   2562                       NULL,
   2563                       loader->face->root.memory,
   2564                       NULL );
   2565   }
   2566 
   2567 
   2568   /*************************************************************************/
   2569   /*                                                                       */
   2570   /* <Function>                                                            */
   2571   /*    TT_Load_Glyph                                                      */
   2572   /*                                                                       */
   2573   /* <Description>                                                         */
   2574   /*    A function used to load a single glyph within a given glyph slot,  */
   2575   /*    for a given size.                                                  */
   2576   /*                                                                       */
   2577   /* <Input>                                                               */
   2578   /*    glyph       :: A handle to a target slot object where the glyph    */
   2579   /*                   will be loaded.                                     */
   2580   /*                                                                       */
   2581   /*    size        :: A handle to the source face size at which the glyph */
   2582   /*                   must be scaled/loaded.                              */
   2583   /*                                                                       */
   2584   /*    glyph_index :: The index of the glyph in the font file.            */
   2585   /*                                                                       */
   2586   /*    load_flags  :: A flag indicating what to load for this glyph.  The */
   2587   /*                   FT_LOAD_XXX constants can be used to control the    */
   2588   /*                   glyph loading process (e.g., whether the outline    */
   2589   /*                   should be scaled, whether to load bitmaps or not,   */
   2590   /*                   whether to hint the outline, etc).                  */
   2591   /*                                                                       */
   2592   /* <Return>                                                              */
   2593   /*    FreeType error code.  0 means success.                             */
   2594   /*                                                                       */
   2595   FT_LOCAL_DEF( FT_Error )
   2596   TT_Load_Glyph( TT_Size       size,
   2597                  TT_GlyphSlot  glyph,
   2598                  FT_UInt       glyph_index,
   2599                  FT_Int32      load_flags )
   2600   {
   2601     FT_Error      error;
   2602     TT_LoaderRec  loader;
   2603 
   2604 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
   2605 #define IS_DEFAULT_INSTANCE  ( ( (TT_Face)glyph->face )->is_default_instance )
   2606 #else
   2607 #define IS_DEFAULT_INSTANCE  1
   2608 #endif
   2609 
   2610 
   2611     FT_TRACE1(( "TT_Load_Glyph: glyph index %d\n", glyph_index ));
   2612 
   2613 #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
   2614 
   2615     /* try to load embedded bitmap (if any) */
   2616     if ( size->strike_index != 0xFFFFFFFFUL      &&
   2617          ( load_flags & FT_LOAD_NO_BITMAP ) == 0 &&
   2618          IS_DEFAULT_INSTANCE                     )
   2619     {
   2620       error = load_sbit_image( size, glyph, glyph_index, load_flags );
   2621       if ( !error )
   2622       {
   2623         if ( FT_IS_SCALABLE( glyph->face ) )
   2624         {
   2625           /* for the bbox we need the header only */
   2626           (void)tt_loader_init( &loader, size, glyph, load_flags, TRUE );
   2627           (void)load_truetype_glyph( &loader, glyph_index, 0, TRUE );
   2628           tt_loader_done( &loader );
   2629           glyph->linearHoriAdvance = loader.linear;
   2630           glyph->linearVertAdvance = loader.vadvance;
   2631 
   2632           /* sanity checks: if `xxxAdvance' in the sbit metric */
   2633           /* structure isn't set, use `linearXXXAdvance'      */
   2634           if ( !glyph->metrics.horiAdvance && glyph->linearHoriAdvance )
   2635             glyph->metrics.horiAdvance =
   2636               FT_MulFix( glyph->linearHoriAdvance,
   2637                          size->root.metrics.x_scale );
   2638           if ( !glyph->metrics.vertAdvance && glyph->linearVertAdvance )
   2639             glyph->metrics.vertAdvance =
   2640               FT_MulFix( glyph->linearVertAdvance,
   2641                          size->root.metrics.y_scale );
   2642         }
   2643 
   2644         return FT_Err_Ok;
   2645       }
   2646     }
   2647 
   2648 #endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */
   2649 
   2650     /* if FT_LOAD_NO_SCALE is not set, `ttmetrics' must be valid */
   2651     if ( !( load_flags & FT_LOAD_NO_SCALE ) && !size->ttmetrics.valid )
   2652     {
   2653       error = FT_THROW( Invalid_Size_Handle );
   2654       goto Exit;
   2655     }
   2656 
   2657     if ( load_flags & FT_LOAD_SBITS_ONLY )
   2658     {
   2659       error = FT_THROW( Invalid_Argument );
   2660       goto Exit;
   2661     }
   2662 
   2663     error = tt_loader_init( &loader, size, glyph, load_flags, FALSE );
   2664     if ( error )
   2665       goto Exit;
   2666 
   2667     glyph->format        = FT_GLYPH_FORMAT_OUTLINE;
   2668     glyph->num_subglyphs = 0;
   2669     glyph->outline.flags = 0;
   2670 
   2671     /* main loading loop */
   2672     error = load_truetype_glyph( &loader, glyph_index, 0, FALSE );
   2673     if ( !error )
   2674     {
   2675       if ( glyph->format == FT_GLYPH_FORMAT_COMPOSITE )
   2676       {
   2677         glyph->num_subglyphs = loader.gloader->base.num_subglyphs;
   2678         glyph->subglyphs     = loader.gloader->base.subglyphs;
   2679       }
   2680       else
   2681       {
   2682         glyph->outline        = loader.gloader->base.outline;
   2683         glyph->outline.flags &= ~FT_OUTLINE_SINGLE_PASS;
   2684 
   2685         /* Translate array so that (0,0) is the glyph's origin.  Note  */
   2686         /* that this behaviour is independent on the value of bit 1 of */
   2687         /* the `flags' field in the `head' table -- at least major     */
   2688         /* applications like Acroread indicate that.                   */
   2689         if ( loader.pp1.x )
   2690           FT_Outline_Translate( &glyph->outline, -loader.pp1.x, 0 );
   2691       }
   2692 
   2693 #ifdef TT_USE_BYTECODE_INTERPRETER
   2694 
   2695       if ( IS_HINTED( load_flags ) )
   2696       {
   2697         if ( loader.exec->GS.scan_control )
   2698         {
   2699           /* convert scan conversion mode to FT_OUTLINE_XXX flags */
   2700           switch ( loader.exec->GS.scan_type )
   2701           {
   2702           case 0: /* simple drop-outs including stubs */
   2703             glyph->outline.flags |= FT_OUTLINE_INCLUDE_STUBS;
   2704             break;
   2705           case 1: /* simple drop-outs excluding stubs */
   2706             /* nothing; it's the default rendering mode */
   2707             break;
   2708           case 4: /* smart drop-outs including stubs */
   2709             glyph->outline.flags |= FT_OUTLINE_SMART_DROPOUTS |
   2710                                     FT_OUTLINE_INCLUDE_STUBS;
   2711             break;
   2712           case 5: /* smart drop-outs excluding stubs  */
   2713             glyph->outline.flags |= FT_OUTLINE_SMART_DROPOUTS;
   2714             break;
   2715 
   2716           default: /* no drop-out control */
   2717             glyph->outline.flags |= FT_OUTLINE_IGNORE_DROPOUTS;
   2718             break;
   2719           }
   2720         }
   2721         else
   2722           glyph->outline.flags |= FT_OUTLINE_IGNORE_DROPOUTS;
   2723       }
   2724 
   2725 #endif /* TT_USE_BYTECODE_INTERPRETER */
   2726 
   2727       error = compute_glyph_metrics( &loader, glyph_index );
   2728     }
   2729 
   2730     tt_loader_done( &loader );
   2731 
   2732     /* Set the `high precision' bit flag.                           */
   2733     /* This is _critical_ to get correct output for monochrome      */
   2734     /* TrueType glyphs at all sizes using the bytecode interpreter. */
   2735     /*                                                              */
   2736     if ( !( load_flags & FT_LOAD_NO_SCALE ) &&
   2737          size->root.metrics.y_ppem < 24     )
   2738       glyph->outline.flags |= FT_OUTLINE_HIGH_PRECISION;
   2739 
   2740   Exit:
   2741 #ifdef FT_DEBUG_LEVEL_TRACE
   2742     if ( error )
   2743       FT_TRACE1(( "  failed (error code 0x%x)\n",
   2744                   error ));
   2745 #endif
   2746 
   2747     return error;
   2748   }
   2749 
   2750 
   2751 /* END */
   2752