lib/tacvt.c

   1 /* tacvt.c */
   2
   3 /*
   4  * Copyright (C) 2011-2012 by Werner Lemberg.
   5  *
   6  * This file is part of the ttfautohint library, and may only be used,
   7  * modified, and distributed under the terms given in `COPYING'.  By
   8  * continuing to use, modify, or distribute this file you indicate that you
   9  * have read `COPYING' and understand and accept it fully.
  10  *
  11  * The file `COPYING' mentioned in the previous paragraph is distributed
  12  * with the ttfautohint library.
  13  */
  14
  15
  16 #include "ta.h"
  17
  18
  19 static FT_Error
  20 TA_sfnt_compute_global_hints(SFNT* sfnt,
  21                              FONT* font)
  22 {
  23   FT_Error error;
  24   FT_Face face = sfnt->face;
  25   FT_UInt idx;
  26
  27
  28   error = ta_loader_init(font->loader);
  29   if (error)
  30     return error;
  31
  32   error = FT_Select_Charmap(face, FT_ENCODING_UNICODE);
  33   if (error)
  34     return TA_Err_Missing_Unicode_CMap;
  35
  36   /* load glyph `o' to trigger all initializations; */
  37   /* XXX make this configurable for non-latin scripts */
  38   /* XXX make this configurable to use a different letter */
  39   idx = FT_Get_Char_Index(face, 'o');
  40   if (!idx)
  41     return TA_Err_Missing_Glyph;
  42
  43   error = ta_loader_load_glyph(font->loader, face, idx,
  44                                font->fallback_script << 30);
  45
  46   return error;
  47 }
  48
  49
  50 static FT_Error
  51 TA_table_build_cvt(FT_Byte** cvt,
  52                    FT_ULong* cvt_len,
  53                    SFNT* sfnt,
  54                    FONT* font)
  55 {
  56   TA_LatinAxis haxis;
  57   TA_LatinAxis vaxis;
  58
  59   FT_UInt i;
  60   FT_UInt buf_len;
  61   FT_UInt len;
  62   FT_Byte* buf;
  63   FT_Byte* buf_p;
  64
  65   FT_Error error;
  66
  67
  68   error = TA_sfnt_compute_global_hints(sfnt, font);
  69   if (error)
  70     return error;
  71
  72   haxis = &((TA_LatinMetrics)font->loader->hints.metrics)->axis[0];
  73   vaxis = &((TA_LatinMetrics)font->loader->hints.metrics)->axis[1];
  74
  75   buf_len = 2 * (cvtl_max_runtime /* runtime values */
  76                  + 2 /* vertical and horizontal standard width */
  77                  + haxis->width_count
  78                  + vaxis->width_count
  79                  + 2 * vaxis->blue_count);
  80
  81   /* buffer length must be a multiple of four */
  82   len = (buf_len + 3) & ~3;
  83   buf = (FT_Byte*)malloc(len);
  84   if (!buf)
  85     return FT_Err_Out_Of_Memory;
  86
  87   /* pad end of buffer with zeros */
  88   buf[len - 1] = 0x00;
  89   buf[len - 2] = 0x00;
  90   buf[len - 3] = 0x00;
  91
  92   buf_p = buf;
  93
  94   /* some CVT values are initialized (and modified) at runtime; */
  95   /* see the `cvtl_xxx' macros in tabytecode.h */
  96   for (i = 0; i < cvtl_max_runtime; i++)
  97   {
  98     *(buf_p++) = 0;
  99     *(buf_p++) = 0;
 100   }
 101
 102   if (haxis->width_count > 0)
 103   {
 104     *(buf_p++) = HIGH(haxis->widths[0].org);
 105     *(buf_p++) = LOW(haxis->widths[0].org);
 106   }
 107   else
 108   {
 109     *(buf_p++) = 0;
 110     *(buf_p++) = 50;
 111   }
 112   if (vaxis->width_count > 0)
 113   {
 114     *(buf_p++) = HIGH(vaxis->widths[0].org);
 115     *(buf_p++) = LOW(vaxis->widths[0].org);
 116   }
 117   else
 118   {
 119     *(buf_p++) = 0;
 120     *(buf_p++) = 50;
 121   }
 122
 123   for (i = 0; i < haxis->width_count; i++)
 124   {
 125     if (haxis->widths[i].org > 0xFFFF)
 126       goto Err;
 127     *(buf_p++) = HIGH(haxis->widths[i].org);
 128     *(buf_p++) = LOW(haxis->widths[i].org);
 129   }
 130
 131   for (i = 0; i < vaxis->width_count; i++)
 132   {
 133     if (vaxis->widths[i].org > 0xFFFF)
 134       goto Err;
 135     *(buf_p++) = HIGH(vaxis->widths[i].org);
 136     *(buf_p++) = LOW(vaxis->widths[i].org);
 137   }
 138
 139   for (i = 0; i < vaxis->blue_count; i++)
 140   {
 141     if (vaxis->blues[i].ref.org > 0xFFFF)
 142       goto Err;
 143     *(buf_p++) = HIGH(vaxis->blues[i].ref.org);
 144     *(buf_p++) = LOW(vaxis->blues[i].ref.org);
 145   }
 146
 147   for (i = 0; i < vaxis->blue_count; i++)
 148   {
 149     if (vaxis->blues[i].shoot.org > 0xFFFF)
 150       goto Err;
 151     *(buf_p++) = HIGH(vaxis->blues[i].shoot.org);
 152     *(buf_p++) = LOW(vaxis->blues[i].shoot.org);
 153   }
 154
 155   *cvt = buf;
 156   *cvt_len = buf_len;
 157
 158   return FT_Err_Ok;
 159
 160 Err:
 161   free(buf);
 162   return TA_Err_Hinter_Overflow;
 163 }
 164
 165
 166 FT_Error
 167 TA_sfnt_build_cvt_table(SFNT* sfnt,
 168                         FONT* font)
 169 {
 170   FT_Error error;
 171
 172   FT_Byte* cvt_buf;
 173   FT_ULong cvt_len;
 174
 175
 176   error = TA_sfnt_add_table_info(sfnt);
 177   if (error)
 178     return error;
 179
 180   error = TA_table_build_cvt(&cvt_buf, &cvt_len, sfnt, font);
 181   if (error)
 182     return error;
 183
 184   /* in case of success, `cvt_buf' gets linked */
 185   /* and is eventually freed in `TA_font_unload' */
 186   error = TA_font_add_table(font,
 187                             &sfnt->table_infos[sfnt->num_table_infos - 1],
 188                             TTAG_cvt, cvt_len, cvt_buf);
 189   if (error)
 190   {
 191     free(cvt_buf);
 192     return error;
 193   }
 194
 195   return FT_Err_Ok;
 196 }
 197
 198 /* end of tacvt.c */