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   FT_Int32 load_flags;
  27
  28
  29   error = FT_Select_Charmap(face, FT_ENCODING_UNICODE);
  30   if (error)
  31   {
  32     if (font->symbol)
  33     {
  34       error = FT_Select_Charmap(face, FT_ENCODING_MS_SYMBOL);
  35       if (error)
  36         return TA_Err_Missing_Symbol_CMap;
  37     }
  38     else
  39       return TA_Err_Missing_Unicode_CMap;
  40   }
  41
  42   if (font->symbol)
  43     idx = 0;
  44   else
  45   {
  46     /* load glyph `o' to trigger all initializations */
  47     /* XXX make this configurable for non-latin scripts */
  48     /* XXX make this configurable to use a different letter */
  49     idx = FT_Get_Char_Index(face, 'o');
  50     if (!idx)
  51       return TA_Err_Missing_Glyph;
  52   }
  53
  54   load_flags = 1 << 29; /* vertical hinting only */
  55   error = ta_loader_load_glyph(font, face, idx, load_flags);
  56
  57   return error;
  58 }
  59
  60
  61 static FT_Error
  62 TA_table_build_cvt(FT_Byte** cvt,
  63                    FT_ULong* cvt_len,
  64                    SFNT* sfnt,
  65                    FONT* font)
  66 {
  67   TA_LatinAxis haxis;
  68   TA_LatinAxis vaxis;
  69
  70   FT_UInt hwidth_count;
  71   FT_UInt vwidth_count;
  72   FT_UInt blue_count;
  73
  74   FT_UInt i;
  75   FT_UInt buf_len;
  76   FT_UInt len;
  77   FT_Byte* buf;
  78   FT_Byte* buf_p;
  79
  80   FT_Error error;
  81
  82
  83   error = TA_sfnt_compute_global_hints(sfnt, font);
  84   if (error)
  85     return error;
  86
  87   if (font->loader->hints.metrics->clazz->script == TA_SCRIPT_DUMMY)
  88   {
  89     haxis = NULL;
  90     vaxis = NULL;
  91
  92     hwidth_count = 0;
  93     vwidth_count = 0;
  94     blue_count = 0;
  95   }
  96   else
  97   {
  98     haxis = &((TA_LatinMetrics)font->loader->hints.metrics)->axis[0];
  99     vaxis = &((TA_LatinMetrics)font->loader->hints.metrics)->axis[1];
 100
 101     hwidth_count = haxis->width_count;
 102     vwidth_count = vaxis->width_count;
 103     blue_count = vaxis->blue_count + 2; /* with artificial blue zones */
 104   }
 105
 106   buf_len = 2 * (cvtl_max_runtime /* runtime values */
 107                  + 2 /* vertical and horizontal standard width */
 108                  + hwidth_count
 109                  + vwidth_count
 110                  + 2 * blue_count);
 111
 112   /* buffer length must be a multiple of four */
 113   len = (buf_len + 3) & ~3;
 114   buf = (FT_Byte*)malloc(len);
 115   if (!buf)
 116     return FT_Err_Out_Of_Memory;
 117
 118   /* pad end of buffer with zeros */
 119   buf[len - 1] = 0x00;
 120   buf[len - 2] = 0x00;
 121   buf[len - 3] = 0x00;
 122
 123   buf_p = buf;
 124
 125   /* some CVT values are initialized (and modified) at runtime; */
 126   /* see the `cvtl_xxx' macros in tabytecode.h */
 127   for (i = 0; i < cvtl_max_runtime; i++)
 128   {
 129     *(buf_p++) = 0;
 130     *(buf_p++) = 0;
 131   }
 132
 133   if (hwidth_count > 0)
 134   {
 135     *(buf_p++) = HIGH(haxis->widths[0].org);
 136     *(buf_p++) = LOW(haxis->widths[0].org);
 137   }
 138   else
 139   {
 140     *(buf_p++) = 0;
 141     *(buf_p++) = 50;
 142   }
 143   if (vwidth_count > 0)
 144   {
 145     *(buf_p++) = HIGH(vaxis->widths[0].org);
 146     *(buf_p++) = LOW(vaxis->widths[0].org);
 147   }
 148   else
 149   {
 150     *(buf_p++) = 0;
 151     *(buf_p++) = 50;
 152   }
 153
 154   for (i = 0; i < hwidth_count; i++)
 155   {
 156     if (haxis->widths[i].org > 0xFFFF)
 157       goto Err;
 158     *(buf_p++) = HIGH(haxis->widths[i].org);
 159     *(buf_p++) = LOW(haxis->widths[i].org);
 160   }
 161
 162   for (i = 0; i < vwidth_count; i++)
 163   {
 164     if (vaxis->widths[i].org > 0xFFFF)
 165       goto Err;
 166     *(buf_p++) = HIGH(vaxis->widths[i].org);
 167     *(buf_p++) = LOW(vaxis->widths[i].org);
 168   }
 169
 170   for (i = 0; i < blue_count; i++)
 171   {
 172     if (vaxis->blues[i].ref.org > 0xFFFF)
 173       goto Err;
 174     *(buf_p++) = HIGH(vaxis->blues[i].ref.org);
 175     *(buf_p++) = LOW(vaxis->blues[i].ref.org);
 176   }
 177
 178   for (i = 0; i < blue_count; i++)
 179   {
 180     if (vaxis->blues[i].shoot.org > 0xFFFF)
 181       goto Err;
 182     *(buf_p++) = HIGH(vaxis->blues[i].shoot.org);
 183     *(buf_p++) = LOW(vaxis->blues[i].shoot.org);
 184   }
 185
 186   *cvt = buf;
 187   *cvt_len = buf_len;
 188
 189   return FT_Err_Ok;
 190
 191 Err:
 192   free(buf);
 193   return TA_Err_Hinter_Overflow;
 194 }
 195
 196
 197 FT_Error
 198 TA_sfnt_build_cvt_table(SFNT* sfnt,
 199                         FONT* font)
 200 {
 201   FT_Error error = FT_Err_Ok;
 202
 203   SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
 204   glyf_Data* data = (glyf_Data*)glyf_table->data;
 205
 206   FT_Byte* cvt_buf;
 207   FT_ULong cvt_len;
 208
 209
 210   error = TA_sfnt_add_table_info(sfnt);
 211   if (error)
 212     goto Exit;
 213
 214   /* `glyf', `cvt', `fpgm', and `prep' are always used in parallel */
 215   if (glyf_table->processed)
 216   {
 217     sfnt->table_infos[sfnt->num_table_infos - 1] = data->cvt_idx;
 218     goto Exit;
 219   }
 220
 221   error = TA_table_build_cvt(&cvt_buf, &cvt_len, sfnt, font);
 222   if (error)
 223     goto Exit;
 224
 225   /* in case of success, `cvt_buf' gets linked */
 226   /* and is eventually freed in `TA_font_unload' */
 227   error = TA_font_add_table(font,
 228                             &sfnt->table_infos[sfnt->num_table_infos - 1],
 229                             TTAG_cvt, cvt_len, cvt_buf);
 230   if (error)
 231     free(cvt_buf);
 232   else
 233     data->cvt_idx = sfnt->table_infos[sfnt->num_table_infos - 1];
 234
 235 Exit:
 236   return error;
 237 }
 238
 239 /* end of tacvt.c */