src/ttfautohint.c

   1 /* ttfautohint.c */
   2
   3 /* written 2011 by Werner Lemberg <wl@gnu.org> */
   4
   5 /* This file needs FreeType 2.4.5 or newer. */
   6
   7
   8 #include <config.h>
   9 #include <stdio.h>
  10
  11 #include <ft2build.h>
  12 #include FT_FREETYPE_H
  13 #include FT_TRUETYPE_TAGS_H
  14
  15 #include "ttfautohint.h"
  16
  17
  18 typedef struct SFNT_Table_ {
  19   FT_ULong tag;
  20   FT_ULong len;
  21   FT_Byte* buf;
  22 } SFNT_Table;
  23
  24
  25 TA_Error
  26 TTF_autohint(FILE *in,
  27              FILE *out)
  28 {
  29   FT_Library lib = NULL;
  30   FT_Face face = NULL;
  31   FT_Long num_faces = 0;
  32   FT_ULong num_tables = 0;
  33
  34   FT_Byte* in_buf;
  35   size_t in_len;
  36
  37   SFNT_Table* SFNT_Tables = NULL;
  38   FT_ULong glyf_idx;
  39
  40   FT_Error error;
  41
  42   FT_ULong i;
  43
  44
  45   /*** load font into memory ***/
  46
  47   fseek(in, 0, SEEK_END);
  48   in_len = ftell(in);
  49   fseek(in, 0, SEEK_SET);
  50
  51   /* a TTF can never be that small */
  52   if (in_len < 100)
  53     return FT_Err_Invalid_Argument;
  54
  55   in_buf = (FT_Byte*)malloc(in_len);
  56   if (!in_buf)
  57     return FT_Err_Out_Of_Memory;
  58
  59   if (fread(in_buf, 1, in_len, in) != in_len)
  60   {
  61     error = FT_Err_Invalid_Stream_Read;
  62     goto Err;
  63   }
  64
  65   error = FT_Init_FreeType(&lib);
  66   if (error)
  67     goto Err;
  68
  69   error = FT_New_Memory_Face(lib, in_buf, in_len, -1, &face);
  70   if (error)
  71     goto Err;
  72   num_faces = face->num_faces;
  73   FT_Done_Face(face);
  74
  75   error = FT_New_Memory_Face(lib, in_buf, in_len, 0, &face);
  76   if (error)
  77     goto Err;
  78
  79   /* check that font is TTF */
  80   if (!FT_IS_SFNT(face))
  81   {
  82     error = FT_Err_Invalid_Argument;
  83     goto Err;
  84   }
  85
  86   error = FT_Sfnt_Table_Info(face, 0, NULL, &num_tables);
  87   if (error)
  88     goto Err;
  89
  90   SFNT_Tables = (SFNT_Table*)calloc(1, num_tables * sizeof (SFNT_Table));
  91   if (!SFNT_Tables)
  92   {
  93     error = FT_Err_Out_Of_Memory;
  94     goto Err;
  95   }
  96
  97   /* collect SFNT table data */
  98   glyf_idx = num_tables;
  99   for (i = 0; i < num_tables; i++)
 100   {
 101     FT_ULong tag, len;
 102
 103
 104     error = FT_Sfnt_Table_Info(face, i, &tag, &len);
 105     if (error && error != FT_Err_Table_Missing)
 106       goto Err;
 107
 108     if (!error)
 109     {
 110       if (tag == TTAG_glyf)
 111         glyf_idx = i;
 112
 113       /* ignore tables which we are going to create by ourselves */
 114       if (!(tag == TTAG_fpgm
 115             || tag == TTAG_prep
 116             || tag == TTAG_cvt))
 117       {
 118         SFNT_Tables[i].tag = tag;
 119         SFNT_Tables[i].len = len;
 120       }
 121     }
 122   }
 123
 124   /* no (non-empty) `glyf' table; this can't be a TTF with outlines */
 125   if (glyf_idx == num_tables)
 126   {
 127     error = FT_Err_Invalid_Argument;
 128     goto Err;
 129   }
 130
 131
 132   /*** split font into SFNT tables ***/
 133
 134   {
 135     SFNT_Table* stp = SFNT_Tables;
 136
 137
 138     for (i = 0; i < num_tables; i++)
 139     {
 140       if (stp->len)
 141       {
 142         stp->buf = (FT_Byte*)malloc(stp->len);
 143         if (!stp->buf)
 144         {
 145           error = FT_Err_Out_Of_Memory;
 146           goto Err;
 147         }
 148
 149         error = FT_Load_Sfnt_Table(face, stp->tag, 0, stp->buf, &stp->len);
 150         if (error)
 151           goto Err;
 152
 153         stp++;
 154       }
 155     }
 156   }
 157
 158   /* compute global hints */
 159   /* construct `fpgm' table */
 160   /* construct `prep' table */
 161   /* construct `cvt ' table */
 162
 163   /* split `glyf' table */
 164   /* handle all glyphs in a loop */
 165     /* strip bytecode */
 166     /* hint the glyph */
 167     /* construct bytecode */
 168
 169   /* construct `glyf' table */
 170   /* build font from SFNT tables */
 171   /* write font from memory */
 172
 173   error = TA_Err_Ok;
 174
 175 Err:
 176   /* in case of error it is expected that the unallocated pointers */
 177   /* are NULL (and counters are zero) */
 178   for (i = 0; i < num_tables; i++)
 179     free(SFNT_Tables[i].buf);
 180   free(SFNT_Tables);
 181   FT_Done_Face(face);
 182   FT_Done_FreeType(lib);
 183   free(in_buf);
 184
 185   return error;
 186 }
 187
 188 /* end of ttfautohint.c */