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
  33   FT_Byte* in_buf;
  34   size_t in_len;
  35
  36   SFNT_Table* SFNT_Table_Infos = NULL;
  37   FT_ULong num_table_infos = 0;
  38
  39   FT_ULong glyf_idx;
  40
  41   FT_Error error;
  42
  43   FT_ULong j;
  44
  45
  46   /*** load font into memory ***/
  47
  48   fseek(in, 0, SEEK_END);
  49   in_len = ftell(in);
  50   fseek(in, 0, SEEK_SET);
  51
  52   /* a TTF can never be that small */
  53   if (in_len < 100)
  54     return FT_Err_Invalid_Argument;
  55
  56   in_buf = (FT_Byte*)malloc(in_len);
  57   if (!in_buf)
  58     return FT_Err_Out_Of_Memory;
  59
  60   if (fread(in_buf, 1, in_len, in) != in_len)
  61   {
  62     error = FT_Err_Invalid_Stream_Read;
  63     goto Err;
  64   }
  65
  66   error = FT_Init_FreeType(&lib);
  67   if (error)
  68     goto Err;
  69
  70   error = FT_New_Memory_Face(lib, in_buf, in_len, -1, &face);
  71   if (error)
  72     goto Err;
  73   num_faces = face->num_faces;
  74   FT_Done_Face(face);
  75
  76   error = FT_New_Memory_Face(lib, in_buf, in_len, 0, &face);
  77   if (error)
  78     goto Err;
  79
  80   /* check that font is TTF */
  81   if (!FT_IS_SFNT(face))
  82   {
  83     error = FT_Err_Invalid_Argument;
  84     goto Err;
  85   }
  86
  87   error = FT_Sfnt_Table_Info(face, 0, NULL, &num_table_infos);
  88   if (error)
  89     goto Err;
  90
  91   SFNT_Table_Infos =
  92     (SFNT_Table*)calloc(1, num_table_infos * sizeof (SFNT_Table));
  93   if (!SFNT_Table_Infos)
  94   {
  95     error = FT_Err_Out_Of_Memory;
  96     goto Err;
  97   }
  98
  99   /* collect SFNT table data */
 100   glyf_idx = num_table_infos;
 101   for (j = 0; j < num_table_infos; j++)
 102   {
 103     FT_ULong tag, len;
 104
 105
 106     error = FT_Sfnt_Table_Info(face, j, &tag, &len);
 107     if (error && error != FT_Err_Table_Missing)
 108       goto Err;
 109
 110     if (!error)
 111     {
 112       if (tag == TTAG_glyf)
 113         glyf_idx = j;
 114
 115       /* ignore tables which we are going to create by ourselves */
 116       if (!(tag == TTAG_fpgm
 117             || tag == TTAG_prep
 118             || tag == TTAG_cvt))
 119       {
 120         SFNT_Table_Infos[j].tag = tag;
 121         SFNT_Table_Infos[j].len = len;
 122       }
 123     }
 124   }
 125
 126   /* no (non-empty) `glyf' table; this can't be a TTF with outlines */
 127   if (glyf_idx == num_table_infos)
 128   {
 129     error = FT_Err_Invalid_Argument;
 130     goto Err;
 131   }
 132
 133
 134   /*** split font into SFNT tables ***/
 135
 136   {
 137     SFNT_Table* sti_p = SFNT_Table_Infos;
 138
 139
 140     for (j = 0; j < num_table_infos; j++)
 141     {
 142       if (sti_p->len)
 143       {
 144         sti_p->buf = (FT_Byte*)malloc(sti_p->len);
 145         if (!sti_p->buf)
 146         {
 147           error = FT_Err_Out_Of_Memory;
 148           goto Err;
 149         }
 150
 151         error = FT_Load_Sfnt_Table(face, sti_p->tag, 0,
 152                                    sti_p->buf, &sti_p->len);
 153         if (error)
 154           goto Err;
 155
 156         sti_p++;
 157       }
 158     }
 159   }
 160
 161   /* compute global hints */
 162   /* construct `fpgm' table */
 163   /* construct `prep' table */
 164   /* construct `cvt ' table */
 165
 166   /* split `glyf' table */
 167   /* handle all glyphs in a loop */
 168     /* strip bytecode */
 169     /* hint the glyph */
 170     /* construct bytecode */
 171
 172   /* construct `glyf' table */
 173   /* build font from SFNT tables */
 174   /* write font from memory */
 175
 176   error = TA_Err_Ok;
 177
 178 Err:
 179   /* in case of error it is expected that the unallocated pointers */
 180   /* are NULL (and counters are zero) */
 181   if (SFNT_Table_Infos)
 182   {
 183     for (j = 0; j < num_table_infos; j++)
 184       free(SFNT_Table_Infos[j].buf);
 185     free(SFNT_Table_Infos);
 186   }
 187   FT_Done_Face(face);
 188   FT_Done_FreeType(lib);
 189   free(in_buf);
 190
 191   return error;
 192 }
 193
 194 /* end of ttfautohint.c */