src/taprep.c

   1 /* taprep.c */
   2
   3 /* written 2011 by Werner Lemberg <wl@gnu.org> */
   4
   5 #include "tabytecode.h"
   6
   7
   8 #define PREP(snippet_name) prep_ ## snippet_name
   9
  10 /* we often need 0x10000 which can't be pushed directly onto the stack, */
  11 /* thus we provide it in the storage area */
  12
  13 unsigned char PREP(store_0x10000) [] = {
  14
  15   PUSHB_1,
  16     sal_0x10000,
  17   PUSHW_2,
  18     0x08, /* 0x800 */
  19     0x00,
  20     0x08, /* 0x800 */
  21     0x00,
  22   MUL, /* 0x10000 */
  23   WS,
  24
  25 };
  26
  27 unsigned char PREP(align_top_a) [] = {
  28
  29   /* optimize the alignment of the top of small letters to the pixel grid */
  30
  31   PUSHB_1,
  32
  33 };
  34
  35 /*  %c, index of alignment blue zone */
  36
  37 unsigned char PREP(align_top_b) [] = {
  38
  39   RCVT,
  40   DUP,
  41   DUP,
  42   PUSHB_1,
  43     40,
  44   ADD,
  45   FLOOR, /* fitted = FLOOR(scaled + 40) */
  46   DUP, /* s: scaled scaled fitted fitted */
  47   ROLL,
  48   NEQ,
  49   IF, /* s: scaled fitted */
  50     PUSHB_1,
  51       sal_0x10000,
  52     RS,
  53     MUL, /* scaled in 16.16 format */
  54     SWAP,
  55     DIV, /* (fitted / scaled) in 16.16 format */
  56
  57     PUSHB_1,
  58       sal_scale,
  59     SWAP,
  60     WS,
  61
  62 };
  63
  64 unsigned char PREP(loop_cvt_a) [] = {
  65
  66     /* loop over vertical CVT entries */
  67     PUSHB_4,
  68
  69 };
  70
  71 /*    %c, first vertical index */
  72 /*    %c, last vertical index */
  73
  74 unsigned char PREP(loop_cvt_b) [] = {
  75
  76       bci_cvt_rescale,
  77       bci_loop,
  78     CALL,
  79
  80     /* loop over blue refs */
  81     PUSHB_4,
  82
  83 };
  84
  85 /*    %c, first blue ref index */
  86 /*    %c, last blue ref index */
  87
  88 unsigned char PREP(loop_cvt_c) [] = {
  89
  90       bci_cvt_rescale,
  91       bci_loop,
  92     CALL,
  93
  94     /* loop over blue shoots */
  95     PUSHB_4,
  96
  97 };
  98
  99 /*    %c, first blue shoot index */
 100 /*    %c, last blue shoot index */
 101
 102 unsigned char PREP(loop_cvt_d) [] = {
 103
 104       bci_cvt_rescale,
 105       bci_loop,
 106     CALL,
 107   EIF,
 108
 109 };
 110
 111 unsigned char PREP(compute_extra_light_a) [] = {
 112
 113   /* compute (vertical) `extra_light' flag */
 114   PUSHB_3,
 115     sal_is_extra_light,
 116     40,
 117
 118 };
 119
 120 /*  %c, index of vertical standard_width */
 121
 122 unsigned char PREP(compute_extra_light_b) [] = {
 123
 124   RCVT,
 125   GT, /* standard_width < 40 */
 126   WS,
 127
 128 };
 129
 130 unsigned char PREP(round_blues_a) [] = {
 131
 132   /* use discrete values for blue zone widths */
 133   PUSHB_4,
 134
 135 };
 136
 137 /*  %c, first blue ref index */
 138 /*  %c, last blue ref index */
 139
 140 unsigned char PREP(round_blues_b) [] = {
 141
 142     bci_blue_round,
 143     bci_loop,
 144   CALL
 145
 146 };
 147
 148
 149 #define COPY_PREP(snippet_name) \
 150           memcpy(buf_p, prep_ ## snippet_name, \
 151                  sizeof (prep_ ## snippet_name)); \
 152           buf_p += sizeof (prep_ ## snippet_name);
 153
 154 static FT_Error
 155 TA_table_build_prep(FT_Byte** prep,
 156                     FT_ULong* prep_len,
 157                     FONT* font)
 158 {
 159   TA_LatinAxis vaxis;
 160   TA_LatinBlue blue_adjustment;
 161   FT_UInt i;
 162
 163   FT_UInt buf_len;
 164   FT_UInt len;
 165   FT_Byte* buf;
 166   FT_Byte* buf_p;
 167
 168
 169   vaxis = &((TA_LatinMetrics)font->loader->hints.metrics)->axis[1];
 170   blue_adjustment = NULL;
 171
 172   for (i = 0; i < vaxis->blue_count; i++)
 173   {
 174     if (vaxis->blues[i].flags & TA_LATIN_BLUE_ADJUSTMENT)
 175     {
 176       blue_adjustment = &vaxis->blues[i];
 177       break;
 178     }
 179   }
 180
 181   buf_len = sizeof (PREP(store_0x10000));
 182
 183   if (blue_adjustment)
 184     buf_len += sizeof (PREP(align_top_a))
 185                + 1
 186                + sizeof (PREP(align_top_b))
 187                + sizeof (PREP(loop_cvt_a))
 188                + 2
 189                + sizeof (PREP(loop_cvt_b))
 190                + 2
 191                + sizeof (PREP(loop_cvt_c))
 192                + 2
 193                + sizeof (PREP(loop_cvt_d));
 194
 195   buf_len += sizeof (PREP(compute_extra_light_a))
 196              + 1
 197              + sizeof (PREP(compute_extra_light_b));
 198
 199   if (CVT_BLUES_SIZE(font))
 200     buf_len += sizeof (PREP(round_blues_a))
 201                + 2
 202                + sizeof (PREP(round_blues_b));
 203
 204   /* buffer length must be a multiple of four */
 205   len = (buf_len + 3) & ~3;
 206   buf = (FT_Byte*)malloc(len);
 207   if (!buf)
 208     return FT_Err_Out_Of_Memory;
 209
 210   /* pad end of buffer with zeros */
 211   buf[len - 1] = 0x00;
 212   buf[len - 2] = 0x00;
 213   buf[len - 3] = 0x00;
 214
 215   /* copy cvt program into buffer and fill in the missing variables */
 216   buf_p = buf;
 217
 218   COPY_PREP(store_0x10000);
 219
 220   if (blue_adjustment)
 221   {
 222     COPY_PREP(align_top_a);
 223     *(buf_p++) = (unsigned char)(CVT_BLUE_SHOOTS_OFFSET(font)
 224                                  + blue_adjustment - vaxis->blues);
 225     COPY_PREP(align_top_b);
 226
 227     COPY_PREP(loop_cvt_a);
 228     *(buf_p++) = (unsigned char)CVT_VERT_WIDTHS_OFFSET(font);
 229     *(buf_p++) = (unsigned char)(CVT_VERT_WIDTHS_OFFSET(font)
 230                                  + CVT_VERT_WIDTHS_SIZE(font) - 1);
 231     COPY_PREP(loop_cvt_b);
 232     *(buf_p++) = (unsigned char)CVT_BLUE_REFS_OFFSET(font);
 233     *(buf_p++) = (unsigned char)(CVT_BLUE_REFS_OFFSET(font)
 234                                  + CVT_BLUES_SIZE(font) - 1);
 235     COPY_PREP(loop_cvt_c);
 236     *(buf_p++) = (unsigned char)CVT_BLUE_SHOOTS_OFFSET(font);
 237     *(buf_p++) = (unsigned char)(CVT_BLUE_SHOOTS_OFFSET(font)
 238                                  + CVT_BLUES_SIZE(font) - 1);
 239     COPY_PREP(loop_cvt_d);
 240   }
 241
 242   COPY_PREP(compute_extra_light_a);
 243   *(buf_p++) = (unsigned char)CVT_VERT_STANDARD_WIDTH_OFFSET(font);
 244   COPY_PREP(compute_extra_light_b);
 245
 246   if (CVT_BLUES_SIZE(font))
 247   {
 248     COPY_PREP(round_blues_a);
 249     *(buf_p++) = (unsigned char)CVT_BLUE_REFS_OFFSET(font);
 250     *(buf_p++) = (unsigned char)(CVT_BLUE_REFS_OFFSET(font)
 251                                  + CVT_BLUES_SIZE(font) - 1);
 252     COPY_PREP(round_blues_b);
 253   }
 254
 255   *prep = buf;
 256   *prep_len = buf_len;
 257
 258   return FT_Err_Ok;
 259 }
 260
 261
 262 FT_Error
 263 TA_sfnt_build_prep_table(SFNT* sfnt,
 264                          FONT* font)
 265 {
 266   FT_Error error;
 267
 268   FT_Byte* prep_buf;
 269   FT_ULong prep_len;
 270
 271
 272   error = TA_sfnt_add_table_info(sfnt);
 273   if (error)
 274     return error;
 275
 276   error = TA_table_build_prep(&prep_buf, &prep_len, font);
 277   if (error)
 278     return error;
 279
 280   /* in case of success, `prep_buf' gets linked */
 281   /* and is eventually freed in `TA_font_unload' */
 282   error = TA_font_add_table(font,
 283                             &sfnt->table_infos[sfnt->num_table_infos - 1],
 284                             TTAG_prep, prep_len, prep_buf);
 285   if (error)
 286   {
 287     free(prep_buf);
 288     return error;
 289   }
 290
 291   return FT_Err_Ok;
 292 }
 293
 294 /* end of taprep.c */