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
 108   ELSE,
 109     PUSHB_2,
 110       sal_scale,
 111       sal_0x10000,
 112     RS,
 113     WS,
 114   EIF,
 115
 116 };
 117
 118 unsigned char PREP(compute_extra_light_a) [] = {
 119
 120   /* compute (vertical) `extra_light' flag */
 121   PUSHB_3,
 122     sal_is_extra_light,
 123     40,
 124
 125 };
 126
 127 /*  %c, index of vertical standard_width */
 128
 129 unsigned char PREP(compute_extra_light_b) [] = {
 130
 131   RCVT,
 132   GT, /* standard_width < 40 */
 133   WS,
 134
 135 };
 136
 137 unsigned char PREP(round_blues_a) [] = {
 138
 139   /* use discrete values for blue zone widths */
 140   PUSHB_4,
 141
 142 };
 143
 144 /*  %c, first blue ref index */
 145 /*  %c, last blue ref index */
 146
 147 unsigned char PREP(round_blues_b) [] = {
 148
 149     bci_blue_round,
 150     bci_loop,
 151   CALL
 152
 153 };
 154
 155
 156 #define COPY_PREP(snippet_name) \
 157           memcpy(buf_p, prep_ ## snippet_name, \
 158                  sizeof (prep_ ## snippet_name)); \
 159           buf_p += sizeof (prep_ ## snippet_name);
 160
 161 static FT_Error
 162 TA_table_build_prep(FT_Byte** prep,
 163                     FT_ULong* prep_len,
 164                     FONT* font)
 165 {
 166   TA_LatinAxis vaxis;
 167   TA_LatinBlue blue_adjustment;
 168   FT_UInt i;
 169
 170   FT_UInt buf_len;
 171   FT_UInt len;
 172   FT_Byte* buf;
 173   FT_Byte* buf_p;
 174
 175
 176   vaxis = &((TA_LatinMetrics)font->loader->hints.metrics)->axis[1];
 177   blue_adjustment = NULL;
 178
 179   for (i = 0; i < vaxis->blue_count; i++)
 180   {
 181     if (vaxis->blues[i].flags & TA_LATIN_BLUE_ADJUSTMENT)
 182     {
 183       blue_adjustment = &vaxis->blues[i];
 184       break;
 185     }
 186   }
 187
 188   buf_len = sizeof (PREP(store_0x10000));
 189
 190   if (blue_adjustment)
 191     buf_len += sizeof (PREP(align_top_a))
 192                + 1
 193                + sizeof (PREP(align_top_b))
 194                + sizeof (PREP(loop_cvt_a))
 195                + 2
 196                + sizeof (PREP(loop_cvt_b))
 197                + 2
 198                + sizeof (PREP(loop_cvt_c))
 199                + 2
 200                + sizeof (PREP(loop_cvt_d));
 201
 202   buf_len += sizeof (PREP(compute_extra_light_a))
 203              + 1
 204              + sizeof (PREP(compute_extra_light_b));
 205
 206   if (CVT_BLUES_SIZE(font))
 207     buf_len += sizeof (PREP(round_blues_a))
 208                + 2
 209                + sizeof (PREP(round_blues_b));
 210
 211   /* buffer length must be a multiple of four */
 212   len = (buf_len + 3) & ~3;
 213   buf = (FT_Byte*)malloc(len);
 214   if (!buf)
 215     return FT_Err_Out_Of_Memory;
 216
 217   /* pad end of buffer with zeros */
 218   buf[len - 1] = 0x00;
 219   buf[len - 2] = 0x00;
 220   buf[len - 3] = 0x00;
 221
 222   /* copy cvt program into buffer and fill in the missing variables */
 223   buf_p = buf;
 224
 225   COPY_PREP(store_0x10000);
 226
 227   if (blue_adjustment)
 228   {
 229     COPY_PREP(align_top_a);
 230     *(buf_p++) = (unsigned char)(CVT_BLUE_SHOOTS_OFFSET(font)
 231                                  + blue_adjustment - vaxis->blues);
 232     COPY_PREP(align_top_b);
 233
 234     COPY_PREP(loop_cvt_a);
 235     *(buf_p++) = (unsigned char)CVT_VERT_WIDTHS_OFFSET(font);
 236     *(buf_p++) = (unsigned char)(CVT_VERT_WIDTHS_OFFSET(font)
 237                                  + CVT_VERT_WIDTHS_SIZE(font) - 1);
 238     COPY_PREP(loop_cvt_b);
 239     *(buf_p++) = (unsigned char)CVT_BLUE_REFS_OFFSET(font);
 240     *(buf_p++) = (unsigned char)(CVT_BLUE_REFS_OFFSET(font)
 241                                  + CVT_BLUES_SIZE(font) - 1);
 242     COPY_PREP(loop_cvt_c);
 243     *(buf_p++) = (unsigned char)CVT_BLUE_SHOOTS_OFFSET(font);
 244     *(buf_p++) = (unsigned char)(CVT_BLUE_SHOOTS_OFFSET(font)
 245                                  + CVT_BLUES_SIZE(font) - 1);
 246     COPY_PREP(loop_cvt_d);
 247   }
 248
 249   COPY_PREP(compute_extra_light_a);
 250   *(buf_p++) = (unsigned char)CVT_VERT_STANDARD_WIDTH_OFFSET(font);
 251   COPY_PREP(compute_extra_light_b);
 252
 253   if (CVT_BLUES_SIZE(font))
 254   {
 255     COPY_PREP(round_blues_a);
 256     *(buf_p++) = (unsigned char)CVT_BLUE_REFS_OFFSET(font);
 257     *(buf_p++) = (unsigned char)(CVT_BLUE_REFS_OFFSET(font)
 258                                  + CVT_BLUES_SIZE(font) - 1);
 259     COPY_PREP(round_blues_b);
 260   }
 261
 262   *prep = buf;
 263   *prep_len = buf_len;
 264
 265   return FT_Err_Ok;
 266 }
 267
 268
 269 FT_Error
 270 TA_sfnt_build_prep_table(SFNT* sfnt,
 271                          FONT* font)
 272 {
 273   FT_Error error;
 274
 275   FT_Byte* prep_buf;
 276   FT_ULong prep_len;
 277
 278
 279   error = TA_sfnt_add_table_info(sfnt);
 280   if (error)
 281     return error;
 282
 283   error = TA_table_build_prep(&prep_buf, &prep_len, font);
 284   if (error)
 285     return error;
 286
 287   /* in case of success, `prep_buf' gets linked */
 288   /* and is eventually freed in `TA_font_unload' */
 289   error = TA_font_add_table(font,
 290                             &sfnt->table_infos[sfnt->num_table_infos - 1],
 291                             TTAG_prep, prep_len, prep_buf);
 292   if (error)
 293   {
 294     free(prep_buf);
 295     return error;
 296   }
 297
 298   return FT_Err_Ok;
 299 }
 300
 301 /* end of taprep.c */