ttobjs.h 18.3 KB
Newer Older
David Turner's avatar
David Turner committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
/***************************************************************************/
/*                                                                         */
/*  ttobjs.h                                                               */
/*                                                                         */
/*    Objects manager (specification).                                     */
/*                                                                         */
/*  Copyright 1996-1999 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used        */
/*  modified and distributed under the terms of the FreeType project       */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#ifndef TTOBJS_H
#define TTOBJS_H


23
24
#include <freetype/internal/ftobjs.h>
#include <freetype/internal/tttypes.h>
David Turner's avatar
David Turner committed
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
#include <tterrors.h>


#ifdef __cplusplus
  extern "C" {
#endif


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    TT_Driver                                                          */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to a TrueType driver object.                              */
  /*                                                                       */
  typedef struct TT_DriverRec_*  TT_Driver;


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    TT_Instance                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to a TrueType size object.                                */
  /*                                                                       */
  typedef struct TT_SizeRec_*  TT_Size;


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    TT_GlyphSlot                                                       */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to a TrueType glyph slot object.                          */
  /*                                                                       */
  /* <Note>                                                                */
  /*    This is a direct typedef of FT_GlyphSlot, as there is nothing      */
  /*    specific about the TrueType glyph slot.                            */
  /*                                                                       */
  typedef FT_GlyphSlot  TT_GlyphSlot;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_GraphicsState                                                   */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The TrueType graphics state used during bytecode interpretation.   */
  /*                                                                       */
  typedef struct  TT_GraphicsState_
  {
    TT_UShort      rp0;
    TT_UShort      rp1;
    TT_UShort      rp2;

    TT_UnitVector  dualVector;
    TT_UnitVector  projVector;
    TT_UnitVector  freeVector;

    TT_Long        loop;
    TT_F26Dot6     minimum_distance;
    TT_Int         round_state;

    TT_Bool        auto_flip;
    TT_F26Dot6     control_value_cutin;
    TT_F26Dot6     single_width_cutin;
    TT_F26Dot6     single_width_value;
    TT_Short       delta_base;
    TT_Short       delta_shift;

    TT_Byte        instruct_control;
    TT_Bool        scan_control;
    TT_Int         scan_type;

    TT_UShort      gep0;
    TT_UShort      gep1;
    TT_UShort      gep2;

  } TT_GraphicsState;


  /*************************************************************************/
  /*                                                                       */
  /*  EXECUTION SUBTABLES                                                  */
  /*                                                                       */
  /*  These sub-tables relate to instruction execution.                    */
  /*                                                                       */
  /*************************************************************************/


#define TT_MAX_CODE_RANGES  3


  /*************************************************************************/
  /*                                                                       */
  /* There can only be 3 active code ranges at once:                       */
  /*   - the Font Program                                                  */
  /*   - the CVT Program                                                   */
  /*   - a glyph's instructions set                                        */
  /*                                                                       */
  typedef enum  TT_CodeRange_Tag_
  {
    tt_coderange_none = 0,
    tt_coderange_font,
    tt_coderange_cvt,
    tt_coderange_glyph

  } TT_CodeRange_Tag;


  typedef struct  TT_CodeRange_
  {
    TT_Byte*  base;
    TT_ULong  size;

  } TT_CodeRange;

  typedef TT_CodeRange  TT_CodeRangeTable[TT_MAX_CODE_RANGES];


  /*************************************************************************/
  /*                                                                       */
  /* Defines a function/instruction definition record.                     */
  /*                                                                       */
  typedef struct  TT_DefRecord_
  {
    TT_Int   range;      /* in which code range is it located? */
    TT_Long  start;      /* where does it start?               */
    TT_UInt  opc;        /* function #, or instruction code    */
    TT_Bool  active;     /* is it active?                      */

  } TT_DefRecord, *TT_DefArray;



  /*************************************************************************/
  /*                                                                       */
  /* Subglyph transformation record.                                       */
  /*                                                                       */
  typedef struct  TT_Transform_
  {
    TT_Fixed    xx, xy;     /* transformation matrix coefficients */
    TT_Fixed    yx, yy;
    TT_F26Dot6  ox, oy;     /* offsets        */

  } TT_Transform;


  /*************************************************************************/
  /*                                                                       */
  /* Subglyph loading record.  Used to load composite components.          */
  /*                                                                       */
  typedef struct  TT_SubglyphRec_
  {
    TT_Long       index;        /* subglyph index; initialized with -1 */
    TT_Bool       is_scaled;    /* is the subglyph scaled?             */
    TT_Bool       is_hinted;    /* should it be hinted?                */
    TT_Bool       preserve_pps; /* preserve phantom points?            */

    TT_Long       file_offset;

    TT_BBox       bbox;
    TT_Pos        left_bearing;
    TT_Pos        advance;

194
    FT_GlyphZone  zone;
David Turner's avatar
David Turner committed
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313

    TT_Long       arg1;         /* first argument                      */
    TT_Long       arg2;         /* second argument                     */

    TT_UShort     element_flag; /* current load element flag           */

    TT_Transform  transform;    /* transformation matrix               */

    TT_Vector     pp1, pp2;     /* phantom points                      */

  } TT_SubGlyphRec, *TT_SubGlyph_Stack;


  /*************************************************************************/
  /*                                                                       */
  /* A note regarding non-squared pixels:                                  */
  /*                                                                       */
  /* (This text will probably go into some docs at some time, for now, it  */
  /*  is kept here to explain some definitions in the TIns_Metrics         */
  /*  record).                                                             */
  /*                                                                       */
  /* The CVT is a one-dimensional array containing values that control     */
  /* certain important characteristics in a font, like the height of all   */
  /* capitals, all lowercase letter, default spacing or stem width/height. */
  /*                                                                       */
  /* These values are found in FUnits in the font file, and must be scaled */
  /* to pixel coordinates before being used by the CVT and glyph programs. */
  /* Unfortunately, when using distinct x and y resolutions (or distinct x */
  /* and y pointsizes), there are two possible scalings.                   */
  /*                                                                       */
  /* A first try was to implement a `lazy' scheme where all values were    */
  /* scaled when first used.  However, while some values are always used   */
  /* in the same direction, some others are used under many different      */
  /* circumstances and orientations.                                       */
  /*                                                                       */
  /* I have found a simpler way to do the same, and it even seems to work  */
  /* in most of the cases:                                                 */
  /*                                                                       */
  /* - All CVT values are scaled to the maximum ppem size.                 */
  /*                                                                       */
  /* - When performing a read or write in the CVT, a ratio factor is used  */
  /*   to perform adequate scaling.  Example:                              */
  /*                                                                       */
  /*     x_ppem = 14                                                       */
  /*     y_ppem = 10                                                       */
  /*                                                                       */
  /*   We choose ppem = x_ppem = 14 as the CVT scaling size.  All cvt      */
  /*   entries are scaled to it.                                           */
  /*                                                                       */
  /*     x_ratio = 1.0                                                     */
  /*     y_ratio = y_ppem/ppem (< 1.0)                                     */
  /*                                                                       */
  /*   We compute the current ratio like:                                  */
  /*                                                                       */
  /*   - If projVector is horizontal,                                      */
  /*       ratio = x_ratio = 1.0                                           */
  /*                                                                       */
  /*   - if projVector is vertical,                                        */
  /*       ratio = y_ratio                                                 */
  /*                                                                       */
  /*   - else,                                                             */
  /*       ratio = sqrt( (proj.x * x_ratio) ^ 2 + (proj.y * y_ratio) ^ 2 ) */
  /*                                                                       */
  /*   Reading a cvt value returns                                         */
  /*     ratio * cvt[index]                                                */
  /*                                                                       */
  /*   Writing a cvt value in pixels:                                      */
  /*     cvt[index] / ratio                                                */
  /*                                                                       */
  /*   The current ppem is simply                                          */
  /*     ratio * ppem                                                      */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* Metrics used by the TrueType size and context objects.                */
  /*                                                                       */
  typedef struct  TT_Size_Metrics_
  {
    /* for non-square pixels */
    TT_Long     x_ratio;
    TT_Long     y_ratio;

    TT_UShort   ppem;               /* maximum ppem size              */
    TT_Long     ratio;              /* current ratio                  */
    TT_Fixed    scale;

    TT_F26Dot6  compensations[4];   /* device-specific compensations  */

    TT_Bool     valid;

    TT_Bool     rotated;            /* `is the glyph rotated?'-flag   */
    TT_Bool     stretched;          /* `is the glyph stretched?'-flag */

  } TT_Size_Metrics;


  /*************************************************************************/
  /*                                                                       */
  /* FreeType execution context type.                                      */
  /*                                                                       */
  /* This is a forward declaration; the full specification is in the file  */
  /* `ttinterp.h'.                                                         */
  /*                                                                       */
  typedef struct TT_ExecContextRec_*  TT_ExecContext;


  /***********************************************************************/
  /*                                                                     */
  /* TrueType size class.                                                */
  /*                                                                     */
  typedef struct  TT_SizeRec_
  {
    FT_SizeRec         root;

    TT_Size_Metrics    ttmetrics;

314
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
David Turner's avatar
David Turner committed
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
    TT_UInt            num_function_defs; /* number of function definitions */
    TT_UInt            max_function_defs;
    TT_DefArray        function_defs;     /* table of function definitions  */

    TT_UInt            num_instruction_defs;  /* number of ins. definitions */
    TT_UInt            max_instruction_defs;
    TT_DefArray        instruction_defs;      /* table of ins. definitions  */

    TT_UInt            max_func;
    TT_UInt            max_ins;

    TT_CodeRangeTable  codeRangeTable;

    TT_GraphicsState   GS;

    TT_ULong           cvt_size;      /* the scaled control value table */
    TT_Long*           cvt;

    TT_UShort          storage_size; /* The storage area is now part of */
    TT_Long*           storage;      /* the instance                    */

336
    FT_GlyphZone       twilight;     /* The instance's twilight zone    */
David Turner's avatar
David Turner committed
337
338
339
340
341
342
343
344
345
346

    /* debugging variables */

    /* When using the debugger, we must keep the */
    /* execution context tied to the instance    */
    /* object rather than asking it on demand.   */

    TT_Bool            debug;
    TT_ExecContext     context;

347
348
#endif /* TT_CONFIG_OPTION_BYTECODE_INTERPRETER */

David Turner's avatar
David Turner committed
349
350
351
352
353
354
355
356
357
358
  } TT_SizeRec;


  /***********************************************************************/
  /*                                                                     */
  /* TrueType driver class.                                              */
  /*                                                                     */
  typedef struct  TT_DriverRec_
  {
    FT_DriverRec    root;
359
360
    TT_ExecContext  context;  /* execution context        */
    FT_GlyphZone    zone;     /* glyph loader points zone */
David Turner's avatar
David Turner committed
361
362
363
364
365
366

    void*           extension_component;

  } TT_DriverRec;


367
368
 /*************************************************************************/
 /*  Face Funcs                                                           */ 
David Turner's avatar
David Turner committed
369

370
371
372
373
374
  LOCAL_DEF TT_Error  TT_Init_Face( FT_Stream      stream,
                                    TT_Face        face,
                                    TT_Int         face_index,
                                    TT_Int         num_params,
                                    FT_Parameter*  params );
David Turner's avatar
David Turner committed
375

376
  LOCAL_DEF void      TT_Done_Face( TT_Face  face );
David Turner's avatar
David Turner committed
377
378


379
380
 /*************************************************************************/
 /*  Size funcs                                                           */ 
David Turner's avatar
David Turner committed
381

382
383
384
  LOCAL_DEF TT_Error  TT_Init_Size ( TT_Size  size );
  LOCAL_DEF void      TT_Done_Size ( TT_Size  size );
  LOCAL_DEF TT_Error  TT_Reset_Size( TT_Size  size );
David Turner's avatar
David Turner committed
385
386


387
388
 /*************************************************************************/
 /*  GlyphSlot funcs                                                      */ 
David Turner's avatar
David Turner committed
389

390
391
  LOCAL_DEF TT_Error  TT_Init_GlyphSlot( TT_GlyphSlot  slot );
  LOCAL_DEF void      TT_Done_GlyphSlot( TT_GlyphSlot  slot );
David Turner's avatar
David Turner committed
392
393


394
395
 /*************************************************************************/
 /*  Driver funcs                                                         */ 
David Turner's avatar
David Turner committed
396

397
398
  LOCAL_DEF  TT_Error  TT_Init_Driver( TT_Driver  driver );
  LOCAL_DEF  void      TT_Done_Driver( TT_Driver  driver );
David Turner's avatar
David Turner committed
399
400
401
402
403
404
405
406
407
408
409


#ifdef __cplusplus
  }
#endif


#endif /* TTOBJS_H */


/* END */