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ftimage.h
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1 /****************************************************************************
2  *
3  * ftimage.h
4  *
5  * FreeType glyph image formats and default raster interface
6  * (specification).
7  *
8  * Copyright (C) 1996-2020 by
9  * David Turner, Robert Wilhelm, and Werner Lemberg.
10  *
11  * This file is part of the FreeType project, and may only be used,
12  * modified, and distributed under the terms of the FreeType project
13  * license, LICENSE.TXT. By continuing to use, modify, or distribute
14  * this file you indicate that you have read the license and
15  * understand and accept it fully.
16  *
17  */
18 
19  /**************************************************************************
20  *
21  * Note: A 'raster' is simply a scan-line converter, used to render
22  * FT_Outlines into FT_Bitmaps.
23  *
24  */
25 
26 
27 #ifndef FTIMAGE_H_
28 #define FTIMAGE_H_
29 
30 
31  /* STANDALONE_ is from ftgrays.c */
32 #ifndef STANDALONE_
33 #endif
34 
35 
37 
38 
39  /**************************************************************************
40  *
41  * @section:
42  * basic_types
43  *
44  */
45 
46 
47  /**************************************************************************
48  *
49  * @type:
50  * FT_Pos
51  *
52  * @description:
53  * The type FT_Pos is used to store vectorial coordinates. Depending on
54  * the context, these can represent distances in integer font units, or
55  * 16.16, or 26.6 fixed-point pixel coordinates.
56  */
57  typedef signed long FT_Pos;
58 
59 
60  /**************************************************************************
61  *
62  * @struct:
63  * FT_Vector
64  *
65  * @description:
66  * A simple structure used to store a 2D vector; coordinates are of the
67  * FT_Pos type.
68  *
69  * @fields:
70  * x ::
71  * The horizontal coordinate.
72  * y ::
73  * The vertical coordinate.
74  */
75  typedef struct FT_Vector_
76  {
79 
81 
82 
83  /**************************************************************************
84  *
85  * @struct:
86  * FT_BBox
87  *
88  * @description:
89  * A structure used to hold an outline's bounding box, i.e., the
90  * coordinates of its extrema in the horizontal and vertical directions.
91  *
92  * @fields:
93  * xMin ::
94  * The horizontal minimum (left-most).
95  *
96  * yMin ::
97  * The vertical minimum (bottom-most).
98  *
99  * xMax ::
100  * The horizontal maximum (right-most).
101  *
102  * yMax ::
103  * The vertical maximum (top-most).
104  *
105  * @note:
106  * The bounding box is specified with the coordinates of the lower left
107  * and the upper right corner. In PostScript, those values are often
108  * called (llx,lly) and (urx,ury), respectively.
109  *
110  * If `yMin` is negative, this value gives the glyph's descender.
111  * Otherwise, the glyph doesn't descend below the baseline. Similarly,
112  * if `ymax` is positive, this value gives the glyph's ascender.
113  *
114  * `xMin` gives the horizontal distance from the glyph's origin to the
115  * left edge of the glyph's bounding box. If `xMin` is negative, the
116  * glyph extends to the left of the origin.
117  */
118  typedef struct FT_BBox_
119  {
122 
124 
125 
126  /**************************************************************************
127  *
128  * @enum:
129  * FT_Pixel_Mode
130  *
131  * @description:
132  * An enumeration type used to describe the format of pixels in a given
133  * bitmap. Note that additional formats may be added in the future.
134  *
135  * @values:
136  * FT_PIXEL_MODE_NONE ::
137  * Value~0 is reserved.
138  *
139  * FT_PIXEL_MODE_MONO ::
140  * A monochrome bitmap, using 1~bit per pixel. Note that pixels are
141  * stored in most-significant order (MSB), which means that the
142  * left-most pixel in a byte has value 128.
143  *
144  * FT_PIXEL_MODE_GRAY ::
145  * An 8-bit bitmap, generally used to represent anti-aliased glyph
146  * images. Each pixel is stored in one byte. Note that the number of
147  * 'gray' levels is stored in the `num_grays` field of the @FT_Bitmap
148  * structure (it generally is 256).
149  *
150  * FT_PIXEL_MODE_GRAY2 ::
151  * A 2-bit per pixel bitmap, used to represent embedded anti-aliased
152  * bitmaps in font files according to the OpenType specification. We
153  * haven't found a single font using this format, however.
154  *
155  * FT_PIXEL_MODE_GRAY4 ::
156  * A 4-bit per pixel bitmap, representing embedded anti-aliased bitmaps
157  * in font files according to the OpenType specification. We haven't
158  * found a single font using this format, however.
159  *
160  * FT_PIXEL_MODE_LCD ::
161  * An 8-bit bitmap, representing RGB or BGR decimated glyph images used
162  * for display on LCD displays; the bitmap is three times wider than
163  * the original glyph image. See also @FT_RENDER_MODE_LCD.
164  *
165  * FT_PIXEL_MODE_LCD_V ::
166  * An 8-bit bitmap, representing RGB or BGR decimated glyph images used
167  * for display on rotated LCD displays; the bitmap is three times
168  * taller than the original glyph image. See also
169  * @FT_RENDER_MODE_LCD_V.
170  *
171  * FT_PIXEL_MODE_BGRA ::
172  * [Since 2.5] An image with four 8-bit channels per pixel,
173  * representing a color image (such as emoticons) with alpha channel.
174  * For each pixel, the format is BGRA, which means, the blue channel
175  * comes first in memory. The color channels are pre-multiplied and in
176  * the sRGB colorspace. For example, full red at half-translucent
177  * opacity will be represented as '00,00,80,80', not '00,00,FF,80'.
178  * See also @FT_LOAD_COLOR.
179  */
180  typedef enum FT_Pixel_Mode_
181  {
190 
191  FT_PIXEL_MODE_MAX /* do not remove */
192 
194 
195 
196  /* these constants are deprecated; use the corresponding `FT_Pixel_Mode` */
197  /* values instead. */
198 #define ft_pixel_mode_none FT_PIXEL_MODE_NONE
199 #define ft_pixel_mode_mono FT_PIXEL_MODE_MONO
200 #define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY
201 #define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2
202 #define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4
203 
204 
205  /**************************************************************************
206  *
207  * @struct:
208  * FT_Bitmap
209  *
210  * @description:
211  * A structure used to describe a bitmap or pixmap to the raster. Note
212  * that we now manage pixmaps of various depths through the `pixel_mode`
213  * field.
214  *
215  * @fields:
216  * rows ::
217  * The number of bitmap rows.
218  *
219  * width ::
220  * The number of pixels in bitmap row.
221  *
222  * pitch ::
223  * The pitch's absolute value is the number of bytes taken by one
224  * bitmap row, including padding. However, the pitch is positive when
225  * the bitmap has a 'down' flow, and negative when it has an 'up' flow.
226  * In all cases, the pitch is an offset to add to a bitmap pointer in
227  * order to go down one row.
228  *
229  * Note that 'padding' means the alignment of a bitmap to a byte
230  * border, and FreeType functions normally align to the smallest
231  * possible integer value.
232  *
233  * For the B/W rasterizer, `pitch` is always an even number.
234  *
235  * To change the pitch of a bitmap (say, to make it a multiple of 4),
236  * use @FT_Bitmap_Convert. Alternatively, you might use callback
237  * functions to directly render to the application's surface; see the
238  * file `example2.cpp` in the tutorial for a demonstration.
239  *
240  * buffer ::
241  * A typeless pointer to the bitmap buffer. This value should be
242  * aligned on 32-bit boundaries in most cases.
243  *
244  * num_grays ::
245  * This field is only used with @FT_PIXEL_MODE_GRAY; it gives the
246  * number of gray levels used in the bitmap.
247  *
248  * pixel_mode ::
249  * The pixel mode, i.e., how pixel bits are stored. See @FT_Pixel_Mode
250  * for possible values.
251  *
252  * palette_mode ::
253  * This field is intended for paletted pixel modes; it indicates how
254  * the palette is stored. Not used currently.
255  *
256  * palette ::
257  * A typeless pointer to the bitmap palette; this field is intended for
258  * paletted pixel modes. Not used currently.
259  */
260  typedef struct FT_Bitmap_
261  {
262  unsigned int rows;
263  unsigned int width;
264  int pitch;
265  unsigned char* buffer;
266  unsigned short num_grays;
267  unsigned char pixel_mode;
268  unsigned char palette_mode;
269  void* palette;
270 
272 
273 
274  /**************************************************************************
275  *
276  * @section:
277  * outline_processing
278  *
279  */
280 
281 
282  /**************************************************************************
283  *
284  * @struct:
285  * FT_Outline
286  *
287  * @description:
288  * This structure is used to describe an outline to the scan-line
289  * converter.
290  *
291  * @fields:
292  * n_contours ::
293  * The number of contours in the outline.
294  *
295  * n_points ::
296  * The number of points in the outline.
297  *
298  * points ::
299  * A pointer to an array of `n_points` @FT_Vector elements, giving the
300  * outline's point coordinates.
301  *
302  * tags ::
303  * A pointer to an array of `n_points` chars, giving each outline
304  * point's type.
305  *
306  * If bit~0 is unset, the point is 'off' the curve, i.e., a Bezier
307  * control point, while it is 'on' if set.
308  *
309  * Bit~1 is meaningful for 'off' points only. If set, it indicates a
310  * third-order Bezier arc control point; and a second-order control
311  * point if unset.
312  *
313  * If bit~2 is set, bits 5-7 contain the drop-out mode (as defined in
314  * the OpenType specification; the value is the same as the argument to
315  * the 'SCANMODE' instruction).
316  *
317  * Bits 3 and~4 are reserved for internal purposes.
318  *
319  * contours ::
320  * An array of `n_contours` shorts, giving the end point of each
321  * contour within the outline. For example, the first contour is
322  * defined by the points '0' to `contours[0]`, the second one is
323  * defined by the points `contours[0]+1` to `contours[1]`, etc.
324  *
325  * flags ::
326  * A set of bit flags used to characterize the outline and give hints
327  * to the scan-converter and hinter on how to convert/grid-fit it. See
328  * @FT_OUTLINE_XXX.
329  *
330  * @note:
331  * The B/W rasterizer only checks bit~2 in the `tags` array for the first
332  * point of each contour. The drop-out mode as given with
333  * @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and
334  * @FT_OUTLINE_INCLUDE_STUBS in `flags` is then overridden.
335  */
336  typedef struct FT_Outline_
337  {
338  short n_contours; /* number of contours in glyph */
339  short n_points; /* number of points in the glyph */
340 
341  FT_Vector* points; /* the outline's points */
342  char* tags; /* the points flags */
343  short* contours; /* the contour end points */
344 
345  int flags; /* outline masks */
346 
348 
349  /* */
350 
351  /* Following limits must be consistent with */
352  /* FT_Outline.{n_contours,n_points} */
353 #define FT_OUTLINE_CONTOURS_MAX SHRT_MAX
354 #define FT_OUTLINE_POINTS_MAX SHRT_MAX
355 
356 
357  /**************************************************************************
358  *
359  * @enum:
360  * FT_OUTLINE_XXX
361  *
362  * @description:
363  * A list of bit-field constants used for the flags in an outline's
364  * `flags` field.
365  *
366  * @values:
367  * FT_OUTLINE_NONE ::
368  * Value~0 is reserved.
369  *
370  * FT_OUTLINE_OWNER ::
371  * If set, this flag indicates that the outline's field arrays (i.e.,
372  * `points`, `flags`, and `contours`) are 'owned' by the outline
373  * object, and should thus be freed when it is destroyed.
374  *
375  * FT_OUTLINE_EVEN_ODD_FILL ::
376  * By default, outlines are filled using the non-zero winding rule. If
377  * set to 1, the outline will be filled using the even-odd fill rule
378  * (only works with the smooth rasterizer).
379  *
380  * FT_OUTLINE_REVERSE_FILL ::
381  * By default, outside contours of an outline are oriented in
382  * clock-wise direction, as defined in the TrueType specification.
383  * This flag is set if the outline uses the opposite direction
384  * (typically for Type~1 fonts). This flag is ignored by the scan
385  * converter.
386  *
387  * FT_OUTLINE_IGNORE_DROPOUTS ::
388  * By default, the scan converter will try to detect drop-outs in an
389  * outline and correct the glyph bitmap to ensure consistent shape
390  * continuity. If set, this flag hints the scan-line converter to
391  * ignore such cases. See below for more information.
392  *
393  * FT_OUTLINE_SMART_DROPOUTS ::
394  * Select smart dropout control. If unset, use simple dropout control.
395  * Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more
396  * information.
397  *
398  * FT_OUTLINE_INCLUDE_STUBS ::
399  * If set, turn pixels on for 'stubs', otherwise exclude them. Ignored
400  * if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for more
401  * information.
402  *
403  * FT_OUTLINE_OVERLAP ::
404  * This flag indicates that this outline contains overlapping contrours
405  * and the anti-aliased renderer should perform oversampling to
406  * mitigate possible artifacts. This flag should _not_ be set for
407  * well designed glyphs without overlaps because it quadruples the
408  * rendering time.
409  *
410  * FT_OUTLINE_HIGH_PRECISION ::
411  * This flag indicates that the scan-line converter should try to
412  * convert this outline to bitmaps with the highest possible quality.
413  * It is typically set for small character sizes. Note that this is
414  * only a hint that might be completely ignored by a given
415  * scan-converter.
416  *
417  * FT_OUTLINE_SINGLE_PASS ::
418  * This flag is set to force a given scan-converter to only use a
419  * single pass over the outline to render a bitmap glyph image.
420  * Normally, it is set for very large character sizes. It is only a
421  * hint that might be completely ignored by a given scan-converter.
422  *
423  * @note:
424  * The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and
425  * @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth rasterizer.
426  *
427  * There exists a second mechanism to pass the drop-out mode to the B/W
428  * rasterizer; see the `tags` field in @FT_Outline.
429  *
430  * Please refer to the description of the 'SCANTYPE' instruction in the
431  * OpenType specification (in file `ttinst1.doc`) how simple drop-outs,
432  * smart drop-outs, and stubs are defined.
433  */
434 #define FT_OUTLINE_NONE 0x0
435 #define FT_OUTLINE_OWNER 0x1
436 #define FT_OUTLINE_EVEN_ODD_FILL 0x2
437 #define FT_OUTLINE_REVERSE_FILL 0x4
438 #define FT_OUTLINE_IGNORE_DROPOUTS 0x8
439 #define FT_OUTLINE_SMART_DROPOUTS 0x10
440 #define FT_OUTLINE_INCLUDE_STUBS 0x20
441 #define FT_OUTLINE_OVERLAP 0x40
442 
443 #define FT_OUTLINE_HIGH_PRECISION 0x100
444 #define FT_OUTLINE_SINGLE_PASS 0x200
445 
446 
447  /* these constants are deprecated; use the corresponding */
448  /* `FT_OUTLINE_XXX` values instead */
449 #define ft_outline_none FT_OUTLINE_NONE
450 #define ft_outline_owner FT_OUTLINE_OWNER
451 #define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL
452 #define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL
453 #define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS
454 #define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION
455 #define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS
456 
457  /* */
458 
459 #define FT_CURVE_TAG( flag ) ( flag & 0x03 )
460 
461  /* see the `tags` field in `FT_Outline` for a description of the values */
462 #define FT_CURVE_TAG_ON 0x01
463 #define FT_CURVE_TAG_CONIC 0x00
464 #define FT_CURVE_TAG_CUBIC 0x02
465 
466 #define FT_CURVE_TAG_HAS_SCANMODE 0x04
467 
468 #define FT_CURVE_TAG_TOUCH_X 0x08 /* reserved for TrueType hinter */
469 #define FT_CURVE_TAG_TOUCH_Y 0x10 /* reserved for TrueType hinter */
470 
471 #define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \
472  FT_CURVE_TAG_TOUCH_Y )
473  /* values 0x20, 0x40, and 0x80 are reserved */
474 
475 
476  /* these constants are deprecated; use the corresponding */
477  /* `FT_CURVE_TAG_XXX` values instead */
478 #define FT_Curve_Tag_On FT_CURVE_TAG_ON
479 #define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC
480 #define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC
481 #define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X
482 #define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y
483 
484 
485  /**************************************************************************
486  *
487  * @functype:
488  * FT_Outline_MoveToFunc
489  *
490  * @description:
491  * A function pointer type used to describe the signature of a 'move to'
492  * function during outline walking/decomposition.
493  *
494  * A 'move to' is emitted to start a new contour in an outline.
495  *
496  * @input:
497  * to ::
498  * A pointer to the target point of the 'move to'.
499  *
500  * user ::
501  * A typeless pointer, which is passed from the caller of the
502  * decomposition function.
503  *
504  * @return:
505  * Error code. 0~means success.
506  */
507  typedef int
509  void* user );
510 
511 #define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc
512 
513 
514  /**************************************************************************
515  *
516  * @functype:
517  * FT_Outline_LineToFunc
518  *
519  * @description:
520  * A function pointer type used to describe the signature of a 'line to'
521  * function during outline walking/decomposition.
522  *
523  * A 'line to' is emitted to indicate a segment in the outline.
524  *
525  * @input:
526  * to ::
527  * A pointer to the target point of the 'line to'.
528  *
529  * user ::
530  * A typeless pointer, which is passed from the caller of the
531  * decomposition function.
532  *
533  * @return:
534  * Error code. 0~means success.
535  */
536  typedef int
538  void* user );
539 
540 #define FT_Outline_LineTo_Func FT_Outline_LineToFunc
541 
542 
543  /**************************************************************************
544  *
545  * @functype:
546  * FT_Outline_ConicToFunc
547  *
548  * @description:
549  * A function pointer type used to describe the signature of a 'conic to'
550  * function during outline walking or decomposition.
551  *
552  * A 'conic to' is emitted to indicate a second-order Bezier arc in the
553  * outline.
554  *
555  * @input:
556  * control ::
557  * An intermediate control point between the last position and the new
558  * target in `to`.
559  *
560  * to ::
561  * A pointer to the target end point of the conic arc.
562  *
563  * user ::
564  * A typeless pointer, which is passed from the caller of the
565  * decomposition function.
566  *
567  * @return:
568  * Error code. 0~means success.
569  */
570  typedef int
572  const FT_Vector* to,
573  void* user );
574 
575 #define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc
576 
577 
578  /**************************************************************************
579  *
580  * @functype:
581  * FT_Outline_CubicToFunc
582  *
583  * @description:
584  * A function pointer type used to describe the signature of a 'cubic to'
585  * function during outline walking or decomposition.
586  *
587  * A 'cubic to' is emitted to indicate a third-order Bezier arc.
588  *
589  * @input:
590  * control1 ::
591  * A pointer to the first Bezier control point.
592  *
593  * control2 ::
594  * A pointer to the second Bezier control point.
595  *
596  * to ::
597  * A pointer to the target end point.
598  *
599  * user ::
600  * A typeless pointer, which is passed from the caller of the
601  * decomposition function.
602  *
603  * @return:
604  * Error code. 0~means success.
605  */
606  typedef int
607  (*FT_Outline_CubicToFunc)( const FT_Vector* control1,
608  const FT_Vector* control2,
609  const FT_Vector* to,
610  void* user );
611 
612 #define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc
613 
614 
615  /**************************************************************************
616  *
617  * @struct:
618  * FT_Outline_Funcs
619  *
620  * @description:
621  * A structure to hold various function pointers used during outline
622  * decomposition in order to emit segments, conic, and cubic Beziers.
623  *
624  * @fields:
625  * move_to ::
626  * The 'move to' emitter.
627  *
628  * line_to ::
629  * The segment emitter.
630  *
631  * conic_to ::
632  * The second-order Bezier arc emitter.
633  *
634  * cubic_to ::
635  * The third-order Bezier arc emitter.
636  *
637  * shift ::
638  * The shift that is applied to coordinates before they are sent to the
639  * emitter.
640  *
641  * delta ::
642  * The delta that is applied to coordinates before they are sent to the
643  * emitter, but after the shift.
644  *
645  * @note:
646  * The point coordinates sent to the emitters are the transformed version
647  * of the original coordinates (this is important for high accuracy
648  * during scan-conversion). The transformation is simple:
649  *
650  * ```
651  * x' = (x << shift) - delta
652  * y' = (y << shift) - delta
653  * ```
654  *
655  * Set the values of `shift` and `delta` to~0 to get the original point
656  * coordinates.
657  */
658  typedef struct FT_Outline_Funcs_
659  {
664 
665  int shift;
667 
669 
670 
671  /**************************************************************************
672  *
673  * @section:
674  * basic_types
675  *
676  */
677 
678 
679  /**************************************************************************
680  *
681  * @macro:
682  * FT_IMAGE_TAG
683  *
684  * @description:
685  * This macro converts four-letter tags to an unsigned long type.
686  *
687  * @note:
688  * Since many 16-bit compilers don't like 32-bit enumerations, you should
689  * redefine this macro in case of problems to something like this:
690  *
691  * ```
692  * #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value
693  * ```
694  *
695  * to get a simple enumeration without assigning special numbers.
696  */
697 #ifndef FT_IMAGE_TAG
698 #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \
699  value = ( ( (unsigned long)_x1 << 24 ) | \
700  ( (unsigned long)_x2 << 16 ) | \
701  ( (unsigned long)_x3 << 8 ) | \
702  (unsigned long)_x4 )
703 #endif /* FT_IMAGE_TAG */
704 
705 
706  /**************************************************************************
707  *
708  * @enum:
709  * FT_Glyph_Format
710  *
711  * @description:
712  * An enumeration type used to describe the format of a given glyph
713  * image. Note that this version of FreeType only supports two image
714  * formats, even though future font drivers will be able to register
715  * their own format.
716  *
717  * @values:
718  * FT_GLYPH_FORMAT_NONE ::
719  * The value~0 is reserved.
720  *
721  * FT_GLYPH_FORMAT_COMPOSITE ::
722  * The glyph image is a composite of several other images. This format
723  * is _only_ used with @FT_LOAD_NO_RECURSE, and is used to report
724  * compound glyphs (like accented characters).
725  *
726  * FT_GLYPH_FORMAT_BITMAP ::
727  * The glyph image is a bitmap, and can be described as an @FT_Bitmap.
728  * You generally need to access the `bitmap` field of the
729  * @FT_GlyphSlotRec structure to read it.
730  *
731  * FT_GLYPH_FORMAT_OUTLINE ::
732  * The glyph image is a vectorial outline made of line segments and
733  * Bezier arcs; it can be described as an @FT_Outline; you generally
734  * want to access the `outline` field of the @FT_GlyphSlotRec structure
735  * to read it.
736  *
737  * FT_GLYPH_FORMAT_PLOTTER ::
738  * The glyph image is a vectorial path with no inside and outside
739  * contours. Some Type~1 fonts, like those in the Hershey family,
740  * contain glyphs in this format. These are described as @FT_Outline,
741  * but FreeType isn't currently capable of rendering them correctly.
742  */
743  typedef enum FT_Glyph_Format_
744  {
746 
747  FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
748  FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP, 'b', 'i', 't', 's' ),
749  FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE, 'o', 'u', 't', 'l' ),
750  FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER, 'p', 'l', 'o', 't' )
751 
753 
754 
755  /* these constants are deprecated; use the corresponding */
756  /* `FT_Glyph_Format` values instead. */
757 #define ft_glyph_format_none FT_GLYPH_FORMAT_NONE
758 #define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE
759 #define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP
760 #define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE
761 #define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER
762 
763 
764  /*************************************************************************/
765  /*************************************************************************/
766  /*************************************************************************/
767  /***** *****/
768  /***** R A S T E R D E F I N I T I O N S *****/
769  /***** *****/
770  /*************************************************************************/
771  /*************************************************************************/
772  /*************************************************************************/
773 
774 
775  /**************************************************************************
776  *
777  * A raster is a scan converter, in charge of rendering an outline into a
778  * bitmap. This section contains the public API for rasters.
779  *
780  * Note that in FreeType 2, all rasters are now encapsulated within
781  * specific modules called 'renderers'. See `ftrender.h` for more details
782  * on renderers.
783  *
784  */
785 
786 
787  /**************************************************************************
788  *
789  * @section:
790  * raster
791  *
792  * @title:
793  * Scanline Converter
794  *
795  * @abstract:
796  * How vectorial outlines are converted into bitmaps and pixmaps.
797  *
798  * @description:
799  * This section contains technical definitions.
800  *
801  * @order:
802  * FT_Raster
803  * FT_Span
804  * FT_SpanFunc
805  *
806  * FT_Raster_Params
807  * FT_RASTER_FLAG_XXX
808  *
809  * FT_Raster_NewFunc
810  * FT_Raster_DoneFunc
811  * FT_Raster_ResetFunc
812  * FT_Raster_SetModeFunc
813  * FT_Raster_RenderFunc
814  * FT_Raster_Funcs
815  *
816  */
817 
818 
819  /**************************************************************************
820  *
821  * @type:
822  * FT_Raster
823  *
824  * @description:
825  * An opaque handle (pointer) to a raster object. Each object can be
826  * used independently to convert an outline into a bitmap or pixmap.
827  */
828  typedef struct FT_RasterRec_* FT_Raster;
829 
830 
831  /**************************************************************************
832  *
833  * @struct:
834  * FT_Span
835  *
836  * @description:
837  * A structure used to model a single span of gray pixels when rendering
838  * an anti-aliased bitmap.
839  *
840  * @fields:
841  * x ::
842  * The span's horizontal start position.
843  *
844  * len ::
845  * The span's length in pixels.
846  *
847  * coverage ::
848  * The span color/coverage, ranging from 0 (background) to 255
849  * (foreground).
850  *
851  * @note:
852  * This structure is used by the span drawing callback type named
853  * @FT_SpanFunc that takes the y~coordinate of the span as a parameter.
854  *
855  * The coverage value is always between 0 and 255. If you want less gray
856  * values, the callback function has to reduce them.
857  */
858  typedef struct FT_Span_
859  {
860  short x;
861  unsigned short len;
862  unsigned char coverage;
863 
865 
866 
867  /**************************************************************************
868  *
869  * @functype:
870  * FT_SpanFunc
871  *
872  * @description:
873  * A function used as a call-back by the anti-aliased renderer in order
874  * to let client applications draw themselves the gray pixel spans on
875  * each scan line.
876  *
877  * @input:
878  * y ::
879  * The scanline's upward y~coordinate.
880  *
881  * count ::
882  * The number of spans to draw on this scanline.
883  *
884  * spans ::
885  * A table of `count` spans to draw on the scanline.
886  *
887  * user ::
888  * User-supplied data that is passed to the callback.
889  *
890  * @note:
891  * This callback allows client applications to directly render the gray
892  * spans of the anti-aliased bitmap to any kind of surfaces.
893  *
894  * This can be used to write anti-aliased outlines directly to a given
895  * background bitmap, and even perform translucency.
896  */
897  typedef void
898  (*FT_SpanFunc)( int y,
899  int count,
900  const FT_Span* spans,
901  void* user );
902 
903 #define FT_Raster_Span_Func FT_SpanFunc
904 
905 
906  /**************************************************************************
907  *
908  * @functype:
909  * FT_Raster_BitTest_Func
910  *
911  * @description:
912  * Deprecated, unimplemented.
913  */
914  typedef int
915  (*FT_Raster_BitTest_Func)( int y,
916  int x,
917  void* user );
918 
919 
920  /**************************************************************************
921  *
922  * @functype:
923  * FT_Raster_BitSet_Func
924  *
925  * @description:
926  * Deprecated, unimplemented.
927  */
928  typedef void
929  (*FT_Raster_BitSet_Func)( int y,
930  int x,
931  void* user );
932 
933 
934  /**************************************************************************
935  *
936  * @enum:
937  * FT_RASTER_FLAG_XXX
938  *
939  * @description:
940  * A list of bit flag constants as used in the `flags` field of a
941  * @FT_Raster_Params structure.
942  *
943  * @values:
944  * FT_RASTER_FLAG_DEFAULT ::
945  * This value is 0.
946  *
947  * FT_RASTER_FLAG_AA ::
948  * This flag is set to indicate that an anti-aliased glyph image should
949  * be generated. Otherwise, it will be monochrome (1-bit).
950  *
951  * FT_RASTER_FLAG_DIRECT ::
952  * This flag is set to indicate direct rendering. In this mode, client
953  * applications must provide their own span callback. This lets them
954  * directly draw or compose over an existing bitmap. If this bit is
955  * _not_ set, the target pixmap's buffer _must_ be zeroed before
956  * rendering and the output will be clipped to its size.
957  *
958  * Direct rendering is only possible with anti-aliased glyphs.
959  *
960  * FT_RASTER_FLAG_CLIP ::
961  * This flag is only used in direct rendering mode. If set, the output
962  * will be clipped to a box specified in the `clip_box` field of the
963  * @FT_Raster_Params structure. Otherwise, the `clip_box` is
964  * effectively set to the bounding box and all spans are generated.
965  */
966 #define FT_RASTER_FLAG_DEFAULT 0x0
967 #define FT_RASTER_FLAG_AA 0x1
968 #define FT_RASTER_FLAG_DIRECT 0x2
969 #define FT_RASTER_FLAG_CLIP 0x4
970 
971  /* these constants are deprecated; use the corresponding */
972  /* `FT_RASTER_FLAG_XXX` values instead */
973 #define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT
974 #define ft_raster_flag_aa FT_RASTER_FLAG_AA
975 #define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT
976 #define ft_raster_flag_clip FT_RASTER_FLAG_CLIP
977 
978 
979  /**************************************************************************
980  *
981  * @struct:
982  * FT_Raster_Params
983  *
984  * @description:
985  * A structure to hold the parameters used by a raster's render function,
986  * passed as an argument to @FT_Outline_Render.
987  *
988  * @fields:
989  * target ::
990  * The target bitmap.
991  *
992  * source ::
993  * A pointer to the source glyph image (e.g., an @FT_Outline).
994  *
995  * flags ::
996  * The rendering flags.
997  *
998  * gray_spans ::
999  * The gray span drawing callback.
1000  *
1001  * black_spans ::
1002  * Unused.
1003  *
1004  * bit_test ::
1005  * Unused.
1006  *
1007  * bit_set ::
1008  * Unused.
1009  *
1010  * user ::
1011  * User-supplied data that is passed to each drawing callback.
1012  *
1013  * clip_box ::
1014  * An optional span clipping box expressed in _integer_ pixels
1015  * (not in 26.6 fixed-point units).
1016  *
1017  * @note:
1018  * The @FT_RASTER_FLAG_AA bit flag must be set in the `flags` to
1019  * generate an anti-aliased glyph bitmap, otherwise a monochrome bitmap
1020  * is generated. The `target` should have appropriate pixel mode and its
1021  * dimensions define the clipping region.
1022  *
1023  * If both @FT_RASTER_FLAG_AA and @FT_RASTER_FLAG_DIRECT bit flags
1024  * are set in `flags`, the raster calls an @FT_SpanFunc callback
1025  * `gray_spans` with `user` data as an argument ignoring `target`. This
1026  * allows direct composition over a pre-existing user surface to perform
1027  * the span drawing and composition. To optionally clip the spans, set
1028  * the @FT_RASTER_FLAG_CLIP flag and `clip_box`. The monochrome raster
1029  * does not support the direct mode.
1030  *
1031  * The gray-level rasterizer always uses 256 gray levels. If you want
1032  * fewer gray levels, you have to use @FT_RASTER_FLAG_DIRECT and reduce
1033  * the levels in the callback function.
1034  */
1035  typedef struct FT_Raster_Params_
1036  {
1038  const void* source;
1039  int flags;
1041  FT_SpanFunc black_spans; /* unused */
1044  void* user;
1046 
1048 
1049 
1050  /**************************************************************************
1051  *
1052  * @functype:
1053  * FT_Raster_NewFunc
1054  *
1055  * @description:
1056  * A function used to create a new raster object.
1057  *
1058  * @input:
1059  * memory ::
1060  * A handle to the memory allocator.
1061  *
1062  * @output:
1063  * raster ::
1064  * A handle to the new raster object.
1065  *
1066  * @return:
1067  * Error code. 0~means success.
1068  *
1069  * @note:
1070  * The `memory` parameter is a typeless pointer in order to avoid
1071  * un-wanted dependencies on the rest of the FreeType code. In practice,
1072  * it is an @FT_Memory object, i.e., a handle to the standard FreeType
1073  * memory allocator. However, this field can be completely ignored by a
1074  * given raster implementation.
1075  */
1076  typedef int
1077  (*FT_Raster_NewFunc)( void* memory,
1078  FT_Raster* raster );
1079 
1080 #define FT_Raster_New_Func FT_Raster_NewFunc
1081 
1082 
1083  /**************************************************************************
1084  *
1085  * @functype:
1086  * FT_Raster_DoneFunc
1087  *
1088  * @description:
1089  * A function used to destroy a given raster object.
1090  *
1091  * @input:
1092  * raster ::
1093  * A handle to the raster object.
1094  */
1095  typedef void
1097 
1098 #define FT_Raster_Done_Func FT_Raster_DoneFunc
1099 
1100 
1101  /**************************************************************************
1102  *
1103  * @functype:
1104  * FT_Raster_ResetFunc
1105  *
1106  * @description:
1107  * FreeType used to provide an area of memory called the 'render pool'
1108  * available to all registered rasterizers. This was not thread safe,
1109  * however, and now FreeType never allocates this pool.
1110  *
1111  * This function is called after a new raster object is created.
1112  *
1113  * @input:
1114  * raster ::
1115  * A handle to the new raster object.
1116  *
1117  * pool_base ::
1118  * Previously, the address in memory of the render pool. Set this to
1119  * `NULL`.
1120  *
1121  * pool_size ::
1122  * Previously, the size in bytes of the render pool. Set this to 0.
1123  *
1124  * @note:
1125  * Rasterizers should rely on dynamic or stack allocation if they want to
1126  * (a handle to the memory allocator is passed to the rasterizer
1127  * constructor).
1128  */
1129  typedef void
1131  unsigned char* pool_base,
1132  unsigned long pool_size );
1133 
1134 #define FT_Raster_Reset_Func FT_Raster_ResetFunc
1135 
1136 
1137  /**************************************************************************
1138  *
1139  * @functype:
1140  * FT_Raster_SetModeFunc
1141  *
1142  * @description:
1143  * This function is a generic facility to change modes or attributes in a
1144  * given raster. This can be used for debugging purposes, or simply to
1145  * allow implementation-specific 'features' in a given raster module.
1146  *
1147  * @input:
1148  * raster ::
1149  * A handle to the new raster object.
1150  *
1151  * mode ::
1152  * A 4-byte tag used to name the mode or property.
1153  *
1154  * args ::
1155  * A pointer to the new mode/property to use.
1156  */
1157  typedef int
1159  unsigned long mode,
1160  void* args );
1161 
1162 #define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc
1163 
1164 
1165  /**************************************************************************
1166  *
1167  * @functype:
1168  * FT_Raster_RenderFunc
1169  *
1170  * @description:
1171  * Invoke a given raster to scan-convert a given glyph image into a
1172  * target bitmap.
1173  *
1174  * @input:
1175  * raster ::
1176  * A handle to the raster object.
1177  *
1178  * params ::
1179  * A pointer to an @FT_Raster_Params structure used to store the
1180  * rendering parameters.
1181  *
1182  * @return:
1183  * Error code. 0~means success.
1184  *
1185  * @note:
1186  * The exact format of the source image depends on the raster's glyph
1187  * format defined in its @FT_Raster_Funcs structure. It can be an
1188  * @FT_Outline or anything else in order to support a large array of
1189  * glyph formats.
1190  *
1191  * Note also that the render function can fail and return a
1192  * `FT_Err_Unimplemented_Feature` error code if the raster used does not
1193  * support direct composition.
1194  */
1195  typedef int
1197  const FT_Raster_Params* params );
1198 
1199 #define FT_Raster_Render_Func FT_Raster_RenderFunc
1200 
1201 
1202  /**************************************************************************
1203  *
1204  * @struct:
1205  * FT_Raster_Funcs
1206  *
1207  * @description:
1208  * A structure used to describe a given raster class to the library.
1209  *
1210  * @fields:
1211  * glyph_format ::
1212  * The supported glyph format for this raster.
1213  *
1214  * raster_new ::
1215  * The raster constructor.
1216  *
1217  * raster_reset ::
1218  * Used to reset the render pool within the raster.
1219  *
1220  * raster_render ::
1221  * A function to render a glyph into a given bitmap.
1222  *
1223  * raster_done ::
1224  * The raster destructor.
1225  */
1226  typedef struct FT_Raster_Funcs_
1227  {
1229 
1235 
1237 
1238  /* */
1239 
1240 
1242 
1243 #endif /* FTIMAGE_H_ */
1244 
1245 
1246 /* END */
1247 
1248 
1249 /* Local Variables: */
1250 /* coding: utf-8 */
1251 /* End: */
#define count(a)
Definition: aptex-macros.h:781
#define mode
Definition: aptex-macros.h:510
int params
Definition: definitions.c:42
#define control
Definition: devnag.c:323
quarterword * raster
Definition: dvips.c:153
static void
Definition: fpif.c:118
#define FT_END_HEADER
Definition: ftheader.h:57
void(* FT_Raster_ResetFunc)(FT_Raster raster, unsigned char *pool_base, unsigned long pool_size)
Definition: ftimage.h:1130
struct FT_Bitmap_ FT_Bitmap
struct FT_BBox_ FT_BBox
#define FT_IMAGE_TAG(value, _x1, _x2, _x3, _x4)
Definition: ftimage.h:698
int(* FT_Raster_BitTest_Func)(int y, int x, void *user)
Definition: ftimage.h:915
void(* FT_Raster_DoneFunc)(FT_Raster raster)
Definition: ftimage.h:1096
int(* FT_Outline_ConicToFunc)(const FT_Vector *control, const FT_Vector *to, void *user)
Definition: ftimage.h:571
FT_Pixel_Mode_
Definition: ftimage.h:181
@ FT_PIXEL_MODE_GRAY2
Definition: ftimage.h:185
@ FT_PIXEL_MODE_LCD_V
Definition: ftimage.h:188
@ FT_PIXEL_MODE_MONO
Definition: ftimage.h:183
@ FT_PIXEL_MODE_NONE
Definition: ftimage.h:182
@ FT_PIXEL_MODE_GRAY
Definition: ftimage.h:184
@ FT_PIXEL_MODE_MAX
Definition: ftimage.h:191
@ FT_PIXEL_MODE_LCD
Definition: ftimage.h:187
@ FT_PIXEL_MODE_BGRA
Definition: ftimage.h:189
@ FT_PIXEL_MODE_GRAY4
Definition: ftimage.h:186
int(* FT_Raster_RenderFunc)(FT_Raster raster, const FT_Raster_Params *params)
Definition: ftimage.h:1196
struct FT_Raster_Params_ FT_Raster_Params
int(* FT_Outline_LineToFunc)(const FT_Vector *to, void *user)
Definition: ftimage.h:537
FT_Glyph_Format_
Definition: ftimage.h:744
@ FT_GLYPH_FORMAT_COMPOSITE
Definition: ftimage.h:747
@ FT_GLYPH_FORMAT_PLOTTER
Definition: ftimage.h:750
@ FT_GLYPH_FORMAT_OUTLINE
Definition: ftimage.h:749
@ FT_GLYPH_FORMAT_BITMAP
Definition: ftimage.h:748
@ FT_GLYPH_FORMAT_NONE
Definition: ftimage.h:745
struct FT_Span_ FT_Span
struct FT_RasterRec_ * FT_Raster
Definition: ftimage.h:828
struct FT_Outline_ FT_Outline
void(* FT_Raster_BitSet_Func)(int y, int x, void *user)
Definition: ftimage.h:929
struct FT_Raster_Funcs_ FT_Raster_Funcs
int(* FT_Raster_SetModeFunc)(FT_Raster raster, unsigned long mode, void *args)
Definition: ftimage.h:1158
int(* FT_Outline_CubicToFunc)(const FT_Vector *control1, const FT_Vector *control2, const FT_Vector *to, void *user)
Definition: ftimage.h:607
void(* FT_SpanFunc)(int y, int count, const FT_Span *spans, void *user)
Definition: ftimage.h:898
struct FT_Vector_ FT_Vector
enum FT_Glyph_Format_ FT_Glyph_Format
enum FT_Pixel_Mode_ FT_Pixel_Mode
int(* FT_Raster_NewFunc)(void *memory, FT_Raster *raster)
Definition: ftimage.h:1077
int(* FT_Outline_MoveToFunc)(const FT_Vector *to, void *user)
Definition: ftimage.h:508
struct FT_Outline_Funcs_ FT_Outline_Funcs
FT_BEGIN_HEADER typedef signed long FT_Pos
Definition: ftimage.h:57
kerning y
Definition: ttdriver.c:212
char args[100]
Definition: fixwrites.c:7
float x
Definition: cordic.py:15
real to[600]
Definition: pmxab.c:87
FT_Pos xMin
Definition: ftimage.h:120
FT_Pos yMax
Definition: ftimage.h:121
FT_Pos yMin
Definition: ftimage.h:120
FT_Pos xMax
Definition: ftimage.h:121
unsigned short num_grays
Definition: ftimage.h:266
unsigned char palette_mode
Definition: ftimage.h:268
unsigned char * buffer
Definition: ftimage.h:265
unsigned int width
Definition: ftimage.h:263
void * palette
Definition: ftimage.h:269
unsigned char pixel_mode
Definition: ftimage.h:267
unsigned int rows
Definition: ftimage.h:262
int pitch
Definition: ftimage.h:264
FT_Outline_ConicToFunc conic_to
Definition: ftimage.h:662
FT_Outline_LineToFunc line_to
Definition: ftimage.h:661
FT_Outline_CubicToFunc cubic_to
Definition: ftimage.h:663
FT_Outline_MoveToFunc move_to
Definition: ftimage.h:660
short n_contours
Definition: ftimage.h:338
int flags
Definition: ftimage.h:345
FT_Vector * points
Definition: ftimage.h:341
short * contours
Definition: ftimage.h:343
short n_points
Definition: ftimage.h:339
char * tags
Definition: ftimage.h:342
FT_Raster_NewFunc raster_new
Definition: ftimage.h:1230
FT_Raster_SetModeFunc raster_set_mode
Definition: ftimage.h:1232
FT_Glyph_Format glyph_format
Definition: ftimage.h:1228
FT_Raster_RenderFunc raster_render
Definition: ftimage.h:1233
FT_Raster_ResetFunc raster_reset
Definition: ftimage.h:1231
FT_Raster_DoneFunc raster_done
Definition: ftimage.h:1234
const void * source
Definition: ftimage.h:1038
const FT_Bitmap * target
Definition: ftimage.h:1037
FT_SpanFunc black_spans
Definition: ftimage.h:1041
FT_SpanFunc gray_spans
Definition: ftimage.h:1040
FT_BBox clip_box
Definition: ftimage.h:1045
FT_Raster_BitSet_Func bit_set
Definition: ftimage.h:1043
FT_Raster_BitTest_Func bit_test
Definition: ftimage.h:1042
unsigned char coverage
Definition: ftimage.h:862
short x
Definition: ftimage.h:860
unsigned short len
Definition: ftimage.h:861
FT_Pos x
Definition: ftimage.h:77
FT_Pos y
Definition: ftimage.h:78
return() int(((double) *(font_tbl[cur_fnt].wtbl+(int)(*(font_tbl[cur_fnt].char_wi+(int)(ch - font_tbl[cur_fnt].char_f)% 256)))/(double)(1L<< 20)) *(double) font_tbl[cur_fnt].scale)
#define pool_size(i)
Definition: gc.c:685