1 /***************************************************************************/
2 /* */
3 /* ftimage.h */
4 /* */
5 /* FreeType glyph image formats and default raster interface */
6 /* (specification). */
7 /* */
8 /* Copyright 1996-2018 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 #include <ft2build.h>
34 #endif
35
36
37 FT_BEGIN_HEADER
38
39
40 /*************************************************************************/
41 /* */
42 /* <Section> */
43 /* basic_types */
44 /* */
45 /*************************************************************************/
46
47
48 /*************************************************************************/
49 /* */
50 /* <Type> */
51 /* FT_Pos */
52 /* */
53 /* <Description> */
54 /* The type FT_Pos is used to store vectorial coordinates. Depending */
55 /* on the context, these can represent distances in integer font */
56 /* units, or 16.16, or 26.6 fixed-point pixel coordinates. */
57 /* */
58 typedef signed long FT_Pos;
59
60
61 /*************************************************************************/
62 /* */
63 /* <Struct> */
64 /* FT_Vector */
65 /* */
66 /* <Description> */
67 /* A simple structure used to store a 2D vector; coordinates are of */
68 /* the FT_Pos type. */
69 /* */
70 /* <Fields> */
71 /* x :: The horizontal coordinate. */
72 /* y :: The vertical coordinate. */
73 /* */
74 typedef struct FT_Vector_
75 {
76 FT_Pos x;
77 FT_Pos y;
78
79 } FT_Vector;
80
81
82 /*************************************************************************/
83 /* */
84 /* <Struct> */
85 /* FT_BBox */
86 /* */
87 /* <Description> */
88 /* A structure used to hold an outline's bounding box, i.e., the */
89 /* coordinates of its extrema in the horizontal and vertical */
90 /* directions. */
91 /* */
92 /* <Fields> */
93 /* xMin :: The horizontal minimum (left-most). */
94 /* */
95 /* yMin :: The vertical minimum (bottom-most). */
96 /* */
97 /* xMax :: The horizontal maximum (right-most). */
98 /* */
99 /* yMax :: The vertical maximum (top-most). */
100 /* */
101 /* <Note> */
102 /* The bounding box is specified with the coordinates of the lower */
103 /* left and the upper right corner. In PostScript, those values are */
104 /* often called (llx,lly) and (urx,ury), respectively. */
105 /* */
106 /* If `yMin' is negative, this value gives the glyph's descender. */
107 /* Otherwise, the glyph doesn't descend below the baseline. */
108 /* Similarly, if `ymax' is positive, this value gives the glyph's */
109 /* ascender. */
110 /* */
111 /* `xMin' gives the horizontal distance from the glyph's origin to */
112 /* the left edge of the glyph's bounding box. If `xMin' is negative, */
113 /* the glyph extends to the left of the origin. */
114 /* */
115 typedef struct FT_BBox_
116 {
117 FT_Pos xMin, yMin;
118 FT_Pos xMax, yMax;
119
120 } FT_BBox;
121
122
123 /*************************************************************************/
124 /* */
125 /* <Enum> */
126 /* FT_Pixel_Mode */
127 /* */
128 /* <Description> */
129 /* An enumeration type used to describe the format of pixels in a */
130 /* given bitmap. Note that additional formats may be added in the */
131 /* future. */
132 /* */
133 /* <Values> */
134 /* FT_PIXEL_MODE_NONE :: */
135 /* Value~0 is reserved. */
136 /* */
137 /* FT_PIXEL_MODE_MONO :: */
138 /* A monochrome bitmap, using 1~bit per pixel. Note that pixels */
139 /* are stored in most-significant order (MSB), which means that */
140 /* the left-most pixel in a byte has value 128. */
141 /* */
142 /* FT_PIXEL_MODE_GRAY :: */
143 /* An 8-bit bitmap, generally used to represent anti-aliased glyph */
144 /* images. Each pixel is stored in one byte. Note that the number */
145 /* of `gray' levels is stored in the `num_grays' field of the */
146 /* @FT_Bitmap structure (it generally is 256). */
147 /* */
148 /* FT_PIXEL_MODE_GRAY2 :: */
149 /* A 2-bit per pixel bitmap, used to represent embedded */
150 /* anti-aliased bitmaps in font files according to the OpenType */
151 /* specification. We haven't found a single font using this */
152 /* format, however. */
153 /* */
154 /* FT_PIXEL_MODE_GRAY4 :: */
155 /* A 4-bit per pixel bitmap, representing embedded anti-aliased */
156 /* bitmaps in font files according to the OpenType specification. */
157 /* We haven't found a single font using this format, however. */
158 /* */
159 /* FT_PIXEL_MODE_LCD :: */
160 /* An 8-bit bitmap, representing RGB or BGR decimated glyph images */
161 /* used for display on LCD displays; the bitmap is three times */
162 /* wider than the original glyph image. See also */
163 /* @FT_RENDER_MODE_LCD. */
164 /* */
165 /* FT_PIXEL_MODE_LCD_V :: */
166 /* An 8-bit bitmap, representing RGB or BGR decimated glyph images */
167 /* used for display on rotated LCD displays; the bitmap is three */
168 /* times 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 */
174 /* channel. For each pixel, the format is BGRA, which means, the */
175 /* blue channel comes first in memory. The color channels are */
176 /* pre-multiplied and in the sRGB colorspace. For example, full */
177 /* red at half-translucent opacity will be represented as */
178 /* `00,00,80,80', not `00,00,FF,80'. See also @FT_LOAD_COLOR. */
179 /* */
180 typedef enum FT_Pixel_Mode_
181 {
182 FT_PIXEL_MODE_NONE = 0,
183 FT_PIXEL_MODE_MONO,
184 FT_PIXEL_MODE_GRAY,
185 FT_PIXEL_MODE_GRAY2,
186 FT_PIXEL_MODE_GRAY4,
187 FT_PIXEL_MODE_LCD,
188 FT_PIXEL_MODE_LCD_V,
189 FT_PIXEL_MODE_BGRA,
190
191 FT_PIXEL_MODE_MAX /* do not remove */
192
193 } FT_Pixel_Mode;
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. */
212 /* Note that we now manage pixmaps of various depths through the */
213 /* `pixel_mode' field. */
214 /* */
215 /* <Fields> */
216 /* rows :: The number of bitmap rows. */
217 /* */
218 /* width :: The number of pixels in bitmap row. */
219 /* */
220 /* pitch :: The pitch's absolute value is the number of bytes */
221 /* taken by one bitmap row, including padding. */
222 /* However, the pitch is positive when the bitmap has */
223 /* a `down' flow, and negative when it has an `up' */
224 /* flow. In all cases, the pitch is an offset to add */
225 /* to a bitmap pointer in order to go down one row. */
226 /* */
227 /* Note that `padding' means the alignment of a */
228 /* bitmap to a byte border, and FreeType functions */
229 /* normally align to the smallest possible integer */
230 /* value. */
231 /* */
232 /* For the B/W rasterizer, `pitch' is always an even */
233 /* number. */
234 /* */
235 /* To change the pitch of a bitmap (say, to make it a */
236 /* multiple of 4), use @FT_Bitmap_Convert. */
237 /* Alternatively, you might use callback functions to */
238 /* directly render to the application's surface; see */
239 /* the file `example2.cpp' in the tutorial for a */
240 /* demonstration. */
241 /* */
242 /* buffer :: A typeless pointer to the bitmap buffer. This */
243 /* value should be aligned on 32-bit boundaries in */
244 /* most cases. */
245 /* */
246 /* num_grays :: This field is only used with */
247 /* @FT_PIXEL_MODE_GRAY; it gives the number of gray */
248 /* levels used in the bitmap. */
249 /* */
250 /* pixel_mode :: The pixel mode, i.e., how pixel bits are stored. */
251 /* See @FT_Pixel_Mode for possible values. */
252 /* */
253 /* palette_mode :: This field is intended for paletted pixel modes; */
254 /* it indicates how the palette is stored. Not */
255 /* used currently. */
256 /* */
257 /* palette :: A typeless pointer to the bitmap palette; this */
258 /* field is intended for paletted pixel modes. Not */
259 /* used currently. */
260 /* */
261 typedef struct FT_Bitmap_
262 {
263 unsigned int rows;
264 unsigned int width;
265 int pitch;
266 unsigned char* buffer;
267 unsigned short num_grays;
268 unsigned char pixel_mode;
269 unsigned char palette_mode;
270 void* palette;
271
272 } FT_Bitmap;
273
274
275 /*************************************************************************/
276 /* */
277 /* <Section> */
278 /* outline_processing */
279 /* */
280 /*************************************************************************/
281
282
283 /*************************************************************************/
284 /* */
285 /* <Struct> */
286 /* FT_Outline */
287 /* */
288 /* <Description> */
289 /* This structure is used to describe an outline to the scan-line */
290 /* converter. */
291 /* */
292 /* <Fields> */
293 /* n_contours :: The number of contours in the outline. */
294 /* */
295 /* n_points :: The number of points in the outline. */
296 /* */
297 /* points :: A pointer to an array of `n_points' @FT_Vector */
298 /* elements, giving the outline's point coordinates. */
299 /* */
300 /* tags :: A pointer to an array of `n_points' chars, giving */
301 /* each outline point's type. */
302 /* */
303 /* If bit~0 is unset, the point is `off' the curve, */
304 /* i.e., a Bezier control point, while it is `on' if */
305 /* set. */
306 /* */
307 /* Bit~1 is meaningful for `off' points only. If set, */
308 /* it indicates a third-order Bezier arc control point; */
309 /* and a second-order control point if unset. */
310 /* */
311 /* If bit~2 is set, bits 5-7 contain the drop-out mode */
312 /* (as defined in the OpenType specification; the value */
313 /* is the same as the argument to the SCANMODE */
314 /* instruction). */
315 /* */
316 /* Bits 3 and~4 are reserved for internal purposes. */
317 /* */
318 /* contours :: An array of `n_contours' shorts, giving the end */
319 /* point of each contour within the outline. For */
320 /* example, the first contour is defined by the points */
321 /* `0' to `contours[0]', the second one is defined by */
322 /* the points `contours[0]+1' to `contours[1]', etc. */
323 /* */
324 /* flags :: A set of bit flags used to characterize the outline */
325 /* and give hints to the scan-converter and hinter on */
326 /* how to convert/grid-fit it. See @FT_OUTLINE_XXX. */
327 /* */
328 /* <Note> */
329 /* The B/W rasterizer only checks bit~2 in the `tags' array for the */
330 /* first point of each contour. The drop-out mode as given with */
331 /* @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and */
332 /* @FT_OUTLINE_INCLUDE_STUBS in `flags' is then overridden. */
333 /* */
334 typedef struct FT_Outline_
335 {
336 short n_contours; /* number of contours in glyph */
337 short n_points; /* number of points in the glyph */
338
339 FT_Vector* points; /* the outline's points */
340 char* tags; /* the points flags */
341 short* contours; /* the contour end points */
342
343 int flags; /* outline masks */
344
345 } FT_Outline;
346
347 /* */
348
349 /* Following limits must be consistent with */
350 /* FT_Outline.{n_contours,n_points} */
351 #define FT_OUTLINE_CONTOURS_MAX SHRT_MAX
352 #define FT_OUTLINE_POINTS_MAX SHRT_MAX
353
354
355 /*************************************************************************/
356 /* */
357 /* <Enum> */
358 /* FT_OUTLINE_XXX */
359 /* */
360 /* <Description> */
361 /* A list of bit-field constants use for the flags in an outline's */
362 /* `flags' field. */
363 /* */
364 /* <Values> */
365 /* FT_OUTLINE_NONE :: */
366 /* Value~0 is reserved. */
367 /* */
368 /* FT_OUTLINE_OWNER :: */
369 /* If set, this flag indicates that the outline's field arrays */
370 /* (i.e., `points', `flags', and `contours') are `owned' by the */
371 /* outline object, and should thus be freed when it is destroyed. */
372 /* */
373 /* FT_OUTLINE_EVEN_ODD_FILL :: */
374 /* By default, outlines are filled using the non-zero winding rule. */
375 /* If set to 1, the outline will be filled using the even-odd fill */
376 /* rule (only works with the smooth rasterizer). */
377 /* */
378 /* FT_OUTLINE_REVERSE_FILL :: */
379 /* By default, outside contours of an outline are oriented in */
380 /* clock-wise direction, as defined in the TrueType specification. */
381 /* This flag is set if the outline uses the opposite direction */
382 /* (typically for Type~1 fonts). This flag is ignored by the scan */
383 /* converter. */
384 /* */
385 /* FT_OUTLINE_IGNORE_DROPOUTS :: */
386 /* By default, the scan converter will try to detect drop-outs in */
387 /* an outline and correct the glyph bitmap to ensure consistent */
388 /* shape continuity. If set, this flag hints the scan-line */
389 /* converter to ignore such cases. See below for more information. */
390 /* */
391 /* FT_OUTLINE_SMART_DROPOUTS :: */
392 /* Select smart dropout control. If unset, use simple dropout */
393 /* control. Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See */
394 /* below for more information. */
395 /* */
396 /* FT_OUTLINE_INCLUDE_STUBS :: */
397 /* If set, turn pixels on for `stubs', otherwise exclude them. */
398 /* Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for */
399 /* more information. */
400 /* */
401 /* FT_OUTLINE_HIGH_PRECISION :: */
402 /* This flag indicates that the scan-line converter should try to */
403 /* convert this outline to bitmaps with the highest possible */
404 /* quality. It is typically set for small character sizes. Note */
405 /* that this is only a hint that might be completely ignored by a */
406 /* given scan-converter. */
407 /* */
408 /* FT_OUTLINE_SINGLE_PASS :: */
409 /* This flag is set to force a given scan-converter to only use a */
410 /* single pass over the outline to render a bitmap glyph image. */
411 /* Normally, it is set for very large character sizes. It is only */
412 /* a hint that might be completely ignored by a given */
413 /* scan-converter. */
414 /* */
415 /* <Note> */
416 /* The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, */
417 /* and @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth */
418 /* rasterizer. */
419 /* */
420 /* There exists a second mechanism to pass the drop-out mode to the */
421 /* B/W rasterizer; see the `tags' field in @FT_Outline. */
422 /* */
423 /* Please refer to the description of the `SCANTYPE' instruction in */
424 /* the OpenType specification (in file `ttinst1.doc') how simple */
425 /* drop-outs, smart drop-outs, and stubs are defined. */
426 /* */
427 #define FT_OUTLINE_NONE 0x0
428 #define FT_OUTLINE_OWNER 0x1
429 #define FT_OUTLINE_EVEN_ODD_FILL 0x2
430 #define FT_OUTLINE_REVERSE_FILL 0x4
431 #define FT_OUTLINE_IGNORE_DROPOUTS 0x8
432 #define FT_OUTLINE_SMART_DROPOUTS 0x10
433 #define FT_OUTLINE_INCLUDE_STUBS 0x20
434
435 #define FT_OUTLINE_HIGH_PRECISION 0x100
436 #define FT_OUTLINE_SINGLE_PASS 0x200
437
438
439 /* these constants are deprecated; use the corresponding */
440 /* `FT_OUTLINE_XXX' values instead */
441 #define ft_outline_none FT_OUTLINE_NONE
442 #define ft_outline_owner FT_OUTLINE_OWNER
443 #define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL
444 #define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL
445 #define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS
446 #define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION
447 #define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS
448
449 /* */
450
451 #define FT_CURVE_TAG( flag ) ( flag & 3 )
452
453 #define FT_CURVE_TAG_ON 1
454 #define FT_CURVE_TAG_CONIC 0
455 #define FT_CURVE_TAG_CUBIC 2
456
457 #define FT_CURVE_TAG_HAS_SCANMODE 4
458
459 #define FT_CURVE_TAG_TOUCH_X 8 /* reserved for the TrueType hinter */
460 #define FT_CURVE_TAG_TOUCH_Y 16 /* reserved for the TrueType hinter */
461
462 #define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \
463 FT_CURVE_TAG_TOUCH_Y )
464
465 #define FT_Curve_Tag_On FT_CURVE_TAG_ON
466 #define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC
467 #define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC
468 #define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X
469 #define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y
470
471
472 /*************************************************************************/
473 /* */
474 /* <FuncType> */
475 /* FT_Outline_MoveToFunc */
476 /* */
477 /* <Description> */
478 /* A function pointer type used to describe the signature of a `move */
479 /* to' function during outline walking/decomposition. */
480 /* */
481 /* A `move to' is emitted to start a new contour in an outline. */
482 /* */
483 /* <Input> */
484 /* to :: A pointer to the target point of the `move to'. */
485 /* */
486 /* user :: A typeless pointer, which is passed from the caller of the */
487 /* decomposition function. */
488 /* */
489 /* <Return> */
490 /* Error code. 0~means success. */
491 /* */
492 typedef int
493 (*FT_Outline_MoveToFunc)( const FT_Vector* to,
494 void* user );
495
496 #define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc
497
498
499 /*************************************************************************/
500 /* */
501 /* <FuncType> */
502 /* FT_Outline_LineToFunc */
503 /* */
504 /* <Description> */
505 /* A function pointer type used to describe the signature of a `line */
506 /* to' function during outline walking/decomposition. */
507 /* */
508 /* A `line to' is emitted to indicate a segment in the outline. */
509 /* */
510 /* <Input> */
511 /* to :: A pointer to the target point of the `line to'. */
512 /* */
513 /* user :: A typeless pointer, which is passed from the caller of the */
514 /* decomposition function. */
515 /* */
516 /* <Return> */
517 /* Error code. 0~means success. */
518 /* */
519 typedef int
520 (*FT_Outline_LineToFunc)( const FT_Vector* to,
521 void* user );
522
523 #define FT_Outline_LineTo_Func FT_Outline_LineToFunc
524
525
526 /*************************************************************************/
527 /* */
528 /* <FuncType> */
529 /* FT_Outline_ConicToFunc */
530 /* */
531 /* <Description> */
532 /* A function pointer type used to describe the signature of a `conic */
533 /* to' function during outline walking or decomposition. */
534 /* */
535 /* A `conic to' is emitted to indicate a second-order Bezier arc in */
536 /* the outline. */
537 /* */
538 /* <Input> */
539 /* control :: An intermediate control point between the last position */
540 /* and the new target in `to'. */
541 /* */
542 /* to :: A pointer to the target end point of the conic arc. */
543 /* */
544 /* user :: A typeless pointer, which is passed from the caller of */
545 /* the decomposition function. */
546 /* */
547 /* <Return> */
548 /* Error code. 0~means success. */
549 /* */
550 typedef int
551 (*FT_Outline_ConicToFunc)( const FT_Vector* control,
552 const FT_Vector* to,
553 void* user );
554
555 #define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc
556
557
558 /*************************************************************************/
559 /* */
560 /* <FuncType> */
561 /* FT_Outline_CubicToFunc */
562 /* */
563 /* <Description> */
564 /* A function pointer type used to describe the signature of a `cubic */
565 /* to' function during outline walking or decomposition. */
566 /* */
567 /* A `cubic to' is emitted to indicate a third-order Bezier arc. */
568 /* */
569 /* <Input> */
570 /* control1 :: A pointer to the first Bezier control point. */
571 /* */
572 /* control2 :: A pointer to the second Bezier control point. */
573 /* */
574 /* to :: A pointer to the target end point. */
575 /* */
576 /* user :: A typeless pointer, which is passed from the caller of */
577 /* the decomposition function. */
578 /* */
579 /* <Return> */
580 /* Error code. 0~means success. */
581 /* */
582 typedef int
583 (*FT_Outline_CubicToFunc)( const FT_Vector* control1,
584 const FT_Vector* control2,
585 const FT_Vector* to,
586 void* user );
587
588 #define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc
589
590
591 /*************************************************************************/
592 /* */
593 /* <Struct> */
594 /* FT_Outline_Funcs */
595 /* */
596 /* <Description> */
597 /* A structure to hold various function pointers used during outline */
598 /* decomposition in order to emit segments, conic, and cubic Beziers. */
599 /* */
600 /* <Fields> */
601 /* move_to :: The `move to' emitter. */
602 /* */
603 /* line_to :: The segment emitter. */
604 /* */
605 /* conic_to :: The second-order Bezier arc emitter. */
606 /* */
607 /* cubic_to :: The third-order Bezier arc emitter. */
608 /* */
609 /* shift :: The shift that is applied to coordinates before they */
610 /* are sent to the emitter. */
611 /* */
612 /* delta :: The delta that is applied to coordinates before they */
613 /* are sent to the emitter, but after the shift. */
614 /* */
615 /* <Note> */
616 /* The point coordinates sent to the emitters are the transformed */
617 /* version of the original coordinates (this is important for high */
618 /* accuracy during scan-conversion). The transformation is simple: */
619 /* */
620 /* { */
621 /* x' = (x << shift) - delta */
622 /* y' = (y << shift) - delta */
623 /* } */
624 /* */
625 /* Set the values of `shift' and `delta' to~0 to get the original */
626 /* point coordinates. */
627 /* */
628 typedef struct FT_Outline_Funcs_
629 {
630 FT_Outline_MoveToFunc move_to;
631 FT_Outline_LineToFunc line_to;
632 FT_Outline_ConicToFunc conic_to;
633 FT_Outline_CubicToFunc cubic_to;
634
635 int shift;
636 FT_Pos delta;
637
638 } FT_Outline_Funcs;
639
640
641 /*************************************************************************/
642 /* */
643 /* <Section> */
644 /* basic_types */
645 /* */
646 /*************************************************************************/
647
648
649 /*************************************************************************/
650 /* */
651 /* <Macro> */
652 /* FT_IMAGE_TAG */
653 /* */
654 /* <Description> */
655 /* This macro converts four-letter tags to an unsigned long type. */
656 /* */
657 /* <Note> */
658 /* Since many 16-bit compilers don't like 32-bit enumerations, you */
659 /* should redefine this macro in case of problems to something like */
660 /* this: */
661 /* */
662 /* { */
663 /* #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value */
664 /* } */
665 /* */
666 /* to get a simple enumeration without assigning special numbers. */
667 /* */
668 #ifndef FT_IMAGE_TAG
669 #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \
670 value = ( ( (unsigned long)_x1 << 24 ) | \
671 ( (unsigned long)_x2 << 16 ) | \
672 ( (unsigned long)_x3 << 8 ) | \
673 (unsigned long)_x4 )
674 #endif /* FT_IMAGE_TAG */
675
676
677 /*************************************************************************/
678 /* */
679 /* <Enum> */
680 /* FT_Glyph_Format */
681 /* */
682 /* <Description> */
683 /* An enumeration type used to describe the format of a given glyph */
684 /* image. Note that this version of FreeType only supports two image */
685 /* formats, even though future font drivers will be able to register */
686 /* their own format. */
687 /* */
688 /* <Values> */
689 /* FT_GLYPH_FORMAT_NONE :: */
690 /* The value~0 is reserved. */
691 /* */
692 /* FT_GLYPH_FORMAT_COMPOSITE :: */
693 /* The glyph image is a composite of several other images. This */
694 /* format is _only_ used with @FT_LOAD_NO_RECURSE, and is used to */
695 /* report compound glyphs (like accented characters). */
696 /* */
697 /* FT_GLYPH_FORMAT_BITMAP :: */
698 /* The glyph image is a bitmap, and can be described as an */
699 /* @FT_Bitmap. You generally need to access the `bitmap' field of */
700 /* the @FT_GlyphSlotRec structure to read it. */
701 /* */
702 /* FT_GLYPH_FORMAT_OUTLINE :: */
703 /* The glyph image is a vectorial outline made of line segments */
704 /* and Bezier arcs; it can be described as an @FT_Outline; you */
705 /* generally want to access the `outline' field of the */
706 /* @FT_GlyphSlotRec structure to read it. */
707 /* */
708 /* FT_GLYPH_FORMAT_PLOTTER :: */
709 /* The glyph image is a vectorial path with no inside and outside */
710 /* contours. Some Type~1 fonts, like those in the Hershey family, */
711 /* contain glyphs in this format. These are described as */
712 /* @FT_Outline, but FreeType isn't currently capable of rendering */
713 /* them correctly. */
714 /* */
715 typedef enum FT_Glyph_Format_
716 {
717 FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE, 0, 0, 0, 0 ),
718
719 FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE, 'c', 'o', 'm', 'p' ),
720 FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP, 'b', 'i', 't', 's' ),
721 FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE, 'o', 'u', 't', 'l' ),
722 FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER, 'p', 'l', 'o', 't' )
723
724 } FT_Glyph_Format;
725
726
727 /* these constants are deprecated; use the corresponding */
728 /* `FT_Glyph_Format' values instead. */
729 #define ft_glyph_format_none FT_GLYPH_FORMAT_NONE
730 #define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE
731 #define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP
732 #define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE
733 #define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER
734
735
736 /*************************************************************************/
737 /*************************************************************************/
738 /*************************************************************************/
739 /***** *****/
740 /***** R A S T E R D E F I N I T I O N S *****/
741 /***** *****/
742 /*************************************************************************/
743 /*************************************************************************/
744 /*************************************************************************/
745
746
747 /*************************************************************************/
748 /* */
749 /* A raster is a scan converter, in charge of rendering an outline into */
750 /* a bitmap. This section contains the public API for rasters. */
751 /* */
752 /* Note that in FreeType 2, all rasters are now encapsulated within */
753 /* specific modules called `renderers'. See `ftrender.h' for more */
754 /* details on renderers. */
755 /* */
756 /*************************************************************************/
757
758
759 /*************************************************************************/
760 /* */
761 /* <Section> */
762 /* raster */
763 /* */
764 /* <Title> */
765 /* Scanline Converter */
766 /* */
767 /* <Abstract> */
768 /* How vectorial outlines are converted into bitmaps and pixmaps. */
769 /* */
770 /* <Description> */
771 /* This section contains technical definitions. */
772 /* */
773 /* <Order> */
774 /* FT_Raster */
775 /* FT_Span */
776 /* FT_SpanFunc */
777 /* */
778 /* FT_Raster_Params */
779 /* FT_RASTER_FLAG_XXX */
780 /* */
781 /* FT_Raster_NewFunc */
782 /* FT_Raster_DoneFunc */
783 /* FT_Raster_ResetFunc */
784 /* FT_Raster_SetModeFunc */
785 /* FT_Raster_RenderFunc */
786 /* FT_Raster_Funcs */
787 /* */
788 /*************************************************************************/
789
790
791 /*************************************************************************/
792 /* */
793 /* <Type> */
794 /* FT_Raster */
795 /* */
796 /* <Description> */
797 /* An opaque handle (pointer) to a raster object. Each object can be */
798 /* used independently to convert an outline into a bitmap or pixmap. */
799 /* */
800 typedef struct FT_RasterRec_* FT_Raster;
801
802
803 /*************************************************************************/
804 /* */
805 /* <Struct> */
806 /* FT_Span */
807 /* */
808 /* <Description> */
809 /* A structure used to model a single span of gray pixels when */
810 /* rendering an anti-aliased bitmap. */
811 /* */
812 /* <Fields> */
813 /* x :: The span's horizontal start position. */
814 /* */
815 /* len :: The span's length in pixels. */
816 /* */
817 /* coverage :: The span color/coverage, ranging from 0 (background) */
818 /* to 255 (foreground). */
819 /* */
820 /* <Note> */
821 /* This structure is used by the span drawing callback type named */
822 /* @FT_SpanFunc that takes the y~coordinate of the span as a */
823 /* parameter. */
824 /* */
825 /* The coverage value is always between 0 and 255. If you want less */
826 /* gray values, the callback function has to reduce them. */
827 /* */
828 typedef struct FT_Span_
829 {
830 short x;
831 unsigned short len;
832 unsigned char coverage;
833
834 } FT_Span;
835
836
837 /*************************************************************************/
838 /* */
839 /* <FuncType> */
840 /* FT_SpanFunc */
841 /* */
842 /* <Description> */
843 /* A function used as a call-back by the anti-aliased renderer in */
844 /* order to let client applications draw themselves the gray pixel */
845 /* spans on each scan line. */
846 /* */
847 /* <Input> */
848 /* y :: The scanline's y~coordinate. */
849 /* */
850 /* count :: The number of spans to draw on this scanline. */
851 /* */
852 /* spans :: A table of `count' spans to draw on the scanline. */
853 /* */
854 /* user :: User-supplied data that is passed to the callback. */
855 /* */
856 /* <Note> */
857 /* This callback allows client applications to directly render the */
858 /* gray spans of the anti-aliased bitmap to any kind of surfaces. */
859 /* */
860 /* This can be used to write anti-aliased outlines directly to a */
861 /* given background bitmap, and even perform translucency. */
862 /* */
863 typedef void
864 (*FT_SpanFunc)( int y,
865 int count,
866 const FT_Span* spans,
867 void* user );
868
869 #define FT_Raster_Span_Func FT_SpanFunc
870
871
872 /*************************************************************************/
873 /* */
874 /* <FuncType> */
875 /* FT_Raster_BitTest_Func */
876 /* */
877 /* <Description> */
878 /* Deprecated, unimplemented. */
879 /* */
880 typedef int
881 (*FT_Raster_BitTest_Func)( int y,
882 int x,
883 void* user );
884
885
886 /*************************************************************************/
887 /* */
888 /* <FuncType> */
889 /* FT_Raster_BitSet_Func */
890 /* */
891 /* <Description> */
892 /* Deprecated, unimplemented. */
893 /* */
894 typedef void
895 (*FT_Raster_BitSet_Func)( int y,
896 int x,
897 void* user );
898
899
900 /*************************************************************************/
901 /* */
902 /* <Enum> */
903 /* FT_RASTER_FLAG_XXX */
904 /* */
905 /* <Description> */
906 /* A list of bit flag constants as used in the `flags' field of a */
907 /* @FT_Raster_Params structure. */
908 /* */
909 /* <Values> */
910 /* FT_RASTER_FLAG_DEFAULT :: This value is 0. */
911 /* */
912 /* FT_RASTER_FLAG_AA :: This flag is set to indicate that an */
913 /* anti-aliased glyph image should be */
914 /* generated. Otherwise, it will be */
915 /* monochrome (1-bit). */
916 /* */
917 /* FT_RASTER_FLAG_DIRECT :: This flag is set to indicate direct */
918 /* rendering. In this mode, client */
919 /* applications must provide their own span */
920 /* callback. This lets them directly */
921 /* draw or compose over an existing bitmap. */
922 /* If this bit is not set, the target */
923 /* pixmap's buffer _must_ be zeroed before */
924 /* rendering. */
925 /* */
926 /* Direct rendering is only possible with */
927 /* anti-aliased glyphs. */
928 /* */
929 /* FT_RASTER_FLAG_CLIP :: This flag is only used in direct */
930 /* rendering mode. If set, the output will */
931 /* be clipped to a box specified in the */
932 /* `clip_box' field of the */
933 /* @FT_Raster_Params structure. */
934 /* */
935 /* Note that by default, the glyph bitmap */
936 /* is clipped to the target pixmap, except */
937 /* in direct rendering mode where all spans */
938 /* are generated if no clipping box is set. */
939 /* */
940 #define FT_RASTER_FLAG_DEFAULT 0x0
941 #define FT_RASTER_FLAG_AA 0x1
942 #define FT_RASTER_FLAG_DIRECT 0x2
943 #define FT_RASTER_FLAG_CLIP 0x4
944
945 /* these constants are deprecated; use the corresponding */
946 /* `FT_RASTER_FLAG_XXX' values instead */
947 #define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT
948 #define ft_raster_flag_aa FT_RASTER_FLAG_AA
949 #define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT
950 #define ft_raster_flag_clip FT_RASTER_FLAG_CLIP
951
952
953 /*************************************************************************/
954 /* */
955 /* <Struct> */
956 /* FT_Raster_Params */
957 /* */
958 /* <Description> */
959 /* A structure to hold the arguments used by a raster's render */
960 /* function. */
961 /* */
962 /* <Fields> */
963 /* target :: The target bitmap. */
964 /* */
965 /* source :: A pointer to the source glyph image (e.g., an */
966 /* @FT_Outline). */
967 /* */
968 /* flags :: The rendering flags. */
969 /* */
970 /* gray_spans :: The gray span drawing callback. */
971 /* */
972 /* black_spans :: Unused. */
973 /* */
974 /* bit_test :: Unused. */
975 /* */
976 /* bit_set :: Unused. */
977 /* */
978 /* user :: User-supplied data that is passed to each drawing */
979 /* callback. */
980 /* */
981 /* clip_box :: An optional clipping box. It is only used in */
982 /* direct rendering mode. Note that coordinates here */
983 /* should be expressed in _integer_ pixels (and not in */
984 /* 26.6 fixed-point units). */
985 /* */
986 /* <Note> */
987 /* An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA */
988 /* bit flag is set in the `flags' field, otherwise a monochrome */
989 /* bitmap is generated. */
990 /* */
991 /* If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the */
992 /* raster will call the `gray_spans' callback to draw gray pixel */
993 /* spans. This allows direct composition over a pre-existing bitmap */
994 /* through user-provided callbacks to perform the span drawing and */
995 /* composition. Not supported by the monochrome rasterizer. */
996 /* */
997 typedef struct FT_Raster_Params_
998 {
999 const FT_Bitmap* target;
1000 const void* source;
1001 int flags;
1002 FT_SpanFunc gray_spans;
1003 FT_SpanFunc black_spans; /* unused */
1004 FT_Raster_BitTest_Func bit_test; /* unused */
1005 FT_Raster_BitSet_Func bit_set; /* unused */
1006 void* user;
1007 FT_BBox clip_box;
1008
1009 } FT_Raster_Params;
1010
1011
1012 /*************************************************************************/
1013 /* */
1014 /* <FuncType> */
1015 /* FT_Raster_NewFunc */
1016 /* */
1017 /* <Description> */
1018 /* A function used to create a new raster object. */
1019 /* */
1020 /* <Input> */
1021 /* memory :: A handle to the memory allocator. */
1022 /* */
1023 /* <Output> */
1024 /* raster :: A handle to the new raster object. */
1025 /* */
1026 /* <Return> */
1027 /* Error code. 0~means success. */
1028 /* */
1029 /* <Note> */
1030 /* The `memory' parameter is a typeless pointer in order to avoid */
1031 /* un-wanted dependencies on the rest of the FreeType code. In */
1032 /* practice, it is an @FT_Memory object, i.e., a handle to the */
1033 /* standard FreeType memory allocator. However, this field can be */
1034 /* completely ignored by a given raster implementation. */
1035 /* */
1036 typedef int
1037 (*FT_Raster_NewFunc)( void* memory,
1038 FT_Raster* raster );
1039
1040 #define FT_Raster_New_Func FT_Raster_NewFunc
1041
1042
1043 /*************************************************************************/
1044 /* */
1045 /* <FuncType> */
1046 /* FT_Raster_DoneFunc */
1047 /* */
1048 /* <Description> */
1049 /* A function used to destroy a given raster object. */
1050 /* */
1051 /* <Input> */
1052 /* raster :: A handle to the raster object. */
1053 /* */
1054 typedef void
1055 (*FT_Raster_DoneFunc)( FT_Raster raster );
1056
1057 #define FT_Raster_Done_Func FT_Raster_DoneFunc
1058
1059
1060 /*************************************************************************/
1061 /* */
1062 /* <FuncType> */
1063 /* FT_Raster_ResetFunc */
1064 /* */
1065 /* <Description> */
1066 /* FreeType used to provide an area of memory called the `render */
1067 /* pool' available to all registered rasterizers. This was not */
1068 /* thread safe, however, and now FreeType never allocates this pool. */
1069 /* */
1070 /* This function is called after a new raster object is created. */
1071 /* */
1072 /* <Input> */
1073 /* raster :: A handle to the new raster object. */
1074 /* */
1075 /* pool_base :: Previously, the address in memory of the render pool. */
1076 /* Set this to NULL. */
1077 /* */
1078 /* pool_size :: Previously, the size in bytes of the render pool. */
1079 /* Set this to 0. */
1080 /* */
1081 /* <Note> */
1082 /* Rasterizers should rely on dynamic or stack allocation if they */
1083 /* want to (a handle to the memory allocator is passed to the */
1084 /* rasterizer constructor). */
1085 /* */
1086 typedef void
1087 (*FT_Raster_ResetFunc)( FT_Raster raster,
1088 unsigned char* pool_base,
1089 unsigned long pool_size );
1090
1091 #define FT_Raster_Reset_Func FT_Raster_ResetFunc
1092
1093
1094 /*************************************************************************/
1095 /* */
1096 /* <FuncType> */
1097 /* FT_Raster_SetModeFunc */
1098 /* */
1099 /* <Description> */
1100 /* This function is a generic facility to change modes or attributes */
1101 /* in a given raster. This can be used for debugging purposes, or */
1102 /* simply to allow implementation-specific `features' in a given */
1103 /* raster module. */
1104 /* */
1105 /* <Input> */
1106 /* raster :: A handle to the new raster object. */
1107 /* */
1108 /* mode :: A 4-byte tag used to name the mode or property. */
1109 /* */
1110 /* args :: A pointer to the new mode/property to use. */
1111 /* */
1112 typedef int
1113 (*FT_Raster_SetModeFunc)( FT_Raster raster,
1114 unsigned long mode,
1115 void* args );
1116
1117 #define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc
1118
1119
1120 /*************************************************************************/
1121 /* */
1122 /* <FuncType> */
1123 /* FT_Raster_RenderFunc */
1124 /* */
1125 /* <Description> */
1126 /* Invoke a given raster to scan-convert a given glyph image into a */
1127 /* target bitmap. */
1128 /* */
1129 /* <Input> */
1130 /* raster :: A handle to the raster object. */
1131 /* */
1132 /* params :: A pointer to an @FT_Raster_Params structure used to */
1133 /* store the rendering parameters. */
1134 /* */
1135 /* <Return> */
1136 /* Error code. 0~means success. */
1137 /* */
1138 /* <Note> */
1139 /* The exact format of the source image depends on the raster's glyph */
1140 /* format defined in its @FT_Raster_Funcs structure. It can be an */
1141 /* @FT_Outline or anything else in order to support a large array of */
1142 /* glyph formats. */
1143 /* */
1144 /* Note also that the render function can fail and return a */
1145 /* `FT_Err_Unimplemented_Feature' error code if the raster used does */
1146 /* not support direct composition. */
1147 /* */
1148 /* XXX: For now, the standard raster doesn't support direct */
1149 /* composition but this should change for the final release (see */
1150 /* the files `demos/src/ftgrays.c' and `demos/src/ftgrays2.c' */
1151 /* for examples of distinct implementations that support direct */
1152 /* composition). */
1153 /* */
1154 typedef int
1155 (*FT_Raster_RenderFunc)( FT_Raster raster,
1156 const FT_Raster_Params* params );
1157
1158 #define FT_Raster_Render_Func FT_Raster_RenderFunc
1159
1160
1161 /*************************************************************************/
1162 /* */
1163 /* <Struct> */
1164 /* FT_Raster_Funcs */
1165 /* */
1166 /* <Description> */
1167 /* A structure used to describe a given raster class to the library. */
1168 /* */
1169 /* <Fields> */
1170 /* glyph_format :: The supported glyph format for this raster. */
1171 /* */
1172 /* raster_new :: The raster constructor. */
1173 /* */
1174 /* raster_reset :: Used to reset the render pool within the raster. */
1175 /* */
1176 /* raster_render :: A function to render a glyph into a given bitmap. */
1177 /* */
1178 /* raster_done :: The raster destructor. */
1179 /* */
1180 typedef struct FT_Raster_Funcs_
1181 {
1182 FT_Glyph_Format glyph_format;
1183
1184 FT_Raster_NewFunc raster_new;
1185 FT_Raster_ResetFunc raster_reset;
1186 FT_Raster_SetModeFunc raster_set_mode;
1187 FT_Raster_RenderFunc raster_render;
1188 FT_Raster_DoneFunc raster_done;
1189
1190 } FT_Raster_Funcs;
1191
1192 /* */
1193
1194
1195 FT_END_HEADER
1196
1197 #endif /* FTIMAGE_H_ */
1198
1199
1200 /* END */
1201
1202
1203 /* Local Variables: */
1204 /* coding: utf-8 */
1205 /* End: */