1 /***************************************************************************/
5 /* FreeType glyph image formats and default raster interface */
8 /* Copyright 1996-2010, 2013 by */
9 /* David Turner, Robert Wilhelm, and Werner Lemberg. */
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. */
17 /***************************************************************************/
19 /*************************************************************************/
21 /* Note: A `raster' is simply a scan-line converter, used to render */
22 /* FT_Outlines into FT_Bitmaps. */
24 /*************************************************************************/
31 /* _STANDALONE_ is from ftgrays.c */
40 /*************************************************************************/
45 /*************************************************************************/
48 /*************************************************************************/
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. */
58 typedef signed long FT_Pos
;
61 /*************************************************************************/
67 /* A simple structure used to store a 2D vector; coordinates are of */
68 /* the FT_Pos type. */
71 /* x :: The horizontal coordinate. */
72 /* y :: The vertical coordinate. */
74 typedef struct FT_Vector_
82 /*************************************************************************/
88 /* A structure used to hold an outline's bounding box, i.e., the */
89 /* coordinates of its extrema in the horizontal and vertical */
93 /* xMin :: The horizontal minimum (left-most). */
95 /* yMin :: The vertical minimum (bottom-most). */
97 /* xMax :: The horizontal maximum (right-most). */
99 /* yMax :: The vertical maximum (top-most). */
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. */
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 */
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. */
115 typedef struct FT_BBox_
123 /*************************************************************************/
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 */
134 /* FT_PIXEL_MODE_NONE :: */
135 /* Value~0 is reserved. */
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. */
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). */
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. */
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. */
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. */
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. */
171 /* FT_PIXEL_MODE_BGRA :: */
172 /* An image with four 8-bit channels per pixel, representing a */
173 /* color image (such as emoticons) with alpha channel. For each */
174 /* pixel, the format is BGRA, which means, the blue channel comes */
175 /* 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. */
180 typedef enum FT_Pixel_Mode_
182 FT_PIXEL_MODE_NONE
= 0,
191 FT_PIXEL_MODE_MAX
/* do not remove */
196 /*************************************************************************/
199 /* ft_pixel_mode_xxx */
202 /* A list of deprecated constants. Use the corresponding */
203 /* @FT_Pixel_Mode values instead. */
206 /* ft_pixel_mode_none :: See @FT_PIXEL_MODE_NONE. */
207 /* ft_pixel_mode_mono :: See @FT_PIXEL_MODE_MONO. */
208 /* ft_pixel_mode_grays :: See @FT_PIXEL_MODE_GRAY. */
209 /* ft_pixel_mode_pal2 :: See @FT_PIXEL_MODE_GRAY2. */
210 /* ft_pixel_mode_pal4 :: See @FT_PIXEL_MODE_GRAY4. */
212 #define ft_pixel_mode_none FT_PIXEL_MODE_NONE
213 #define ft_pixel_mode_mono FT_PIXEL_MODE_MONO
214 #define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY
215 #define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2
216 #define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4
222 /*************************************************************************/
225 /* FT_Palette_Mode */
228 /* THIS TYPE IS DEPRECATED. DO NOT USE IT! */
230 /* An enumeration type to describe the format of a bitmap palette, */
231 /* used with ft_pixel_mode_pal4 and ft_pixel_mode_pal8. */
234 /* ft_palette_mode_rgb :: The palette is an array of 3-byte RGB */
237 /* ft_palette_mode_rgba :: The palette is an array of 4-byte RGBA */
241 /* As ft_pixel_mode_pal2, pal4 and pal8 are currently unused by */
242 /* FreeType, these types are not handled by the library itself. */
244 typedef enum FT_Palette_Mode_
246 ft_palette_mode_rgb
= 0,
247 ft_palette_mode_rgba
,
249 ft_palette_mode_max
/* do not remove */
258 /*************************************************************************/
264 /* A structure used to describe a bitmap or pixmap to the raster. */
265 /* Note that we now manage pixmaps of various depths through the */
266 /* `pixel_mode' field. */
269 /* rows :: The number of bitmap rows. */
271 /* width :: The number of pixels in bitmap row. */
273 /* pitch :: The pitch's absolute value is the number of bytes */
274 /* taken by one bitmap row, including padding. */
275 /* However, the pitch is positive when the bitmap has */
276 /* a `down' flow, and negative when it has an `up' */
277 /* flow. In all cases, the pitch is an offset to add */
278 /* to a bitmap pointer in order to go down one row. */
280 /* Note that `padding' means the alignment of a */
281 /* bitmap to a byte border, and FreeType functions */
282 /* normally align to the smallest possible integer */
285 /* For the B/W rasterizer, `pitch' is always an even */
288 /* To change the pitch of a bitmap (say, to make it a */
289 /* multiple of 4), use @FT_Bitmap_Convert. */
290 /* Alternatively, you might use callback functions to */
291 /* directly render to the application's surface; see */
292 /* the file `example2.cpp' in the tutorial for a */
295 /* buffer :: A typeless pointer to the bitmap buffer. This */
296 /* value should be aligned on 32-bit boundaries in */
299 /* num_grays :: This field is only used with */
300 /* @FT_PIXEL_MODE_GRAY; it gives the number of gray */
301 /* levels used in the bitmap. */
303 /* pixel_mode :: The pixel mode, i.e., how pixel bits are stored. */
304 /* See @FT_Pixel_Mode for possible values. */
306 /* palette_mode :: This field is intended for paletted pixel modes; */
307 /* it indicates how the palette is stored. Not */
308 /* used currently. */
310 /* palette :: A typeless pointer to the bitmap palette; this */
311 /* field is intended for paletted pixel modes. Not */
312 /* used currently. */
315 /* For now, the only pixel modes supported by FreeType are mono and */
316 /* grays. However, drivers might be added in the future to support */
317 /* more `colorful' options. */
319 typedef struct FT_Bitmap_
324 unsigned char* buffer
;
333 /*************************************************************************/
336 /* outline_processing */
338 /*************************************************************************/
341 /*************************************************************************/
347 /* This structure is used to describe an outline to the scan-line */
351 /* n_contours :: The number of contours in the outline. */
353 /* n_points :: The number of points in the outline. */
355 /* points :: A pointer to an array of `n_points' @FT_Vector */
356 /* elements, giving the outline's point coordinates. */
358 /* tags :: A pointer to an array of `n_points' chars, giving */
359 /* each outline point's type. */
361 /* If bit~0 is unset, the point is `off' the curve, */
362 /* i.e., a Bézier control point, while it is `on' if */
365 /* Bit~1 is meaningful for `off' points only. If set, */
366 /* it indicates a third-order Bézier arc control point; */
367 /* and a second-order control point if unset. */
369 /* If bit~2 is set, bits 5-7 contain the drop-out mode */
370 /* (as defined in the OpenType specification; the value */
371 /* is the same as the argument to the SCANMODE */
374 /* Bits 3 and~4 are reserved for internal purposes. */
376 /* contours :: An array of `n_contours' shorts, giving the end */
377 /* point of each contour within the outline. For */
378 /* example, the first contour is defined by the points */
379 /* `0' to `contours[0]', the second one is defined by */
380 /* the points `contours[0]+1' to `contours[1]', etc. */
382 /* flags :: A set of bit flags used to characterize the outline */
383 /* and give hints to the scan-converter and hinter on */
384 /* how to convert/grid-fit it. See @FT_OUTLINE_FLAGS. */
387 /* The B/W rasterizer only checks bit~2 in the `tags' array for the */
388 /* first point of each contour. The drop-out mode as given with */
389 /* @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and */
390 /* @FT_OUTLINE_INCLUDE_STUBS in `flags' is then overridden. */
392 typedef struct FT_Outline_
394 short n_contours
; /* number of contours in glyph */
395 short n_points
; /* number of points in the glyph */
397 FT_Vector
* points
; /* the outline's points */
398 char* tags
; /* the points flags */
399 short* contours
; /* the contour end points */
401 int flags
; /* outline masks */
405 /* Following limits must be consistent with */
406 /* FT_Outline.{n_contours,n_points} */
407 #define FT_OUTLINE_CONTOURS_MAX SHRT_MAX
408 #define FT_OUTLINE_POINTS_MAX SHRT_MAX
411 /*************************************************************************/
414 /* FT_OUTLINE_FLAGS */
417 /* A list of bit-field constants use for the flags in an outline's */
421 /* FT_OUTLINE_NONE :: */
422 /* Value~0 is reserved. */
424 /* FT_OUTLINE_OWNER :: */
425 /* If set, this flag indicates that the outline's field arrays */
426 /* (i.e., `points', `flags', and `contours') are `owned' by the */
427 /* outline object, and should thus be freed when it is destroyed. */
429 /* FT_OUTLINE_EVEN_ODD_FILL :: */
430 /* By default, outlines are filled using the non-zero winding rule. */
431 /* If set to 1, the outline will be filled using the even-odd fill */
432 /* rule (only works with the smooth rasterizer). */
434 /* FT_OUTLINE_REVERSE_FILL :: */
435 /* By default, outside contours of an outline are oriented in */
436 /* clock-wise direction, as defined in the TrueType specification. */
437 /* This flag is set if the outline uses the opposite direction */
438 /* (typically for Type~1 fonts). This flag is ignored by the scan */
441 /* FT_OUTLINE_IGNORE_DROPOUTS :: */
442 /* By default, the scan converter will try to detect drop-outs in */
443 /* an outline and correct the glyph bitmap to ensure consistent */
444 /* shape continuity. If set, this flag hints the scan-line */
445 /* converter to ignore such cases. See below for more information. */
447 /* FT_OUTLINE_SMART_DROPOUTS :: */
448 /* Select smart dropout control. If unset, use simple dropout */
449 /* control. Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See */
450 /* below for more information. */
452 /* FT_OUTLINE_INCLUDE_STUBS :: */
453 /* If set, turn pixels on for `stubs', otherwise exclude them. */
454 /* Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for */
455 /* more information. */
457 /* FT_OUTLINE_HIGH_PRECISION :: */
458 /* This flag indicates that the scan-line converter should try to */
459 /* convert this outline to bitmaps with the highest possible */
460 /* quality. It is typically set for small character sizes. Note */
461 /* that this is only a hint that might be completely ignored by a */
462 /* given scan-converter. */
464 /* FT_OUTLINE_SINGLE_PASS :: */
465 /* This flag is set to force a given scan-converter to only use a */
466 /* single pass over the outline to render a bitmap glyph image. */
467 /* Normally, it is set for very large character sizes. It is only */
468 /* a hint that might be completely ignored by a given */
469 /* scan-converter. */
472 /* The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, */
473 /* and @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth */
476 /* There exists a second mechanism to pass the drop-out mode to the */
477 /* B/W rasterizer; see the `tags' field in @FT_Outline. */
479 /* Please refer to the description of the `SCANTYPE' instruction in */
480 /* the OpenType specification (in file `ttinst1.doc') how simple */
481 /* drop-outs, smart drop-outs, and stubs are defined. */
483 #define FT_OUTLINE_NONE 0x0
484 #define FT_OUTLINE_OWNER 0x1
485 #define FT_OUTLINE_EVEN_ODD_FILL 0x2
486 #define FT_OUTLINE_REVERSE_FILL 0x4
487 #define FT_OUTLINE_IGNORE_DROPOUTS 0x8
488 #define FT_OUTLINE_SMART_DROPOUTS 0x10
489 #define FT_OUTLINE_INCLUDE_STUBS 0x20
491 #define FT_OUTLINE_HIGH_PRECISION 0x100
492 #define FT_OUTLINE_SINGLE_PASS 0x200
495 /*************************************************************************
501 * These constants are deprecated. Please use the corresponding
502 * @FT_OUTLINE_FLAGS values.
505 * ft_outline_none :: See @FT_OUTLINE_NONE.
506 * ft_outline_owner :: See @FT_OUTLINE_OWNER.
507 * ft_outline_even_odd_fill :: See @FT_OUTLINE_EVEN_ODD_FILL.
508 * ft_outline_reverse_fill :: See @FT_OUTLINE_REVERSE_FILL.
509 * ft_outline_ignore_dropouts :: See @FT_OUTLINE_IGNORE_DROPOUTS.
510 * ft_outline_high_precision :: See @FT_OUTLINE_HIGH_PRECISION.
511 * ft_outline_single_pass :: See @FT_OUTLINE_SINGLE_PASS.
513 #define ft_outline_none FT_OUTLINE_NONE
514 #define ft_outline_owner FT_OUTLINE_OWNER
515 #define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL
516 #define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL
517 #define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS
518 #define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION
519 #define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS
523 #define FT_CURVE_TAG( flag ) ( flag & 3 )
525 #define FT_CURVE_TAG_ON 1
526 #define FT_CURVE_TAG_CONIC 0
527 #define FT_CURVE_TAG_CUBIC 2
529 #define FT_CURVE_TAG_HAS_SCANMODE 4
531 #define FT_CURVE_TAG_TOUCH_X 8 /* reserved for the TrueType hinter */
532 #define FT_CURVE_TAG_TOUCH_Y 16 /* reserved for the TrueType hinter */
534 #define FT_CURVE_TAG_TOUCH_BOTH ( FT_CURVE_TAG_TOUCH_X | \
535 FT_CURVE_TAG_TOUCH_Y )
537 #define FT_Curve_Tag_On FT_CURVE_TAG_ON
538 #define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC
539 #define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC
540 #define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X
541 #define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y
544 /*************************************************************************/
547 /* FT_Outline_MoveToFunc */
550 /* A function pointer type used to describe the signature of a `move */
551 /* to' function during outline walking/decomposition. */
553 /* A `move to' is emitted to start a new contour in an outline. */
556 /* to :: A pointer to the target point of the `move to'. */
558 /* user :: A typeless pointer which is passed from the caller of the */
559 /* decomposition function. */
562 /* Error code. 0~means success. */
565 (*FT_Outline_MoveToFunc
)( const FT_Vector
* to
,
568 #define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc
571 /*************************************************************************/
574 /* FT_Outline_LineToFunc */
577 /* A function pointer type used to describe the signature of a `line */
578 /* to' function during outline walking/decomposition. */
580 /* A `line to' is emitted to indicate a segment in the outline. */
583 /* to :: A pointer to the target point of the `line to'. */
585 /* user :: A typeless pointer which is passed from the caller of the */
586 /* decomposition function. */
589 /* Error code. 0~means success. */
592 (*FT_Outline_LineToFunc
)( const FT_Vector
* to
,
595 #define FT_Outline_LineTo_Func FT_Outline_LineToFunc
598 /*************************************************************************/
601 /* FT_Outline_ConicToFunc */
604 /* A function pointer type used to describe the signature of a `conic */
605 /* to' function during outline walking or decomposition. */
607 /* A `conic to' is emitted to indicate a second-order Bézier arc in */
611 /* control :: An intermediate control point between the last position */
612 /* and the new target in `to'. */
614 /* to :: A pointer to the target end point of the conic arc. */
616 /* user :: A typeless pointer which is passed from the caller of */
617 /* the decomposition function. */
620 /* Error code. 0~means success. */
623 (*FT_Outline_ConicToFunc
)( const FT_Vector
* control
,
627 #define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc
630 /*************************************************************************/
633 /* FT_Outline_CubicToFunc */
636 /* A function pointer type used to describe the signature of a `cubic */
637 /* to' function during outline walking or decomposition. */
639 /* A `cubic to' is emitted to indicate a third-order Bézier arc. */
642 /* control1 :: A pointer to the first Bézier control point. */
644 /* control2 :: A pointer to the second Bézier control point. */
646 /* to :: A pointer to the target end point. */
648 /* user :: A typeless pointer which is passed from the caller of */
649 /* the decomposition function. */
652 /* Error code. 0~means success. */
655 (*FT_Outline_CubicToFunc
)( const FT_Vector
* control1
,
656 const FT_Vector
* control2
,
660 #define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc
663 /*************************************************************************/
666 /* FT_Outline_Funcs */
669 /* A structure to hold various function pointers used during outline */
670 /* decomposition in order to emit segments, conic, and cubic Béziers. */
673 /* move_to :: The `move to' emitter. */
675 /* line_to :: The segment emitter. */
677 /* conic_to :: The second-order Bézier arc emitter. */
679 /* cubic_to :: The third-order Bézier arc emitter. */
681 /* shift :: The shift that is applied to coordinates before they */
682 /* are sent to the emitter. */
684 /* delta :: The delta that is applied to coordinates before they */
685 /* are sent to the emitter, but after the shift. */
688 /* The point coordinates sent to the emitters are the transformed */
689 /* version of the original coordinates (this is important for high */
690 /* accuracy during scan-conversion). The transformation is simple: */
693 /* x' = (x << shift) - delta */
694 /* y' = (x << shift) - delta */
697 /* Set the values of `shift' and `delta' to~0 to get the original */
698 /* point coordinates. */
700 typedef struct FT_Outline_Funcs_
702 FT_Outline_MoveToFunc move_to
;
703 FT_Outline_LineToFunc line_to
;
704 FT_Outline_ConicToFunc conic_to
;
705 FT_Outline_CubicToFunc cubic_to
;
713 /*************************************************************************/
718 /*************************************************************************/
721 /*************************************************************************/
727 /* This macro converts four-letter tags to an unsigned long type. */
730 /* Since many 16-bit compilers don't like 32-bit enumerations, you */
731 /* should redefine this macro in case of problems to something like */
735 /* #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value */
738 /* to get a simple enumeration without assigning special numbers. */
741 #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \
742 value = ( ( (unsigned long)_x1 << 24 ) | \
743 ( (unsigned long)_x2 << 16 ) | \
744 ( (unsigned long)_x3 << 8 ) | \
746 #endif /* FT_IMAGE_TAG */
749 /*************************************************************************/
752 /* FT_Glyph_Format */
755 /* An enumeration type used to describe the format of a given glyph */
756 /* image. Note that this version of FreeType only supports two image */
757 /* formats, even though future font drivers will be able to register */
758 /* their own format. */
761 /* FT_GLYPH_FORMAT_NONE :: */
762 /* The value~0 is reserved. */
764 /* FT_GLYPH_FORMAT_COMPOSITE :: */
765 /* The glyph image is a composite of several other images. This */
766 /* format is _only_ used with @FT_LOAD_NO_RECURSE, and is used to */
767 /* report compound glyphs (like accented characters). */
769 /* FT_GLYPH_FORMAT_BITMAP :: */
770 /* The glyph image is a bitmap, and can be described as an */
771 /* @FT_Bitmap. You generally need to access the `bitmap' field of */
772 /* the @FT_GlyphSlotRec structure to read it. */
774 /* FT_GLYPH_FORMAT_OUTLINE :: */
775 /* The glyph image is a vectorial outline made of line segments */
776 /* and Bézier arcs; it can be described as an @FT_Outline; you */
777 /* generally want to access the `outline' field of the */
778 /* @FT_GlyphSlotRec structure to read it. */
780 /* FT_GLYPH_FORMAT_PLOTTER :: */
781 /* The glyph image is a vectorial path with no inside and outside */
782 /* contours. Some Type~1 fonts, like those in the Hershey family, */
783 /* contain glyphs in this format. These are described as */
784 /* @FT_Outline, but FreeType isn't currently capable of rendering */
785 /* them correctly. */
787 typedef enum FT_Glyph_Format_
789 FT_IMAGE_TAG( FT_GLYPH_FORMAT_NONE
, 0, 0, 0, 0 ),
791 FT_IMAGE_TAG( FT_GLYPH_FORMAT_COMPOSITE
, 'c', 'o', 'm', 'p' ),
792 FT_IMAGE_TAG( FT_GLYPH_FORMAT_BITMAP
, 'b', 'i', 't', 's' ),
793 FT_IMAGE_TAG( FT_GLYPH_FORMAT_OUTLINE
, 'o', 'u', 't', 'l' ),
794 FT_IMAGE_TAG( FT_GLYPH_FORMAT_PLOTTER
, 'p', 'l', 'o', 't' )
799 /*************************************************************************/
802 /* ft_glyph_format_xxx */
805 /* A list of deprecated constants. Use the corresponding */
806 /* @FT_Glyph_Format values instead. */
809 /* ft_glyph_format_none :: See @FT_GLYPH_FORMAT_NONE. */
810 /* ft_glyph_format_composite :: See @FT_GLYPH_FORMAT_COMPOSITE. */
811 /* ft_glyph_format_bitmap :: See @FT_GLYPH_FORMAT_BITMAP. */
812 /* ft_glyph_format_outline :: See @FT_GLYPH_FORMAT_OUTLINE. */
813 /* ft_glyph_format_plotter :: See @FT_GLYPH_FORMAT_PLOTTER. */
815 #define ft_glyph_format_none FT_GLYPH_FORMAT_NONE
816 #define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE
817 #define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP
818 #define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE
819 #define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER
822 /*************************************************************************/
823 /*************************************************************************/
824 /*************************************************************************/
826 /***** R A S T E R D E F I N I T I O N S *****/
828 /*************************************************************************/
829 /*************************************************************************/
830 /*************************************************************************/
833 /*************************************************************************/
835 /* A raster is a scan converter, in charge of rendering an outline into */
836 /* a a bitmap. This section contains the public API for rasters. */
838 /* Note that in FreeType 2, all rasters are now encapsulated within */
839 /* specific modules called `renderers'. See `freetype/ftrender.h' for */
840 /* more details on renderers. */
842 /*************************************************************************/
845 /*************************************************************************/
851 /* Scanline Converter */
854 /* How vectorial outlines are converted into bitmaps and pixmaps. */
857 /* This section contains technical definitions. */
859 /*************************************************************************/
862 /*************************************************************************/
868 /* A handle (pointer) to a raster object. Each object can be used */
869 /* independently to convert an outline into a bitmap or pixmap. */
871 typedef struct FT_RasterRec_
* FT_Raster
;
874 /*************************************************************************/
880 /* A structure used to model a single span of gray (or black) pixels */
881 /* when rendering a monochrome or anti-aliased bitmap. */
884 /* x :: The span's horizontal start position. */
886 /* len :: The span's length in pixels. */
888 /* coverage :: The span color/coverage, ranging from 0 (background) */
889 /* to 255 (foreground). Only used for anti-aliased */
893 /* This structure is used by the span drawing callback type named */
894 /* @FT_SpanFunc which takes the y~coordinate of the span as a */
897 /* The coverage value is always between 0 and 255. If you want less */
898 /* gray values, the callback function has to reduce them. */
900 typedef struct FT_Span_
904 unsigned char coverage
;
909 /*************************************************************************/
915 /* A function used as a call-back by the anti-aliased renderer in */
916 /* order to let client applications draw themselves the gray pixel */
917 /* spans on each scan line. */
920 /* y :: The scanline's y~coordinate. */
922 /* count :: The number of spans to draw on this scanline. */
924 /* spans :: A table of `count' spans to draw on the scanline. */
926 /* user :: User-supplied data that is passed to the callback. */
929 /* This callback allows client applications to directly render the */
930 /* gray spans of the anti-aliased bitmap to any kind of surfaces. */
932 /* This can be used to write anti-aliased outlines directly to a */
933 /* given background bitmap, and even perform translucency. */
935 /* Note that the `count' field cannot be greater than a fixed value */
936 /* defined by the `FT_MAX_GRAY_SPANS' configuration macro in */
937 /* `ftoption.h'. By default, this value is set to~32, which means */
938 /* that if there are more than 32~spans on a given scanline, the */
939 /* callback is called several times with the same `y' parameter in */
940 /* order to draw all callbacks. */
942 /* Otherwise, the callback is only called once per scan-line, and */
943 /* only for those scanlines that do have `gray' pixels on them. */
946 (*FT_SpanFunc
)( int y
,
948 const FT_Span
* spans
,
951 #define FT_Raster_Span_Func FT_SpanFunc
954 /*************************************************************************/
957 /* FT_Raster_BitTest_Func */
960 /* THIS TYPE IS DEPRECATED. DO NOT USE IT. */
962 /* A function used as a call-back by the monochrome scan-converter */
963 /* to test whether a given target pixel is already set to the drawing */
964 /* `color'. These tests are crucial to implement drop-out control */
965 /* per-se the TrueType spec. */
968 /* y :: The pixel's y~coordinate. */
970 /* x :: The pixel's x~coordinate. */
972 /* user :: User-supplied data that is passed to the callback. */
975 /* 1~if the pixel is `set', 0~otherwise. */
978 (*FT_Raster_BitTest_Func
)( int y
,
983 /*************************************************************************/
986 /* FT_Raster_BitSet_Func */
989 /* THIS TYPE IS DEPRECATED. DO NOT USE IT. */
991 /* A function used as a call-back by the monochrome scan-converter */
992 /* to set an individual target pixel. This is crucial to implement */
993 /* drop-out control according to the TrueType specification. */
996 /* y :: The pixel's y~coordinate. */
998 /* x :: The pixel's x~coordinate. */
1000 /* user :: User-supplied data that is passed to the callback. */
1003 /* 1~if the pixel is `set', 0~otherwise. */
1006 (*FT_Raster_BitSet_Func
)( int y
,
1011 /*************************************************************************/
1014 /* FT_RASTER_FLAG_XXX */
1017 /* A list of bit flag constants as used in the `flags' field of a */
1018 /* @FT_Raster_Params structure. */
1021 /* FT_RASTER_FLAG_DEFAULT :: This value is 0. */
1023 /* FT_RASTER_FLAG_AA :: This flag is set to indicate that an */
1024 /* anti-aliased glyph image should be */
1025 /* generated. Otherwise, it will be */
1026 /* monochrome (1-bit). */
1028 /* FT_RASTER_FLAG_DIRECT :: This flag is set to indicate direct */
1029 /* rendering. In this mode, client */
1030 /* applications must provide their own span */
1031 /* callback. This lets them directly */
1032 /* draw or compose over an existing bitmap. */
1033 /* If this bit is not set, the target */
1034 /* pixmap's buffer _must_ be zeroed before */
1037 /* Note that for now, direct rendering is */
1038 /* only possible with anti-aliased glyphs. */
1040 /* FT_RASTER_FLAG_CLIP :: This flag is only used in direct */
1041 /* rendering mode. If set, the output will */
1042 /* be clipped to a box specified in the */
1043 /* `clip_box' field of the */
1044 /* @FT_Raster_Params structure. */
1046 /* Note that by default, the glyph bitmap */
1047 /* is clipped to the target pixmap, except */
1048 /* in direct rendering mode where all spans */
1049 /* are generated if no clipping box is set. */
1051 #define FT_RASTER_FLAG_DEFAULT 0x0
1052 #define FT_RASTER_FLAG_AA 0x1
1053 #define FT_RASTER_FLAG_DIRECT 0x2
1054 #define FT_RASTER_FLAG_CLIP 0x4
1057 #define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT
1058 #define ft_raster_flag_aa FT_RASTER_FLAG_AA
1059 #define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT
1060 #define ft_raster_flag_clip FT_RASTER_FLAG_CLIP
1063 /*************************************************************************/
1066 /* FT_Raster_Params */
1069 /* A structure to hold the arguments used by a raster's render */
1073 /* target :: The target bitmap. */
1075 /* source :: A pointer to the source glyph image (e.g., an */
1078 /* flags :: The rendering flags. */
1080 /* gray_spans :: The gray span drawing callback. */
1082 /* black_spans :: The black span drawing callback. UNIMPLEMENTED! */
1084 /* bit_test :: The bit test callback. UNIMPLEMENTED! */
1086 /* bit_set :: The bit set callback. UNIMPLEMENTED! */
1088 /* user :: User-supplied data that is passed to each drawing */
1091 /* clip_box :: An optional clipping box. It is only used in */
1092 /* direct rendering mode. Note that coordinates here */
1093 /* should be expressed in _integer_ pixels (and not in */
1094 /* 26.6 fixed-point units). */
1097 /* An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA */
1098 /* bit flag is set in the `flags' field, otherwise a monochrome */
1099 /* bitmap is generated. */
1101 /* If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the */
1102 /* raster will call the `gray_spans' callback to draw gray pixel */
1103 /* spans, in the case of an aa glyph bitmap, it will call */
1104 /* `black_spans', and `bit_test' and `bit_set' in the case of a */
1105 /* monochrome bitmap. This allows direct composition over a */
1106 /* pre-existing bitmap through user-provided callbacks to perform the */
1107 /* span drawing/composition. */
1109 /* Note that the `bit_test' and `bit_set' callbacks are required when */
1110 /* rendering a monochrome bitmap, as they are crucial to implement */
1111 /* correct drop-out control as defined in the TrueType specification. */
1113 typedef struct FT_Raster_Params_
1115 const FT_Bitmap
* target
;
1118 FT_SpanFunc gray_spans
;
1119 FT_SpanFunc black_spans
; /* doesn't work! */
1120 FT_Raster_BitTest_Func bit_test
; /* doesn't work! */
1121 FT_Raster_BitSet_Func bit_set
; /* doesn't work! */
1128 /*************************************************************************/
1131 /* FT_Raster_NewFunc */
1134 /* A function used to create a new raster object. */
1137 /* memory :: A handle to the memory allocator. */
1140 /* raster :: A handle to the new raster object. */
1143 /* Error code. 0~means success. */
1146 /* The `memory' parameter is a typeless pointer in order to avoid */
1147 /* un-wanted dependencies on the rest of the FreeType code. In */
1148 /* practice, it is an @FT_Memory object, i.e., a handle to the */
1149 /* standard FreeType memory allocator. However, this field can be */
1150 /* completely ignored by a given raster implementation. */
1153 (*FT_Raster_NewFunc
)( void* memory
,
1154 FT_Raster
* raster
);
1156 #define FT_Raster_New_Func FT_Raster_NewFunc
1159 /*************************************************************************/
1162 /* FT_Raster_DoneFunc */
1165 /* A function used to destroy a given raster object. */
1168 /* raster :: A handle to the raster object. */
1171 (*FT_Raster_DoneFunc
)( FT_Raster raster
);
1173 #define FT_Raster_Done_Func FT_Raster_DoneFunc
1176 /*************************************************************************/
1179 /* FT_Raster_ResetFunc */
1182 /* FreeType provides an area of memory called the `render pool', */
1183 /* available to all registered rasters. This pool can be freely used */
1184 /* during a given scan-conversion but is shared by all rasters. Its */
1185 /* content is thus transient. */
1187 /* This function is called each time the render pool changes, or just */
1188 /* after a new raster object is created. */
1191 /* raster :: A handle to the new raster object. */
1193 /* pool_base :: The address in memory of the render pool. */
1195 /* pool_size :: The size in bytes of the render pool. */
1198 /* Rasters can ignore the render pool and rely on dynamic memory */
1199 /* allocation if they want to (a handle to the memory allocator is */
1200 /* passed to the raster constructor). However, this is not */
1201 /* recommended for efficiency purposes. */
1204 (*FT_Raster_ResetFunc
)( FT_Raster raster
,
1205 unsigned char* pool_base
,
1206 unsigned long pool_size
);
1208 #define FT_Raster_Reset_Func FT_Raster_ResetFunc
1211 /*************************************************************************/
1214 /* FT_Raster_SetModeFunc */
1217 /* This function is a generic facility to change modes or attributes */
1218 /* in a given raster. This can be used for debugging purposes, or */
1219 /* simply to allow implementation-specific `features' in a given */
1220 /* raster module. */
1223 /* raster :: A handle to the new raster object. */
1225 /* mode :: A 4-byte tag used to name the mode or property. */
1227 /* args :: A pointer to the new mode/property to use. */
1230 (*FT_Raster_SetModeFunc
)( FT_Raster raster
,
1234 #define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc
1237 /*************************************************************************/
1240 /* FT_Raster_RenderFunc */
1243 /* Invoke a given raster to scan-convert a given glyph image into a */
1244 /* target bitmap. */
1247 /* raster :: A handle to the raster object. */
1249 /* params :: A pointer to an @FT_Raster_Params structure used to */
1250 /* store the rendering parameters. */
1253 /* Error code. 0~means success. */
1256 /* The exact format of the source image depends on the raster's glyph */
1257 /* format defined in its @FT_Raster_Funcs structure. It can be an */
1258 /* @FT_Outline or anything else in order to support a large array of */
1259 /* glyph formats. */
1261 /* Note also that the render function can fail and return a */
1262 /* `FT_Err_Unimplemented_Feature' error code if the raster used does */
1263 /* not support direct composition. */
1265 /* XXX: For now, the standard raster doesn't support direct */
1266 /* composition but this should change for the final release (see */
1267 /* the files `demos/src/ftgrays.c' and `demos/src/ftgrays2.c' */
1268 /* for examples of distinct implementations which support direct */
1272 (*FT_Raster_RenderFunc
)( FT_Raster raster
,
1273 const FT_Raster_Params
* params
);
1275 #define FT_Raster_Render_Func FT_Raster_RenderFunc
1278 /*************************************************************************/
1281 /* FT_Raster_Funcs */
1284 /* A structure used to describe a given raster class to the library. */
1287 /* glyph_format :: The supported glyph format for this raster. */
1289 /* raster_new :: The raster constructor. */
1291 /* raster_reset :: Used to reset the render pool within the raster. */
1293 /* raster_render :: A function to render a glyph into a given bitmap. */
1295 /* raster_done :: The raster destructor. */
1297 typedef struct FT_Raster_Funcs_
1299 FT_Glyph_Format glyph_format
;
1300 FT_Raster_NewFunc raster_new
;
1301 FT_Raster_ResetFunc raster_reset
;
1302 FT_Raster_SetModeFunc raster_set_mode
;
1303 FT_Raster_RenderFunc raster_render
;
1304 FT_Raster_DoneFunc raster_done
;
1314 #endif /* __FTIMAGE_H__ */
1320 /* Local Variables: */