1 /****************************************************************************
2 *
3 * ftgrays.c
4 *
5 * A new `perfect' anti-aliasing renderer (body).
6 *
7 * Copyright (C) 2000-2019 by
8 * David Turner, Robert Wilhelm, and Werner Lemberg.
9 *
10 * This file is part of the FreeType project, and may only be used,
11 * modified, and distributed under the terms of the FreeType project
12 * license, LICENSE.TXT. By continuing to use, modify, or distribute
13 * this file you indicate that you have read the license and
14 * understand and accept it fully.
15 *
16 */
17
18 /**************************************************************************
19 *
20 * This file can be compiled without the rest of the FreeType engine, by
21 * defining the STANDALONE_ macro when compiling it. You also need to
22 * put the files `ftgrays.h' and `ftimage.h' into the current
23 * compilation directory. Typically, you could do something like
24 *
25 * - copy `src/smooth/ftgrays.c' (this file) to your current directory
26 *
27 * - copy `include/freetype/ftimage.h' and `src/smooth/ftgrays.h' to the
28 * same directory
29 *
30 * - compile `ftgrays' with the STANDALONE_ macro defined, as in
31 *
32 * cc -c -DSTANDALONE_ ftgrays.c
33 *
34 * The renderer can be initialized with a call to
35 * `ft_gray_raster.raster_new'; an anti-aliased bitmap can be generated
36 * with a call to `ft_gray_raster.raster_render'.
37 *
38 * See the comments and documentation in the file `ftimage.h' for more
39 * details on how the raster works.
40 *
41 */
42
43 /**************************************************************************
44 *
45 * This is a new anti-aliasing scan-converter for FreeType 2. The
46 * algorithm used here is _very_ different from the one in the standard
47 * `ftraster' module. Actually, `ftgrays' computes the _exact_
48 * coverage of the outline on each pixel cell by straight segments.
49 *
50 * It is based on ideas that I initially found in Raph Levien's
51 * excellent LibArt graphics library (see https://www.levien.com/libart
52 * for more information, though the web pages do not tell anything
53 * about the renderer; you'll have to dive into the source code to
54 * understand how it works).
55 *
56 * Note, however, that this is a _very_ different implementation
57 * compared to Raph's. Coverage information is stored in a very
58 * different way, and I don't use sorted vector paths. Also, it doesn't
59 * use floating point values.
60 *
61 * Bézier segments are flattened by splitting them until their deviation
62 * from straight line becomes much smaller than a pixel. Therefore, the
63 * pixel coverage by a Bézier curve is calculated approximately. To
64 * estimate the deviation, we use the distance from the control point
65 * to the conic chord centre or the cubic chord trisection. These
66 * distances vanish fast after each split. In the conic case, they vanish
67 * predictably and the number of necessary splits can be calculated.
68 *
69 * This renderer has the following advantages:
70 *
71 * - It doesn't need an intermediate bitmap. Instead, one can supply a
72 * callback function that will be called by the renderer to draw gray
73 * spans on any target surface. You can thus do direct composition on
74 * any kind of bitmap, provided that you give the renderer the right
75 * callback.
76 *
77 * - A perfect anti-aliaser, i.e., it computes the _exact_ coverage on
78 * each pixel cell by straight segments.
79 *
80 * - It performs a single pass on the outline (the `standard' FT2
81 * renderer makes two passes).
82 *
83 * - It can easily be modified to render to _any_ number of gray levels
84 * cheaply.
85 *
86 * - For small (< 80) pixel sizes, it is faster than the standard
87 * renderer.
88 *
89 */
90
91
92 /**************************************************************************
93 *
94 * The macro FT_COMPONENT is used in trace mode. It is an implicit
95 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
96 * messages during execution.
97 */
98 #undef FT_COMPONENT
99 #define FT_COMPONENT smooth
100
101
102 #ifdef STANDALONE_
103
104
105 /* The size in bytes of the render pool used by the scan-line converter */
106 /* to do all of its work. */
107 #define FT_RENDER_POOL_SIZE 16384L
108
109
110 /* Auxiliary macros for token concatenation. */
111 #define FT_ERR_XCAT( x, y ) x ## y
112 #define FT_ERR_CAT( x, y ) FT_ERR_XCAT( x, y )
113
114 #define FT_BEGIN_STMNT do {
115 #define FT_END_STMNT } while ( 0 )
116
117 #define FT_MIN( a, b ) ( (a) < (b) ? (a) : (b) )
118 #define FT_MAX( a, b ) ( (a) > (b) ? (a) : (b) )
119 #define FT_ABS( a ) ( (a) < 0 ? -(a) : (a) )
120
121
122 /*
123 * Approximate sqrt(x*x+y*y) using the `alpha max plus beta min'
124 * algorithm. We use alpha = 1, beta = 3/8, giving us results with a
125 * largest error less than 7% compared to the exact value.
126 */
127 #define FT_HYPOT( x, y ) \
128 ( x = FT_ABS( x ), \
129 y = FT_ABS( y ), \
130 x > y ? x + ( 3 * y >> 3 ) \
131 : y + ( 3 * x >> 3 ) )
132
133
134 /* define this to dump debugging information */
135 /* #define FT_DEBUG_LEVEL_TRACE */
136
137
138 #ifdef FT_DEBUG_LEVEL_TRACE
139 #include <stdio.h>
140 #include <stdarg.h>
141 #endif
142
143 #include <stddef.h>
144 #include <string.h>
145 #include <setjmp.h>
146 #include <limits.h>
147 #define FT_CHAR_BIT CHAR_BIT
148 #define FT_UINT_MAX UINT_MAX
149 #define FT_INT_MAX INT_MAX
150 #define FT_ULONG_MAX ULONG_MAX
151
152 #define ADD_LONG( a, b ) \
153 (long)( (unsigned long)(a) + (unsigned long)(b) )
154 #define SUB_LONG( a, b ) \
155 (long)( (unsigned long)(a) - (unsigned long)(b) )
156 #define MUL_LONG( a, b ) \
157 (long)( (unsigned long)(a) * (unsigned long)(b) )
158 #define NEG_LONG( a ) \
159 (long)( -(unsigned long)(a) )
160
161
162 #define ft_memset memset
163
164 #define ft_setjmp setjmp
165 #define ft_longjmp longjmp
166 #define ft_jmp_buf jmp_buf
167
168 typedef ptrdiff_t FT_PtrDist;
169
170
171 #define ErrRaster_Invalid_Mode -2
172 #define ErrRaster_Invalid_Outline -1
173 #define ErrRaster_Invalid_Argument -3
174 #define ErrRaster_Memory_Overflow -4
175
176 #define FT_BEGIN_HEADER
177 #define FT_END_HEADER
178
179 #include "ftimage.h"
180 #include "ftgrays.h"
181
182
183 /* This macro is used to indicate that a function parameter is unused. */
184 /* Its purpose is simply to reduce compiler warnings. Note also that */
185 /* simply defining it as `(void)x' doesn't avoid warnings with certain */
186 /* ANSI compilers (e.g. LCC). */
187 #define FT_UNUSED( x ) (x) = (x)
188
189
190 /* we only use level 5 & 7 tracing messages; cf. ftdebug.h */
191
192 #ifdef FT_DEBUG_LEVEL_TRACE
193
194 void
195 FT_Message( const char* fmt,
196 ... )
197 {
198 va_list ap;
199
200
201 va_start( ap, fmt );
202 vfprintf( stderr, fmt, ap );
203 va_end( ap );
204 }
205
206
207 /* empty function useful for setting a breakpoint to catch errors */
208 int
209 FT_Throw( int error,
210 int line,
211 const char* file )
212 {
213 FT_UNUSED( error );
214 FT_UNUSED( line );
215 FT_UNUSED( file );
216
217 return 0;
218 }
219
220
221 /* we don't handle tracing levels in stand-alone mode; */
222 #ifndef FT_TRACE5
223 #define FT_TRACE5( varformat ) FT_Message varformat
224 #endif
225 #ifndef FT_TRACE7
226 #define FT_TRACE7( varformat ) FT_Message varformat
227 #endif
228 #ifndef FT_ERROR
229 #define FT_ERROR( varformat ) FT_Message varformat
230 #endif
231
232 #define FT_THROW( e ) \
233 ( FT_Throw( FT_ERR_CAT( ErrRaster_, e ), \
234 __LINE__, \
235 __FILE__ ) | \
236 FT_ERR_CAT( ErrRaster_, e ) )
237
238 #else /* !FT_DEBUG_LEVEL_TRACE */
239
240 #define FT_TRACE5( x ) do { } while ( 0 ) /* nothing */
241 #define FT_TRACE7( x ) do { } while ( 0 ) /* nothing */
242 #define FT_ERROR( x ) do { } while ( 0 ) /* nothing */
243 #define FT_THROW( e ) FT_ERR_CAT( ErrRaster_, e )
244
245
246 #endif /* !FT_DEBUG_LEVEL_TRACE */
247
248
249 #define FT_DEFINE_OUTLINE_FUNCS( class_, \
250 move_to_, line_to_, \
251 conic_to_, cubic_to_, \
252 shift_, delta_ ) \
253 static const FT_Outline_Funcs class_ = \
254 { \
255 move_to_, \
256 line_to_, \
257 conic_to_, \
258 cubic_to_, \
259 shift_, \
260 delta_ \
261 };
262
263 #define FT_DEFINE_RASTER_FUNCS( class_, glyph_format_, \
264 raster_new_, raster_reset_, \
265 raster_set_mode_, raster_render_, \
266 raster_done_ ) \
267 const FT_Raster_Funcs class_ = \
268 { \
269 glyph_format_, \
270 raster_new_, \
271 raster_reset_, \
272 raster_set_mode_, \
273 raster_render_, \
274 raster_done_ \
275 };
276
277
278 #else /* !STANDALONE_ */
279
280
281 #include <ft2build.h>
282 #include "ftgrays.h"
283 #include FT_INTERNAL_OBJECTS_H
284 #include FT_INTERNAL_DEBUG_H
285 #include FT_INTERNAL_CALC_H
286 #include FT_OUTLINE_H
287
288 #include "ftsmerrs.h"
289
290 #define Smooth_Err_Invalid_Mode Smooth_Err_Cannot_Render_Glyph
291 #define Smooth_Err_Memory_Overflow Smooth_Err_Out_Of_Memory
292 #define ErrRaster_Memory_Overflow Smooth_Err_Out_Of_Memory
293
294
295 #endif /* !STANDALONE_ */
296
297
298 #ifndef FT_MEM_SET
299 #define FT_MEM_SET( d, s, c ) ft_memset( d, s, c )
300 #endif
301
302 #ifndef FT_MEM_ZERO
303 #define FT_MEM_ZERO( dest, count ) FT_MEM_SET( dest, 0, count )
304 #endif
305
306 #ifndef FT_ZERO
307 #define FT_ZERO( p ) FT_MEM_ZERO( p, sizeof ( *(p) ) )
308 #endif
309
310 /* as usual, for the speed hungry :-) */
311
312 #undef RAS_ARG
313 #undef RAS_ARG_
314 #undef RAS_VAR
315 #undef RAS_VAR_
316
317 #ifndef FT_STATIC_RASTER
318
319 #define RAS_ARG gray_PWorker worker
320 #define RAS_ARG_ gray_PWorker worker,
321
322 #define RAS_VAR worker
323 #define RAS_VAR_ worker,
324
325 #else /* FT_STATIC_RASTER */
326
327 #define RAS_ARG void
328 #define RAS_ARG_ /* empty */
329 #define RAS_VAR /* empty */
330 #define RAS_VAR_ /* empty */
331
332 #endif /* FT_STATIC_RASTER */
333
334
335 /* must be at least 6 bits! */
336 #define PIXEL_BITS 8
337
338 #define ONE_PIXEL ( 1 << PIXEL_BITS )
339 #define TRUNC( x ) (TCoord)( (x) >> PIXEL_BITS )
340 #define FRACT( x ) (TCoord)( (x) & ( ONE_PIXEL - 1 ) )
341
342 #if PIXEL_BITS >= 6
343 #define UPSCALE( x ) ( (x) * ( ONE_PIXEL >> 6 ) )
344 #define DOWNSCALE( x ) ( (x) >> ( PIXEL_BITS - 6 ) )
345 #else
346 #define UPSCALE( x ) ( (x) >> ( 6 - PIXEL_BITS ) )
347 #define DOWNSCALE( x ) ( (x) * ( 64 >> PIXEL_BITS ) )
348 #endif
349
350
351 /* Compute `dividend / divisor' and return both its quotient and */
352 /* remainder, cast to a specific type. This macro also ensures that */
353 /* the remainder is always positive. We use the remainder to keep */
354 /* track of accumulating errors and compensate for them. */
355 #define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \
356 FT_BEGIN_STMNT \
357 (quotient) = (type)( (dividend) / (divisor) ); \
358 (remainder) = (type)( (dividend) % (divisor) ); \
359 if ( (remainder) < 0 ) \
360 { \
361 (quotient)--; \
362 (remainder) += (type)(divisor); \
363 } \
364 FT_END_STMNT
365
366 #ifdef __arm__
367 /* Work around a bug specific to GCC which make the compiler fail to */
368 /* optimize a division and modulo operation on the same parameters */
369 /* into a single call to `__aeabi_idivmod'. See */
370 /* */
371 /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43721 */
372 #undef FT_DIV_MOD
373 #define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \
374 FT_BEGIN_STMNT \
375 (quotient) = (type)( (dividend) / (divisor) ); \
376 (remainder) = (type)( (dividend) - (quotient) * (divisor) ); \
377 if ( (remainder) < 0 ) \
378 { \
379 (quotient)--; \
380 (remainder) += (type)(divisor); \
381 } \
382 FT_END_STMNT
383 #endif /* __arm__ */
384
385
386 /* These macros speed up repetitive divisions by replacing them */
387 /* with multiplications and right shifts. */
388 #define FT_UDIVPREP( c, b ) \
389 long b ## _r = c ? (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) \
390 : 0
391 #define FT_UDIV( a, b ) \
392 (TCoord)( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >> \
393 ( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )
394
395
396 /**************************************************************************
397 *
398 * TYPE DEFINITIONS
399 */
400
401 /* don't change the following types to FT_Int or FT_Pos, since we might */
402 /* need to define them to "float" or "double" when experimenting with */
403 /* new algorithms */
404
405 typedef long TPos; /* subpixel coordinate */
406 typedef int TCoord; /* integer scanline/pixel coordinate */
407 typedef int TArea; /* cell areas, coordinate products */
408
409
410 typedef struct TCell_* PCell;
411
412 typedef struct TCell_
413 {
414 TCoord x; /* same with gray_TWorker.ex */
415 TCoord cover; /* same with gray_TWorker.cover */
416 TArea area;
417 PCell next;
418
419 } TCell;
420
421 typedef struct TPixmap_
422 {
423 unsigned char* origin; /* pixmap origin at the bottom-left */
424 int pitch; /* pitch to go down one row */
425
426 } TPixmap;
427
428 /* maximum number of gray cells in the buffer */
429 #if FT_RENDER_POOL_SIZE > 2048
430 #define FT_MAX_GRAY_POOL ( FT_RENDER_POOL_SIZE / sizeof ( TCell ) )
431 #else
432 #define FT_MAX_GRAY_POOL ( 2048 / sizeof ( TCell ) )
433 #endif
434
435 /* FT_Span buffer size for direct rendering only */
436 #define FT_MAX_GRAY_SPANS 10
437
438
439 #if defined( _MSC_VER ) /* Visual C++ (and Intel C++) */
440 /* We disable the warning `structure was padded due to */
441 /* __declspec(align())' in order to compile cleanly with */
442 /* the maximum level of warnings. */
443 #pragma warning( push )
444 #pragma warning( disable : 4324 )
445 #endif /* _MSC_VER */
446
447 typedef struct gray_TWorker_
448 {
449 ft_jmp_buf jump_buffer;
450
451 TCoord ex, ey;
452 TCoord min_ex, max_ex;
453 TCoord min_ey, max_ey;
454
455 TArea area;
456 TCoord cover;
457 int invalid;
458
459 PCell* ycells;
460 PCell cells;
461 FT_PtrDist max_cells;
462 FT_PtrDist num_cells;
463
464 TPos x, y;
465
466 FT_Outline outline;
467 TPixmap target;
468
469 FT_Raster_Span_Func render_span;
470 void* render_span_data;
471 FT_Span spans[FT_MAX_GRAY_SPANS];
472 int num_spans;
473
474 } gray_TWorker, *gray_PWorker;
475
476 #if defined( _MSC_VER )
477 #pragma warning( pop )
478 #endif
479
480
481 #ifndef FT_STATIC_RASTER
482 #define ras (*worker)
483 #else
484 static gray_TWorker ras;
485 #endif
486
487
488 typedef struct gray_TRaster_
489 {
490 void* memory;
491
492 } gray_TRaster, *gray_PRaster;
493
494
495 #ifdef FT_DEBUG_LEVEL_TRACE
496
497 /* to be called while in the debugger -- */
498 /* this function causes a compiler warning since it is unused otherwise */
499 static void
500 gray_dump_cells( RAS_ARG )
501 {
502 int y;
503
504
505 for ( y = ras.min_ey; y < ras.max_ey; y++ )
506 {
507 PCell cell = ras.ycells[y - ras.min_ey];
508
509
510 printf( "%3d:", y );
511
512 for ( ; cell != NULL; cell = cell->next )
513 printf( " (%3d, c:%4d, a:%6d)",
514 cell->x, cell->cover, cell->area );
515 printf( "\n" );
516 }
517 }
518
519 #endif /* FT_DEBUG_LEVEL_TRACE */
520
521
522 /**************************************************************************
523 *
524 * Record the current cell in the linked list.
525 */
526 static void
527 gray_record_cell( RAS_ARG )
528 {
529 PCell *pcell, cell;
530 TCoord x = ras.ex;
531
532
533 pcell = &ras.ycells[ras.ey - ras.min_ey];
534 while ( ( cell = *pcell ) )
535 {
536 if ( cell->x > x )
537 break;
538
539 if ( cell->x == x )
540 goto Found;
541
542 pcell = &cell->next;
543 }
544
545 if ( ras.num_cells >= ras.max_cells )
546 ft_longjmp( ras.jump_buffer, 1 );
547
548 /* insert new cell */
549 cell = ras.cells + ras.num_cells++;
550 cell->x = x;
551 cell->area = ras.area;
552 cell->cover = ras.cover;
553
554 cell->next = *pcell;
555 *pcell = cell;
556
557 return;
558
559 Found:
560 /* update old cell */
561 cell->area += ras.area;
562 cell->cover += ras.cover;
563 }
564
565
566 /**************************************************************************
567 *
568 * Set the current cell to a new position.
569 */
570 static void
571 gray_set_cell( RAS_ARG_ TCoord ex,
572 TCoord ey )
573 {
574 /* Move the cell pointer to a new position. We set the `invalid' */
575 /* flag to indicate that the cell isn't part of those we're interested */
576 /* in during the render phase. This means that: */
577 /* */
578 /* . the new vertical position must be within min_ey..max_ey-1. */
579 /* . the new horizontal position must be strictly less than max_ex */
580 /* */
581 /* Note that if a cell is to the left of the clipping region, it is */
582 /* actually set to the (min_ex-1) horizontal position. */
583
584 /* record the current one if it is valid and substantial */
585 if ( !ras.invalid && ( ras.area || ras.cover ) )
586 gray_record_cell( RAS_VAR );
587
588 ras.area = 0;
589 ras.cover = 0;
590 ras.ex = FT_MAX( ex, ras.min_ex - 1 );
591 ras.ey = ey;
592
593 ras.invalid = ( ey >= ras.max_ey || ey < ras.min_ey ||
594 ex >= ras.max_ex );
595 }
596
597
598 #ifndef FT_LONG64
599
600 /**************************************************************************
601 *
602 * Render a scanline as one or more cells.
603 */
604 static void
605 gray_render_scanline( RAS_ARG_ TCoord ey,
606 TPos x1,
607 TCoord y1,
608 TPos x2,
609 TCoord y2 )
610 {
611 TCoord ex1, ex2, fx1, fx2, first, dy, delta, mod;
612 TPos p, dx;
613 int incr;
614
615
616 ex1 = TRUNC( x1 );
617 ex2 = TRUNC( x2 );
618
619 /* trivial case. Happens often */
620 if ( y1 == y2 )
621 {
622 gray_set_cell( RAS_VAR_ ex2, ey );
623 return;
624 }
625
626 fx1 = FRACT( x1 );
627 fx2 = FRACT( x2 );
628
629 /* everything is located in a single cell. That is easy! */
630 /* */
631 if ( ex1 == ex2 )
632 goto End;
633
634 /* ok, we'll have to render a run of adjacent cells on the same */
635 /* scanline... */
636 /* */
637 dx = x2 - x1;
638 dy = y2 - y1;
639
640 if ( dx > 0 )
641 {
642 p = ( ONE_PIXEL - fx1 ) * dy;
643 first = ONE_PIXEL;
644 incr = 1;
645 }
646 else
647 {
648 p = fx1 * dy;
649 first = 0;
650 incr = -1;
651 dx = -dx;
652 }
653
654 /* the fractional part of y-delta is mod/dx. It is essential to */
655 /* keep track of its accumulation for accurate rendering. */
656 /* XXX: y-delta and x-delta below should be related. */
657 FT_DIV_MOD( TCoord, p, dx, delta, mod );
658
659 ras.area += (TArea)( ( fx1 + first ) * delta );
660 ras.cover += delta;
661 y1 += delta;
662 ex1 += incr;
663 gray_set_cell( RAS_VAR_ ex1, ey );
664
665 if ( ex1 != ex2 )
666 {
667 TCoord lift, rem;
668
669
670 p = ONE_PIXEL * dy;
671 FT_DIV_MOD( TCoord, p, dx, lift, rem );
672
673 do
674 {
675 delta = lift;
676 mod += rem;
677 if ( mod >= (TCoord)dx )
678 {
679 mod -= (TCoord)dx;
680 delta++;
681 }
682
683 ras.area += (TArea)( ONE_PIXEL * delta );
684 ras.cover += delta;
685 y1 += delta;
686 ex1 += incr;
687 gray_set_cell( RAS_VAR_ ex1, ey );
688 } while ( ex1 != ex2 );
689 }
690
691 fx1 = ONE_PIXEL - first;
692
693 End:
694 dy = y2 - y1;
695
696 ras.area += (TArea)( ( fx1 + fx2 ) * dy );
697 ras.cover += dy;
698 }
699
700
701 /**************************************************************************
702 *
703 * Render a given line as a series of scanlines.
704 */
705 static void
706 gray_render_line( RAS_ARG_ TPos to_x,
707 TPos to_y )
708 {
709 TCoord ey1, ey2, fy1, fy2, first, delta, mod;
710 TPos p, dx, dy, x, x2;
711 int incr;
712
713
714 ey1 = TRUNC( ras.y );
715 ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */
716
717 /* perform vertical clipping */
718 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
719 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
720 goto End;
721
722 fy1 = FRACT( ras.y );
723 fy2 = FRACT( to_y );
724
725 /* everything is on a single scanline */
726 if ( ey1 == ey2 )
727 {
728 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 );
729 goto End;
730 }
731
732 dx = to_x - ras.x;
733 dy = to_y - ras.y;
734
735 /* vertical line - avoid calling gray_render_scanline */
736 if ( dx == 0 )
737 {
738 TCoord ex = TRUNC( ras.x );
739 TCoord two_fx = FRACT( ras.x ) << 1;
740 TArea area;
741
742
743 if ( dy > 0)
744 {
745 first = ONE_PIXEL;
746 incr = 1;
747 }
748 else
749 {
750 first = 0;
751 incr = -1;
752 }
753
754 delta = first - fy1;
755 ras.area += (TArea)two_fx * delta;
756 ras.cover += delta;
757 ey1 += incr;
758
759 gray_set_cell( RAS_VAR_ ex, ey1 );
760
761 delta = first + first - ONE_PIXEL;
762 area = (TArea)two_fx * delta;
763 while ( ey1 != ey2 )
764 {
765 ras.area += area;
766 ras.cover += delta;
767 ey1 += incr;
768
769 gray_set_cell( RAS_VAR_ ex, ey1 );
770 }
771
772 delta = fy2 - ONE_PIXEL + first;
773 ras.area += (TArea)two_fx * delta;
774 ras.cover += delta;
775
776 goto End;
777 }
778
779 /* ok, we have to render several scanlines */
780 if ( dy > 0)
781 {
782 p = ( ONE_PIXEL - fy1 ) * dx;
783 first = ONE_PIXEL;
784 incr = 1;
785 }
786 else
787 {
788 p = fy1 * dx;
789 first = 0;
790 incr = -1;
791 dy = -dy;
792 }
793
794 /* the fractional part of x-delta is mod/dy. It is essential to */
795 /* keep track of its accumulation for accurate rendering. */
796 FT_DIV_MOD( TCoord, p, dy, delta, mod );
797
798 x = ras.x + delta;
799 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, first );
800
801 ey1 += incr;
802 gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
803
804 if ( ey1 != ey2 )
805 {
806 TCoord lift, rem;
807
808
809 p = ONE_PIXEL * dx;
810 FT_DIV_MOD( TCoord, p, dy, lift, rem );
811
812 do
813 {
814 delta = lift;
815 mod += rem;
816 if ( mod >= (TCoord)dy )
817 {
818 mod -= (TCoord)dy;
819 delta++;
820 }
821
822 x2 = x + delta;
823 gray_render_scanline( RAS_VAR_ ey1,
824 x, ONE_PIXEL - first,
825 x2, first );
826 x = x2;
827
828 ey1 += incr;
829 gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
830 } while ( ey1 != ey2 );
831 }
832
833 gray_render_scanline( RAS_VAR_ ey1,
834 x, ONE_PIXEL - first,
835 to_x, fy2 );
836
837 End:
838 ras.x = to_x;
839 ras.y = to_y;
840 }
841
842 #else
843
844 /**************************************************************************
845 *
846 * Render a straight line across multiple cells in any direction.
847 */
848 static void
849 gray_render_line( RAS_ARG_ TPos to_x,
850 TPos to_y )
851 {
852 TPos dx, dy;
853 TCoord fx1, fy1, fx2, fy2;
854 TCoord ex1, ey1, ex2, ey2;
855
856
857 ey1 = TRUNC( ras.y );
858 ey2 = TRUNC( to_y );
859
860 /* perform vertical clipping */
861 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
862 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
863 goto End;
864
865 ex1 = TRUNC( ras.x );
866 ex2 = TRUNC( to_x );
867
868 fx1 = FRACT( ras.x );
869 fy1 = FRACT( ras.y );
870
871 dx = to_x - ras.x;
872 dy = to_y - ras.y;
873
874 if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */
875 ;
876 else if ( dy == 0 ) /* ex1 != ex2 */ /* any horizontal line */
877 {
878 gray_set_cell( RAS_VAR_ ex2, ey2 );
879 goto End;
880 }
881 else if ( dx == 0 )
882 {
883 if ( dy > 0 ) /* vertical line up */
884 do
885 {
886 fy2 = ONE_PIXEL;
887 ras.cover += ( fy2 - fy1 );
888 ras.area += ( fy2 - fy1 ) * fx1 * 2;
889 fy1 = 0;
890 ey1++;
891 gray_set_cell( RAS_VAR_ ex1, ey1 );
892 } while ( ey1 != ey2 );
893 else /* vertical line down */
894 do
895 {
896 fy2 = 0;
897 ras.cover += ( fy2 - fy1 );
898 ras.area += ( fy2 - fy1 ) * fx1 * 2;
899 fy1 = ONE_PIXEL;
900 ey1--;
901 gray_set_cell( RAS_VAR_ ex1, ey1 );
902 } while ( ey1 != ey2 );
903 }
904 else /* any other line */
905 {
906 TPos prod = dx * (TPos)fy1 - dy * (TPos)fx1;
907 FT_UDIVPREP( ex1 != ex2, dx );
908 FT_UDIVPREP( ey1 != ey2, dy );
909
910
911 /* The fundamental value `prod' determines which side and the */
912 /* exact coordinate where the line exits current cell. It is */
913 /* also easily updated when moving from one cell to the next. */
914 do
915 {
916 if ( prod <= 0 &&
917 prod - dx * ONE_PIXEL > 0 ) /* left */
918 {
919 fx2 = 0;
920 fy2 = FT_UDIV( -prod, -dx );
921 prod -= dy * ONE_PIXEL;
922 ras.cover += ( fy2 - fy1 );
923 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
924 fx1 = ONE_PIXEL;
925 fy1 = fy2;
926 ex1--;
927 }
928 else if ( prod - dx * ONE_PIXEL <= 0 &&
929 prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 ) /* up */
930 {
931 prod -= dx * ONE_PIXEL;
932 fx2 = FT_UDIV( -prod, dy );
933 fy2 = ONE_PIXEL;
934 ras.cover += ( fy2 - fy1 );
935 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
936 fx1 = fx2;
937 fy1 = 0;
938 ey1++;
939 }
940 else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 &&
941 prod + dy * ONE_PIXEL >= 0 ) /* right */
942 {
943 prod += dy * ONE_PIXEL;
944 fx2 = ONE_PIXEL;
945 fy2 = FT_UDIV( prod, dx );
946 ras.cover += ( fy2 - fy1 );
947 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
948 fx1 = 0;
949 fy1 = fy2;
950 ex1++;
951 }
952 else /* ( prod + dy * ONE_PIXEL < 0 &&
953 prod > 0 ) down */
954 {
955 fx2 = FT_UDIV( prod, -dy );
956 fy2 = 0;
957 prod += dx * ONE_PIXEL;
958 ras.cover += ( fy2 - fy1 );
959 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
960 fx1 = fx2;
961 fy1 = ONE_PIXEL;
962 ey1--;
963 }
964
965 gray_set_cell( RAS_VAR_ ex1, ey1 );
966 } while ( ex1 != ex2 || ey1 != ey2 );
967 }
968
969 fx2 = FRACT( to_x );
970 fy2 = FRACT( to_y );
971
972 ras.cover += ( fy2 - fy1 );
973 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
974
975 End:
976 ras.x = to_x;
977 ras.y = to_y;
978 }
979
980 #endif
981
982 static void
983 gray_split_conic( FT_Vector* base )
984 {
985 TPos a, b;
986
987
988 base[4].x = base[2].x;
989 a = base[0].x + base[1].x;
990 b = base[1].x + base[2].x;
991 base[3].x = b >> 1;
992 base[2].x = ( a + b ) >> 2;
993 base[1].x = a >> 1;
994
995 base[4].y = base[2].y;
996 a = base[0].y + base[1].y;
997 b = base[1].y + base[2].y;
998 base[3].y = b >> 1;
999 base[2].y = ( a + b ) >> 2;
1000 base[1].y = a >> 1;
1001 }
1002
1003
1004 static void
1005 gray_render_conic( RAS_ARG_ const FT_Vector* control,
1006 const FT_Vector* to )
1007 {
1008 FT_Vector bez_stack[16 * 2 + 1]; /* enough to accommodate bisections */
1009 FT_Vector* arc = bez_stack;
1010 TPos dx, dy;
1011 int draw, split;
1012
1013
1014 arc[0].x = UPSCALE( to->x );
1015 arc[0].y = UPSCALE( to->y );
1016 arc[1].x = UPSCALE( control->x );
1017 arc[1].y = UPSCALE( control->y );
1018 arc[2].x = ras.x;
1019 arc[2].y = ras.y;
1020
1021 /* short-cut the arc that crosses the current band */
1022 if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
1023 TRUNC( arc[1].y ) >= ras.max_ey &&
1024 TRUNC( arc[2].y ) >= ras.max_ey ) ||
1025 ( TRUNC( arc[0].y ) < ras.min_ey &&
1026 TRUNC( arc[1].y ) < ras.min_ey &&
1027 TRUNC( arc[2].y ) < ras.min_ey ) )
1028 {
1029 ras.x = arc[0].x;
1030 ras.y = arc[0].y;
1031 return;
1032 }
1033
1034 dx = FT_ABS( arc[2].x + arc[0].x - 2 * arc[1].x );
1035 dy = FT_ABS( arc[2].y + arc[0].y - 2 * arc[1].y );
1036 if ( dx < dy )
1037 dx = dy;
1038
1039 /* We can calculate the number of necessary bisections because */
1040 /* each bisection predictably reduces deviation exactly 4-fold. */
1041 /* Even 32-bit deviation would vanish after 16 bisections. */
1042 draw = 1;
1043 while ( dx > ONE_PIXEL / 4 )
1044 {
1045 dx >>= 2;
1046 draw <<= 1;
1047 }
1048
1049 /* We use decrement counter to count the total number of segments */
1050 /* to draw starting from 2^level. Before each draw we split as */
1051 /* many times as there are trailing zeros in the counter. */
1052 do
1053 {
1054 split = draw & ( -draw ); /* isolate the rightmost 1-bit */
1055 while ( ( split >>= 1 ) )
1056 {
1057 gray_split_conic( arc );
1058 arc += 2;
1059 }
1060
1061 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1062 arc -= 2;
1063
1064 } while ( --draw );
1065 }
1066
1067
1068 static void
1069 gray_split_cubic( FT_Vector* base )
1070 {
1071 TPos a, b, c;
1072
1073
1074 base[6].x = base[3].x;
1075 a = base[0].x + base[1].x;
1076 b = base[1].x + base[2].x;
1077 c = base[2].x + base[3].x;
1078 base[5].x = c >> 1;
1079 c += b;
1080 base[4].x = c >> 2;
1081 base[1].x = a >> 1;
1082 a += b;
1083 base[2].x = a >> 2;
1084 base[3].x = ( a + c ) >> 3;
1085
1086 base[6].y = base[3].y;
1087 a = base[0].y + base[1].y;
1088 b = base[1].y + base[2].y;
1089 c = base[2].y + base[3].y;
1090 base[5].y = c >> 1;
1091 c += b;
1092 base[4].y = c >> 2;
1093 base[1].y = a >> 1;
1094 a += b;
1095 base[2].y = a >> 2;
1096 base[3].y = ( a + c ) >> 3;
1097 }
1098
1099
1100 static void
1101 gray_render_cubic( RAS_ARG_ const FT_Vector* control1,
1102 const FT_Vector* control2,
1103 const FT_Vector* to )
1104 {
1105 FT_Vector bez_stack[16 * 3 + 1]; /* enough to accommodate bisections */
1106 FT_Vector* arc = bez_stack;
1107
1108
1109 arc[0].x = UPSCALE( to->x );
1110 arc[0].y = UPSCALE( to->y );
1111 arc[1].x = UPSCALE( control2->x );
1112 arc[1].y = UPSCALE( control2->y );
1113 arc[2].x = UPSCALE( control1->x );
1114 arc[2].y = UPSCALE( control1->y );
1115 arc[3].x = ras.x;
1116 arc[3].y = ras.y;
1117
1118 /* short-cut the arc that crosses the current band */
1119 if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
1120 TRUNC( arc[1].y ) >= ras.max_ey &&
1121 TRUNC( arc[2].y ) >= ras.max_ey &&
1122 TRUNC( arc[3].y ) >= ras.max_ey ) ||
1123 ( TRUNC( arc[0].y ) < ras.min_ey &&
1124 TRUNC( arc[1].y ) < ras.min_ey &&
1125 TRUNC( arc[2].y ) < ras.min_ey &&
1126 TRUNC( arc[3].y ) < ras.min_ey ) )
1127 {
1128 ras.x = arc[0].x;
1129 ras.y = arc[0].y;
1130 return;
1131 }
1132
1133 for (;;)
1134 {
1135 /* with each split, control points quickly converge towards */
1136 /* chord trisection points and the vanishing distances below */
1137 /* indicate when the segment is flat enough to draw */
1138 if ( FT_ABS( 2 * arc[0].x - 3 * arc[1].x + arc[3].x ) > ONE_PIXEL / 2 ||
1139 FT_ABS( 2 * arc[0].y - 3 * arc[1].y + arc[3].y ) > ONE_PIXEL / 2 ||
1140 FT_ABS( arc[0].x - 3 * arc[2].x + 2 * arc[3].x ) > ONE_PIXEL / 2 ||
1141 FT_ABS( arc[0].y - 3 * arc[2].y + 2 * arc[3].y ) > ONE_PIXEL / 2 )
1142 goto Split;
1143
1144 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1145
1146 if ( arc == bez_stack )
1147 return;
1148
1149 arc -= 3;
1150 continue;
1151
1152 Split:
1153 gray_split_cubic( arc );
1154 arc += 3;
1155 }
1156 }
1157
1158
1159 static int
1160 gray_move_to( const FT_Vector* to,
1161 gray_PWorker worker )
1162 {
1163 TPos x, y;
1164
1165
1166 /* start to a new position */
1167 x = UPSCALE( to->x );
1168 y = UPSCALE( to->y );
1169
1170 gray_set_cell( RAS_VAR_ TRUNC( x ), TRUNC( y ) );
1171
1172 ras.x = x;
1173 ras.y = y;
1174 return 0;
1175 }
1176
1177
1178 static int
1179 gray_line_to( const FT_Vector* to,
1180 gray_PWorker worker )
1181 {
1182 gray_render_line( RAS_VAR_ UPSCALE( to->x ), UPSCALE( to->y ) );
1183 return 0;
1184 }
1185
1186
1187 static int
1188 gray_conic_to( const FT_Vector* control,
1189 const FT_Vector* to,
1190 gray_PWorker worker )
1191 {
1192 gray_render_conic( RAS_VAR_ control, to );
1193 return 0;
1194 }
1195
1196
1197 static int
1198 gray_cubic_to( const FT_Vector* control1,
1199 const FT_Vector* control2,
1200 const FT_Vector* to,
1201 gray_PWorker worker )
1202 {
1203 gray_render_cubic( RAS_VAR_ control1, control2, to );
1204 return 0;
1205 }
1206
1207
1208 static void
1209 gray_hline( RAS_ARG_ TCoord x,
1210 TCoord y,
1211 TArea coverage,
1212 TCoord acount )
1213 {
1214 /* scale the coverage from 0..(ONE_PIXEL*ONE_PIXEL*2) to 0..256 */
1215 coverage >>= PIXEL_BITS * 2 + 1 - 8;
1216
1217 /* compute the line's coverage depending on the outline fill rule */
1218 if ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL )
1219 {
1220 coverage &= 511;
1221
1222 if ( coverage >= 256 )
1223 coverage = 511 - coverage;
1224 }
1225 else /* default non-zero winding rule */
1226 {
1227 if ( coverage < 0 )
1228 coverage = ~coverage; /* the same as -coverage - 1 */
1229
1230 if ( coverage >= 256 )
1231 coverage = 255;
1232 }
1233
1234 if ( ras.num_spans >= 0 ) /* for FT_RASTER_FLAG_DIRECT only */
1235 {
1236 FT_Span* span = ras.spans + ras.num_spans++;
1237
1238
1239 span->x = (short)x;
1240 span->len = (unsigned short)acount;
1241 span->coverage = (unsigned char)coverage;
1242
1243 if ( ras.num_spans == FT_MAX_GRAY_SPANS )
1244 {
1245 /* flush the span buffer and reset the count */
1246 ras.render_span( y, ras.num_spans, ras.spans, ras.render_span_data );
1247 ras.num_spans = 0;
1248 }
1249 }
1250 else
1251 {
1252 unsigned char* q = ras.target.origin - ras.target.pitch * y + x;
1253 unsigned char c = (unsigned char)coverage;
1254
1255
1256 /* For small-spans it is faster to do it by ourselves than
1257 * calling `memset'. This is mainly due to the cost of the
1258 * function call.
1259 */
1260 switch ( acount )
1261 {
1262 case 7:
1263 *q++ = c;
1264 /* fall through */
1265 case 6:
1266 *q++ = c;
1267 /* fall through */
1268 case 5:
1269 *q++ = c;
1270 /* fall through */
1271 case 4:
1272 *q++ = c;
1273 /* fall through */
1274 case 3:
1275 *q++ = c;
1276 /* fall through */
1277 case 2:
1278 *q++ = c;
1279 /* fall through */
1280 case 1:
1281 *q = c;
1282 /* fall through */
1283 case 0:
1284 break;
1285 default:
1286 FT_MEM_SET( q, c, acount );
1287 }
1288 }
1289 }
1290
1291
1292 static void
1293 gray_sweep( RAS_ARG )
1294 {
1295 int y;
1296
1297
1298 for ( y = ras.min_ey; y < ras.max_ey; y++ )
1299 {
1300 PCell cell = ras.ycells[y - ras.min_ey];
1301 TCoord x = ras.min_ex;
1302 TArea cover = 0;
1303 TArea area;
1304
1305
1306 for ( ; cell != NULL; cell = cell->next )
1307 {
1308 if ( cover != 0 && cell->x > x )
1309 gray_hline( RAS_VAR_ x, y, cover, cell->x - x );
1310
1311 cover += (TArea)cell->cover * ( ONE_PIXEL * 2 );
1312 area = cover - cell->area;
1313
1314 if ( area != 0 && cell->x >= ras.min_ex )
1315 gray_hline( RAS_VAR_ cell->x, y, area, 1 );
1316
1317 x = cell->x + 1;
1318 }
1319
1320 if ( cover != 0 )
1321 gray_hline( RAS_VAR_ x, y, cover, ras.max_ex - x );
1322
1323 if ( ras.num_spans > 0 ) /* for FT_RASTER_FLAG_DIRECT only */
1324 {
1325 /* flush the span buffer and reset the count */
1326 ras.render_span( y, ras.num_spans, ras.spans, ras.render_span_data );
1327 ras.num_spans = 0;
1328 }
1329 }
1330 }
1331
1332
1333 #ifdef STANDALONE_
1334
1335 /**************************************************************************
1336 *
1337 * The following functions should only compile in stand-alone mode,
1338 * i.e., when building this component without the rest of FreeType.
1339 *
1340 */
1341
1342 /**************************************************************************
1343 *
1344 * @Function:
1345 * FT_Outline_Decompose
1346 *
1347 * @Description:
1348 * Walk over an outline's structure to decompose it into individual
1349 * segments and Bézier arcs. This function is also able to emit
1350 * `move to' and `close to' operations to indicate the start and end
1351 * of new contours in the outline.
1352 *
1353 * @Input:
1354 * outline ::
1355 * A pointer to the source target.
1356 *
1357 * func_interface ::
1358 * A table of `emitters', i.e., function pointers
1359 * called during decomposition to indicate path
1360 * operations.
1361 *
1362 * @InOut:
1363 * user ::
1364 * A typeless pointer which is passed to each
1365 * emitter during the decomposition. It can be
1366 * used to store the state during the
1367 * decomposition.
1368 *
1369 * @Return:
1370 * Error code. 0 means success.
1371 */
1372 static int
1373 FT_Outline_Decompose( const FT_Outline* outline,
1374 const FT_Outline_Funcs* func_interface,
1375 void* user )
1376 {
1377 #undef SCALED
1378 #define SCALED( x ) ( (x) * ( 1L << shift ) - delta )
1379
1380 FT_Vector v_last;
1381 FT_Vector v_control;
1382 FT_Vector v_start;
1383
1384 FT_Vector* point;
1385 FT_Vector* limit;
1386 char* tags;
1387
1388 int error;
1389
1390 int n; /* index of contour in outline */
1391 int first; /* index of first point in contour */
1392 char tag; /* current point's state */
1393
1394 int shift;
1395 TPos delta;
1396
1397
1398 if ( !outline )
1399 return FT_THROW( Invalid_Outline );
1400
1401 if ( !func_interface )
1402 return FT_THROW( Invalid_Argument );
1403
1404 shift = func_interface->shift;
1405 delta = func_interface->delta;
1406 first = 0;
1407
1408 for ( n = 0; n < outline->n_contours; n++ )
1409 {
1410 int last; /* index of last point in contour */
1411
1412
1413 FT_TRACE5(( "FT_Outline_Decompose: Outline %d\n", n ));
1414
1415 last = outline->contours[n];
1416 if ( last < 0 )
1417 goto Invalid_Outline;
1418 limit = outline->points + last;
1419
1420 v_start = outline->points[first];
1421 v_start.x = SCALED( v_start.x );
1422 v_start.y = SCALED( v_start.y );
1423
1424 v_last = outline->points[last];
1425 v_last.x = SCALED( v_last.x );
1426 v_last.y = SCALED( v_last.y );
1427
1428 v_control = v_start;
1429
1430 point = outline->points + first;
1431 tags = outline->tags + first;
1432 tag = FT_CURVE_TAG( tags[0] );
1433
1434 /* A contour cannot start with a cubic control point! */
1435 if ( tag == FT_CURVE_TAG_CUBIC )
1436 goto Invalid_Outline;
1437
1438 /* check first point to determine origin */
1439 if ( tag == FT_CURVE_TAG_CONIC )
1440 {
1441 /* first point is conic control. Yes, this happens. */
1442 if ( FT_CURVE_TAG( outline->tags[last] ) == FT_CURVE_TAG_ON )
1443 {
1444 /* start at last point if it is on the curve */
1445 v_start = v_last;
1446 limit--;
1447 }
1448 else
1449 {
1450 /* if both first and last points are conic, */
1451 /* start at their middle and record its position */
1452 /* for closure */
1453 v_start.x = ( v_start.x + v_last.x ) / 2;
1454 v_start.y = ( v_start.y + v_last.y ) / 2;
1455
1456 v_last = v_start;
1457 }
1458 point--;
1459 tags--;
1460 }
1461
1462 FT_TRACE5(( " move to (%.2f, %.2f)\n",
1463 v_start.x / 64.0, v_start.y / 64.0 ));
1464 error = func_interface->move_to( &v_start, user );
1465 if ( error )
1466 goto Exit;
1467
1468 while ( point < limit )
1469 {
1470 point++;
1471 tags++;
1472
1473 tag = FT_CURVE_TAG( tags[0] );
1474 switch ( tag )
1475 {
1476 case FT_CURVE_TAG_ON: /* emit a single line_to */
1477 {
1478 FT_Vector vec;
1479
1480
1481 vec.x = SCALED( point->x );
1482 vec.y = SCALED( point->y );
1483
1484 FT_TRACE5(( " line to (%.2f, %.2f)\n",
1485 vec.x / 64.0, vec.y / 64.0 ));
1486 error = func_interface->line_to( &vec, user );
1487 if ( error )
1488 goto Exit;
1489 continue;
1490 }
1491
1492 case FT_CURVE_TAG_CONIC: /* consume conic arcs */
1493 v_control.x = SCALED( point->x );
1494 v_control.y = SCALED( point->y );
1495
1496 Do_Conic:
1497 if ( point < limit )
1498 {
1499 FT_Vector vec;
1500 FT_Vector v_middle;
1501
1502
1503 point++;
1504 tags++;
1505 tag = FT_CURVE_TAG( tags[0] );
1506
1507 vec.x = SCALED( point->x );
1508 vec.y = SCALED( point->y );
1509
1510 if ( tag == FT_CURVE_TAG_ON )
1511 {
1512 FT_TRACE5(( " conic to (%.2f, %.2f)"
1513 " with control (%.2f, %.2f)\n",
1514 vec.x / 64.0, vec.y / 64.0,
1515 v_control.x / 64.0, v_control.y / 64.0 ));
1516 error = func_interface->conic_to( &v_control, &vec, user );
1517 if ( error )
1518 goto Exit;
1519 continue;
1520 }
1521
1522 if ( tag != FT_CURVE_TAG_CONIC )
1523 goto Invalid_Outline;
1524
1525 v_middle.x = ( v_control.x + vec.x ) / 2;
1526 v_middle.y = ( v_control.y + vec.y ) / 2;
1527
1528 FT_TRACE5(( " conic to (%.2f, %.2f)"
1529 " with control (%.2f, %.2f)\n",
1530 v_middle.x / 64.0, v_middle.y / 64.0,
1531 v_control.x / 64.0, v_control.y / 64.0 ));
1532 error = func_interface->conic_to( &v_control, &v_middle, user );
1533 if ( error )
1534 goto Exit;
1535
1536 v_control = vec;
1537 goto Do_Conic;
1538 }
1539
1540 FT_TRACE5(( " conic to (%.2f, %.2f)"
1541 " with control (%.2f, %.2f)\n",
1542 v_start.x / 64.0, v_start.y / 64.0,
1543 v_control.x / 64.0, v_control.y / 64.0 ));
1544 error = func_interface->conic_to( &v_control, &v_start, user );
1545 goto Close;
1546
1547 default: /* FT_CURVE_TAG_CUBIC */
1548 {
1549 FT_Vector vec1, vec2;
1550
1551
1552 if ( point + 1 > limit ||
1553 FT_CURVE_TAG( tags[1] ) != FT_CURVE_TAG_CUBIC )
1554 goto Invalid_Outline;
1555
1556 point += 2;
1557 tags += 2;
1558
1559 vec1.x = SCALED( point[-2].x );
1560 vec1.y = SCALED( point[-2].y );
1561
1562 vec2.x = SCALED( point[-1].x );
1563 vec2.y = SCALED( point[-1].y );
1564
1565 if ( point <= limit )
1566 {
1567 FT_Vector vec;
1568
1569
1570 vec.x = SCALED( point->x );
1571 vec.y = SCALED( point->y );
1572
1573 FT_TRACE5(( " cubic to (%.2f, %.2f)"
1574 " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
1575 vec.x / 64.0, vec.y / 64.0,
1576 vec1.x / 64.0, vec1.y / 64.0,
1577 vec2.x / 64.0, vec2.y / 64.0 ));
1578 error = func_interface->cubic_to( &vec1, &vec2, &vec, user );
1579 if ( error )
1580 goto Exit;
1581 continue;
1582 }
1583
1584 FT_TRACE5(( " cubic to (%.2f, %.2f)"
1585 " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
1586 v_start.x / 64.0, v_start.y / 64.0,
1587 vec1.x / 64.0, vec1.y / 64.0,
1588 vec2.x / 64.0, vec2.y / 64.0 ));
1589 error = func_interface->cubic_to( &vec1, &vec2, &v_start, user );
1590 goto Close;
1591 }
1592 }
1593 }
1594
1595 /* close the contour with a line segment */
1596 FT_TRACE5(( " line to (%.2f, %.2f)\n",
1597 v_start.x / 64.0, v_start.y / 64.0 ));
1598 error = func_interface->line_to( &v_start, user );
1599
1600 Close:
1601 if ( error )
1602 goto Exit;
1603
1604 first = last + 1;
1605 }
1606
1607 FT_TRACE5(( "FT_Outline_Decompose: Done\n", n ));
1608 return 0;
1609
1610 Exit:
1611 FT_TRACE5(( "FT_Outline_Decompose: Error 0x%x\n", error ));
1612 return error;
1613
1614 Invalid_Outline:
1615 return FT_THROW( Invalid_Outline );
1616 }
1617
1618 #endif /* STANDALONE_ */
1619
1620
1621 FT_DEFINE_OUTLINE_FUNCS(
1622 func_interface,
1623
1624 (FT_Outline_MoveTo_Func) gray_move_to, /* move_to */
1625 (FT_Outline_LineTo_Func) gray_line_to, /* line_to */
1626 (FT_Outline_ConicTo_Func)gray_conic_to, /* conic_to */
1627 (FT_Outline_CubicTo_Func)gray_cubic_to, /* cubic_to */
1628
1629 0, /* shift */
1630 0 /* delta */
1631 )
1632
1633
1634 static int
1635 gray_convert_glyph_inner( RAS_ARG,
1636 int continued )
1637 {
1638 int error;
1639
1640
1641 if ( ft_setjmp( ras.jump_buffer ) == 0 )
1642 {
1643 if ( continued )
1644 FT_Trace_Disable();
1645 error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras );
1646 if ( continued )
1647 FT_Trace_Enable();
1648
1649 if ( !ras.invalid )
1650 gray_record_cell( RAS_VAR );
1651
1652 FT_TRACE7(( "band [%d..%d]: %d cell%s\n",
1653 ras.min_ey,
1654 ras.max_ey,
1655 ras.num_cells,
1656 ras.num_cells == 1 ? "" : "s" ));
1657 }
1658 else
1659 {
1660 error = FT_THROW( Memory_Overflow );
1661
1662 FT_TRACE7(( "band [%d..%d]: to be bisected\n",
1663 ras.min_ey, ras.max_ey ));
1664 }
1665
1666 return error;
1667 }
1668
1669
1670 static int
1671 gray_convert_glyph( RAS_ARG )
1672 {
1673 const TCoord yMin = ras.min_ey;
1674 const TCoord yMax = ras.max_ey;
1675
1676 TCell buffer[FT_MAX_GRAY_POOL];
1677 size_t height = (size_t)( yMax - yMin );
1678 size_t n = FT_MAX_GRAY_POOL / 8;
1679 TCoord y;
1680 TCoord bands[32]; /* enough to accommodate bisections */
1681 TCoord* band;
1682
1683 int continued = 0;
1684
1685
1686 /* set up vertical bands */
1687 if ( height > n )
1688 {
1689 /* two divisions rounded up */
1690 n = ( height + n - 1 ) / n;
1691 height = ( height + n - 1 ) / n;
1692 }
1693
1694 /* memory management */
1695 n = ( height * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) / sizeof ( TCell );
1696
1697 ras.cells = buffer + n;
1698 ras.max_cells = (FT_PtrDist)( FT_MAX_GRAY_POOL - n );
1699 ras.ycells = (PCell*)buffer;
1700
1701 for ( y = yMin; y < yMax; )
1702 {
1703 ras.min_ey = y;
1704 y += height;
1705 ras.max_ey = FT_MIN( y, yMax );
1706
1707 band = bands;
1708 band[1] = ras.min_ey;
1709 band[0] = ras.max_ey;
1710
1711 do
1712 {
1713 TCoord width = band[0] - band[1];
1714 int error;
1715
1716
1717 FT_MEM_ZERO( ras.ycells, height * sizeof ( PCell ) );
1718
1719 ras.num_cells = 0;
1720 ras.invalid = 1;
1721 ras.min_ey = band[1];
1722 ras.max_ey = band[0];
1723
1724 error = gray_convert_glyph_inner( RAS_VAR, continued );
1725 continued = 1;
1726
1727 if ( !error )
1728 {
1729 gray_sweep( RAS_VAR );
1730 band--;
1731 continue;
1732 }
1733 else if ( error != ErrRaster_Memory_Overflow )
1734 return 1;
1735
1736 /* render pool overflow; we will reduce the render band by half */
1737 width >>= 1;
1738
1739 /* this should never happen even with tiny rendering pool */
1740 if ( width == 0 )
1741 {
1742 FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" ));
1743 return 1;
1744 }
1745
1746 band++;
1747 band[1] = band[0];
1748 band[0] += width;
1749 } while ( band >= bands );
1750 }
1751
1752 return 0;
1753 }
1754
1755
1756 static int
1757 gray_raster_render( FT_Raster raster,
1758 const FT_Raster_Params* params )
1759 {
1760 const FT_Outline* outline = (const FT_Outline*)params->source;
1761 const FT_Bitmap* target_map = params->target;
1762
1763 #ifndef FT_STATIC_RASTER
1764 gray_TWorker worker[1];
1765 #endif
1766
1767
1768 if ( !raster )
1769 return FT_THROW( Invalid_Argument );
1770
1771 /* this version does not support monochrome rendering */
1772 if ( !( params->flags & FT_RASTER_FLAG_AA ) )
1773 return FT_THROW( Invalid_Mode );
1774
1775 if ( !outline )
1776 return FT_THROW( Invalid_Outline );
1777
1778 /* return immediately if the outline is empty */
1779 if ( outline->n_points == 0 || outline->n_contours <= 0 )
1780 return 0;
1781
1782 if ( !outline->contours || !outline->points )
1783 return FT_THROW( Invalid_Outline );
1784
1785 if ( outline->n_points !=
1786 outline->contours[outline->n_contours - 1] + 1 )
1787 return FT_THROW( Invalid_Outline );
1788
1789 ras.outline = *outline;
1790
1791 if ( params->flags & FT_RASTER_FLAG_DIRECT )
1792 {
1793 if ( !params->gray_spans )
1794 return 0;
1795
1796 ras.render_span = (FT_Raster_Span_Func)params->gray_spans;
1797 ras.render_span_data = params->user;
1798 ras.num_spans = 0;
1799
1800 ras.min_ex = params->clip_box.xMin;
1801 ras.min_ey = params->clip_box.yMin;
1802 ras.max_ex = params->clip_box.xMax;
1803 ras.max_ey = params->clip_box.yMax;
1804 }
1805 else
1806 {
1807 /* if direct mode is not set, we must have a target bitmap */
1808 if ( !target_map )
1809 return FT_THROW( Invalid_Argument );
1810
1811 /* nothing to do */
1812 if ( !target_map->width || !target_map->rows )
1813 return 0;
1814
1815 if ( !target_map->buffer )
1816 return FT_THROW( Invalid_Argument );
1817
1818 if ( target_map->pitch < 0 )
1819 ras.target.origin = target_map->buffer;
1820 else
1821 ras.target.origin = target_map->buffer
1822 + ( target_map->rows - 1 ) * (unsigned int)target_map->pitch;
1823
1824 ras.target.pitch = target_map->pitch;
1825
1826 ras.render_span = (FT_Raster_Span_Func)NULL;
1827 ras.render_span_data = NULL;
1828 ras.num_spans = -1; /* invalid */
1829
1830 ras.min_ex = 0;
1831 ras.min_ey = 0;
1832 ras.max_ex = (FT_Pos)target_map->width;
1833 ras.max_ey = (FT_Pos)target_map->rows;
1834 }
1835
1836 /* exit if nothing to do */
1837 if ( ras.max_ex <= ras.min_ex || ras.max_ey <= ras.min_ey )
1838 return 0;
1839
1840 return gray_convert_glyph( RAS_VAR );
1841 }
1842
1843
1844 /**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/
1845 /**** a static object. *****/
1846
1847 #ifdef STANDALONE_
1848
1849 static int
1850 gray_raster_new( void* memory,
1851 FT_Raster* araster )
1852 {
1853 static gray_TRaster the_raster;
1854
1855 FT_UNUSED( memory );
1856
1857
1858 *araster = (FT_Raster)&the_raster;
1859 FT_ZERO( &the_raster );
1860
1861 return 0;
1862 }
1863
1864
1865 static void
1866 gray_raster_done( FT_Raster raster )
1867 {
1868 /* nothing */
1869 FT_UNUSED( raster );
1870 }
1871
1872 #else /* !STANDALONE_ */
1873
1874 static int
1875 gray_raster_new( FT_Memory memory,
1876 FT_Raster* araster )
1877 {
1878 FT_Error error;
1879 gray_PRaster raster = NULL;
1880
1881
1882 *araster = 0;
1883 if ( !FT_ALLOC( raster, sizeof ( gray_TRaster ) ) )
1884 {
1885 raster->memory = memory;
1886 *araster = (FT_Raster)raster;
1887 }
1888
1889 return error;
1890 }
1891
1892
1893 static void
1894 gray_raster_done( FT_Raster raster )
1895 {
1896 FT_Memory memory = (FT_Memory)((gray_PRaster)raster)->memory;
1897
1898
1899 FT_FREE( raster );
1900 }
1901
1902 #endif /* !STANDALONE_ */
1903
1904
1905 static void
1906 gray_raster_reset( FT_Raster raster,
1907 unsigned char* pool_base,
1908 unsigned long pool_size )
1909 {
1910 FT_UNUSED( raster );
1911 FT_UNUSED( pool_base );
1912 FT_UNUSED( pool_size );
1913 }
1914
1915
1916 static int
1917 gray_raster_set_mode( FT_Raster raster,
1918 unsigned long mode,
1919 void* args )
1920 {
1921 FT_UNUSED( raster );
1922 FT_UNUSED( mode );
1923 FT_UNUSED( args );
1924
1925
1926 return 0; /* nothing to do */
1927 }
1928
1929
1930 FT_DEFINE_RASTER_FUNCS(
1931 ft_grays_raster,
1932
1933 FT_GLYPH_FORMAT_OUTLINE,
1934
1935 (FT_Raster_New_Func) gray_raster_new, /* raster_new */
1936 (FT_Raster_Reset_Func) gray_raster_reset, /* raster_reset */
1937 (FT_Raster_Set_Mode_Func)gray_raster_set_mode, /* raster_set_mode */
1938 (FT_Raster_Render_Func) gray_raster_render, /* raster_render */
1939 (FT_Raster_Done_Func) gray_raster_done /* raster_done */
1940 )
1941
1942
1943 /* END */
1944
1945
1946 /* Local Variables: */
1947 /* coding: utf-8 */
1948 /* End: */