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.
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 * This renderer has the following advantages:
62 *
63 * - It doesn't need an intermediate bitmap. Instead, one can supply a
64 * callback function that will be called by the renderer to draw gray
65 * spans on any target surface. You can thus do direct composition on
66 * any kind of bitmap, provided that you give the renderer the right
67 * callback.
68 *
69 * - A perfect anti-aliaser, i.e., it computes the _exact_ coverage on
70 * each pixel cell.
71 *
72 * - It performs a single pass on the outline (the `standard' FT2
73 * renderer makes two passes).
74 *
75 * - It can easily be modified to render to _any_ number of gray levels
76 * cheaply.
77 *
78 * - For small (< 20) pixel sizes, it is faster than the standard
79 * renderer.
80 *
81 */
82
83
84 /**************************************************************************
85 *
86 * The macro FT_COMPONENT is used in trace mode. It is an implicit
87 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
88 * messages during execution.
89 */
90 #undef FT_COMPONENT
91 #define FT_COMPONENT smooth
92
93
94 #ifdef STANDALONE_
95
96
97 /* The size in bytes of the render pool used by the scan-line converter */
98 /* to do all of its work. */
99 #define FT_RENDER_POOL_SIZE 16384L
100
101
102 /* Auxiliary macros for token concatenation. */
103 #define FT_ERR_XCAT( x, y ) x ## y
104 #define FT_ERR_CAT( x, y ) FT_ERR_XCAT( x, y )
105
106 #define FT_BEGIN_STMNT do {
107 #define FT_END_STMNT } while ( 0 )
108
109 #define FT_MIN( a, b ) ( (a) < (b) ? (a) : (b) )
110 #define FT_MAX( a, b ) ( (a) > (b) ? (a) : (b) )
111 #define FT_ABS( a ) ( (a) < 0 ? -(a) : (a) )
112
113
114 /*
115 * Approximate sqrt(x*x+y*y) using the `alpha max plus beta min'
116 * algorithm. We use alpha = 1, beta = 3/8, giving us results with a
117 * largest error less than 7% compared to the exact value.
118 */
119 #define FT_HYPOT( x, y ) \
120 ( x = FT_ABS( x ), \
121 y = FT_ABS( y ), \
122 x > y ? x + ( 3 * y >> 3 ) \
123 : y + ( 3 * x >> 3 ) )
124
125
126 /* define this to dump debugging information */
127 /* #define FT_DEBUG_LEVEL_TRACE */
128
129
130 #ifdef FT_DEBUG_LEVEL_TRACE
131 #include <stdio.h>
132 #include <stdarg.h>
133 #endif
134
135 #include <stddef.h>
136 #include <string.h>
137 #include <setjmp.h>
138 #include <limits.h>
139 #define FT_CHAR_BIT CHAR_BIT
140 #define FT_UINT_MAX UINT_MAX
141 #define FT_INT_MAX INT_MAX
142 #define FT_ULONG_MAX ULONG_MAX
143
144 #define ADD_LONG( a, b ) \
145 (long)( (unsigned long)(a) + (unsigned long)(b) )
146 #define SUB_LONG( a, b ) \
147 (long)( (unsigned long)(a) - (unsigned long)(b) )
148 #define MUL_LONG( a, b ) \
149 (long)( (unsigned long)(a) * (unsigned long)(b) )
150 #define NEG_LONG( a ) \
151 (long)( -(unsigned long)(a) )
152
153
154 #define ft_memset memset
155
156 #define ft_setjmp setjmp
157 #define ft_longjmp longjmp
158 #define ft_jmp_buf jmp_buf
159
160 typedef ptrdiff_t FT_PtrDist;
161
162
163 #define ErrRaster_Invalid_Mode -2
164 #define ErrRaster_Invalid_Outline -1
165 #define ErrRaster_Invalid_Argument -3
166 #define ErrRaster_Memory_Overflow -4
167
168 #define FT_BEGIN_HEADER
169 #define FT_END_HEADER
170
171 #include "ftimage.h"
172 #include "ftgrays.h"
173
174
175 /* This macro is used to indicate that a function parameter is unused. */
176 /* Its purpose is simply to reduce compiler warnings. Note also that */
177 /* simply defining it as `(void)x' doesn't avoid warnings with certain */
178 /* ANSI compilers (e.g. LCC). */
179 #define FT_UNUSED( x ) (x) = (x)
180
181
182 /* we only use level 5 & 7 tracing messages; cf. ftdebug.h */
183
184 #ifdef FT_DEBUG_LEVEL_TRACE
185
186 void
187 FT_Message( const char* fmt,
188 ... )
189 {
190 va_list ap;
191
192
193 va_start( ap, fmt );
194 vfprintf( stderr, fmt, ap );
195 va_end( ap );
196 }
197
198
199 /* empty function useful for setting a breakpoint to catch errors */
200 int
201 FT_Throw( int error,
202 int line,
203 const char* file )
204 {
205 FT_UNUSED( error );
206 FT_UNUSED( line );
207 FT_UNUSED( file );
208
209 return 0;
210 }
211
212
213 /* we don't handle tracing levels in stand-alone mode; */
214 #ifndef FT_TRACE5
215 #define FT_TRACE5( varformat ) FT_Message varformat
216 #endif
217 #ifndef FT_TRACE7
218 #define FT_TRACE7( varformat ) FT_Message varformat
219 #endif
220 #ifndef FT_ERROR
221 #define FT_ERROR( varformat ) FT_Message varformat
222 #endif
223
224 #define FT_THROW( e ) \
225 ( FT_Throw( FT_ERR_CAT( ErrRaster_, e ), \
226 __LINE__, \
227 __FILE__ ) | \
228 FT_ERR_CAT( ErrRaster_, e ) )
229
230 #else /* !FT_DEBUG_LEVEL_TRACE */
231
232 #define FT_TRACE5( x ) do { } while ( 0 ) /* nothing */
233 #define FT_TRACE7( x ) do { } while ( 0 ) /* nothing */
234 #define FT_ERROR( x ) do { } while ( 0 ) /* nothing */
235 #define FT_THROW( e ) FT_ERR_CAT( ErrRaster_, e )
236
237
238 #endif /* !FT_DEBUG_LEVEL_TRACE */
239
240
241 #define FT_DEFINE_OUTLINE_FUNCS( class_, \
242 move_to_, line_to_, \
243 conic_to_, cubic_to_, \
244 shift_, delta_ ) \
245 static const FT_Outline_Funcs class_ = \
246 { \
247 move_to_, \
248 line_to_, \
249 conic_to_, \
250 cubic_to_, \
251 shift_, \
252 delta_ \
253 };
254
255 #define FT_DEFINE_RASTER_FUNCS( class_, glyph_format_, \
256 raster_new_, raster_reset_, \
257 raster_set_mode_, raster_render_, \
258 raster_done_ ) \
259 const FT_Raster_Funcs class_ = \
260 { \
261 glyph_format_, \
262 raster_new_, \
263 raster_reset_, \
264 raster_set_mode_, \
265 raster_render_, \
266 raster_done_ \
267 };
268
269
270 #else /* !STANDALONE_ */
271
272
273 #include <ft2build.h>
274 #include "ftgrays.h"
275 #include FT_INTERNAL_OBJECTS_H
276 #include FT_INTERNAL_DEBUG_H
277 #include FT_INTERNAL_CALC_H
278 #include FT_OUTLINE_H
279
280 #include "ftsmerrs.h"
281
282 #define Smooth_Err_Invalid_Mode Smooth_Err_Cannot_Render_Glyph
283 #define Smooth_Err_Memory_Overflow Smooth_Err_Out_Of_Memory
284 #define ErrRaster_Memory_Overflow Smooth_Err_Out_Of_Memory
285
286
287 #endif /* !STANDALONE_ */
288
289
290 #ifndef FT_MEM_SET
291 #define FT_MEM_SET( d, s, c ) ft_memset( d, s, c )
292 #endif
293
294 #ifndef FT_MEM_ZERO
295 #define FT_MEM_ZERO( dest, count ) FT_MEM_SET( dest, 0, count )
296 #endif
297
298 #ifndef FT_ZERO
299 #define FT_ZERO( p ) FT_MEM_ZERO( p, sizeof ( *(p) ) )
300 #endif
301
302 /* as usual, for the speed hungry :-) */
303
304 #undef RAS_ARG
305 #undef RAS_ARG_
306 #undef RAS_VAR
307 #undef RAS_VAR_
308
309 #ifndef FT_STATIC_RASTER
310
311 #define RAS_ARG gray_PWorker worker
312 #define RAS_ARG_ gray_PWorker worker,
313
314 #define RAS_VAR worker
315 #define RAS_VAR_ worker,
316
317 #else /* FT_STATIC_RASTER */
318
319 #define RAS_ARG void
320 #define RAS_ARG_ /* empty */
321 #define RAS_VAR /* empty */
322 #define RAS_VAR_ /* empty */
323
324 #endif /* FT_STATIC_RASTER */
325
326
327 /* must be at least 6 bits! */
328 #define PIXEL_BITS 8
329
330 #undef FLOOR
331 #undef CEILING
332 #undef TRUNC
333 #undef SCALED
334
335 #define ONE_PIXEL ( 1 << PIXEL_BITS )
336 #define TRUNC( x ) ( (TCoord)( (x) >> PIXEL_BITS ) )
337 #define SUBPIXELS( x ) ( (TPos)(x) * ONE_PIXEL )
338 #define FLOOR( x ) ( (x) & -ONE_PIXEL )
339 #define CEILING( x ) ( ( (x) + ONE_PIXEL - 1 ) & -ONE_PIXEL )
340 #define ROUND( x ) ( ( (x) + ONE_PIXEL / 2 ) & -ONE_PIXEL )
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 ( ( (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
436 #if defined( _MSC_VER ) /* Visual C++ (and Intel C++) */
437 /* We disable the warning `structure was padded due to */
438 /* __declspec(align())' in order to compile cleanly with */
439 /* the maximum level of warnings. */
440 #pragma warning( push )
441 #pragma warning( disable : 4324 )
442 #endif /* _MSC_VER */
443
444 typedef struct gray_TWorker_
445 {
446 ft_jmp_buf jump_buffer;
447
448 TCoord ex, ey;
449 TCoord min_ex, max_ex;
450 TCoord min_ey, max_ey;
451
452 TArea area;
453 TCoord cover;
454 int invalid;
455
456 PCell* ycells;
457 PCell cells;
458 FT_PtrDist max_cells;
459 FT_PtrDist num_cells;
460
461 TPos x, y;
462
463 FT_Outline outline;
464 TPixmap target;
465
466 FT_Raster_Span_Func render_span;
467 void* render_span_data;
468
469 } gray_TWorker, *gray_PWorker;
470
471 #if defined( _MSC_VER )
472 #pragma warning( pop )
473 #endif
474
475
476 #ifndef FT_STATIC_RASTER
477 #define ras (*worker)
478 #else
479 static gray_TWorker ras;
480 #endif
481
482
483 typedef struct gray_TRaster_
484 {
485 void* memory;
486
487 } gray_TRaster, *gray_PRaster;
488
489
490 #ifdef FT_DEBUG_LEVEL_TRACE
491
492 /* to be called while in the debugger -- */
493 /* this function causes a compiler warning since it is unused otherwise */
494 static void
495 gray_dump_cells( RAS_ARG )
496 {
497 int y;
498
499
500 for ( y = ras.min_ey; y < ras.max_ey; y++ )
501 {
502 PCell cell = ras.ycells[y - ras.min_ey];
503
504
505 printf( "%3d:", y );
506
507 for ( ; cell != NULL; cell = cell->next )
508 printf( " (%3d, c:%4d, a:%6d)",
509 cell->x, cell->cover, cell->area );
510 printf( "\n" );
511 }
512 }
513
514 #endif /* FT_DEBUG_LEVEL_TRACE */
515
516
517 /**************************************************************************
518 *
519 * Record the current cell in the table.
520 */
521 static void
522 gray_record_cell( RAS_ARG )
523 {
524 PCell *pcell, cell;
525 TCoord x = ras.ex;
526
527
528 pcell = &ras.ycells[ras.ey - ras.min_ey];
529 for (;;)
530 {
531 cell = *pcell;
532 if ( !cell || cell->x > x )
533 break;
534
535 if ( cell->x == x )
536 goto Found;
537
538 pcell = &cell->next;
539 }
540
541 if ( ras.num_cells >= ras.max_cells )
542 ft_longjmp( ras.jump_buffer, 1 );
543
544 /* insert new cell */
545 cell = ras.cells + ras.num_cells++;
546 cell->x = x;
547 cell->area = ras.area;
548 cell->cover = ras.cover;
549
550 cell->next = *pcell;
551 *pcell = cell;
552
553 return;
554
555 Found:
556 /* update old cell */
557 cell->area += ras.area;
558 cell->cover += ras.cover;
559 }
560
561
562 /**************************************************************************
563 *
564 * Set the current cell to a new position.
565 */
566 static void
567 gray_set_cell( RAS_ARG_ TCoord ex,
568 TCoord ey )
569 {
570 /* Move the cell pointer to a new position. We set the `invalid' */
571 /* flag to indicate that the cell isn't part of those we're interested */
572 /* in during the render phase. This means that: */
573 /* */
574 /* . the new vertical position must be within min_ey..max_ey-1. */
575 /* . the new horizontal position must be strictly less than max_ex */
576 /* */
577 /* Note that if a cell is to the left of the clipping region, it is */
578 /* actually set to the (min_ex-1) horizontal position. */
579
580 if ( ex < ras.min_ex )
581 ex = ras.min_ex - 1;
582
583 /* record the current one if it is valid and substantial */
584 if ( !ras.invalid && ( ras.area || ras.cover ) )
585 gray_record_cell( RAS_VAR );
586
587 ras.area = 0;
588 ras.cover = 0;
589 ras.ex = ex;
590 ras.ey = ey;
591
592 ras.invalid = ( ey >= ras.max_ey || ey < ras.min_ey ||
593 ex >= ras.max_ex );
594 }
595
596
597 #ifndef FT_LONG64
598
599 /**************************************************************************
600 *
601 * Render a scanline as one or more cells.
602 */
603 static void
604 gray_render_scanline( RAS_ARG_ TCoord ey,
605 TPos x1,
606 TCoord y1,
607 TPos x2,
608 TCoord y2 )
609 {
610 TCoord ex1, ex2, fx1, fx2, first, dy, delta, mod;
611 TPos p, dx;
612 int incr;
613
614
615 ex1 = TRUNC( x1 );
616 ex2 = TRUNC( x2 );
617
618 /* trivial case. Happens often */
619 if ( y1 == y2 )
620 {
621 gray_set_cell( RAS_VAR_ ex2, ey );
622 return;
623 }
624
625 fx1 = (TCoord)( x1 - SUBPIXELS( ex1 ) );
626 fx2 = (TCoord)( x2 - SUBPIXELS( ex2 ) );
627
628 /* everything is located in a single cell. That is easy! */
629 /* */
630 if ( ex1 == ex2 )
631 goto End;
632
633 /* ok, we'll have to render a run of adjacent cells on the same */
634 /* scanline... */
635 /* */
636 dx = x2 - x1;
637 dy = y2 - y1;
638
639 if ( dx > 0 )
640 {
641 p = ( ONE_PIXEL - fx1 ) * dy;
642 first = ONE_PIXEL;
643 incr = 1;
644 }
645 else
646 {
647 p = fx1 * dy;
648 first = 0;
649 incr = -1;
650 dx = -dx;
651 }
652
653 FT_DIV_MOD( TCoord, p, dx, delta, mod );
654
655 ras.area += (TArea)( ( fx1 + first ) * delta );
656 ras.cover += delta;
657 y1 += delta;
658 ex1 += incr;
659 gray_set_cell( RAS_VAR_ ex1, ey );
660
661 if ( ex1 != ex2 )
662 {
663 TCoord lift, rem;
664
665
666 p = ONE_PIXEL * dy;
667 FT_DIV_MOD( TCoord, p, dx, lift, rem );
668
669 do
670 {
671 delta = lift;
672 mod += rem;
673 if ( mod >= (TCoord)dx )
674 {
675 mod -= (TCoord)dx;
676 delta++;
677 }
678
679 ras.area += (TArea)( ONE_PIXEL * delta );
680 ras.cover += delta;
681 y1 += delta;
682 ex1 += incr;
683 gray_set_cell( RAS_VAR_ ex1, ey );
684 } while ( ex1 != ex2 );
685 }
686
687 fx1 = ONE_PIXEL - first;
688
689 End:
690 dy = y2 - y1;
691
692 ras.area += (TArea)( ( fx1 + fx2 ) * dy );
693 ras.cover += dy;
694 }
695
696
697 /**************************************************************************
698 *
699 * Render a given line as a series of scanlines.
700 */
701 static void
702 gray_render_line( RAS_ARG_ TPos to_x,
703 TPos to_y )
704 {
705 TCoord ey1, ey2, fy1, fy2, first, delta, mod;
706 TPos p, dx, dy, x, x2;
707 int incr;
708
709
710 ey1 = TRUNC( ras.y );
711 ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */
712
713 /* perform vertical clipping */
714 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
715 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
716 goto End;
717
718 fy1 = (TCoord)( ras.y - SUBPIXELS( ey1 ) );
719 fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) );
720
721 /* everything is on a single scanline */
722 if ( ey1 == ey2 )
723 {
724 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 );
725 goto End;
726 }
727
728 dx = to_x - ras.x;
729 dy = to_y - ras.y;
730
731 /* vertical line - avoid calling gray_render_scanline */
732 if ( dx == 0 )
733 {
734 TCoord ex = TRUNC( ras.x );
735 TCoord two_fx = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 );
736 TArea area;
737
738
739 if ( dy > 0)
740 {
741 first = ONE_PIXEL;
742 incr = 1;
743 }
744 else
745 {
746 first = 0;
747 incr = -1;
748 }
749
750 delta = first - fy1;
751 ras.area += (TArea)two_fx * delta;
752 ras.cover += delta;
753 ey1 += incr;
754
755 gray_set_cell( RAS_VAR_ ex, ey1 );
756
757 delta = first + first - ONE_PIXEL;
758 area = (TArea)two_fx * delta;
759 while ( ey1 != ey2 )
760 {
761 ras.area += area;
762 ras.cover += delta;
763 ey1 += incr;
764
765 gray_set_cell( RAS_VAR_ ex, ey1 );
766 }
767
768 delta = fy2 - ONE_PIXEL + first;
769 ras.area += (TArea)two_fx * delta;
770 ras.cover += delta;
771
772 goto End;
773 }
774
775 /* ok, we have to render several scanlines */
776 if ( dy > 0)
777 {
778 p = ( ONE_PIXEL - fy1 ) * dx;
779 first = ONE_PIXEL;
780 incr = 1;
781 }
782 else
783 {
784 p = fy1 * dx;
785 first = 0;
786 incr = -1;
787 dy = -dy;
788 }
789
790 FT_DIV_MOD( TCoord, p, dy, delta, mod );
791
792 x = ras.x + delta;
793 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, first );
794
795 ey1 += incr;
796 gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
797
798 if ( ey1 != ey2 )
799 {
800 TCoord lift, rem;
801
802
803 p = ONE_PIXEL * dx;
804 FT_DIV_MOD( TCoord, p, dy, lift, rem );
805
806 do
807 {
808 delta = lift;
809 mod += rem;
810 if ( mod >= (TCoord)dy )
811 {
812 mod -= (TCoord)dy;
813 delta++;
814 }
815
816 x2 = x + delta;
817 gray_render_scanline( RAS_VAR_ ey1,
818 x, ONE_PIXEL - first,
819 x2, first );
820 x = x2;
821
822 ey1 += incr;
823 gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
824 } while ( ey1 != ey2 );
825 }
826
827 gray_render_scanline( RAS_VAR_ ey1,
828 x, ONE_PIXEL - first,
829 to_x, fy2 );
830
831 End:
832 ras.x = to_x;
833 ras.y = to_y;
834 }
835
836 #else
837
838 /**************************************************************************
839 *
840 * Render a straight line across multiple cells in any direction.
841 */
842 static void
843 gray_render_line( RAS_ARG_ TPos to_x,
844 TPos to_y )
845 {
846 TPos dx, dy, fx1, fy1, fx2, fy2;
847 TCoord ex1, ex2, ey1, ey2;
848
849
850 ey1 = TRUNC( ras.y );
851 ey2 = TRUNC( to_y );
852
853 /* perform vertical clipping */
854 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
855 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
856 goto End;
857
858 ex1 = TRUNC( ras.x );
859 ex2 = TRUNC( to_x );
860
861 fx1 = ras.x - SUBPIXELS( ex1 );
862 fy1 = ras.y - SUBPIXELS( ey1 );
863
864 dx = to_x - ras.x;
865 dy = to_y - ras.y;
866
867 if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */
868 ;
869 else if ( dy == 0 ) /* ex1 != ex2 */ /* any horizontal line */
870 {
871 ex1 = ex2;
872 gray_set_cell( RAS_VAR_ ex1, ey1 );
873 }
874 else if ( dx == 0 )
875 {
876 if ( dy > 0 ) /* vertical line up */
877 do
878 {
879 fy2 = ONE_PIXEL;
880 ras.cover += ( fy2 - fy1 );
881 ras.area += ( fy2 - fy1 ) * fx1 * 2;
882 fy1 = 0;
883 ey1++;
884 gray_set_cell( RAS_VAR_ ex1, ey1 );
885 } while ( ey1 != ey2 );
886 else /* vertical line down */
887 do
888 {
889 fy2 = 0;
890 ras.cover += ( fy2 - fy1 );
891 ras.area += ( fy2 - fy1 ) * fx1 * 2;
892 fy1 = ONE_PIXEL;
893 ey1--;
894 gray_set_cell( RAS_VAR_ ex1, ey1 );
895 } while ( ey1 != ey2 );
896 }
897 else /* any other line */
898 {
899 TPos prod = dx * fy1 - dy * fx1;
900 FT_UDIVPREP( ex1 != ex2, dx );
901 FT_UDIVPREP( ey1 != ey2, dy );
902
903
904 /* The fundamental value `prod' determines which side and the */
905 /* exact coordinate where the line exits current cell. It is */
906 /* also easily updated when moving from one cell to the next. */
907 do
908 {
909 if ( prod <= 0 &&
910 prod - dx * ONE_PIXEL > 0 ) /* left */
911 {
912 fx2 = 0;
913 fy2 = (TPos)FT_UDIV( -prod, -dx );
914 prod -= dy * ONE_PIXEL;
915 ras.cover += ( fy2 - fy1 );
916 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
917 fx1 = ONE_PIXEL;
918 fy1 = fy2;
919 ex1--;
920 }
921 else if ( prod - dx * ONE_PIXEL <= 0 &&
922 prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 ) /* up */
923 {
924 prod -= dx * ONE_PIXEL;
925 fx2 = (TPos)FT_UDIV( -prod, dy );
926 fy2 = ONE_PIXEL;
927 ras.cover += ( fy2 - fy1 );
928 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
929 fx1 = fx2;
930 fy1 = 0;
931 ey1++;
932 }
933 else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 &&
934 prod + dy * ONE_PIXEL >= 0 ) /* right */
935 {
936 prod += dy * ONE_PIXEL;
937 fx2 = ONE_PIXEL;
938 fy2 = (TPos)FT_UDIV( prod, dx );
939 ras.cover += ( fy2 - fy1 );
940 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
941 fx1 = 0;
942 fy1 = fy2;
943 ex1++;
944 }
945 else /* ( prod + dy * ONE_PIXEL < 0 &&
946 prod > 0 ) down */
947 {
948 fx2 = (TPos)FT_UDIV( prod, -dy );
949 fy2 = 0;
950 prod += dx * ONE_PIXEL;
951 ras.cover += ( fy2 - fy1 );
952 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
953 fx1 = fx2;
954 fy1 = ONE_PIXEL;
955 ey1--;
956 }
957
958 gray_set_cell( RAS_VAR_ ex1, ey1 );
959 } while ( ex1 != ex2 || ey1 != ey2 );
960 }
961
962 fx2 = to_x - SUBPIXELS( ex2 );
963 fy2 = to_y - SUBPIXELS( ey2 );
964
965 ras.cover += ( fy2 - fy1 );
966 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
967
968 End:
969 ras.x = to_x;
970 ras.y = to_y;
971 }
972
973 #endif
974
975 static void
976 gray_split_conic( FT_Vector* base )
977 {
978 TPos a, b;
979
980
981 base[4].x = base[2].x;
982 b = base[1].x;
983 a = base[3].x = ( base[2].x + b ) / 2;
984 b = base[1].x = ( base[0].x + b ) / 2;
985 base[2].x = ( a + b ) / 2;
986
987 base[4].y = base[2].y;
988 b = base[1].y;
989 a = base[3].y = ( base[2].y + b ) / 2;
990 b = base[1].y = ( base[0].y + b ) / 2;
991 base[2].y = ( a + b ) / 2;
992 }
993
994
995 static void
996 gray_render_conic( RAS_ARG_ const FT_Vector* control,
997 const FT_Vector* to )
998 {
999 FT_Vector bez_stack[16 * 2 + 1]; /* enough to accommodate bisections */
1000 FT_Vector* arc = bez_stack;
1001 TPos dx, dy;
1002 int draw, split;
1003
1004
1005 arc[0].x = UPSCALE( to->x );
1006 arc[0].y = UPSCALE( to->y );
1007 arc[1].x = UPSCALE( control->x );
1008 arc[1].y = UPSCALE( control->y );
1009 arc[2].x = ras.x;
1010 arc[2].y = ras.y;
1011
1012 /* short-cut the arc that crosses the current band */
1013 if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
1014 TRUNC( arc[1].y ) >= ras.max_ey &&
1015 TRUNC( arc[2].y ) >= ras.max_ey ) ||
1016 ( TRUNC( arc[0].y ) < ras.min_ey &&
1017 TRUNC( arc[1].y ) < ras.min_ey &&
1018 TRUNC( arc[2].y ) < ras.min_ey ) )
1019 {
1020 ras.x = arc[0].x;
1021 ras.y = arc[0].y;
1022 return;
1023 }
1024
1025 dx = FT_ABS( arc[2].x + arc[0].x - 2 * arc[1].x );
1026 dy = FT_ABS( arc[2].y + arc[0].y - 2 * arc[1].y );
1027 if ( dx < dy )
1028 dx = dy;
1029
1030 /* We can calculate the number of necessary bisections because */
1031 /* each bisection predictably reduces deviation exactly 4-fold. */
1032 /* Even 32-bit deviation would vanish after 16 bisections. */
1033 draw = 1;
1034 while ( dx > ONE_PIXEL / 4 )
1035 {
1036 dx >>= 2;
1037 draw <<= 1;
1038 }
1039
1040 /* We use decrement counter to count the total number of segments */
1041 /* to draw starting from 2^level. Before each draw we split as */
1042 /* many times as there are trailing zeros in the counter. */
1043 do
1044 {
1045 split = 1;
1046 while ( ( draw & split ) == 0 )
1047 {
1048 gray_split_conic( arc );
1049 arc += 2;
1050 split <<= 1;
1051 }
1052
1053 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1054 arc -= 2;
1055
1056 } while ( --draw );
1057 }
1058
1059
1060 static void
1061 gray_split_cubic( FT_Vector* base )
1062 {
1063 TPos a, b, c, d;
1064
1065
1066 base[6].x = base[3].x;
1067 c = base[1].x;
1068 d = base[2].x;
1069 base[1].x = a = ( base[0].x + c ) / 2;
1070 base[5].x = b = ( base[3].x + d ) / 2;
1071 c = ( c + d ) / 2;
1072 base[2].x = a = ( a + c ) / 2;
1073 base[4].x = b = ( b + c ) / 2;
1074 base[3].x = ( a + b ) / 2;
1075
1076 base[6].y = base[3].y;
1077 c = base[1].y;
1078 d = base[2].y;
1079 base[1].y = a = ( base[0].y + c ) / 2;
1080 base[5].y = b = ( base[3].y + d ) / 2;
1081 c = ( c + d ) / 2;
1082 base[2].y = a = ( a + c ) / 2;
1083 base[4].y = b = ( b + c ) / 2;
1084 base[3].y = ( a + b ) / 2;
1085 }
1086
1087
1088 static void
1089 gray_render_cubic( RAS_ARG_ const FT_Vector* control1,
1090 const FT_Vector* control2,
1091 const FT_Vector* to )
1092 {
1093 FT_Vector bez_stack[16 * 3 + 1]; /* enough to accommodate bisections */
1094 FT_Vector* arc = bez_stack;
1095 TPos dx, dy, dx_, dy_;
1096 TPos dx1, dy1, dx2, dy2;
1097 TPos L, s, s_limit;
1098
1099
1100 arc[0].x = UPSCALE( to->x );
1101 arc[0].y = UPSCALE( to->y );
1102 arc[1].x = UPSCALE( control2->x );
1103 arc[1].y = UPSCALE( control2->y );
1104 arc[2].x = UPSCALE( control1->x );
1105 arc[2].y = UPSCALE( control1->y );
1106 arc[3].x = ras.x;
1107 arc[3].y = ras.y;
1108
1109 /* short-cut the arc that crosses the current band */
1110 if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
1111 TRUNC( arc[1].y ) >= ras.max_ey &&
1112 TRUNC( arc[2].y ) >= ras.max_ey &&
1113 TRUNC( arc[3].y ) >= ras.max_ey ) ||
1114 ( TRUNC( arc[0].y ) < ras.min_ey &&
1115 TRUNC( arc[1].y ) < ras.min_ey &&
1116 TRUNC( arc[2].y ) < ras.min_ey &&
1117 TRUNC( arc[3].y ) < ras.min_ey ) )
1118 {
1119 ras.x = arc[0].x;
1120 ras.y = arc[0].y;
1121 return;
1122 }
1123
1124 for (;;)
1125 {
1126 /* Decide whether to split or draw. See `Rapid Termination */
1127 /* Evaluation for Recursive Subdivision of Bezier Curves' by Thomas */
1128 /* F. Hain, at */
1129 /* http://www.cis.southalabama.edu/~hain/general/Publications/Bezier/Camera-ready%20CISST02%202.pdf */
1130
1131 /* dx and dy are x and y components of the P0-P3 chord vector. */
1132 dx = dx_ = arc[3].x - arc[0].x;
1133 dy = dy_ = arc[3].y - arc[0].y;
1134
1135 L = FT_HYPOT( dx_, dy_ );
1136
1137 /* Avoid possible arithmetic overflow below by splitting. */
1138 if ( L > 32767 )
1139 goto Split;
1140
1141 /* Max deviation may be as much as (s/L) * 3/4 (if Hain's v = 1). */
1142 s_limit = L * (TPos)( ONE_PIXEL / 6 );
1143
1144 /* s is L * the perpendicular distance from P1 to the line P0-P3. */
1145 dx1 = arc[1].x - arc[0].x;
1146 dy1 = arc[1].y - arc[0].y;
1147 s = FT_ABS( SUB_LONG( MUL_LONG( dy, dx1 ), MUL_LONG( dx, dy1 ) ) );
1148
1149 if ( s > s_limit )
1150 goto Split;
1151
1152 /* s is L * the perpendicular distance from P2 to the line P0-P3. */
1153 dx2 = arc[2].x - arc[0].x;
1154 dy2 = arc[2].y - arc[0].y;
1155 s = FT_ABS( SUB_LONG( MUL_LONG( dy, dx2 ), MUL_LONG( dx, dy2 ) ) );
1156
1157 if ( s > s_limit )
1158 goto Split;
1159
1160 /* Split super curvy segments where the off points are so far
1161 from the chord that the angles P0-P1-P3 or P0-P2-P3 become
1162 acute as detected by appropriate dot products. */
1163 if ( dx1 * ( dx1 - dx ) + dy1 * ( dy1 - dy ) > 0 ||
1164 dx2 * ( dx2 - dx ) + dy2 * ( dy2 - dy ) > 0 )
1165 goto Split;
1166
1167 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1168
1169 if ( arc == bez_stack )
1170 return;
1171
1172 arc -= 3;
1173 continue;
1174
1175 Split:
1176 gray_split_cubic( arc );
1177 arc += 3;
1178 }
1179 }
1180
1181
1182 static int
1183 gray_move_to( const FT_Vector* to,
1184 gray_PWorker worker )
1185 {
1186 TPos x, y;
1187
1188
1189 /* start to a new position */
1190 x = UPSCALE( to->x );
1191 y = UPSCALE( to->y );
1192
1193 gray_set_cell( RAS_VAR_ TRUNC( x ), TRUNC( y ) );
1194
1195 ras.x = x;
1196 ras.y = y;
1197 return 0;
1198 }
1199
1200
1201 static int
1202 gray_line_to( const FT_Vector* to,
1203 gray_PWorker worker )
1204 {
1205 gray_render_line( RAS_VAR_ UPSCALE( to->x ), UPSCALE( to->y ) );
1206 return 0;
1207 }
1208
1209
1210 static int
1211 gray_conic_to( const FT_Vector* control,
1212 const FT_Vector* to,
1213 gray_PWorker worker )
1214 {
1215 gray_render_conic( RAS_VAR_ control, to );
1216 return 0;
1217 }
1218
1219
1220 static int
1221 gray_cubic_to( const FT_Vector* control1,
1222 const FT_Vector* control2,
1223 const FT_Vector* to,
1224 gray_PWorker worker )
1225 {
1226 gray_render_cubic( RAS_VAR_ control1, control2, to );
1227 return 0;
1228 }
1229
1230
1231 static void
1232 gray_hline( RAS_ARG_ TCoord x,
1233 TCoord y,
1234 TArea coverage,
1235 TCoord acount )
1236 {
1237 /* scale the coverage from 0..(ONE_PIXEL*ONE_PIXEL*2) to 0..256 */
1238 coverage >>= PIXEL_BITS * 2 + 1 - 8;
1239 if ( coverage < 0 )
1240 coverage = -coverage - 1;
1241
1242 /* compute the line's coverage depending on the outline fill rule */
1243 if ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL )
1244 {
1245 coverage &= 511;
1246
1247 if ( coverage >= 256 )
1248 coverage = 511 - coverage;
1249 }
1250 else
1251 {
1252 /* normal non-zero winding rule */
1253 if ( coverage >= 256 )
1254 coverage = 255;
1255 }
1256
1257 if ( ras.render_span ) /* for FT_RASTER_FLAG_DIRECT only */
1258 {
1259 FT_Span span;
1260
1261
1262 span.x = (short)x;
1263 span.len = (unsigned short)acount;
1264 span.coverage = (unsigned char)coverage;
1265
1266 ras.render_span( y, 1, &span, ras.render_span_data );
1267 }
1268 else
1269 {
1270 unsigned char* q = ras.target.origin - ras.target.pitch * y + x;
1271 unsigned char c = (unsigned char)coverage;
1272
1273
1274 /* For small-spans it is faster to do it by ourselves than
1275 * calling `memset'. This is mainly due to the cost of the
1276 * function call.
1277 */
1278 switch ( acount )
1279 {
1280 case 7: *q++ = c;
1281 case 6: *q++ = c;
1282 case 5: *q++ = c;
1283 case 4: *q++ = c;
1284 case 3: *q++ = c;
1285 case 2: *q++ = c;
1286 case 1: *q = c;
1287 case 0: break;
1288 default:
1289 FT_MEM_SET( q, c, acount );
1290 }
1291 }
1292 }
1293
1294
1295 static void
1296 gray_sweep( RAS_ARG )
1297 {
1298 int y;
1299
1300
1301 for ( y = ras.min_ey; y < ras.max_ey; y++ )
1302 {
1303 PCell cell = ras.ycells[y - ras.min_ey];
1304 TCoord x = ras.min_ex;
1305 TArea cover = 0;
1306 TArea area;
1307
1308
1309 for ( ; cell != NULL; cell = cell->next )
1310 {
1311 if ( cover != 0 && cell->x > x )
1312 gray_hline( RAS_VAR_ x, y, cover, cell->x - x );
1313
1314 cover += (TArea)cell->cover * ( ONE_PIXEL * 2 );
1315 area = cover - cell->area;
1316
1317 if ( area != 0 && cell->x >= ras.min_ex )
1318 gray_hline( RAS_VAR_ cell->x, y, area, 1 );
1319
1320 x = cell->x + 1;
1321 }
1322
1323 if ( cover != 0 )
1324 gray_hline( RAS_VAR_ x, y, cover, ras.max_ex - x );
1325 }
1326 }
1327
1328
1329 #ifdef STANDALONE_
1330
1331 /**************************************************************************
1332 *
1333 * The following functions should only compile in stand-alone mode,
1334 * i.e., when building this component without the rest of FreeType.
1335 *
1336 */
1337
1338 /**************************************************************************
1339 *
1340 * @Function:
1341 * FT_Outline_Decompose
1342 *
1343 * @Description:
1344 * Walk over an outline's structure to decompose it into individual
1345 * segments and Bézier arcs. This function is also able to emit
1346 * `move to' and `close to' operations to indicate the start and end
1347 * of new contours in the outline.
1348 *
1349 * @Input:
1350 * outline ::
1351 * A pointer to the source target.
1352 *
1353 * func_interface ::
1354 * A table of `emitters', i.e., function pointers
1355 * called during decomposition to indicate path
1356 * operations.
1357 *
1358 * @InOut:
1359 * user ::
1360 * A typeless pointer which is passed to each
1361 * emitter during the decomposition. It can be
1362 * used to store the state during the
1363 * decomposition.
1364 *
1365 * @Return:
1366 * Error code. 0 means success.
1367 */
1368 static int
1369 FT_Outline_Decompose( const FT_Outline* outline,
1370 const FT_Outline_Funcs* func_interface,
1371 void* user )
1372 {
1373 #undef SCALED
1374 #define SCALED( x ) ( ( (x) << shift ) - delta )
1375
1376 FT_Vector v_last;
1377 FT_Vector v_control;
1378 FT_Vector v_start;
1379
1380 FT_Vector* point;
1381 FT_Vector* limit;
1382 char* tags;
1383
1384 int error;
1385
1386 int n; /* index of contour in outline */
1387 int first; /* index of first point in contour */
1388 char tag; /* current point's state */
1389
1390 int shift;
1391 TPos delta;
1392
1393
1394 if ( !outline )
1395 return FT_THROW( Invalid_Outline );
1396
1397 if ( !func_interface )
1398 return FT_THROW( Invalid_Argument );
1399
1400 shift = func_interface->shift;
1401 delta = func_interface->delta;
1402 first = 0;
1403
1404 for ( n = 0; n < outline->n_contours; n++ )
1405 {
1406 int last; /* index of last point in contour */
1407
1408
1409 FT_TRACE5(( "FT_Outline_Decompose: Outline %d\n", n ));
1410
1411 last = outline->contours[n];
1412 if ( last < 0 )
1413 goto Invalid_Outline;
1414 limit = outline->points + last;
1415
1416 v_start = outline->points[first];
1417 v_start.x = SCALED( v_start.x );
1418 v_start.y = SCALED( v_start.y );
1419
1420 v_last = outline->points[last];
1421 v_last.x = SCALED( v_last.x );
1422 v_last.y = SCALED( v_last.y );
1423
1424 v_control = v_start;
1425
1426 point = outline->points + first;
1427 tags = outline->tags + first;
1428 tag = FT_CURVE_TAG( tags[0] );
1429
1430 /* A contour cannot start with a cubic control point! */
1431 if ( tag == FT_CURVE_TAG_CUBIC )
1432 goto Invalid_Outline;
1433
1434 /* check first point to determine origin */
1435 if ( tag == FT_CURVE_TAG_CONIC )
1436 {
1437 /* first point is conic control. Yes, this happens. */
1438 if ( FT_CURVE_TAG( outline->tags[last] ) == FT_CURVE_TAG_ON )
1439 {
1440 /* start at last point if it is on the curve */
1441 v_start = v_last;
1442 limit--;
1443 }
1444 else
1445 {
1446 /* if both first and last points are conic, */
1447 /* start at their middle and record its position */
1448 /* for closure */
1449 v_start.x = ( v_start.x + v_last.x ) / 2;
1450 v_start.y = ( v_start.y + v_last.y ) / 2;
1451
1452 v_last = v_start;
1453 }
1454 point--;
1455 tags--;
1456 }
1457
1458 FT_TRACE5(( " move to (%.2f, %.2f)\n",
1459 v_start.x / 64.0, v_start.y / 64.0 ));
1460 error = func_interface->move_to( &v_start, user );
1461 if ( error )
1462 goto Exit;
1463
1464 while ( point < limit )
1465 {
1466 point++;
1467 tags++;
1468
1469 tag = FT_CURVE_TAG( tags[0] );
1470 switch ( tag )
1471 {
1472 case FT_CURVE_TAG_ON: /* emit a single line_to */
1473 {
1474 FT_Vector vec;
1475
1476
1477 vec.x = SCALED( point->x );
1478 vec.y = SCALED( point->y );
1479
1480 FT_TRACE5(( " line to (%.2f, %.2f)\n",
1481 vec.x / 64.0, vec.y / 64.0 ));
1482 error = func_interface->line_to( &vec, user );
1483 if ( error )
1484 goto Exit;
1485 continue;
1486 }
1487
1488 case FT_CURVE_TAG_CONIC: /* consume conic arcs */
1489 v_control.x = SCALED( point->x );
1490 v_control.y = SCALED( point->y );
1491
1492 Do_Conic:
1493 if ( point < limit )
1494 {
1495 FT_Vector vec;
1496 FT_Vector v_middle;
1497
1498
1499 point++;
1500 tags++;
1501 tag = FT_CURVE_TAG( tags[0] );
1502
1503 vec.x = SCALED( point->x );
1504 vec.y = SCALED( point->y );
1505
1506 if ( tag == FT_CURVE_TAG_ON )
1507 {
1508 FT_TRACE5(( " conic to (%.2f, %.2f)"
1509 " with control (%.2f, %.2f)\n",
1510 vec.x / 64.0, vec.y / 64.0,
1511 v_control.x / 64.0, v_control.y / 64.0 ));
1512 error = func_interface->conic_to( &v_control, &vec, user );
1513 if ( error )
1514 goto Exit;
1515 continue;
1516 }
1517
1518 if ( tag != FT_CURVE_TAG_CONIC )
1519 goto Invalid_Outline;
1520
1521 v_middle.x = ( v_control.x + vec.x ) / 2;
1522 v_middle.y = ( v_control.y + vec.y ) / 2;
1523
1524 FT_TRACE5(( " conic to (%.2f, %.2f)"
1525 " with control (%.2f, %.2f)\n",
1526 v_middle.x / 64.0, v_middle.y / 64.0,
1527 v_control.x / 64.0, v_control.y / 64.0 ));
1528 error = func_interface->conic_to( &v_control, &v_middle, user );
1529 if ( error )
1530 goto Exit;
1531
1532 v_control = vec;
1533 goto Do_Conic;
1534 }
1535
1536 FT_TRACE5(( " conic to (%.2f, %.2f)"
1537 " with control (%.2f, %.2f)\n",
1538 v_start.x / 64.0, v_start.y / 64.0,
1539 v_control.x / 64.0, v_control.y / 64.0 ));
1540 error = func_interface->conic_to( &v_control, &v_start, user );
1541 goto Close;
1542
1543 default: /* FT_CURVE_TAG_CUBIC */
1544 {
1545 FT_Vector vec1, vec2;
1546
1547
1548 if ( point + 1 > limit ||
1549 FT_CURVE_TAG( tags[1] ) != FT_CURVE_TAG_CUBIC )
1550 goto Invalid_Outline;
1551
1552 point += 2;
1553 tags += 2;
1554
1555 vec1.x = SCALED( point[-2].x );
1556 vec1.y = SCALED( point[-2].y );
1557
1558 vec2.x = SCALED( point[-1].x );
1559 vec2.y = SCALED( point[-1].y );
1560
1561 if ( point <= limit )
1562 {
1563 FT_Vector vec;
1564
1565
1566 vec.x = SCALED( point->x );
1567 vec.y = SCALED( point->y );
1568
1569 FT_TRACE5(( " cubic to (%.2f, %.2f)"
1570 " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
1571 vec.x / 64.0, vec.y / 64.0,
1572 vec1.x / 64.0, vec1.y / 64.0,
1573 vec2.x / 64.0, vec2.y / 64.0 ));
1574 error = func_interface->cubic_to( &vec1, &vec2, &vec, user );
1575 if ( error )
1576 goto Exit;
1577 continue;
1578 }
1579
1580 FT_TRACE5(( " cubic to (%.2f, %.2f)"
1581 " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
1582 v_start.x / 64.0, v_start.y / 64.0,
1583 vec1.x / 64.0, vec1.y / 64.0,
1584 vec2.x / 64.0, vec2.y / 64.0 ));
1585 error = func_interface->cubic_to( &vec1, &vec2, &v_start, user );
1586 goto Close;
1587 }
1588 }
1589 }
1590
1591 /* close the contour with a line segment */
1592 FT_TRACE5(( " line to (%.2f, %.2f)\n",
1593 v_start.x / 64.0, v_start.y / 64.0 ));
1594 error = func_interface->line_to( &v_start, user );
1595
1596 Close:
1597 if ( error )
1598 goto Exit;
1599
1600 first = last + 1;
1601 }
1602
1603 FT_TRACE5(( "FT_Outline_Decompose: Done\n", n ));
1604 return 0;
1605
1606 Exit:
1607 FT_TRACE5(( "FT_Outline_Decompose: Error 0x%x\n", error ));
1608 return error;
1609
1610 Invalid_Outline:
1611 return FT_THROW( Invalid_Outline );
1612 }
1613
1614 #endif /* STANDALONE_ */
1615
1616
1617 FT_DEFINE_OUTLINE_FUNCS(
1618 func_interface,
1619
1620 (FT_Outline_MoveTo_Func) gray_move_to, /* move_to */
1621 (FT_Outline_LineTo_Func) gray_line_to, /* line_to */
1622 (FT_Outline_ConicTo_Func)gray_conic_to, /* conic_to */
1623 (FT_Outline_CubicTo_Func)gray_cubic_to, /* cubic_to */
1624
1625 0, /* shift */
1626 0 /* delta */
1627 )
1628
1629
1630 static int
1631 gray_convert_glyph_inner( RAS_ARG,
1632 int continued )
1633 {
1634 volatile int error = 0;
1635
1636
1637 if ( ft_setjmp( ras.jump_buffer ) == 0 )
1638 {
1639 if ( continued )
1640 FT_Trace_Disable();
1641 error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras );
1642 if ( continued )
1643 FT_Trace_Enable();
1644
1645 if ( !ras.invalid )
1646 gray_record_cell( RAS_VAR );
1647
1648 FT_TRACE7(( "band [%d..%d]: %d cell%s\n",
1649 ras.min_ey,
1650 ras.max_ey,
1651 ras.num_cells,
1652 ras.num_cells == 1 ? "" : "s" ));
1653 }
1654 else
1655 {
1656 error = FT_THROW( Memory_Overflow );
1657
1658 FT_TRACE7(( "band [%d..%d]: to be bisected\n",
1659 ras.min_ey, ras.max_ey ));
1660 }
1661
1662 return error;
1663 }
1664
1665
1666 static int
1667 gray_convert_glyph( RAS_ARG )
1668 {
1669 const TCoord yMin = ras.min_ey;
1670 const TCoord yMax = ras.max_ey;
1671
1672 TCell buffer[FT_MAX_GRAY_POOL];
1673 size_t height = (size_t)( yMax - yMin );
1674 size_t n = FT_MAX_GRAY_POOL / 8;
1675 TCoord y;
1676 TCoord bands[32]; /* enough to accommodate bisections */
1677 TCoord* band;
1678
1679 int continued = 0;
1680
1681
1682 /* set up vertical bands */
1683 if ( height > n )
1684 {
1685 /* two divisions rounded up */
1686 n = ( height + n - 1 ) / n;
1687 height = ( height + n - 1 ) / n;
1688 }
1689
1690 /* memory management */
1691 n = ( height * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) / sizeof ( TCell );
1692
1693 ras.cells = buffer + n;
1694 ras.max_cells = (FT_PtrDist)( FT_MAX_GRAY_POOL - n );
1695 ras.ycells = (PCell*)buffer;
1696
1697 for ( y = yMin; y < yMax; )
1698 {
1699 ras.min_ey = y;
1700 y += height;
1701 ras.max_ey = FT_MIN( y, yMax );
1702
1703 band = bands;
1704 band[1] = ras.min_ey;
1705 band[0] = ras.max_ey;
1706
1707 do
1708 {
1709 TCoord width = band[0] - band[1];
1710 int error;
1711
1712
1713 FT_MEM_ZERO( ras.ycells, height * sizeof ( PCell ) );
1714
1715 ras.num_cells = 0;
1716 ras.invalid = 1;
1717 ras.min_ey = band[1];
1718 ras.max_ey = band[0];
1719
1720 error = gray_convert_glyph_inner( RAS_VAR, continued );
1721 continued = 1;
1722
1723 if ( !error )
1724 {
1725 gray_sweep( RAS_VAR );
1726 band--;
1727 continue;
1728 }
1729 else if ( error != ErrRaster_Memory_Overflow )
1730 return 1;
1731
1732 /* render pool overflow; we will reduce the render band by half */
1733 width >>= 1;
1734
1735 /* this should never happen even with tiny rendering pool */
1736 if ( width == 0 )
1737 {
1738 FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" ));
1739 return 1;
1740 }
1741
1742 band++;
1743 band[1] = band[0];
1744 band[0] += width;
1745 } while ( band >= bands );
1746 }
1747
1748 return 0;
1749 }
1750
1751
1752 static int
1753 gray_raster_render( FT_Raster raster,
1754 const FT_Raster_Params* params )
1755 {
1756 const FT_Outline* outline = (const FT_Outline*)params->source;
1757 const FT_Bitmap* target_map = params->target;
1758 FT_BBox clip;
1759
1760 #ifndef FT_STATIC_RASTER
1761 gray_TWorker worker[1];
1762 #endif
1763
1764
1765 if ( !raster )
1766 return FT_THROW( Invalid_Argument );
1767
1768 /* this version does not support monochrome rendering */
1769 if ( !( params->flags & FT_RASTER_FLAG_AA ) )
1770 return FT_THROW( Invalid_Mode );
1771
1772 if ( !outline )
1773 return FT_THROW( Invalid_Outline );
1774
1775 /* return immediately if the outline is empty */
1776 if ( outline->n_points == 0 || outline->n_contours <= 0 )
1777 return 0;
1778
1779 if ( !outline->contours || !outline->points )
1780 return FT_THROW( Invalid_Outline );
1781
1782 if ( outline->n_points !=
1783 outline->contours[outline->n_contours - 1] + 1 )
1784 return FT_THROW( Invalid_Outline );
1785
1786 ras.outline = *outline;
1787
1788 if ( params->flags & FT_RASTER_FLAG_DIRECT )
1789 {
1790 if ( !params->gray_spans )
1791 return 0;
1792
1793 ras.render_span = (FT_Raster_Span_Func)params->gray_spans;
1794 ras.render_span_data = params->user;
1795 }
1796 else
1797 {
1798 /* if direct mode is not set, we must have a target bitmap */
1799 if ( !target_map )
1800 return FT_THROW( Invalid_Argument );
1801
1802 /* nothing to do */
1803 if ( !target_map->width || !target_map->rows )
1804 return 0;
1805
1806 if ( !target_map->buffer )
1807 return FT_THROW( Invalid_Argument );
1808
1809 if ( target_map->pitch < 0 )
1810 ras.target.origin = target_map->buffer;
1811 else
1812 ras.target.origin = target_map->buffer
1813 + ( target_map->rows - 1 ) * (unsigned int)target_map->pitch;
1814
1815 ras.target.pitch = target_map->pitch;
1816
1817 ras.render_span = (FT_Raster_Span_Func)NULL;
1818 ras.render_span_data = NULL;
1819 }
1820
1821 /* compute clipping box */
1822 if ( params->flags & FT_RASTER_FLAG_DIRECT &&
1823 params->flags & FT_RASTER_FLAG_CLIP )
1824 clip = params->clip_box;
1825 else
1826 {
1827 /* compute clip box from target pixmap */
1828 clip.xMin = 0;
1829 clip.yMin = 0;
1830 clip.xMax = (FT_Pos)target_map->width;
1831 clip.yMax = (FT_Pos)target_map->rows;
1832 }
1833
1834 /* clip to target bitmap, exit if nothing to do */
1835 ras.min_ex = clip.xMin;
1836 ras.min_ey = clip.yMin;
1837 ras.max_ex = clip.xMax;
1838 ras.max_ey = clip.yMax;
1839
1840 if ( ras.max_ex <= ras.min_ex || ras.max_ey <= ras.min_ey )
1841 return 0;
1842
1843 return gray_convert_glyph( RAS_VAR );
1844 }
1845
1846
1847 /**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/
1848 /**** a static object. *****/
1849
1850 #ifdef STANDALONE_
1851
1852 static int
1853 gray_raster_new( void* memory,
1854 FT_Raster* araster )
1855 {
1856 static gray_TRaster the_raster;
1857
1858 FT_UNUSED( memory );
1859
1860
1861 *araster = (FT_Raster)&the_raster;
1862 FT_ZERO( &the_raster );
1863
1864 return 0;
1865 }
1866
1867
1868 static void
1869 gray_raster_done( FT_Raster raster )
1870 {
1871 /* nothing */
1872 FT_UNUSED( raster );
1873 }
1874
1875 #else /* !STANDALONE_ */
1876
1877 static int
1878 gray_raster_new( FT_Memory memory,
1879 FT_Raster* araster )
1880 {
1881 FT_Error error;
1882 gray_PRaster raster = NULL;
1883
1884
1885 *araster = 0;
1886 if ( !FT_ALLOC( raster, sizeof ( gray_TRaster ) ) )
1887 {
1888 raster->memory = memory;
1889 *araster = (FT_Raster)raster;
1890 }
1891
1892 return error;
1893 }
1894
1895
1896 static void
1897 gray_raster_done( FT_Raster raster )
1898 {
1899 FT_Memory memory = (FT_Memory)((gray_PRaster)raster)->memory;
1900
1901
1902 FT_FREE( raster );
1903 }
1904
1905 #endif /* !STANDALONE_ */
1906
1907
1908 static void
1909 gray_raster_reset( FT_Raster raster,
1910 unsigned char* pool_base,
1911 unsigned long pool_size )
1912 {
1913 FT_UNUSED( raster );
1914 FT_UNUSED( pool_base );
1915 FT_UNUSED( pool_size );
1916 }
1917
1918
1919 static int
1920 gray_raster_set_mode( FT_Raster raster,
1921 unsigned long mode,
1922 void* args )
1923 {
1924 FT_UNUSED( raster );
1925 FT_UNUSED( mode );
1926 FT_UNUSED( args );
1927
1928
1929 return 0; /* nothing to do */
1930 }
1931
1932
1933 FT_DEFINE_RASTER_FUNCS(
1934 ft_grays_raster,
1935
1936 FT_GLYPH_FORMAT_OUTLINE,
1937
1938 (FT_Raster_New_Func) gray_raster_new, /* raster_new */
1939 (FT_Raster_Reset_Func) gray_raster_reset, /* raster_reset */
1940 (FT_Raster_Set_Mode_Func)gray_raster_set_mode, /* raster_set_mode */
1941 (FT_Raster_Render_Func) gray_raster_render, /* raster_render */
1942 (FT_Raster_Done_Func) gray_raster_done /* raster_done */
1943 )
1944
1945
1946 /* END */
1947
1948
1949 /* Local Variables: */
1950 /* coding: utf-8 */
1951 /* End: */