1/***************************************************************************/
2/* */
3/* ftgrays.c */
4/* */
5/* A new `perfect' anti-aliasing renderer (body). */
6/* */
7/* Copyright 2000-2018 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 http://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 trace_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
160typedef 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#include "ftspic.h"
283
284#define Smooth_Err_Invalid_Mode Smooth_Err_Cannot_Render_Glyph
285#define Smooth_Err_Memory_Overflow Smooth_Err_Out_Of_Memory
286#define ErrRaster_Memory_Overflow Smooth_Err_Out_Of_Memory
287
288
289#endif /* !STANDALONE_ */
290
291
292#ifndef FT_MEM_SET
293#define FT_MEM_SET( d, s, c ) ft_memset( d, s, c )
294#endif
295
296#ifndef FT_MEM_ZERO
297#define FT_MEM_ZERO( dest, count ) FT_MEM_SET( dest, 0, count )
298#endif
299
300#ifndef FT_ZERO
301#define FT_ZERO( p ) FT_MEM_ZERO( p, sizeof ( *(p) ) )
302#endif
303
304 /* as usual, for the speed hungry :-) */
305
306#undef RAS_ARG
307#undef RAS_ARG_
308#undef RAS_VAR
309#undef RAS_VAR_
310
311#ifndef FT_STATIC_RASTER
312
313#define RAS_ARG gray_PWorker worker
314#define RAS_ARG_ gray_PWorker worker,
315
316#define RAS_VAR worker
317#define RAS_VAR_ worker,
318
319#else /* FT_STATIC_RASTER */
320
321#define RAS_ARG void
322#define RAS_ARG_ /* empty */
323#define RAS_VAR /* empty */
324#define RAS_VAR_ /* empty */
325
326#endif /* FT_STATIC_RASTER */
327
328
329 /* must be at least 6 bits! */
330#define PIXEL_BITS 8
331
332#undef FLOOR
333#undef CEILING
334#undef TRUNC
335#undef SCALED
336
337#define ONE_PIXEL ( 1 << PIXEL_BITS )
338#define TRUNC( x ) ( (TCoord)( (x) >> PIXEL_BITS ) )
339#define SUBPIXELS( x ) ( (TPos)(x) * ONE_PIXEL )
340#define FLOOR( x ) ( (x) & -ONE_PIXEL )
341#define CEILING( x ) ( ( (x) + ONE_PIXEL - 1 ) & -ONE_PIXEL )
342#define ROUND( x ) ( ( (x) + ONE_PIXEL / 2 ) & -ONE_PIXEL )
343
344#if PIXEL_BITS >= 6
345#define UPSCALE( x ) ( (x) * ( ONE_PIXEL >> 6 ) )
346#define DOWNSCALE( x ) ( (x) >> ( PIXEL_BITS - 6 ) )
347#else
348#define UPSCALE( x ) ( (x) >> ( 6 - PIXEL_BITS ) )
349#define DOWNSCALE( x ) ( (x) * ( 64 >> PIXEL_BITS ) )
350#endif
351
352
353 /* Compute `dividend / divisor' and return both its quotient and */
354 /* remainder, cast to a specific type. This macro also ensures that */
355 /* the remainder is always positive. We use the remainder to keep */
356 /* track of accumulating errors and compensate for them. */
357#define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \
358 FT_BEGIN_STMNT \
359 (quotient) = (type)( (dividend) / (divisor) ); \
360 (remainder) = (type)( (dividend) % (divisor) ); \
361 if ( (remainder) < 0 ) \
362 { \
363 (quotient)--; \
364 (remainder) += (type)(divisor); \
365 } \
366 FT_END_STMNT
367
368#ifdef __arm__
369 /* Work around a bug specific to GCC which make the compiler fail to */
370 /* optimize a division and modulo operation on the same parameters */
371 /* into a single call to `__aeabi_idivmod'. See */
372 /* */
373 /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43721 */
374#undef FT_DIV_MOD
375#define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \
376 FT_BEGIN_STMNT \
377 (quotient) = (type)( (dividend) / (divisor) ); \
378 (remainder) = (type)( (dividend) - (quotient) * (divisor) ); \
379 if ( (remainder) < 0 ) \
380 { \
381 (quotient)--; \
382 (remainder) += (type)(divisor); \
383 } \
384 FT_END_STMNT
385#endif /* __arm__ */
386
387
388 /* These macros speed up repetitive divisions by replacing them */
389 /* with multiplications and right shifts. */
390#define FT_UDIVPREP( c, b ) \
391 long b ## _r = c ? (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) \
392 : 0
393#define FT_UDIV( a, b ) \
394 ( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >> \
395 ( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )
396
397
398 /*************************************************************************/
399 /* */
400 /* TYPE DEFINITIONS */
401 /* */
402
403 /* don't change the following types to FT_Int or FT_Pos, since we might */
404 /* need to define them to "float" or "double" when experimenting with */
405 /* new algorithms */
406
407 typedef long TPos; /* subpixel coordinate */
408 typedef int TCoord; /* integer scanline/pixel coordinate */
409 typedef int TArea; /* cell areas, coordinate products */
410
411
412 typedef struct TCell_* PCell;
413
414 typedef struct TCell_
415 {
416 TCoord x; /* same with gray_TWorker.ex */
417 TCoord cover; /* same with gray_TWorker.cover */
418 TArea area;
419 PCell next;
420
421 } TCell;
422
423 typedef struct TPixmap_
424 {
425 unsigned char* origin; /* pixmap origin at the bottom-left */
426 int pitch; /* pitch to go down one row */
427
428 } TPixmap;
429
430 /* maximum number of gray cells in the buffer */
431#if FT_RENDER_POOL_SIZE > 2048
432#define FT_MAX_GRAY_POOL ( FT_RENDER_POOL_SIZE / sizeof ( TCell ) )
433#else
434#define FT_MAX_GRAY_POOL ( 2048 / sizeof ( TCell ) )
435#endif
436
437
438#if defined( _MSC_VER ) /* Visual C++ (and Intel C++) */
439 /* We disable the warning `structure was padded due to */
440 /* __declspec(align())' in order to compile cleanly with */
441 /* the maximum level of warnings. */
442#pragma warning( push )
443#pragma warning( disable : 4324 )
444#endif /* _MSC_VER */
445
446 typedef struct gray_TWorker_
447 {
448 ft_jmp_buf jump_buffer;
449
450 TCoord ex, ey;
451 TCoord min_ex, max_ex;
452 TCoord min_ey, max_ey;
453
454 TArea area;
455 TCoord cover;
456 int invalid;
457
458 PCell* ycells;
459 PCell cells;
460 FT_PtrDist max_cells;
461 FT_PtrDist num_cells;
462
463 TPos x, y;
464
465 FT_Outline outline;
466 TPixmap target;
467
468 FT_Raster_Span_Func render_span;
469 void* render_span_data;
470
471 } gray_TWorker, *gray_PWorker;
472
473#if defined( _MSC_VER )
474#pragma warning( pop )
475#endif
476
477
478#ifndef FT_STATIC_RASTER
479#define ras (*worker)
480#else
481 static gray_TWorker ras;
482#endif
483
484
485 typedef struct gray_TRaster_
486 {
487 void* memory;
488
489 } gray_TRaster, *gray_PRaster;
490
491
492#ifdef FT_DEBUG_LEVEL_TRACE
493
494 /* to be called while in the debugger -- */
495 /* this function causes a compiler warning since it is unused otherwise */
496 static void
497 gray_dump_cells( RAS_ARG )
498 {
499 int y;
500
501
502 for ( y = ras.min_ey; y < ras.max_ey; y++ )
503 {
504 PCell cell = ras.ycells[y - ras.min_ey];
505
506
507 printf( "%3d:", y );
508
509 for ( ; cell != NULL; cell = cell->next )
510 printf( " (%3d, c:%4d, a:%6d)",
511 cell->x, cell->cover, cell->area );
512 printf( "\n" );
513 }
514 }
515
516#endif /* FT_DEBUG_LEVEL_TRACE */
517
518
519 /*************************************************************************/
520 /* */
521 /* Record the current cell in the table. */
522 /* */
523 static void
524 gray_record_cell( RAS_ARG )
525 {
526 PCell *pcell, cell;
527 TCoord x = ras.ex;
528
529
530 pcell = &ras.ycells[ras.ey - ras.min_ey];
531 for (;;)
532 {
533 cell = *pcell;
534 if ( !cell || cell->x > x )
535 break;
536
537 if ( cell->x == x )
538 goto Found;
539
540 pcell = &cell->next;
541 }
542
543 if ( ras.num_cells >= ras.max_cells )
544 ft_longjmp( ras.jump_buffer, 1 );
545
546 /* insert new cell */
547 cell = ras.cells + ras.num_cells++;
548 cell->x = x;
549 cell->area = ras.area;
550 cell->cover = ras.cover;
551
552 cell->next = *pcell;
553 *pcell = cell;
554
555 return;
556
557 Found:
558 /* update old cell */
559 cell->area += ras.area;
560 cell->cover += ras.cover;
561 }
562
563
564 /*************************************************************************/
565 /* */
566 /* Set the current cell to a new position. */
567 /* */
568 static void
569 gray_set_cell( RAS_ARG_ TCoord ex,
570 TCoord ey )
571 {
572 /* Move the cell pointer to a new position. We set the `invalid' */
573 /* flag to indicate that the cell isn't part of those we're interested */
574 /* in during the render phase. This means that: */
575 /* */
576 /* . the new vertical position must be within min_ey..max_ey-1. */
577 /* . the new horizontal position must be strictly less than max_ex */
578 /* */
579 /* Note that if a cell is to the left of the clipping region, it is */
580 /* actually set to the (min_ex-1) horizontal position. */
581
582 if ( ex < ras.min_ex )
583 ex = ras.min_ex - 1;
584
585 /* record the current one if it is valid and substantial */
586 if ( !ras.invalid && ( ras.area || ras.cover ) )
587 gray_record_cell( RAS_VAR );
588
589 ras.area = 0;
590 ras.cover = 0;
591 ras.ex = ex;
592 ras.ey = ey;
593
594 ras.invalid = ( ey >= ras.max_ey || ey < ras.min_ey ||
595 ex >= ras.max_ex );
596 }
597
598
599#ifndef FT_LONG64
600
601 /*************************************************************************/
602 /* */
603 /* Render a scanline as one or more cells. */
604 /* */
605 static void
606 gray_render_scanline( RAS_ARG_ TCoord ey,
607 TPos x1,
608 TCoord y1,
609 TPos x2,
610 TCoord y2 )
611 {
612 TCoord ex1, ex2, fx1, fx2, first, dy, delta, mod;
613 TPos p, dx;
614 int incr;
615
616
617 ex1 = TRUNC( x1 );
618 ex2 = TRUNC( x2 );
619
620 /* trivial case. Happens often */
621 if ( y1 == y2 )
622 {
623 gray_set_cell( RAS_VAR_ ex2, ey );
624 return;
625 }
626
627 fx1 = (TCoord)( x1 - SUBPIXELS( ex1 ) );
628 fx2 = (TCoord)( x2 - SUBPIXELS( ex2 ) );
629
630 /* everything is located in a single cell. That is easy! */
631 /* */
632 if ( ex1 == ex2 )
633 goto End;
634
635 /* ok, we'll have to render a run of adjacent cells on the same */
636 /* scanline... */
637 /* */
638 dx = x2 - x1;
639 dy = y2 - y1;
640
641 if ( dx > 0 )
642 {
643 p = ( ONE_PIXEL - fx1 ) * dy;
644 first = ONE_PIXEL;
645 incr = 1;
646 }
647 else
648 {
649 p = fx1 * dy;
650 first = 0;
651 incr = -1;
652 dx = -dx;
653 }
654
655 FT_DIV_MOD( TCoord, p, dx, delta, mod );
656
657 ras.area += (TArea)( ( fx1 + first ) * delta );
658 ras.cover += delta;
659 y1 += delta;
660 ex1 += incr;
661 gray_set_cell( RAS_VAR_ ex1, ey );
662
663 if ( ex1 != ex2 )
664 {
665 TCoord lift, rem;
666
667
668 p = ONE_PIXEL * dy;
669 FT_DIV_MOD( TCoord, p, dx, lift, rem );
670
671 do
672 {
673 delta = lift;
674 mod += rem;
675 if ( mod >= (TCoord)dx )
676 {
677 mod -= (TCoord)dx;
678 delta++;
679 }
680
681 ras.area += (TArea)( ONE_PIXEL * delta );
682 ras.cover += delta;
683 y1 += delta;
684 ex1 += incr;
685 gray_set_cell( RAS_VAR_ ex1, ey );
686 } while ( ex1 != ex2 );
687 }
688
689 fx1 = ONE_PIXEL - first;
690
691 End:
692 dy = y2 - y1;
693
694 ras.area += (TArea)( ( fx1 + fx2 ) * dy );
695 ras.cover += dy;
696 }
697
698
699 /*************************************************************************/
700 /* */
701 /* Render a given line as a series of scanlines. */
702 /* */
703 static void
704 gray_render_line( RAS_ARG_ TPos to_x,
705 TPos to_y )
706 {
707 TCoord ey1, ey2, fy1, fy2, first, delta, mod;
708 TPos p, dx, dy, x, x2;
709 int incr;
710
711
712 ey1 = TRUNC( ras.y );
713 ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */
714
715 /* perform vertical clipping */
716 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
717 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
718 goto End;
719
720 fy1 = (TCoord)( ras.y - SUBPIXELS( ey1 ) );
721 fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) );
722
723 /* everything is on a single scanline */
724 if ( ey1 == ey2 )
725 {
726 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 );
727 goto End;
728 }
729
730 dx = to_x - ras.x;
731 dy = to_y - ras.y;
732
733 /* vertical line - avoid calling gray_render_scanline */
734 if ( dx == 0 )
735 {
736 TCoord ex = TRUNC( ras.x );
737 TCoord two_fx = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 );
738 TArea area;
739
740
741 if ( dy > 0)
742 {
743 first = ONE_PIXEL;
744 incr = 1;
745 }
746 else
747 {
748 first = 0;
749 incr = -1;
750 }
751
752 delta = first - fy1;
753 ras.area += (TArea)two_fx * delta;
754 ras.cover += delta;
755 ey1 += incr;
756
757 gray_set_cell( RAS_VAR_ ex, ey1 );
758
759 delta = first + first - ONE_PIXEL;
760 area = (TArea)two_fx * delta;
761 while ( ey1 != ey2 )
762 {
763 ras.area += area;
764 ras.cover += delta;
765 ey1 += incr;
766
767 gray_set_cell( RAS_VAR_ ex, ey1 );
768 }
769
770 delta = fy2 - ONE_PIXEL + first;
771 ras.area += (TArea)two_fx * delta;
772 ras.cover += delta;
773
774 goto End;
775 }
776
777 /* ok, we have to render several scanlines */
778 if ( dy > 0)
779 {
780 p = ( ONE_PIXEL - fy1 ) * dx;
781 first = ONE_PIXEL;
782 incr = 1;
783 }
784 else
785 {
786 p = fy1 * dx;
787 first = 0;
788 incr = -1;
789 dy = -dy;
790 }
791
792 FT_DIV_MOD( TCoord, p, dy, delta, mod );
793
794 x = ras.x + delta;
795 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, first );
796
797 ey1 += incr;
798 gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
799
800 if ( ey1 != ey2 )
801 {
802 TCoord lift, rem;
803
804
805 p = ONE_PIXEL * dx;
806 FT_DIV_MOD( TCoord, p, dy, lift, rem );
807
808 do
809 {
810 delta = lift;
811 mod += rem;
812 if ( mod >= (TCoord)dy )
813 {
814 mod -= (TCoord)dy;
815 delta++;
816 }
817
818 x2 = x + delta;
819 gray_render_scanline( RAS_VAR_ ey1,
820 x, ONE_PIXEL - first,
821 x2, first );
822 x = x2;
823
824 ey1 += incr;
825 gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
826 } while ( ey1 != ey2 );
827 }
828
829 gray_render_scanline( RAS_VAR_ ey1,
830 x, ONE_PIXEL - first,
831 to_x, fy2 );
832
833 End:
834 ras.x = to_x;
835 ras.y = to_y;
836 }
837
838#else
839
840 /*************************************************************************/
841 /* */
842 /* Render a straight line across multiple cells in any direction. */
843 /* */
844 static void
845 gray_render_line( RAS_ARG_ TPos to_x,
846 TPos to_y )
847 {
848 TPos dx, dy, fx1, fy1, fx2, fy2;
849 TCoord ex1, ex2, ey1, ey2;
850
851
852 ey1 = TRUNC( ras.y );
853 ey2 = TRUNC( to_y );
854
855 /* perform vertical clipping */
856 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
857 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
858 goto End;
859
860 ex1 = TRUNC( ras.x );
861 ex2 = TRUNC( to_x );
862
863 fx1 = ras.x - SUBPIXELS( ex1 );
864 fy1 = ras.y - SUBPIXELS( ey1 );
865
866 dx = to_x - ras.x;
867 dy = to_y - ras.y;
868
869 if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */
870 ;
871 else if ( dy == 0 ) /* ex1 != ex2 */ /* any horizontal line */
872 {
873 ex1 = ex2;
874 gray_set_cell( RAS_VAR_ ex1, ey1 );
875 }
876 else if ( dx == 0 )
877 {
878 if ( dy > 0 ) /* vertical line up */
879 do
880 {
881 fy2 = ONE_PIXEL;
882 ras.cover += ( fy2 - fy1 );
883 ras.area += ( fy2 - fy1 ) * fx1 * 2;
884 fy1 = 0;
885 ey1++;
886 gray_set_cell( RAS_VAR_ ex1, ey1 );
887 } while ( ey1 != ey2 );
888 else /* vertical line down */
889 do
890 {
891 fy2 = 0;
892 ras.cover += ( fy2 - fy1 );
893 ras.area += ( fy2 - fy1 ) * fx1 * 2;
894 fy1 = ONE_PIXEL;
895 ey1--;
896 gray_set_cell( RAS_VAR_ ex1, ey1 );
897 } while ( ey1 != ey2 );
898 }
899 else /* any other line */
900 {
901 TPos prod = dx * fy1 - dy * fx1;
902 FT_UDIVPREP( ex1 != ex2, dx );
903 FT_UDIVPREP( ey1 != ey2, dy );
904
905
906 /* The fundamental value `prod' determines which side and the */
907 /* exact coordinate where the line exits current cell. It is */
908 /* also easily updated when moving from one cell to the next. */
909 do
910 {
911 if ( prod <= 0 &&
912 prod - dx * ONE_PIXEL > 0 ) /* left */
913 {
914 fx2 = 0;
915 fy2 = (TPos)FT_UDIV( -prod, -dx );
916 prod -= dy * ONE_PIXEL;
917 ras.cover += ( fy2 - fy1 );
918 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
919 fx1 = ONE_PIXEL;
920 fy1 = fy2;
921 ex1--;
922 }
923 else if ( prod - dx * ONE_PIXEL <= 0 &&
924 prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 ) /* up */
925 {
926 prod -= dx * ONE_PIXEL;
927 fx2 = (TPos)FT_UDIV( -prod, dy );
928 fy2 = ONE_PIXEL;
929 ras.cover += ( fy2 - fy1 );
930 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
931 fx1 = fx2;
932 fy1 = 0;
933 ey1++;
934 }
935 else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 &&
936 prod + dy * ONE_PIXEL >= 0 ) /* right */
937 {
938 prod += dy * ONE_PIXEL;
939 fx2 = ONE_PIXEL;
940 fy2 = (TPos)FT_UDIV( prod, dx );
941 ras.cover += ( fy2 - fy1 );
942 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
943 fx1 = 0;
944 fy1 = fy2;
945 ex1++;
946 }
947 else /* ( prod + dy * ONE_PIXEL < 0 &&
948 prod > 0 ) down */
949 {
950 fx2 = (TPos)FT_UDIV( prod, -dy );
951 fy2 = 0;
952 prod += dx * ONE_PIXEL;
953 ras.cover += ( fy2 - fy1 );
954 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
955 fx1 = fx2;
956 fy1 = ONE_PIXEL;
957 ey1--;
958 }
959
960 gray_set_cell( RAS_VAR_ ex1, ey1 );
961 } while ( ex1 != ex2 || ey1 != ey2 );
962 }
963
964 fx2 = to_x - SUBPIXELS( ex2 );
965 fy2 = to_y - SUBPIXELS( ey2 );
966
967 ras.cover += ( fy2 - fy1 );
968 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
969
970 End:
971 ras.x = to_x;
972 ras.y = to_y;
973 }
974
975#endif
976
977 static void
978 gray_split_conic( FT_Vector* base )
979 {
980 TPos a, b;
981
982
983 base[4].x = base[2].x;
984 b = base[1].x;
985 a = base[3].x = ( base[2].x + b ) / 2;
986 b = base[1].x = ( base[0].x + b ) / 2;
987 base[2].x = ( a + b ) / 2;
988
989 base[4].y = base[2].y;
990 b = base[1].y;
991 a = base[3].y = ( base[2].y + b ) / 2;
992 b = base[1].y = ( base[0].y + b ) / 2;
993 base[2].y = ( a + b ) / 2;
994 }
995
996
997 static void
998 gray_render_conic( RAS_ARG_ const FT_Vector* control,
999 const FT_Vector* to )
1000 {
1001 FT_Vector bez_stack[16 * 2 + 1]; /* enough to accommodate bisections */
1002 FT_Vector* arc = bez_stack;
1003 TPos dx, dy;
1004 int draw, split;
1005
1006
1007 arc[0].x = UPSCALE( to->x );
1008 arc[0].y = UPSCALE( to->y );
1009 arc[1].x = UPSCALE( control->x );
1010 arc[1].y = UPSCALE( control->y );
1011 arc[2].x = ras.x;
1012 arc[2].y = ras.y;
1013
1014 /* short-cut the arc that crosses the current band */
1015 if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
1016 TRUNC( arc[1].y ) >= ras.max_ey &&
1017 TRUNC( arc[2].y ) >= ras.max_ey ) ||
1018 ( TRUNC( arc[0].y ) < ras.min_ey &&
1019 TRUNC( arc[1].y ) < ras.min_ey &&
1020 TRUNC( arc[2].y ) < ras.min_ey ) )
1021 {
1022 ras.x = arc[0].x;
1023 ras.y = arc[0].y;
1024 return;
1025 }
1026
1027 dx = FT_ABS( arc[2].x + arc[0].x - 2 * arc[1].x );
1028 dy = FT_ABS( arc[2].y + arc[0].y - 2 * arc[1].y );
1029 if ( dx < dy )
1030 dx = dy;
1031
1032 /* We can calculate the number of necessary bisections because */
1033 /* each bisection predictably reduces deviation exactly 4-fold. */
1034 /* Even 32-bit deviation would vanish after 16 bisections. */
1035 draw = 1;
1036 while ( dx > ONE_PIXEL / 4 )
1037 {
1038 dx >>= 2;
1039 draw <<= 1;
1040 }
1041
1042 /* We use decrement counter to count the total number of segments */
1043 /* to draw starting from 2^level. Before each draw we split as */
1044 /* many times as there are trailing zeros in the counter. */
1045 do
1046 {
1047 split = 1;
1048 while ( ( draw & split ) == 0 )
1049 {
1050 gray_split_conic( arc );
1051 arc += 2;
1052 split <<= 1;
1053 }
1054
1055 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1056 arc -= 2;
1057
1058 } while ( --draw );
1059 }
1060
1061
1062 static void
1063 gray_split_cubic( FT_Vector* base )
1064 {
1065 TPos a, b, c, d;
1066
1067
1068 base[6].x = base[3].x;
1069 c = base[1].x;
1070 d = base[2].x;
1071 base[1].x = a = ( base[0].x + c ) / 2;
1072 base[5].x = b = ( base[3].x + d ) / 2;
1073 c = ( c + d ) / 2;
1074 base[2].x = a = ( a + c ) / 2;
1075 base[4].x = b = ( b + c ) / 2;
1076 base[3].x = ( a + b ) / 2;
1077
1078 base[6].y = base[3].y;
1079 c = base[1].y;
1080 d = base[2].y;
1081 base[1].y = a = ( base[0].y + c ) / 2;
1082 base[5].y = b = ( base[3].y + d ) / 2;
1083 c = ( c + d ) / 2;
1084 base[2].y = a = ( a + c ) / 2;
1085 base[4].y = b = ( b + c ) / 2;
1086 base[3].y = ( a + b ) / 2;
1087 }
1088
1089
1090 static void
1091 gray_render_cubic( RAS_ARG_ const FT_Vector* control1,
1092 const FT_Vector* control2,
1093 const FT_Vector* to )
1094 {
1095 FT_Vector bez_stack[16 * 3 + 1]; /* enough to accommodate bisections */
1096 FT_Vector* arc = bez_stack;
1097 TPos dx, dy, dx_, dy_;
1098 TPos dx1, dy1, dx2, dy2;
1099 TPos L, s, s_limit;
1100
1101
1102 arc[0].x = UPSCALE( to->x );
1103 arc[0].y = UPSCALE( to->y );
1104 arc[1].x = UPSCALE( control2->x );
1105 arc[1].y = UPSCALE( control2->y );
1106 arc[2].x = UPSCALE( control1->x );
1107 arc[2].y = UPSCALE( control1->y );
1108 arc[3].x = ras.x;
1109 arc[3].y = ras.y;
1110
1111 /* short-cut the arc that crosses the current band */
1112 if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
1113 TRUNC( arc[1].y ) >= ras.max_ey &&
1114 TRUNC( arc[2].y ) >= ras.max_ey &&
1115 TRUNC( arc[3].y ) >= ras.max_ey ) ||
1116 ( TRUNC( arc[0].y ) < ras.min_ey &&
1117 TRUNC( arc[1].y ) < ras.min_ey &&
1118 TRUNC( arc[2].y ) < ras.min_ey &&
1119 TRUNC( arc[3].y ) < ras.min_ey ) )
1120 {
1121 ras.x = arc[0].x;
1122 ras.y = arc[0].y;
1123 return;
1124 }
1125
1126 for (;;)
1127 {
1128 /* Decide whether to split or draw. See `Rapid Termination */
1129 /* Evaluation for Recursive Subdivision of Bezier Curves' by Thomas */
1130 /* F. Hain, at */
1131 /* http://www.cis.southalabama.edu/~hain/general/Publications/Bezier/Camera-ready%20CISST02%202.pdf */
1132
1133 /* dx and dy are x and y components of the P0-P3 chord vector. */
1134 dx = dx_ = arc[3].x - arc[0].x;
1135 dy = dy_ = arc[3].y - arc[0].y;
1136
1137 L = FT_HYPOT( dx_, dy_ );
1138
1139 /* Avoid possible arithmetic overflow below by splitting. */
1140 if ( L > 32767 )
1141 goto Split;
1142
1143 /* Max deviation may be as much as (s/L) * 3/4 (if Hain's v = 1). */
1144 s_limit = L * (TPos)( ONE_PIXEL / 6 );
1145
1146 /* s is L * the perpendicular distance from P1 to the line P0-P3. */
1147 dx1 = arc[1].x - arc[0].x;
1148 dy1 = arc[1].y - arc[0].y;
1149 s = FT_ABS( SUB_LONG( MUL_LONG( dy, dx1 ), MUL_LONG( dx, dy1 ) ) );
1150
1151 if ( s > s_limit )
1152 goto Split;
1153
1154 /* s is L * the perpendicular distance from P2 to the line P0-P3. */
1155 dx2 = arc[2].x - arc[0].x;
1156 dy2 = arc[2].y - arc[0].y;
1157 s = FT_ABS( SUB_LONG( MUL_LONG( dy, dx2 ), MUL_LONG( dx, dy2 ) ) );
1158
1159 if ( s > s_limit )
1160 goto Split;
1161
1162 /* Split super curvy segments where the off points are so far
1163 from the chord that the angles P0-P1-P3 or P0-P2-P3 become
1164 acute as detected by appropriate dot products. */
1165 if ( dx1 * ( dx1 - dx ) + dy1 * ( dy1 - dy ) > 0 ||
1166 dx2 * ( dx2 - dx ) + dy2 * ( dy2 - dy ) > 0 )
1167 goto Split;
1168
1169 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1170
1171 if ( arc == bez_stack )
1172 return;
1173
1174 arc -= 3;
1175 continue;
1176
1177 Split:
1178 gray_split_cubic( arc );
1179 arc += 3;
1180 }
1181 }
1182
1183
1184 static int
1185 gray_move_to( const FT_Vector* to,
1186 gray_PWorker worker )
1187 {
1188 TPos x, y;
1189
1190
1191 /* start to a new position */
1192 x = UPSCALE( to->x );
1193 y = UPSCALE( to->y );
1194
1195 gray_set_cell( RAS_VAR_ TRUNC( x ), TRUNC( y ) );
1196
1197 ras.x = x;
1198 ras.y = y;
1199 return 0;
1200 }
1201
1202
1203 static int
1204 gray_line_to( const FT_Vector* to,
1205 gray_PWorker worker )
1206 {
1207 gray_render_line( RAS_VAR_ UPSCALE( to->x ), UPSCALE( to->y ) );
1208 return 0;
1209 }
1210
1211
1212 static int
1213 gray_conic_to( const FT_Vector* control,
1214 const FT_Vector* to,
1215 gray_PWorker worker )
1216 {
1217 gray_render_conic( RAS_VAR_ control, to );
1218 return 0;
1219 }
1220
1221
1222 static int
1223 gray_cubic_to( const FT_Vector* control1,
1224 const FT_Vector* control2,
1225 const FT_Vector* to,
1226 gray_PWorker worker )
1227 {
1228 gray_render_cubic( RAS_VAR_ control1, control2, to );
1229 return 0;
1230 }
1231
1232
1233 static void
1234 gray_hline( RAS_ARG_ TCoord x,
1235 TCoord y,
1236 TArea coverage,
1237 TCoord acount )
1238 {
1239 /* scale the coverage from 0..(ONE_PIXEL*ONE_PIXEL*2) to 0..256 */
1240 coverage >>= PIXEL_BITS * 2 + 1 - 8;
1241 if ( coverage < 0 )
1242 coverage = -coverage - 1;
1243
1244 /* compute the line's coverage depending on the outline fill rule */
1245 if ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL )
1246 {
1247 coverage &= 511;
1248
1249 if ( coverage >= 256 )
1250 coverage = 511 - coverage;
1251 }
1252 else
1253 {
1254 /* normal non-zero winding rule */
1255 if ( coverage >= 256 )
1256 coverage = 255;
1257 }
1258
1259 if ( ras.render_span ) /* for FT_RASTER_FLAG_DIRECT only */
1260 {
1261 FT_Span span;
1262
1263
1264 span.x = (short)x;
1265 span.len = (unsigned short)acount;
1266 span.coverage = (unsigned char)coverage;
1267
1268 ras.render_span( y, 1, &span, ras.render_span_data );
1269 }
1270 else
1271 {
1272 unsigned char* q = ras.target.origin - ras.target.pitch * y + x;
1273 unsigned char c = (unsigned char)coverage;
1274
1275
1276 /* For small-spans it is faster to do it by ourselves than
1277 * calling `memset'. This is mainly due to the cost of the
1278 * function call.
1279 */
1280 switch ( acount )
1281 {
1282 case 7: *q++ = c;
1283 case 6: *q++ = c;
1284 case 5: *q++ = c;
1285 case 4: *q++ = c;
1286 case 3: *q++ = c;
1287 case 2: *q++ = c;
1288 case 1: *q = c;
1289 case 0: break;
1290 default:
1291 FT_MEM_SET( q, c, acount );
1292 }
1293 }
1294 }
1295
1296
1297 static void
1298 gray_sweep( RAS_ARG )
1299 {
1300 int y;
1301
1302
1303 for ( y = ras.min_ey; y < ras.max_ey; y++ )
1304 {
1305 PCell cell = ras.ycells[y - ras.min_ey];
1306 TCoord x = ras.min_ex;
1307 TArea cover = 0;
1308 TArea area;
1309
1310
1311 for ( ; cell != NULL; cell = cell->next )
1312 {
1313 if ( cover != 0 && cell->x > x )
1314 gray_hline( RAS_VAR_ x, y, cover, cell->x - x );
1315
1316 cover += (TArea)cell->cover * ( ONE_PIXEL * 2 );
1317 area = cover - cell->area;
1318
1319 if ( area != 0 && cell->x >= ras.min_ex )
1320 gray_hline( RAS_VAR_ cell->x, y, area, 1 );
1321
1322 x = cell->x + 1;
1323 }
1324
1325 if ( cover != 0 )
1326 gray_hline( RAS_VAR_ x, y, cover, ras.max_ex - x );
1327 }
1328 }
1329
1330
1331#ifdef STANDALONE_
1332
1333 /*************************************************************************/
1334 /* */
1335 /* The following functions should only compile in stand-alone mode, */
1336 /* i.e., when building this component without the rest of FreeType. */
1337 /* */
1338 /*************************************************************************/
1339
1340 /*************************************************************************/
1341 /* */
1342 /* <Function> */
1343 /* FT_Outline_Decompose */
1344 /* */
1345 /* <Description> */
1346 /* Walk over an outline's structure to decompose it into individual */
1347 /* segments and Bézier arcs. This function is also able to emit */
1348 /* `move to' and `close to' operations to indicate the start and end */
1349 /* of new contours in the outline. */
1350 /* */
1351 /* <Input> */
1352 /* outline :: A pointer to the source target. */
1353 /* */
1354 /* func_interface :: A table of `emitters', i.e., function pointers */
1355 /* called during decomposition to indicate path */
1356 /* operations. */
1357 /* */
1358 /* <InOut> */
1359 /* user :: A typeless pointer which is passed to each */
1360 /* emitter during the decomposition. It can be */
1361 /* used to store the state during the */
1362 /* decomposition. */
1363 /* */
1364 /* <Return> */
1365 /* Error code. 0 means success. */
1366 /* */
1367 static int
1368 FT_Outline_Decompose( const FT_Outline* outline,
1369 const FT_Outline_Funcs* func_interface,
1370 void* user )
1371 {
1372#undef SCALED
1373#define SCALED( x ) ( ( (x) << shift ) - delta )
1374
1375 FT_Vector v_last;
1376 FT_Vector v_control;
1377 FT_Vector v_start;
1378
1379 FT_Vector* point;
1380 FT_Vector* limit;
1381 char* tags;
1382
1383 int error;
1384
1385 int n; /* index of contour in outline */
1386 int first; /* index of first point in contour */
1387 char tag; /* current point's state */
1388
1389 int shift;
1390 TPos delta;
1391
1392
1393 if ( !outline )
1394 return FT_THROW( Invalid_Outline );
1395
1396 if ( !func_interface )
1397 return FT_THROW( Invalid_Argument );
1398
1399 shift = func_interface->shift;
1400 delta = func_interface->delta;
1401 first = 0;
1402
1403 for ( n = 0; n < outline->n_contours; n++ )
1404 {
1405 int last; /* index of last point in contour */
1406
1407
1408 FT_TRACE5(( "FT_Outline_Decompose: Outline %d\n", n ));
1409
1410 last = outline->contours[n];
1411 if ( last < 0 )
1412 goto Invalid_Outline;
1413 limit = outline->points + last;
1414
1415 v_start = outline->points[first];
1416 v_start.x = SCALED( v_start.x );
1417 v_start.y = SCALED( v_start.y );
1418
1419 v_last = outline->points[last];
1420 v_last.x = SCALED( v_last.x );
1421 v_last.y = SCALED( v_last.y );
1422
1423 v_control = v_start;
1424
1425 point = outline->points + first;
1426 tags = outline->tags + first;
1427 tag = FT_CURVE_TAG( tags[0] );
1428
1429 /* A contour cannot start with a cubic control point! */
1430 if ( tag == FT_CURVE_TAG_CUBIC )
1431 goto Invalid_Outline;
1432
1433 /* check first point to determine origin */
1434 if ( tag == FT_CURVE_TAG_CONIC )
1435 {
1436 /* first point is conic control. Yes, this happens. */
1437 if ( FT_CURVE_TAG( outline->tags[last] ) == FT_CURVE_TAG_ON )
1438 {
1439 /* start at last point if it is on the curve */
1440 v_start = v_last;
1441 limit--;
1442 }
1443 else
1444 {
1445 /* if both first and last points are conic, */
1446 /* start at their middle and record its position */
1447 /* for closure */
1448 v_start.x = ( v_start.x + v_last.x ) / 2;
1449 v_start.y = ( v_start.y + v_last.y ) / 2;
1450
1451 v_last = v_start;
1452 }
1453 point--;
1454 tags--;
1455 }
1456
1457 FT_TRACE5(( " move to (%.2f, %.2f)\n",
1458 v_start.x / 64.0, v_start.y / 64.0 ));
1459 error = func_interface->move_to( &v_start, user );
1460 if ( error )
1461 goto Exit;
1462
1463 while ( point < limit )
1464 {
1465 point++;
1466 tags++;
1467
1468 tag = FT_CURVE_TAG( tags[0] );
1469 switch ( tag )
1470 {
1471 case FT_CURVE_TAG_ON: /* emit a single line_to */
1472 {
1473 FT_Vector vec;
1474
1475
1476 vec.x = SCALED( point->x );
1477 vec.y = SCALED( point->y );
1478
1479 FT_TRACE5(( " line to (%.2f, %.2f)\n",
1480 vec.x / 64.0, vec.y / 64.0 ));
1481 error = func_interface->line_to( &vec, user );
1482 if ( error )
1483 goto Exit;
1484 continue;
1485 }
1486
1487 case FT_CURVE_TAG_CONIC: /* consume conic arcs */
1488 v_control.x = SCALED( point->x );
1489 v_control.y = SCALED( point->y );
1490
1491 Do_Conic:
1492 if ( point < limit )
1493 {
1494 FT_Vector vec;
1495 FT_Vector v_middle;
1496
1497
1498 point++;
1499 tags++;
1500 tag = FT_CURVE_TAG( tags[0] );
1501
1502 vec.x = SCALED( point->x );
1503 vec.y = SCALED( point->y );
1504
1505 if ( tag == FT_CURVE_TAG_ON )
1506 {
1507 FT_TRACE5(( " conic to (%.2f, %.2f)"
1508 " with control (%.2f, %.2f)\n",
1509 vec.x / 64.0, vec.y / 64.0,
1510 v_control.x / 64.0, v_control.y / 64.0 ));
1511 error = func_interface->conic_to( &v_control, &vec, user );
1512 if ( error )
1513 goto Exit;
1514 continue;
1515 }
1516
1517 if ( tag != FT_CURVE_TAG_CONIC )
1518 goto Invalid_Outline;
1519
1520 v_middle.x = ( v_control.x + vec.x ) / 2;
1521 v_middle.y = ( v_control.y + vec.y ) / 2;
1522
1523 FT_TRACE5(( " conic to (%.2f, %.2f)"
1524 " with control (%.2f, %.2f)\n",
1525 v_middle.x / 64.0, v_middle.y / 64.0,
1526 v_control.x / 64.0, v_control.y / 64.0 ));
1527 error = func_interface->conic_to( &v_control, &v_middle, user );
1528 if ( error )
1529 goto Exit;
1530
1531 v_control = vec;
1532 goto Do_Conic;
1533 }
1534
1535 FT_TRACE5(( " conic to (%.2f, %.2f)"
1536 " with control (%.2f, %.2f)\n",
1537 v_start.x / 64.0, v_start.y / 64.0,
1538 v_control.x / 64.0, v_control.y / 64.0 ));
1539 error = func_interface->conic_to( &v_control, &v_start, user );
1540 goto Close;
1541
1542 default: /* FT_CURVE_TAG_CUBIC */
1543 {
1544 FT_Vector vec1, vec2;
1545
1546
1547 if ( point + 1 > limit ||
1548 FT_CURVE_TAG( tags[1] ) != FT_CURVE_TAG_CUBIC )
1549 goto Invalid_Outline;
1550
1551 point += 2;
1552 tags += 2;
1553
1554 vec1.x = SCALED( point[-2].x );
1555 vec1.y = SCALED( point[-2].y );
1556
1557 vec2.x = SCALED( point[-1].x );
1558 vec2.y = SCALED( point[-1].y );
1559
1560 if ( point <= limit )
1561 {
1562 FT_Vector vec;
1563
1564
1565 vec.x = SCALED( point->x );
1566 vec.y = SCALED( point->y );
1567
1568 FT_TRACE5(( " cubic to (%.2f, %.2f)"
1569 " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
1570 vec.x / 64.0, vec.y / 64.0,
1571 vec1.x / 64.0, vec1.y / 64.0,
1572 vec2.x / 64.0, vec2.y / 64.0 ));
1573 error = func_interface->cubic_to( &vec1, &vec2, &vec, user );
1574 if ( error )
1575 goto Exit;
1576 continue;
1577 }
1578
1579 FT_TRACE5(( " cubic to (%.2f, %.2f)"
1580 " with controls (%.2f, %.2f) and (%.2f, %.2f)\n",
1581 v_start.x / 64.0, v_start.y / 64.0,
1582 vec1.x / 64.0, vec1.y / 64.0,
1583 vec2.x / 64.0, vec2.y / 64.0 ));
1584 error = func_interface->cubic_to( &vec1, &vec2, &v_start, user );
1585 goto Close;
1586 }
1587 }
1588 }
1589
1590 /* close the contour with a line segment */
1591 FT_TRACE5(( " line to (%.2f, %.2f)\n",
1592 v_start.x / 64.0, v_start.y / 64.0 ));
1593 error = func_interface->line_to( &v_start, user );
1594
1595 Close:
1596 if ( error )
1597 goto Exit;
1598
1599 first = last + 1;
1600 }
1601
1602 FT_TRACE5(( "FT_Outline_Decompose: Done\n", n ));
1603 return 0;
1604
1605 Exit:
1606 FT_TRACE5(( "FT_Outline_Decompose: Error 0x%x\n", error ));
1607 return error;
1608
1609 Invalid_Outline:
1610 return FT_THROW( Invalid_Outline );
1611 }
1612
1613
1614 /*************************************************************************/
1615 /* */
1616 /* <Function> */
1617 /* FT_Outline_Get_CBox */
1618 /* */
1619 /* <Description> */
1620 /* Return an outline's `control box'. The control box encloses all */
1621 /* the outline's points, including Bézier control points. Though it */
1622 /* coincides with the exact bounding box for most glyphs, it can be */
1623 /* slightly larger in some situations (like when rotating an outline */
1624 /* that contains Bézier outside arcs). */
1625 /* */
1626 /* Computing the control box is very fast, while getting the bounding */
1627 /* box can take much more time as it needs to walk over all segments */
1628 /* and arcs in the outline. To get the latter, you can use the */
1629 /* `ftbbox' component, which is dedicated to this single task. */
1630 /* */
1631 /* <Input> */
1632 /* outline :: A pointer to the source outline descriptor. */
1633 /* */
1634 /* <Output> */
1635 /* acbox :: The outline's control box. */
1636 /* */
1637 /* <Note> */
1638 /* See @FT_Glyph_Get_CBox for a discussion of tricky fonts. */
1639 /* */
1640
1641 static void
1642 FT_Outline_Get_CBox( const FT_Outline* outline,
1643 FT_BBox *acbox )
1644 {
1645 TPos xMin, yMin, xMax, yMax;
1646
1647
1648 if ( outline && acbox )
1649 {
1650 if ( outline->n_points == 0 )
1651 {
1652 xMin = 0;
1653 yMin = 0;
1654 xMax = 0;
1655 yMax = 0;
1656 }
1657 else
1658 {
1659 FT_Vector* vec = outline->points;
1660 FT_Vector* limit = vec + outline->n_points;
1661
1662
1663 xMin = xMax = vec->x;
1664 yMin = yMax = vec->y;
1665 vec++;
1666
1667 for ( ; vec < limit; vec++ )
1668 {
1669 TPos x, y;
1670
1671
1672 x = vec->x;
1673 if ( x < xMin ) xMin = x;
1674 if ( x > xMax ) xMax = x;
1675
1676 y = vec->y;
1677 if ( y < yMin ) yMin = y;
1678 if ( y > yMax ) yMax = y;
1679 }
1680 }
1681 acbox->xMin = xMin;
1682 acbox->xMax = xMax;
1683 acbox->yMin = yMin;
1684 acbox->yMax = yMax;
1685 }
1686 }
1687
1688#endif /* STANDALONE_ */
1689
1690
1691 FT_DEFINE_OUTLINE_FUNCS(
1692 func_interface,
1693
1694 (FT_Outline_MoveTo_Func) gray_move_to, /* move_to */
1695 (FT_Outline_LineTo_Func) gray_line_to, /* line_to */
1696 (FT_Outline_ConicTo_Func)gray_conic_to, /* conic_to */
1697 (FT_Outline_CubicTo_Func)gray_cubic_to, /* cubic_to */
1698
1699 0, /* shift */
1700 0 /* delta */
1701 )
1702
1703
1704 static int
1705 gray_convert_glyph_inner( RAS_ARG )
1706 {
1707
1708 volatile int error = 0;
1709
1710#ifdef FT_CONFIG_OPTION_PIC
1711 FT_Outline_Funcs func_interface;
1712 Init_Class_func_interface(&func_interface);
1713#endif
1714
1715 if ( ft_setjmp( ras.jump_buffer ) == 0 )
1716 {
1717 error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras );
1718 if ( !ras.invalid )
1719 gray_record_cell( RAS_VAR );
1720
1721 FT_TRACE7(( "band [%d..%d]: %d cell%s\n",
1722 ras.min_ey,
1723 ras.max_ey,
1724 ras.num_cells,
1725 ras.num_cells == 1 ? "" : "s" ));
1726 }
1727 else
1728 {
1729 error = FT_THROW( Memory_Overflow );
1730
1731 FT_TRACE7(( "band [%d..%d]: to be bisected\n",
1732 ras.min_ey, ras.max_ey ));
1733 }
1734
1735 return error;
1736 }
1737
1738
1739 static int
1740 gray_convert_glyph( RAS_ARG )
1741 {
1742 const TCoord yMin = ras.min_ey;
1743 const TCoord yMax = ras.max_ey;
1744 const TCoord xMin = ras.min_ex;
1745 const TCoord xMax = ras.max_ex;
1746
1747 TCell buffer[FT_MAX_GRAY_POOL];
1748 size_t height = (size_t)( yMax - yMin );
1749 size_t n = FT_MAX_GRAY_POOL / 8;
1750 TCoord y;
1751 TCoord bands[32]; /* enough to accommodate bisections */
1752 TCoord* band;
1753
1754
1755 /* set up vertical bands */
1756 if ( height > n )
1757 {
1758 /* two divisions rounded up */
1759 n = ( height + n - 1 ) / n;
1760 height = ( height + n - 1 ) / n;
1761 }
1762
1763 /* memory management */
1764 n = ( height * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) / sizeof ( TCell );
1765
1766 ras.cells = buffer + n;
1767 ras.max_cells = (FT_PtrDist)( FT_MAX_GRAY_POOL - n );
1768 ras.ycells = (PCell*)buffer;
1769
1770 for ( y = yMin; y < yMax; )
1771 {
1772 ras.min_ey = y;
1773 y += height;
1774 ras.max_ey = FT_MIN( y, yMax );
1775
1776 band = bands;
1777 band[1] = xMin;
1778 band[0] = xMax;
1779
1780 do
1781 {
1782 TCoord width = band[0] - band[1];
1783 int error;
1784
1785
1786 FT_MEM_ZERO( ras.ycells, height * sizeof ( PCell ) );
1787
1788 ras.num_cells = 0;
1789 ras.invalid = 1;
1790 ras.min_ex = band[1];
1791 ras.max_ex = band[0];
1792
1793 error = gray_convert_glyph_inner( RAS_VAR );
1794
1795 if ( !error )
1796 {
1797 gray_sweep( RAS_VAR );
1798 band--;
1799 continue;
1800 }
1801 else if ( error != ErrRaster_Memory_Overflow )
1802 return 1;
1803
1804 /* render pool overflow; we will reduce the render band by half */
1805 width >>= 1;
1806
1807 /* this should never happen even with tiny rendering pool */
1808 if ( width == 0 )
1809 {
1810 FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" ));
1811 return 1;
1812 }
1813
1814 band++;
1815 band[1] = band[0];
1816 band[0] += width;
1817 } while ( band >= bands );
1818 }
1819
1820 return 0;
1821 }
1822
1823
1824 static int
1825 gray_raster_render( FT_Raster raster,
1826 const FT_Raster_Params* params )
1827 {
1828 const FT_Outline* outline = (const FT_Outline*)params->source;
1829 const FT_Bitmap* target_map = params->target;
1830 FT_BBox cbox, clip;
1831
1832#ifndef FT_STATIC_RASTER
1833 gray_TWorker worker[1];
1834#endif
1835
1836
1837 if ( !raster )
1838 return FT_THROW( Invalid_Argument );
1839
1840 /* this version does not support monochrome rendering */
1841 if ( !( params->flags & FT_RASTER_FLAG_AA ) )
1842 return FT_THROW( Invalid_Mode );
1843
1844 if ( !outline )
1845 return FT_THROW( Invalid_Outline );
1846
1847 /* return immediately if the outline is empty */
1848 if ( outline->n_points == 0 || outline->n_contours <= 0 )
1849 return 0;
1850
1851 if ( !outline->contours || !outline->points )
1852 return FT_THROW( Invalid_Outline );
1853
1854 if ( outline->n_points !=
1855 outline->contours[outline->n_contours - 1] + 1 )
1856 return FT_THROW( Invalid_Outline );
1857
1858 ras.outline = *outline;
1859
1860 if ( params->flags & FT_RASTER_FLAG_DIRECT )
1861 {
1862 if ( !params->gray_spans )
1863 return 0;
1864
1865 ras.render_span = (FT_Raster_Span_Func)params->gray_spans;
1866 ras.render_span_data = params->user;
1867 }
1868 else
1869 {
1870 /* if direct mode is not set, we must have a target bitmap */
1871 if ( !target_map )
1872 return FT_THROW( Invalid_Argument );
1873
1874 /* nothing to do */
1875 if ( !target_map->width || !target_map->rows )
1876 return 0;
1877
1878 if ( !target_map->buffer )
1879 return FT_THROW( Invalid_Argument );
1880
1881 if ( target_map->pitch < 0 )
1882 ras.target.origin = target_map->buffer;
1883 else
1884 ras.target.origin = target_map->buffer
1885 + ( target_map->rows - 1 ) * (unsigned int)target_map->pitch;
1886
1887 ras.target.pitch = target_map->pitch;
1888
1889 ras.render_span = (FT_Raster_Span_Func)NULL;
1890 ras.render_span_data = NULL;
1891 }
1892
1893 FT_Outline_Get_CBox( outline, &cbox );
1894
1895 /* reject too large outline coordinates */
1896 if ( cbox.xMin < -0x1000000L || cbox.xMax > 0x1000000L ||
1897 cbox.yMin < -0x1000000L || cbox.yMax > 0x1000000L )
1898 return FT_THROW( Invalid_Outline );
1899
1900 /* truncate the bounding box to integer pixels */
1901 cbox.xMin = cbox.xMin >> 6;
1902 cbox.yMin = cbox.yMin >> 6;
1903 cbox.xMax = ( cbox.xMax + 63 ) >> 6;
1904 cbox.yMax = ( cbox.yMax + 63 ) >> 6;
1905
1906 /* compute clipping box */
1907 if ( !( params->flags & FT_RASTER_FLAG_DIRECT ) )
1908 {
1909 /* compute clip box from target pixmap */
1910 clip.xMin = 0;
1911 clip.yMin = 0;
1912 clip.xMax = (FT_Pos)target_map->width;
1913 clip.yMax = (FT_Pos)target_map->rows;
1914 }
1915 else if ( params->flags & FT_RASTER_FLAG_CLIP )
1916 clip = params->clip_box;
1917 else
1918 {
1919 clip.xMin = -32768L;
1920 clip.yMin = -32768L;
1921 clip.xMax = 32767L;
1922 clip.yMax = 32767L;
1923 }
1924
1925 /* clip to target bitmap, exit if nothing to do */
1926 ras.min_ex = FT_MAX( cbox.xMin, clip.xMin );
1927 ras.min_ey = FT_MAX( cbox.yMin, clip.yMin );
1928 ras.max_ex = FT_MIN( cbox.xMax, clip.xMax );
1929 ras.max_ey = FT_MIN( cbox.yMax, clip.yMax );
1930
1931 if ( ras.max_ex <= ras.min_ex || ras.max_ey <= ras.min_ey )
1932 return 0;
1933
1934 return gray_convert_glyph( RAS_VAR );
1935 }
1936
1937
1938 /**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/
1939 /**** a static object. *****/
1940
1941#ifdef STANDALONE_
1942
1943 static int
1944 gray_raster_new( void* memory,
1945 FT_Raster* araster )
1946 {
1947 static gray_TRaster the_raster;
1948
1949 FT_UNUSED( memory );
1950
1951
1952 *araster = (FT_Raster)&the_raster;
1953 FT_ZERO( &the_raster );
1954
1955 return 0;
1956 }
1957
1958
1959 static void
1960 gray_raster_done( FT_Raster raster )
1961 {
1962 /* nothing */
1963 FT_UNUSED( raster );
1964 }
1965
1966#else /* !STANDALONE_ */
1967
1968 static int
1969 gray_raster_new( FT_Memory memory,
1970 FT_Raster* araster )
1971 {
1972 FT_Error error;
1973 gray_PRaster raster = NULL;
1974
1975
1976 *araster = 0;
1977 if ( !FT_ALLOC( raster, sizeof ( gray_TRaster ) ) )
1978 {
1979 raster->memory = memory;
1980 *araster = (FT_Raster)raster;
1981 }
1982
1983 return error;
1984 }
1985
1986
1987 static void
1988 gray_raster_done( FT_Raster raster )
1989 {
1990 FT_Memory memory = (FT_Memory)((gray_PRaster)raster)->memory;
1991
1992
1993 FT_FREE( raster );
1994 }
1995
1996#endif /* !STANDALONE_ */
1997
1998
1999 static void
2000 gray_raster_reset( FT_Raster raster,
2001 unsigned char* pool_base,
2002 unsigned long pool_size )
2003 {
2004 FT_UNUSED( raster );
2005 FT_UNUSED( pool_base );
2006 FT_UNUSED( pool_size );
2007 }
2008
2009
2010 static int
2011 gray_raster_set_mode( FT_Raster raster,
2012 unsigned long mode,
2013 void* args )
2014 {
2015 FT_UNUSED( raster );
2016 FT_UNUSED( mode );
2017 FT_UNUSED( args );
2018
2019
2020 return 0; /* nothing to do */
2021 }
2022
2023
2024 FT_DEFINE_RASTER_FUNCS(
2025 ft_grays_raster,
2026
2027 FT_GLYPH_FORMAT_OUTLINE,
2028
2029 (FT_Raster_New_Func) gray_raster_new, /* raster_new */
2030 (FT_Raster_Reset_Func) gray_raster_reset, /* raster_reset */
2031 (FT_Raster_Set_Mode_Func)gray_raster_set_mode, /* raster_set_mode */
2032 (FT_Raster_Render_Func) gray_raster_render, /* raster_render */
2033 (FT_Raster_Done_Func) gray_raster_done /* raster_done */
2034 )
2035
2036
2037/* END */
2038
2039
2040/* Local Variables: */
2041/* coding: utf-8 */
2042/* End: */
2043