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. */
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 { \
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_
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;
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
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;
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 );
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;
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
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 )
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
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 )
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
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
|
28 * same directory
29 *
30 * - compile `ftgrays' with the STANDALONE_ macro defined, as in
31 *
32 * cc -c -DSTANDALONE_ ftgrays.c
33 *
34 * The renderer can be initialized with a call to
35 * `ft_gray_raster.raster_new'; an anti-aliased bitmap can be generated
36 * with a call to `ft_gray_raster.raster_render'.
37 *
38 * See the comments and documentation in the file `ftimage.h' for more
39 * details on how the raster works.
40 *
41 */
42
43 /**************************************************************************
44 *
45 * This is a new anti-aliasing scan-converter for FreeType 2. The
46 * algorithm used here is _very_ different from the one in the standard
47 * `ftraster' module. Actually, `ftgrays' computes the _exact_
48 * coverage of the outline on each pixel cell by straight segments.
49 *
50 * It is based on ideas that I initially found in Raph Levien's
51 * excellent LibArt graphics library (see https://www.levien.com/libart
52 * for more information, though the web pages do not tell anything
53 * about the renderer; you'll have to dive into the source code to
54 * understand how it works).
55 *
56 * Note, however, that this is a _very_ different implementation
57 * compared to Raph's. Coverage information is stored in a very
58 * different way, and I don't use sorted vector paths. Also, it doesn't
59 * use floating point values.
60 *
61 * Bézier segments are flattened by splitting them until their deviation
62 * from straight line becomes much smaller than a pixel. Therefore, the
63 * pixel coverage by a Bézier curve is calculated approximately. To
64 * estimate the deviation, we use the distance from the control point
65 * to the conic chord centre or the cubic chord trisection. These
66 * distances vanish fast after each split. In the conic case, they vanish
67 * predictably and the number of necessary splits can be calculated.
68 *
69 * This renderer has the following advantages:
70 *
71 * - It doesn't need an intermediate bitmap. Instead, one can supply a
72 * callback function that will be called by the renderer to draw gray
73 * spans on any target surface. You can thus do direct composition on
74 * any kind of bitmap, provided that you give the renderer the right
75 * callback.
76 *
77 * - A perfect anti-aliaser, i.e., it computes the _exact_ coverage on
78 * each pixel cell by straight segments.
79 *
80 * - It performs a single pass on the outline (the `standard' FT2
81 * renderer makes two passes).
82 *
83 * - It can easily be modified to render to _any_ number of gray levels
84 * cheaply.
85 *
86 * - For small (< 80) pixel sizes, it is faster than the standard
87 * renderer.
88 *
89 */
90
91
92 /**************************************************************************
93 *
94 * The macro FT_COMPONENT is used in trace mode. It is an implicit
95 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
96 * messages during execution.
97 */
98 #undef FT_COMPONENT
99 #define FT_COMPONENT smooth
100
101
102 #ifdef STANDALONE_
103
104
105 /* The size in bytes of the render pool used by the scan-line converter */
106 /* to do all of its work. */
318
319 #define RAS_ARG gray_PWorker worker
320 #define RAS_ARG_ gray_PWorker worker,
321
322 #define RAS_VAR worker
323 #define RAS_VAR_ worker,
324
325 #else /* FT_STATIC_RASTER */
326
327 #define RAS_ARG void
328 #define RAS_ARG_ /* empty */
329 #define RAS_VAR /* empty */
330 #define RAS_VAR_ /* empty */
331
332 #endif /* FT_STATIC_RASTER */
333
334
335 /* must be at least 6 bits! */
336 #define PIXEL_BITS 8
337
338 #define ONE_PIXEL ( 1 << PIXEL_BITS )
339 #define TRUNC( x ) (TCoord)( (x) >> PIXEL_BITS )
340 #define FRACT( x ) (TCoord)( (x) & ( ONE_PIXEL - 1 ) )
341
342 #if PIXEL_BITS >= 6
343 #define UPSCALE( x ) ( (x) * ( ONE_PIXEL >> 6 ) )
344 #define DOWNSCALE( x ) ( (x) >> ( PIXEL_BITS - 6 ) )
345 #else
346 #define UPSCALE( x ) ( (x) >> ( 6 - PIXEL_BITS ) )
347 #define DOWNSCALE( x ) ( (x) * ( 64 >> PIXEL_BITS ) )
348 #endif
349
350
351 /* Compute `dividend / divisor' and return both its quotient and */
352 /* remainder, cast to a specific type. This macro also ensures that */
353 /* the remainder is always positive. We use the remainder to keep */
354 /* track of accumulating errors and compensate for them. */
355 #define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \
356 FT_BEGIN_STMNT \
357 (quotient) = (type)( (dividend) / (divisor) ); \
358 (remainder) = (type)( (dividend) % (divisor) ); \
359 if ( (remainder) < 0 ) \
360 { \
372 #undef FT_DIV_MOD
373 #define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \
374 FT_BEGIN_STMNT \
375 (quotient) = (type)( (dividend) / (divisor) ); \
376 (remainder) = (type)( (dividend) - (quotient) * (divisor) ); \
377 if ( (remainder) < 0 ) \
378 { \
379 (quotient)--; \
380 (remainder) += (type)(divisor); \
381 } \
382 FT_END_STMNT
383 #endif /* __arm__ */
384
385
386 /* These macros speed up repetitive divisions by replacing them */
387 /* with multiplications and right shifts. */
388 #define FT_UDIVPREP( c, b ) \
389 long b ## _r = c ? (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) \
390 : 0
391 #define FT_UDIV( a, b ) \
392 (TCoord)( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >> \
393 ( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )
394
395
396 /**************************************************************************
397 *
398 * TYPE DEFINITIONS
399 */
400
401 /* don't change the following types to FT_Int or FT_Pos, since we might */
402 /* need to define them to "float" or "double" when experimenting with */
403 /* new algorithms */
404
405 typedef long TPos; /* subpixel coordinate */
406 typedef int TCoord; /* integer scanline/pixel coordinate */
407 typedef int TArea; /* cell areas, coordinate products */
408
409
410 typedef struct TCell_* PCell;
411
412 typedef struct TCell_
415 TCoord cover; /* same with gray_TWorker.cover */
416 TArea area;
417 PCell next;
418
419 } TCell;
420
421 typedef struct TPixmap_
422 {
423 unsigned char* origin; /* pixmap origin at the bottom-left */
424 int pitch; /* pitch to go down one row */
425
426 } TPixmap;
427
428 /* maximum number of gray cells in the buffer */
429 #if FT_RENDER_POOL_SIZE > 2048
430 #define FT_MAX_GRAY_POOL ( FT_RENDER_POOL_SIZE / sizeof ( TCell ) )
431 #else
432 #define FT_MAX_GRAY_POOL ( 2048 / sizeof ( TCell ) )
433 #endif
434
435 /* FT_Span buffer size for direct rendering only */
436 #define FT_MAX_GRAY_SPANS 10
437
438
439 #if defined( _MSC_VER ) /* Visual C++ (and Intel C++) */
440 /* We disable the warning `structure was padded due to */
441 /* __declspec(align())' in order to compile cleanly with */
442 /* the maximum level of warnings. */
443 #pragma warning( push )
444 #pragma warning( disable : 4324 )
445 #endif /* _MSC_VER */
446
447 typedef struct gray_TWorker_
448 {
449 ft_jmp_buf jump_buffer;
450
451 TCoord ex, ey;
452 TCoord min_ex, max_ex;
453 TCoord min_ey, max_ey;
454
455 TArea area;
456 TCoord cover;
457 int invalid;
458
459 PCell* ycells;
460 PCell cells;
461 FT_PtrDist max_cells;
462 FT_PtrDist num_cells;
463
464 TPos x, y;
465
466 FT_Outline outline;
467 TPixmap target;
468
469 FT_Raster_Span_Func render_span;
470 void* render_span_data;
471 FT_Span spans[FT_MAX_GRAY_SPANS];
472 int num_spans;
473
474 } gray_TWorker, *gray_PWorker;
475
476 #if defined( _MSC_VER )
477 #pragma warning( pop )
478 #endif
479
480
481 #ifndef FT_STATIC_RASTER
482 #define ras (*worker)
483 #else
484 static gray_TWorker ras;
485 #endif
486
487
488 typedef struct gray_TRaster_
489 {
490 void* memory;
491
492 } gray_TRaster, *gray_PRaster;
504
505 for ( y = ras.min_ey; y < ras.max_ey; y++ )
506 {
507 PCell cell = ras.ycells[y - ras.min_ey];
508
509
510 printf( "%3d:", y );
511
512 for ( ; cell != NULL; cell = cell->next )
513 printf( " (%3d, c:%4d, a:%6d)",
514 cell->x, cell->cover, cell->area );
515 printf( "\n" );
516 }
517 }
518
519 #endif /* FT_DEBUG_LEVEL_TRACE */
520
521
522 /**************************************************************************
523 *
524 * Record the current cell in the linked list.
525 */
526 static void
527 gray_record_cell( RAS_ARG )
528 {
529 PCell *pcell, cell;
530 TCoord x = ras.ex;
531
532
533 pcell = &ras.ycells[ras.ey - ras.min_ey];
534 while ( ( cell = *pcell ) )
535 {
536 if ( cell->x > x )
537 break;
538
539 if ( cell->x == x )
540 goto Found;
541
542 pcell = &cell->next;
543 }
544
545 if ( ras.num_cells >= ras.max_cells )
546 ft_longjmp( ras.jump_buffer, 1 );
547
548 /* insert new cell */
549 cell = ras.cells + ras.num_cells++;
550 cell->x = x;
551 cell->area = ras.area;
552 cell->cover = ras.cover;
553
554 cell->next = *pcell;
555 *pcell = cell;
556
564
565
566 /**************************************************************************
567 *
568 * Set the current cell to a new position.
569 */
570 static void
571 gray_set_cell( RAS_ARG_ TCoord ex,
572 TCoord ey )
573 {
574 /* Move the cell pointer to a new position. We set the `invalid' */
575 /* flag to indicate that the cell isn't part of those we're interested */
576 /* in during the render phase. This means that: */
577 /* */
578 /* . the new vertical position must be within min_ey..max_ey-1. */
579 /* . the new horizontal position must be strictly less than max_ex */
580 /* */
581 /* Note that if a cell is to the left of the clipping region, it is */
582 /* actually set to the (min_ex-1) horizontal position. */
583
584 /* record the current one if it is valid and substantial */
585 if ( !ras.invalid && ( ras.area || ras.cover ) )
586 gray_record_cell( RAS_VAR );
587
588 ras.area = 0;
589 ras.cover = 0;
590 ras.ex = FT_MAX( ex, ras.min_ex - 1 );
591 ras.ey = ey;
592
593 ras.invalid = ( ey >= ras.max_ey || ey < ras.min_ey ||
594 ex >= ras.max_ex );
595 }
596
597
598 #ifndef FT_LONG64
599
600 /**************************************************************************
601 *
602 * Render a scanline as one or more cells.
603 */
604 static void
605 gray_render_scanline( RAS_ARG_ TCoord ey,
606 TPos x1,
607 TCoord y1,
608 TPos x2,
609 TCoord y2 )
610 {
611 TCoord ex1, ex2, fx1, fx2, first, dy, delta, mod;
612 TPos p, dx;
613 int incr;
614
615
616 ex1 = TRUNC( x1 );
617 ex2 = TRUNC( x2 );
618
619 /* trivial case. Happens often */
620 if ( y1 == y2 )
621 {
622 gray_set_cell( RAS_VAR_ ex2, ey );
623 return;
624 }
625
626 fx1 = FRACT( x1 );
627 fx2 = FRACT( x2 );
628
629 /* everything is located in a single cell. That is easy! */
630 /* */
631 if ( ex1 == ex2 )
632 goto End;
633
634 /* ok, we'll have to render a run of adjacent cells on the same */
635 /* scanline... */
636 /* */
637 dx = x2 - x1;
638 dy = y2 - y1;
639
640 if ( dx > 0 )
641 {
642 p = ( ONE_PIXEL - fx1 ) * dy;
643 first = ONE_PIXEL;
644 incr = 1;
645 }
646 else
647 {
648 p = fx1 * dy;
649 first = 0;
650 incr = -1;
651 dx = -dx;
652 }
653
654 /* the fractional part of y-delta is mod/dx. It is essential to */
655 /* keep track of its accumulation for accurate rendering. */
656 /* XXX: y-delta and x-delta below should be related. */
657 FT_DIV_MOD( TCoord, p, dx, delta, mod );
658
659 ras.area += (TArea)( ( fx1 + first ) * delta );
660 ras.cover += delta;
661 y1 += delta;
662 ex1 += incr;
663 gray_set_cell( RAS_VAR_ ex1, ey );
664
665 if ( ex1 != ex2 )
666 {
667 TCoord lift, rem;
668
669
670 p = ONE_PIXEL * dy;
671 FT_DIV_MOD( TCoord, p, dx, lift, rem );
672
673 do
674 {
675 delta = lift;
676 mod += rem;
702 *
703 * Render a given line as a series of scanlines.
704 */
705 static void
706 gray_render_line( RAS_ARG_ TPos to_x,
707 TPos to_y )
708 {
709 TCoord ey1, ey2, fy1, fy2, first, delta, mod;
710 TPos p, dx, dy, x, x2;
711 int incr;
712
713
714 ey1 = TRUNC( ras.y );
715 ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */
716
717 /* perform vertical clipping */
718 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
719 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
720 goto End;
721
722 fy1 = FRACT( ras.y );
723 fy2 = FRACT( to_y );
724
725 /* everything is on a single scanline */
726 if ( ey1 == ey2 )
727 {
728 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 );
729 goto End;
730 }
731
732 dx = to_x - ras.x;
733 dy = to_y - ras.y;
734
735 /* vertical line - avoid calling gray_render_scanline */
736 if ( dx == 0 )
737 {
738 TCoord ex = TRUNC( ras.x );
739 TCoord two_fx = FRACT( ras.x ) << 1;
740 TArea area;
741
742
743 if ( dy > 0)
744 {
745 first = ONE_PIXEL;
746 incr = 1;
747 }
748 else
749 {
750 first = 0;
751 incr = -1;
752 }
753
754 delta = first - fy1;
755 ras.area += (TArea)two_fx * delta;
756 ras.cover += delta;
757 ey1 += incr;
758
759 gray_set_cell( RAS_VAR_ ex, ey1 );
774 ras.cover += delta;
775
776 goto End;
777 }
778
779 /* ok, we have to render several scanlines */
780 if ( dy > 0)
781 {
782 p = ( ONE_PIXEL - fy1 ) * dx;
783 first = ONE_PIXEL;
784 incr = 1;
785 }
786 else
787 {
788 p = fy1 * dx;
789 first = 0;
790 incr = -1;
791 dy = -dy;
792 }
793
794 /* the fractional part of x-delta is mod/dy. It is essential to */
795 /* keep track of its accumulation for accurate rendering. */
796 FT_DIV_MOD( TCoord, p, dy, delta, mod );
797
798 x = ras.x + delta;
799 gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, first );
800
801 ey1 += incr;
802 gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 );
803
804 if ( ey1 != ey2 )
805 {
806 TCoord lift, rem;
807
808
809 p = ONE_PIXEL * dx;
810 FT_DIV_MOD( TCoord, p, dy, lift, rem );
811
812 do
813 {
814 delta = lift;
815 mod += rem;
832
833 gray_render_scanline( RAS_VAR_ ey1,
834 x, ONE_PIXEL - first,
835 to_x, fy2 );
836
837 End:
838 ras.x = to_x;
839 ras.y = to_y;
840 }
841
842 #else
843
844 /**************************************************************************
845 *
846 * Render a straight line across multiple cells in any direction.
847 */
848 static void
849 gray_render_line( RAS_ARG_ TPos to_x,
850 TPos to_y )
851 {
852 TPos dx, dy;
853 TCoord fx1, fy1, fx2, fy2;
854 TCoord ex1, ey1, ex2, ey2;
855
856
857 ey1 = TRUNC( ras.y );
858 ey2 = TRUNC( to_y );
859
860 /* perform vertical clipping */
861 if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) ||
862 ( ey1 < ras.min_ey && ey2 < ras.min_ey ) )
863 goto End;
864
865 ex1 = TRUNC( ras.x );
866 ex2 = TRUNC( to_x );
867
868 fx1 = FRACT( ras.x );
869 fy1 = FRACT( ras.y );
870
871 dx = to_x - ras.x;
872 dy = to_y - ras.y;
873
874 if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */
875 ;
876 else if ( dy == 0 ) /* ex1 != ex2 */ /* any horizontal line */
877 {
878 gray_set_cell( RAS_VAR_ ex2, ey2 );
879 goto End;
880 }
881 else if ( dx == 0 )
882 {
883 if ( dy > 0 ) /* vertical line up */
884 do
885 {
886 fy2 = ONE_PIXEL;
887 ras.cover += ( fy2 - fy1 );
888 ras.area += ( fy2 - fy1 ) * fx1 * 2;
889 fy1 = 0;
890 ey1++;
891 gray_set_cell( RAS_VAR_ ex1, ey1 );
892 } while ( ey1 != ey2 );
893 else /* vertical line down */
894 do
895 {
896 fy2 = 0;
897 ras.cover += ( fy2 - fy1 );
898 ras.area += ( fy2 - fy1 ) * fx1 * 2;
899 fy1 = ONE_PIXEL;
900 ey1--;
901 gray_set_cell( RAS_VAR_ ex1, ey1 );
902 } while ( ey1 != ey2 );
903 }
904 else /* any other line */
905 {
906 TPos prod = dx * (TPos)fy1 - dy * (TPos)fx1;
907 FT_UDIVPREP( ex1 != ex2, dx );
908 FT_UDIVPREP( ey1 != ey2, dy );
909
910
911 /* The fundamental value `prod' determines which side and the */
912 /* exact coordinate where the line exits current cell. It is */
913 /* also easily updated when moving from one cell to the next. */
914 do
915 {
916 if ( prod <= 0 &&
917 prod - dx * ONE_PIXEL > 0 ) /* left */
918 {
919 fx2 = 0;
920 fy2 = FT_UDIV( -prod, -dx );
921 prod -= dy * ONE_PIXEL;
922 ras.cover += ( fy2 - fy1 );
923 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
924 fx1 = ONE_PIXEL;
925 fy1 = fy2;
926 ex1--;
927 }
928 else if ( prod - dx * ONE_PIXEL <= 0 &&
929 prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 ) /* up */
930 {
931 prod -= dx * ONE_PIXEL;
932 fx2 = FT_UDIV( -prod, dy );
933 fy2 = ONE_PIXEL;
934 ras.cover += ( fy2 - fy1 );
935 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
936 fx1 = fx2;
937 fy1 = 0;
938 ey1++;
939 }
940 else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 &&
941 prod + dy * ONE_PIXEL >= 0 ) /* right */
942 {
943 prod += dy * ONE_PIXEL;
944 fx2 = ONE_PIXEL;
945 fy2 = FT_UDIV( prod, dx );
946 ras.cover += ( fy2 - fy1 );
947 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
948 fx1 = 0;
949 fy1 = fy2;
950 ex1++;
951 }
952 else /* ( prod + dy * ONE_PIXEL < 0 &&
953 prod > 0 ) down */
954 {
955 fx2 = FT_UDIV( prod, -dy );
956 fy2 = 0;
957 prod += dx * ONE_PIXEL;
958 ras.cover += ( fy2 - fy1 );
959 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
960 fx1 = fx2;
961 fy1 = ONE_PIXEL;
962 ey1--;
963 }
964
965 gray_set_cell( RAS_VAR_ ex1, ey1 );
966 } while ( ex1 != ex2 || ey1 != ey2 );
967 }
968
969 fx2 = FRACT( to_x );
970 fy2 = FRACT( to_y );
971
972 ras.cover += ( fy2 - fy1 );
973 ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
974
975 End:
976 ras.x = to_x;
977 ras.y = to_y;
978 }
979
980 #endif
981
982 static void
983 gray_split_conic( FT_Vector* base )
984 {
985 TPos a, b;
986
987
988 base[4].x = base[2].x;
989 a = base[0].x + base[1].x;
990 b = base[1].x + base[2].x;
991 base[3].x = b >> 1;
992 base[2].x = ( a + b ) >> 2;
993 base[1].x = a >> 1;
994
995 base[4].y = base[2].y;
996 a = base[0].y + base[1].y;
997 b = base[1].y + base[2].y;
998 base[3].y = b >> 1;
999 base[2].y = ( a + b ) >> 2;
1000 base[1].y = a >> 1;
1001 }
1002
1003
1004 static void
1005 gray_render_conic( RAS_ARG_ const FT_Vector* control,
1006 const FT_Vector* to )
1007 {
1008 FT_Vector bez_stack[16 * 2 + 1]; /* enough to accommodate bisections */
1009 FT_Vector* arc = bez_stack;
1010 TPos dx, dy;
1011 int draw, split;
1012
1013
1014 arc[0].x = UPSCALE( to->x );
1015 arc[0].y = UPSCALE( to->y );
1016 arc[1].x = UPSCALE( control->x );
1017 arc[1].y = UPSCALE( control->y );
1018 arc[2].x = ras.x;
1019 arc[2].y = ras.y;
1020
1034 dx = FT_ABS( arc[2].x + arc[0].x - 2 * arc[1].x );
1035 dy = FT_ABS( arc[2].y + arc[0].y - 2 * arc[1].y );
1036 if ( dx < dy )
1037 dx = dy;
1038
1039 /* We can calculate the number of necessary bisections because */
1040 /* each bisection predictably reduces deviation exactly 4-fold. */
1041 /* Even 32-bit deviation would vanish after 16 bisections. */
1042 draw = 1;
1043 while ( dx > ONE_PIXEL / 4 )
1044 {
1045 dx >>= 2;
1046 draw <<= 1;
1047 }
1048
1049 /* We use decrement counter to count the total number of segments */
1050 /* to draw starting from 2^level. Before each draw we split as */
1051 /* many times as there are trailing zeros in the counter. */
1052 do
1053 {
1054 split = draw & ( -draw ); /* isolate the rightmost 1-bit */
1055 while ( ( split >>= 1 ) )
1056 {
1057 gray_split_conic( arc );
1058 arc += 2;
1059 }
1060
1061 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1062 arc -= 2;
1063
1064 } while ( --draw );
1065 }
1066
1067
1068 static void
1069 gray_split_cubic( FT_Vector* base )
1070 {
1071 TPos a, b, c;
1072
1073
1074 base[6].x = base[3].x;
1075 a = base[0].x + base[1].x;
1076 b = base[1].x + base[2].x;
1077 c = base[2].x + base[3].x;
1078 base[5].x = c >> 1;
1079 c += b;
1080 base[4].x = c >> 2;
1081 base[1].x = a >> 1;
1082 a += b;
1083 base[2].x = a >> 2;
1084 base[3].x = ( a + c ) >> 3;
1085
1086 base[6].y = base[3].y;
1087 a = base[0].y + base[1].y;
1088 b = base[1].y + base[2].y;
1089 c = base[2].y + base[3].y;
1090 base[5].y = c >> 1;
1091 c += b;
1092 base[4].y = c >> 2;
1093 base[1].y = a >> 1;
1094 a += b;
1095 base[2].y = a >> 2;
1096 base[3].y = ( a + c ) >> 3;
1097 }
1098
1099
1100 static void
1101 gray_render_cubic( RAS_ARG_ const FT_Vector* control1,
1102 const FT_Vector* control2,
1103 const FT_Vector* to )
1104 {
1105 FT_Vector bez_stack[16 * 3 + 1]; /* enough to accommodate bisections */
1106 FT_Vector* arc = bez_stack;
1107
1108
1109 arc[0].x = UPSCALE( to->x );
1110 arc[0].y = UPSCALE( to->y );
1111 arc[1].x = UPSCALE( control2->x );
1112 arc[1].y = UPSCALE( control2->y );
1113 arc[2].x = UPSCALE( control1->x );
1114 arc[2].y = UPSCALE( control1->y );
1115 arc[3].x = ras.x;
1116 arc[3].y = ras.y;
1117
1118 /* short-cut the arc that crosses the current band */
1119 if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
1120 TRUNC( arc[1].y ) >= ras.max_ey &&
1121 TRUNC( arc[2].y ) >= ras.max_ey &&
1122 TRUNC( arc[3].y ) >= ras.max_ey ) ||
1123 ( TRUNC( arc[0].y ) < ras.min_ey &&
1124 TRUNC( arc[1].y ) < ras.min_ey &&
1125 TRUNC( arc[2].y ) < ras.min_ey &&
1126 TRUNC( arc[3].y ) < ras.min_ey ) )
1127 {
1128 ras.x = arc[0].x;
1129 ras.y = arc[0].y;
1130 return;
1131 }
1132
1133 for (;;)
1134 {
1135 /* with each split, control points quickly converge towards */
1136 /* chord trisection points and the vanishing distances below */
1137 /* indicate when the segment is flat enough to draw */
1138 if ( FT_ABS( 2 * arc[0].x - 3 * arc[1].x + arc[3].x ) > ONE_PIXEL / 2 ||
1139 FT_ABS( 2 * arc[0].y - 3 * arc[1].y + arc[3].y ) > ONE_PIXEL / 2 ||
1140 FT_ABS( arc[0].x - 3 * arc[2].x + 2 * arc[3].x ) > ONE_PIXEL / 2 ||
1141 FT_ABS( arc[0].y - 3 * arc[2].y + 2 * arc[3].y ) > ONE_PIXEL / 2 )
1142 goto Split;
1143
1144 gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
1145
1146 if ( arc == bez_stack )
1147 return;
1148
1149 arc -= 3;
1150 continue;
1151
1152 Split:
1153 gray_split_cubic( arc );
1154 arc += 3;
1155 }
1156 }
1157
1158
1159 static int
1160 gray_move_to( const FT_Vector* to,
1161 gray_PWorker worker )
1196
1197 static int
1198 gray_cubic_to( const FT_Vector* control1,
1199 const FT_Vector* control2,
1200 const FT_Vector* to,
1201 gray_PWorker worker )
1202 {
1203 gray_render_cubic( RAS_VAR_ control1, control2, to );
1204 return 0;
1205 }
1206
1207
1208 static void
1209 gray_hline( RAS_ARG_ TCoord x,
1210 TCoord y,
1211 TArea coverage,
1212 TCoord acount )
1213 {
1214 /* scale the coverage from 0..(ONE_PIXEL*ONE_PIXEL*2) to 0..256 */
1215 coverage >>= PIXEL_BITS * 2 + 1 - 8;
1216
1217 /* compute the line's coverage depending on the outline fill rule */
1218 if ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL )
1219 {
1220 coverage &= 511;
1221
1222 if ( coverage >= 256 )
1223 coverage = 511 - coverage;
1224 }
1225 else /* default non-zero winding rule */
1226 {
1227 if ( coverage < 0 )
1228 coverage = ~coverage; /* the same as -coverage - 1 */
1229
1230 if ( coverage >= 256 )
1231 coverage = 255;
1232 }
1233
1234 if ( ras.num_spans >= 0 ) /* for FT_RASTER_FLAG_DIRECT only */
1235 {
1236 FT_Span* span = ras.spans + ras.num_spans++;
1237
1238
1239 span->x = (short)x;
1240 span->len = (unsigned short)acount;
1241 span->coverage = (unsigned char)coverage;
1242
1243 if ( ras.num_spans == FT_MAX_GRAY_SPANS )
1244 {
1245 /* flush the span buffer and reset the count */
1246 ras.render_span( y, ras.num_spans, ras.spans, ras.render_span_data );
1247 ras.num_spans = 0;
1248 }
1249 }
1250 else
1251 {
1252 unsigned char* q = ras.target.origin - ras.target.pitch * y + x;
1253 unsigned char c = (unsigned char)coverage;
1254
1255
1256 /* For small-spans it is faster to do it by ourselves than
1257 * calling `memset'. This is mainly due to the cost of the
1258 * function call.
1259 */
1260 switch ( acount )
1261 {
1262 case 7:
1263 *q++ = c;
1264 /* fall through */
1265 case 6:
1266 *q++ = c;
1267 /* fall through */
1268 case 5:
1269 *q++ = c;
1270 /* fall through */
1271 case 4:
1272 *q++ = c;
1273 /* fall through */
1274 case 3:
1275 *q++ = c;
1276 /* fall through */
1277 case 2:
1278 *q++ = c;
1279 /* fall through */
1280 case 1:
1281 *q = c;
1282 /* fall through */
1283 case 0:
1284 break;
1285 default:
1286 FT_MEM_SET( q, c, acount );
1287 }
1288 }
1289 }
1290
1291
1292 static void
1293 gray_sweep( RAS_ARG )
1294 {
1295 int y;
1296
1297
1298 for ( y = ras.min_ey; y < ras.max_ey; y++ )
1299 {
1300 PCell cell = ras.ycells[y - ras.min_ey];
1301 TCoord x = ras.min_ex;
1302 TArea cover = 0;
1303 TArea area;
1304
1305
1306 for ( ; cell != NULL; cell = cell->next )
1307 {
1308 if ( cover != 0 && cell->x > x )
1309 gray_hline( RAS_VAR_ x, y, cover, cell->x - x );
1310
1311 cover += (TArea)cell->cover * ( ONE_PIXEL * 2 );
1312 area = cover - cell->area;
1313
1314 if ( area != 0 && cell->x >= ras.min_ex )
1315 gray_hline( RAS_VAR_ cell->x, y, area, 1 );
1316
1317 x = cell->x + 1;
1318 }
1319
1320 if ( cover != 0 )
1321 gray_hline( RAS_VAR_ x, y, cover, ras.max_ex - x );
1322
1323 if ( ras.num_spans > 0 ) /* for FT_RASTER_FLAG_DIRECT only */
1324 {
1325 /* flush the span buffer and reset the count */
1326 ras.render_span( y, ras.num_spans, ras.spans, ras.render_span_data );
1327 ras.num_spans = 0;
1328 }
1329 }
1330 }
1331
1332
1333 #ifdef STANDALONE_
1334
1335 /**************************************************************************
1336 *
1337 * The following functions should only compile in stand-alone mode,
1338 * i.e., when building this component without the rest of FreeType.
1339 *
1340 */
1341
1342 /**************************************************************************
1343 *
1344 * @Function:
1345 * FT_Outline_Decompose
1346 *
1347 * @Description:
1348 * Walk over an outline's structure to decompose it into individual
1358 * A table of `emitters', i.e., function pointers
1359 * called during decomposition to indicate path
1360 * operations.
1361 *
1362 * @InOut:
1363 * user ::
1364 * A typeless pointer which is passed to each
1365 * emitter during the decomposition. It can be
1366 * used to store the state during the
1367 * decomposition.
1368 *
1369 * @Return:
1370 * Error code. 0 means success.
1371 */
1372 static int
1373 FT_Outline_Decompose( const FT_Outline* outline,
1374 const FT_Outline_Funcs* func_interface,
1375 void* user )
1376 {
1377 #undef SCALED
1378 #define SCALED( x ) ( (x) * ( 1L << shift ) - delta )
1379
1380 FT_Vector v_last;
1381 FT_Vector v_control;
1382 FT_Vector v_start;
1383
1384 FT_Vector* point;
1385 FT_Vector* limit;
1386 char* tags;
1387
1388 int error;
1389
1390 int n; /* index of contour in outline */
1391 int first; /* index of first point in contour */
1392 char tag; /* current point's state */
1393
1394 int shift;
1395 TPos delta;
1396
1397
1398 if ( !outline )
1618 #endif /* STANDALONE_ */
1619
1620
1621 FT_DEFINE_OUTLINE_FUNCS(
1622 func_interface,
1623
1624 (FT_Outline_MoveTo_Func) gray_move_to, /* move_to */
1625 (FT_Outline_LineTo_Func) gray_line_to, /* line_to */
1626 (FT_Outline_ConicTo_Func)gray_conic_to, /* conic_to */
1627 (FT_Outline_CubicTo_Func)gray_cubic_to, /* cubic_to */
1628
1629 0, /* shift */
1630 0 /* delta */
1631 )
1632
1633
1634 static int
1635 gray_convert_glyph_inner( RAS_ARG,
1636 int continued )
1637 {
1638 int error;
1639
1640
1641 if ( ft_setjmp( ras.jump_buffer ) == 0 )
1642 {
1643 if ( continued )
1644 FT_Trace_Disable();
1645 error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras );
1646 if ( continued )
1647 FT_Trace_Enable();
1648
1649 if ( !ras.invalid )
1650 gray_record_cell( RAS_VAR );
1651
1652 FT_TRACE7(( "band [%d..%d]: %d cell%s\n",
1653 ras.min_ey,
1654 ras.max_ey,
1655 ras.num_cells,
1656 ras.num_cells == 1 ? "" : "s" ));
1657 }
1658 else
1742 FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" ));
1743 return 1;
1744 }
1745
1746 band++;
1747 band[1] = band[0];
1748 band[0] += width;
1749 } while ( band >= bands );
1750 }
1751
1752 return 0;
1753 }
1754
1755
1756 static int
1757 gray_raster_render( FT_Raster raster,
1758 const FT_Raster_Params* params )
1759 {
1760 const FT_Outline* outline = (const FT_Outline*)params->source;
1761 const FT_Bitmap* target_map = params->target;
1762
1763 #ifndef FT_STATIC_RASTER
1764 gray_TWorker worker[1];
1765 #endif
1766
1767
1768 if ( !raster )
1769 return FT_THROW( Invalid_Argument );
1770
1771 /* this version does not support monochrome rendering */
1772 if ( !( params->flags & FT_RASTER_FLAG_AA ) )
1773 return FT_THROW( Invalid_Mode );
1774
1775 if ( !outline )
1776 return FT_THROW( Invalid_Outline );
1777
1778 /* return immediately if the outline is empty */
1779 if ( outline->n_points == 0 || outline->n_contours <= 0 )
1780 return 0;
1781
1782 if ( !outline->contours || !outline->points )
1783 return FT_THROW( Invalid_Outline );
1784
1785 if ( outline->n_points !=
1786 outline->contours[outline->n_contours - 1] + 1 )
1787 return FT_THROW( Invalid_Outline );
1788
1789 ras.outline = *outline;
1790
1791 if ( params->flags & FT_RASTER_FLAG_DIRECT )
1792 {
1793 if ( !params->gray_spans )
1794 return 0;
1795
1796 ras.render_span = (FT_Raster_Span_Func)params->gray_spans;
1797 ras.render_span_data = params->user;
1798 ras.num_spans = 0;
1799
1800 ras.min_ex = params->clip_box.xMin;
1801 ras.min_ey = params->clip_box.yMin;
1802 ras.max_ex = params->clip_box.xMax;
1803 ras.max_ey = params->clip_box.yMax;
1804 }
1805 else
1806 {
1807 /* if direct mode is not set, we must have a target bitmap */
1808 if ( !target_map )
1809 return FT_THROW( Invalid_Argument );
1810
1811 /* nothing to do */
1812 if ( !target_map->width || !target_map->rows )
1813 return 0;
1814
1815 if ( !target_map->buffer )
1816 return FT_THROW( Invalid_Argument );
1817
1818 if ( target_map->pitch < 0 )
1819 ras.target.origin = target_map->buffer;
1820 else
1821 ras.target.origin = target_map->buffer
1822 + ( target_map->rows - 1 ) * (unsigned int)target_map->pitch;
1823
1824 ras.target.pitch = target_map->pitch;
1825
1826 ras.render_span = (FT_Raster_Span_Func)NULL;
1827 ras.render_span_data = NULL;
1828 ras.num_spans = -1; /* invalid */
1829
1830 ras.min_ex = 0;
1831 ras.min_ey = 0;
1832 ras.max_ex = (FT_Pos)target_map->width;
1833 ras.max_ey = (FT_Pos)target_map->rows;
1834 }
1835
1836 /* exit if nothing to do */
1837 if ( ras.max_ex <= ras.min_ex || ras.max_ey <= ras.min_ey )
1838 return 0;
1839
1840 return gray_convert_glyph( RAS_VAR );
1841 }
1842
1843
1844 /**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/
1845 /**** a static object. *****/
1846
1847 #ifdef STANDALONE_
1848
1849 static int
1850 gray_raster_new( void* memory,
1851 FT_Raster* araster )
1852 {
1853 static gray_TRaster the_raster;
1854
1855 FT_UNUSED( memory );
1856
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