/***************************************************************************/ /* */ /* ftgrays.c */ /* */ /* A new `perfect' anti-aliasing renderer (body). */ /* */ /* Copyright 2000-2003, 2005-2014 by */ /* David Turner, Robert Wilhelm, and Werner Lemberg. */ /* */ /* This file is part of the FreeType project, and may only be used, */ /* modified, and distributed under the terms of the FreeType project */ /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ /* this file you indicate that you have read the license and */ /* understand and accept it fully. */ /* */ /***************************************************************************/ /*************************************************************************/ /* */ /* This is a new anti-aliasing scan-converter for FreeType 2. The */ /* algorithm used here is _very_ different from the one in the standard */ /* `ftraster' module. Actually, `ftgrays' computes the _exact_ */ /* coverage of the outline on each pixel cell. */ /* */ /* It is based on ideas that I initially found in Raph Levien's */ /* excellent LibArt graphics library (see http://www.levien.com/libart */ /* for more information, though the web pages do not tell anything */ /* about the renderer; you'll have to dive into the source code to */ /* understand how it works). */ /* */ /* Note, however, that this is a _very_ different implementation */ /* compared to Raph's. Coverage information is stored in a very */ /* different way, and I don't use sorted vector paths. Also, it doesn't */ /* use floating point values. */ /* */ /* This renderer has the following advantages: */ /* */ /* - It doesn't need an intermediate bitmap. Instead, one can supply a */ /* callback function that will be called by the renderer to draw gray */ /* spans on any target surface. You can thus do direct composition on */ /* any kind of bitmap, provided that you give the renderer the right */ /* callback. */ /* */ /* - A perfect anti-aliaser, i.e., it computes the _exact_ coverage on */ /* each pixel cell. */ /* */ /* - It performs a single pass on the outline (the `standard' FT2 */ /* renderer makes two passes). */ /* */ /* - It can easily be modified to render to _any_ number of gray levels */ /* cheaply. */ /* */ /* - For small (< 20) pixel sizes, it is faster than the standard */ /* renderer. */ /* */ /*************************************************************************/ #include "sw_ft_raster.h" #include "sw_ft_math.h" /* Auxiliary macros for token concatenation. */ #define SW_FT_ERR_XCAT( x, y ) x ## y #define SW_FT_ERR_CAT( x, y ) SW_FT_ERR_XCAT( x, y ) #define SW_FT_BEGIN_STMNT do { #define SW_FT_END_STMNT } while ( 0 ) #include #include #include #include #define SW_FT_UINT_MAX UINT_MAX #define SW_FT_INT_MAX INT_MAX #define SW_FT_ULONG_MAX ULONG_MAX #define SW_FT_CHAR_BIT CHAR_BIT #define ft_memset memset #define ft_setjmp setjmp #define ft_longjmp longjmp #define ft_jmp_buf jmp_buf typedef ptrdiff_t SW_FT_PtrDist; #define ErrRaster_Invalid_Mode -2 #define ErrRaster_Invalid_Outline -1 #define ErrRaster_Invalid_Argument -3 #define ErrRaster_Memory_Overflow -4 #define SW_FT_BEGIN_HEADER #define SW_FT_END_HEADER /* This macro is used to indicate that a function parameter is unused. */ /* Its purpose is simply to reduce compiler warnings. Note also that */ /* simply defining it as `(void)x' doesn't avoid warnings with certain */ /* ANSI compilers (e.g. LCC). */ #define SW_FT_UNUSED( x ) (x) = (x) #define SW_FT_THROW( e ) SW_FT_ERR_CAT( ErrRaster_, e ) /* The size in bytes of the render pool used by the scan-line converter */ /* to do all of its work. */ #define SW_FT_RENDER_POOL_SIZE 16384L typedef int (*SW_FT_Outline_MoveToFunc)( const SW_FT_Vector* to, void* user ); #define SW_FT_Outline_MoveTo_Func SW_FT_Outline_MoveToFunc typedef int (*SW_FT_Outline_LineToFunc)( const SW_FT_Vector* to, void* user ); #define SW_FT_Outline_LineTo_Func SW_FT_Outline_LineToFunc typedef int (*SW_FT_Outline_ConicToFunc)( const SW_FT_Vector* control, const SW_FT_Vector* to, void* user ); #define SW_FT_Outline_ConicTo_Func SW_FT_Outline_ConicToFunc typedef int (*SW_FT_Outline_CubicToFunc)( const SW_FT_Vector* control1, const SW_FT_Vector* control2, const SW_FT_Vector* to, void* user ); #define SW_FT_Outline_CubicTo_Func SW_FT_Outline_CubicToFunc typedef struct SW_FT_Outline_Funcs_ { SW_FT_Outline_MoveToFunc move_to; SW_FT_Outline_LineToFunc line_to; SW_FT_Outline_ConicToFunc conic_to; SW_FT_Outline_CubicToFunc cubic_to; int shift; SW_FT_Pos delta; } SW_FT_Outline_Funcs; #define SW_FT_DEFINE_OUTLINE_FUNCS( class_, \ move_to_, line_to_, \ conic_to_, cubic_to_, \ shift_, delta_ ) \ static const SW_FT_Outline_Funcs class_ = \ { \ move_to_, \ line_to_, \ conic_to_, \ cubic_to_, \ shift_, \ delta_ \ }; #define SW_FT_DEFINE_RASTER_FUNCS( class_, \ raster_new_, raster_reset_, \ raster_render_, \ raster_done_ ) \ const SW_FT_Raster_Funcs class_ = \ { \ raster_new_, \ raster_reset_, \ raster_render_, \ raster_done_ \ }; #ifndef SW_FT_MEM_SET #define SW_FT_MEM_SET( d, s, c ) ft_memset( d, s, c ) #endif #ifndef SW_FT_MEM_ZERO #define SW_FT_MEM_ZERO( dest, count ) SW_FT_MEM_SET( dest, 0, count ) #endif /* as usual, for the speed hungry :-) */ #undef RAS_ARG #undef RAS_ARG_ #undef RAS_VAR #undef RAS_VAR_ #ifndef SW_FT_STATIC_RASTER #define RAS_ARG gray_PWorker worker #define RAS_ARG_ gray_PWorker worker, #define RAS_VAR worker #define RAS_VAR_ worker, #else /* SW_FT_STATIC_RASTER */ #define RAS_ARG /* empty */ #define RAS_ARG_ /* empty */ #define RAS_VAR /* empty */ #define RAS_VAR_ /* empty */ #endif /* SW_FT_STATIC_RASTER */ /* must be at least 6 bits! */ #define PIXEL_BITS 8 #undef FLOOR #undef CEILING #undef TRUNC #undef SCALED #define ONE_PIXEL ( 1L << PIXEL_BITS ) #define PIXEL_MASK ( -1L << PIXEL_BITS ) #define TRUNC( x ) ( (TCoord)( (x) >> PIXEL_BITS ) ) #define SUBPIXELS( x ) ( (TPos)(x) << PIXEL_BITS ) #define FLOOR( x ) ( (x) & -ONE_PIXEL ) #define CEILING( x ) ( ( (x) + ONE_PIXEL - 1 ) & -ONE_PIXEL ) #define ROUND( x ) ( ( (x) + ONE_PIXEL / 2 ) & -ONE_PIXEL ) #if PIXEL_BITS >= 6 #define UPSCALE( x ) ( (x) << ( PIXEL_BITS - 6 ) ) #define DOWNSCALE( x ) ( (x) >> ( PIXEL_BITS - 6 ) ) #else #define UPSCALE( x ) ( (x) >> ( 6 - PIXEL_BITS ) ) #define DOWNSCALE( x ) ( (x) << ( 6 - PIXEL_BITS ) ) #endif /* Compute `dividend / divisor' and return both its quotient and */ /* remainder, cast to a specific type. This macro also ensures that */ /* the remainder is always positive. */ #define SW_FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \ SW_FT_BEGIN_STMNT \ (quotient) = (type)( (dividend) / (divisor) ); \ (remainder) = (type)( (dividend) % (divisor) ); \ if ( (remainder) < 0 ) \ { \ (quotient)--; \ (remainder) += (type)(divisor); \ } \ SW_FT_END_STMNT #ifdef __arm__ /* Work around a bug specific to GCC which make the compiler fail to */ /* optimize a division and modulo operation on the same parameters */ /* into a single call to `__aeabi_idivmod'. See */ /* */ /* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43721 */ #undef SW_FT_DIV_MOD #define SW_FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \ SW_FT_BEGIN_STMNT \ (quotient) = (type)( (dividend) / (divisor) ); \ (remainder) = (type)( (dividend) - (quotient) * (divisor) ); \ if ( (remainder) < 0 ) \ { \ (quotient)--; \ (remainder) += (type)(divisor); \ } \ SW_FT_END_STMNT #endif /* __arm__ */ /* These macros speed up repetitive divisions by replacing them */ /* with multiplications and right shifts. */ #define SW_FT_UDIVPREP( b ) \ long b ## _r = (long)( SW_FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) #define SW_FT_UDIV( a, b ) \ ( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >> \ ( sizeof( long ) * SW_FT_CHAR_BIT - PIXEL_BITS ) ) /*************************************************************************/ /* */ /* TYPE DEFINITIONS */ /* */ /* don't change the following types to SW_FT_Int or SW_FT_Pos, since we might */ /* need to define them to "float" or "double" when experimenting with */ /* new algorithms */ typedef long TCoord; /* integer scanline/pixel coordinate */ typedef long TPos; /* sub-pixel coordinate */ /* determine the type used to store cell areas. This normally takes at */ /* least PIXEL_BITS*2 + 1 bits. On 16-bit systems, we need to use */ /* `long' instead of `int', otherwise bad things happen */ #if PIXEL_BITS <= 7 typedef int TArea; #else /* PIXEL_BITS >= 8 */ /* approximately determine the size of integers using an ANSI-C header */ #if SW_FT_UINT_MAX == 0xFFFFU typedef long TArea; #else typedef int TArea; #endif #endif /* PIXEL_BITS >= 8 */ /* maximum number of gray spans in a call to the span callback */ #define SW_FT_MAX_GRAY_SPANS 256 typedef struct TCell_* PCell; typedef struct TCell_ { TPos x; /* same with gray_TWorker.ex */ TCoord cover; /* same with gray_TWorker.cover */ TArea area; PCell next; } TCell; #if defined( _MSC_VER ) /* Visual C++ (and Intel C++) */ /* We disable the warning `structure was padded due to */ /* __declspec(align())' in order to compile cleanly with */ /* the maximum level of warnings. */ #pragma warning( push ) #pragma warning( disable : 4324 ) #endif /* _MSC_VER */ typedef struct gray_TWorker_ { TCoord ex, ey; TPos min_ex, max_ex; TPos min_ey, max_ey; TPos count_ex, count_ey; TArea area; TCoord cover; int invalid; PCell cells; SW_FT_PtrDist max_cells; SW_FT_PtrDist num_cells; TPos x, y; SW_FT_Vector bez_stack[32 * 3 + 1]; int lev_stack[32]; SW_FT_Outline outline; SW_FT_BBox clip_box; SW_FT_Span gray_spans[SW_FT_MAX_GRAY_SPANS]; int num_gray_spans; SW_FT_Raster_Span_Func render_span; void* render_span_data; int span_y; int band_size; int band_shoot; ft_jmp_buf jump_buffer; void* buffer; long buffer_size; PCell* ycells; TPos ycount; } gray_TWorker, *gray_PWorker; #if defined( _MSC_VER ) #pragma warning( pop ) #endif #ifndef SW_FT_STATIC_RASTER #define ras (*worker) #else static gray_TWorker ras; #endif typedef struct gray_TRaster_ { void* memory; } gray_TRaster, *gray_PRaster; /*************************************************************************/ /* */ /* Initialize the cells table. */ /* */ static void gray_init_cells( RAS_ARG_ void* buffer, long byte_size ) { ras.buffer = buffer; ras.buffer_size = byte_size; ras.ycells = (PCell*) buffer; ras.cells = NULL; ras.max_cells = 0; ras.num_cells = 0; ras.area = 0; ras.cover = 0; ras.invalid = 1; } /*************************************************************************/ /* */ /* Compute the outline bounding box. */ /* */ static void gray_compute_cbox( RAS_ARG ) { SW_FT_Outline* outline = &ras.outline; SW_FT_Vector* vec = outline->points; SW_FT_Vector* limit = vec + outline->n_points; if ( outline->n_points <= 0 ) { ras.min_ex = ras.max_ex = 0; ras.min_ey = ras.max_ey = 0; return; } ras.min_ex = ras.max_ex = vec->x; ras.min_ey = ras.max_ey = vec->y; vec++; for ( ; vec < limit; vec++ ) { TPos x = vec->x; TPos y = vec->y; if ( x < ras.min_ex ) ras.min_ex = x; if ( x > ras.max_ex ) ras.max_ex = x; if ( y < ras.min_ey ) ras.min_ey = y; if ( y > ras.max_ey ) ras.max_ey = y; } /* truncate the bounding box to integer pixels */ ras.min_ex = ras.min_ex >> 6; ras.min_ey = ras.min_ey >> 6; ras.max_ex = ( ras.max_ex + 63 ) >> 6; ras.max_ey = ( ras.max_ey + 63 ) >> 6; } /*************************************************************************/ /* */ /* Record the current cell in the table. */ /* */ static PCell gray_find_cell( RAS_ARG ) { PCell *pcell, cell; TPos x = ras.ex; if ( x > ras.count_ex ) x = ras.count_ex; pcell = &ras.ycells[ras.ey]; for (;;) { cell = *pcell; if ( cell == NULL || cell->x > x ) break; if ( cell->x == x ) goto Exit; pcell = &cell->next; } if ( ras.num_cells >= ras.max_cells ) ft_longjmp( ras.jump_buffer, 1 ); cell = ras.cells + ras.num_cells++; cell->x = x; cell->area = 0; cell->cover = 0; cell->next = *pcell; *pcell = cell; Exit: return cell; } static void gray_record_cell( RAS_ARG ) { if ( ras.area | ras.cover ) { PCell cell = gray_find_cell( RAS_VAR ); cell->area += ras.area; cell->cover += ras.cover; } } /*************************************************************************/ /* */ /* Set the current cell to a new position. */ /* */ static void gray_set_cell( RAS_ARG_ TCoord ex, TCoord ey ) { /* Move the cell pointer to a new position. We set the `invalid' */ /* flag to indicate that the cell isn't part of those we're interested */ /* in during the render phase. This means that: */ /* */ /* . the new vertical position must be within min_ey..max_ey-1. */ /* . the new horizontal position must be strictly less than max_ex */ /* */ /* Note that if a cell is to the left of the clipping region, it is */ /* actually set to the (min_ex-1) horizontal position. */ /* All cells that are on the left of the clipping region go to the */ /* min_ex - 1 horizontal position. */ ey -= ras.min_ey; if ( ex > ras.max_ex ) ex = ras.max_ex; ex -= ras.min_ex; if ( ex < 0 ) ex = -1; /* are we moving to a different cell ? */ if ( ex != ras.ex || ey != ras.ey ) { /* record the current one if it is valid */ if ( !ras.invalid ) gray_record_cell( RAS_VAR ); ras.area = 0; ras.cover = 0; ras.ex = ex; ras.ey = ey; } ras.invalid = ( (unsigned)ey >= (unsigned)ras.count_ey || ex >= ras.count_ex ); } /*************************************************************************/ /* */ /* Start a new contour at a given cell. */ /* */ static void gray_start_cell( RAS_ARG_ TCoord ex, TCoord ey ) { if ( ex > ras.max_ex ) ex = (TCoord)( ras.max_ex ); if ( ex < ras.min_ex ) ex = (TCoord)( ras.min_ex - 1 ); ras.area = 0; ras.cover = 0; ras.ex = ex - ras.min_ex; ras.ey = ey - ras.min_ey; ras.invalid = 0; gray_set_cell( RAS_VAR_ ex, ey ); } /*************************************************************************/ /* */ /* Render a straight line across multiple cells in any direction. */ /* */ static void gray_render_line( RAS_ARG_ TPos to_x, TPos to_y ) { TPos dx, dy, fx1, fy1, fx2, fy2; TCoord ex1, ex2, ey1, ey2; ex1 = TRUNC( ras.x ); ex2 = TRUNC( to_x ); ey1 = TRUNC( ras.y ); ey2 = TRUNC( to_y ); /* perform vertical clipping */ if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) || ( ey1 < ras.min_ey && ey2 < ras.min_ey ) ) goto End; dx = to_x - ras.x; dy = to_y - ras.y; fx1 = ras.x - SUBPIXELS( ex1 ); fy1 = ras.y - SUBPIXELS( ey1 ); if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */ ; else if ( dy == 0 ) /* ex1 != ex2 */ /* any horizontal line */ { ex1 = ex2; gray_set_cell( RAS_VAR_ ex1, ey1 ); } else if ( dx == 0 ) { if ( dy > 0 ) /* vertical line up */ do { fy2 = ONE_PIXEL; ras.cover += ( fy2 - fy1 ); ras.area += ( fy2 - fy1 ) * fx1 * 2; fy1 = 0; ey1++; gray_set_cell( RAS_VAR_ ex1, ey1 ); } while ( ey1 != ey2 ); else /* vertical line down */ do { fy2 = 0; ras.cover += ( fy2 - fy1 ); ras.area += ( fy2 - fy1 ) * fx1 * 2; fy1 = ONE_PIXEL; ey1--; gray_set_cell( RAS_VAR_ ex1, ey1 ); } while ( ey1 != ey2 ); } else /* any other line */ { TArea prod = dx * fy1 - dy * fx1; SW_FT_UDIVPREP( dx ); SW_FT_UDIVPREP( dy ); /* The fundamental value `prod' determines which side and the */ /* exact coordinate where the line exits current cell. It is */ /* also easily updated when moving from one cell to the next. */ do { if ( prod <= 0 && prod - dx * ONE_PIXEL > 0 ) /* left */ { fx2 = 0; fy2 = (TPos)SW_FT_UDIV( -prod, -dx ); prod -= dy * ONE_PIXEL; ras.cover += ( fy2 - fy1 ); ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 ); fx1 = ONE_PIXEL; fy1 = fy2; ex1--; } else if ( prod - dx * ONE_PIXEL <= 0 && prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 ) /* up */ { prod -= dx * ONE_PIXEL; fx2 = (TPos)SW_FT_UDIV( -prod, dy ); fy2 = ONE_PIXEL; ras.cover += ( fy2 - fy1 ); ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 ); fx1 = fx2; fy1 = 0; ey1++; } else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 && prod + dy * ONE_PIXEL >= 0 ) /* right */ { prod += dy * ONE_PIXEL; fx2 = ONE_PIXEL; fy2 = (TPos)SW_FT_UDIV( prod, dx ); ras.cover += ( fy2 - fy1 ); ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 ); fx1 = 0; fy1 = fy2; ex1++; } else /* ( prod + dy * ONE_PIXEL < 0 && prod > 0 ) down */ { fx2 = (TPos)SW_FT_UDIV( prod, -dy ); fy2 = 0; prod += dx * ONE_PIXEL; ras.cover += ( fy2 - fy1 ); ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 ); fx1 = fx2; fy1 = ONE_PIXEL; ey1--; } gray_set_cell( RAS_VAR_ ex1, ey1 ); } while ( ex1 != ex2 || ey1 != ey2 ); } fx2 = to_x - SUBPIXELS( ex2 ); fy2 = to_y - SUBPIXELS( ey2 ); ras.cover += ( fy2 - fy1 ); ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 ); End: ras.x = to_x; ras.y = to_y; } static void gray_split_conic( SW_FT_Vector* base ) { TPos a, b; base[4].x = base[2].x; b = base[1].x; a = base[3].x = ( base[2].x + b ) / 2; b = base[1].x = ( base[0].x + b ) / 2; base[2].x = ( a + b ) / 2; base[4].y = base[2].y; b = base[1].y; a = base[3].y = ( base[2].y + b ) / 2; b = base[1].y = ( base[0].y + b ) / 2; base[2].y = ( a + b ) / 2; } static void gray_render_conic( RAS_ARG_ const SW_FT_Vector* control, const SW_FT_Vector* to ) { TPos dx, dy; TPos min, max, y; int top, level; int* levels; SW_FT_Vector* arc; levels = ras.lev_stack; arc = ras.bez_stack; arc[0].x = UPSCALE( to->x ); arc[0].y = UPSCALE( to->y ); arc[1].x = UPSCALE( control->x ); arc[1].y = UPSCALE( control->y ); arc[2].x = ras.x; arc[2].y = ras.y; top = 0; dx = SW_FT_ABS( arc[2].x + arc[0].x - 2 * arc[1].x ); dy = SW_FT_ABS( arc[2].y + arc[0].y - 2 * arc[1].y ); if ( dx < dy ) dx = dy; if ( dx < ONE_PIXEL / 4 ) goto Draw; /* short-cut the arc that crosses the current band */ min = max = arc[0].y; y = arc[1].y; if ( y < min ) min = y; if ( y > max ) max = y; y = arc[2].y; if ( y < min ) min = y; if ( y > max ) max = y; if ( TRUNC( min ) >= ras.max_ey || TRUNC( max ) < ras.min_ey ) goto Draw; level = 0; do { dx >>= 2; level++; } while ( dx > ONE_PIXEL / 4 ); levels[0] = level; do { level = levels[top]; if ( level > 0 ) { gray_split_conic( arc ); arc += 2; top++; levels[top] = levels[top - 1] = level - 1; continue; } Draw: gray_render_line( RAS_VAR_ arc[0].x, arc[0].y ); top--; arc -= 2; } while ( top >= 0 ); } static void gray_split_cubic( SW_FT_Vector* base ) { TPos a, b, c, d; base[6].x = base[3].x; c = base[1].x; d = base[2].x; base[1].x = a = ( base[0].x + c ) / 2; base[5].x = b = ( base[3].x + d ) / 2; c = ( c + d ) / 2; base[2].x = a = ( a + c ) / 2; base[4].x = b = ( b + c ) / 2; base[3].x = ( a + b ) / 2; base[6].y = base[3].y; c = base[1].y; d = base[2].y; base[1].y = a = ( base[0].y + c ) / 2; base[5].y = b = ( base[3].y + d ) / 2; c = ( c + d ) / 2; base[2].y = a = ( a + c ) / 2; base[4].y = b = ( b + c ) / 2; base[3].y = ( a + b ) / 2; } static void gray_render_cubic( RAS_ARG_ const SW_FT_Vector* control1, const SW_FT_Vector* control2, const SW_FT_Vector* to ) { SW_FT_Vector* arc; TPos min, max, y; arc = ras.bez_stack; arc[0].x = UPSCALE( to->x ); arc[0].y = UPSCALE( to->y ); arc[1].x = UPSCALE( control2->x ); arc[1].y = UPSCALE( control2->y ); arc[2].x = UPSCALE( control1->x ); arc[2].y = UPSCALE( control1->y ); arc[3].x = ras.x; arc[3].y = ras.y; /* Short-cut the arc that crosses the current band. */ min = max = arc[0].y; y = arc[1].y; if ( y < min ) min = y; if ( y > max ) max = y; y = arc[2].y; if ( y < min ) min = y; if ( y > max ) max = y; y = arc[3].y; if ( y < min ) min = y; if ( y > max ) max = y; if ( TRUNC( min ) >= ras.max_ey || TRUNC( max ) < ras.min_ey ) goto Draw; for (;;) { /* Decide whether to split or draw. See `Rapid Termination */ /* Evaluation for Recursive Subdivision of Bezier Curves' by Thomas */ /* F. Hain, at */ /* http://www.cis.southalabama.edu/~hain/general/Publications/Bezier/Camera-ready%20CISST02%202.pdf */ { TPos dx, dy, dx_, dy_; TPos dx1, dy1, dx2, dy2; TPos L, s, s_limit; /* dx and dy are x and y components of the P0-P3 chord vector. */ dx = dx_ = arc[3].x - arc[0].x; dy = dy_ = arc[3].y - arc[0].y; L = SW_FT_HYPOT( dx_, dy_ ); /* Avoid possible arithmetic overflow below by splitting. */ if ( L > 32767 ) goto Split; /* Max deviation may be as much as (s/L) * 3/4 (if Hain's v = 1). */ s_limit = L * (TPos)( ONE_PIXEL / 6 ); /* s is L * the perpendicular distance from P1 to the line P0-P3. */ dx1 = arc[1].x - arc[0].x; dy1 = arc[1].y - arc[0].y; s = SW_FT_ABS( dy * dx1 - dx * dy1 ); if ( s > s_limit ) goto Split; /* s is L * the perpendicular distance from P2 to the line P0-P3. */ dx2 = arc[2].x - arc[0].x; dy2 = arc[2].y - arc[0].y; s = SW_FT_ABS( dy * dx2 - dx * dy2 ); if ( s > s_limit ) goto Split; /* Split super curvy segments where the off points are so far from the chord that the angles P0-P1-P3 or P0-P2-P3 become acute as detected by appropriate dot products. */ if ( dx1 * ( dx1 - dx ) + dy1 * ( dy1 - dy ) > 0 || dx2 * ( dx2 - dx ) + dy2 * ( dy2 - dy ) > 0 ) goto Split; /* No reason to split. */ goto Draw; } Split: gray_split_cubic( arc ); arc += 3; continue; Draw: gray_render_line( RAS_VAR_ arc[0].x, arc[0].y ); if ( arc == ras.bez_stack ) return; arc -= 3; } } static int gray_move_to( const SW_FT_Vector* to, gray_PWorker worker ) { TPos x, y; /* record current cell, if any */ if ( !ras.invalid ) gray_record_cell( RAS_VAR ); /* start to a new position */ x = UPSCALE( to->x ); y = UPSCALE( to->y ); gray_start_cell( RAS_VAR_ TRUNC( x ), TRUNC( y ) ); worker->x = x; worker->y = y; return 0; } static int gray_line_to( const SW_FT_Vector* to, gray_PWorker worker ) { gray_render_line( RAS_VAR_ UPSCALE( to->x ), UPSCALE( to->y ) ); return 0; } static int gray_conic_to( const SW_FT_Vector* control, const SW_FT_Vector* to, gray_PWorker worker ) { gray_render_conic( RAS_VAR_ control, to ); return 0; } static int gray_cubic_to( const SW_FT_Vector* control1, const SW_FT_Vector* control2, const SW_FT_Vector* to, gray_PWorker worker ) { gray_render_cubic( RAS_VAR_ control1, control2, to ); return 0; } static void gray_hline( RAS_ARG_ TCoord x, TCoord y, TPos area, TCoord acount ) { int coverage; /* compute the coverage line's coverage, depending on the */ /* outline fill rule */ /* */ /* the coverage percentage is area/(PIXEL_BITS*PIXEL_BITS*2) */ /* */ coverage = (int)( area >> ( PIXEL_BITS * 2 + 1 - 8 ) ); /* use range 0..256 */ if ( coverage < 0 ) coverage = -coverage; if ( ras.outline.flags & SW_FT_OUTLINE_EVEN_ODD_FILL ) { coverage &= 511; if ( coverage > 256 ) coverage = 512 - coverage; else if ( coverage == 256 ) coverage = 255; } else { /* normal non-zero winding rule */ if ( coverage >= 256 ) coverage = 255; } y += (TCoord)ras.min_ey; x += (TCoord)ras.min_ex; /* SW_FT_Span.x is a 16-bit short, so limit our coordinates appropriately */ if ( x >= 32767 ) x = 32767; /* SW_FT_Span.y is an integer, so limit our coordinates appropriately */ if ( y >= SW_FT_INT_MAX ) y = SW_FT_INT_MAX; if ( coverage ) { SW_FT_Span* span; int count; /* see whether we can add this span to the current list */ count = ras.num_gray_spans; span = ras.gray_spans + count - 1; if ( count > 0 && ras.span_y == y && (int)span->x + span->len == (int)x && span->coverage == coverage ) { span->len = (unsigned short)( span->len + acount ); return; } if ( count >= SW_FT_MAX_GRAY_SPANS ) { if ( ras.render_span && count > 0 ) ras.render_span(count, ras.gray_spans, ras.render_span_data ); #ifdef DEBUG_GRAYS if ( 1 ) { int n; fprintf( stderr, "count = %3d ", count ); span = ras.gray_spans; for ( n = 0; n < count; n++, span++ ) fprintf( stderr, "[%d , %d..%d] : %d ", span->y, span->x, span->x + span->len - 1, span->coverage ); fprintf( stderr, "\n" ); } #endif /* DEBUG_GRAYS */ ras.num_gray_spans = 0; //ras.span_y = (int)y; span = ras.gray_spans; } else span++; /* add a gray span to the current list */ span->x = (short)x; span->y = (short)y; span->len = (unsigned short)acount; span->coverage = (unsigned char)coverage; ras.num_gray_spans++; } } static void gray_sweep( RAS_ARG) { int yindex; if ( ras.num_cells == 0 ) return; ras.num_gray_spans = 0; for ( yindex = 0; yindex < ras.ycount; yindex++ ) { PCell cell = ras.ycells[yindex]; TCoord cover = 0; TCoord x = 0; for ( ; cell != NULL; cell = cell->next ) { TPos area; if ( cell->x > x && cover != 0 ) gray_hline( RAS_VAR_ x, yindex, cover * ( ONE_PIXEL * 2 ), cell->x - x ); cover += cell->cover; area = cover * ( ONE_PIXEL * 2 ) - cell->area; if ( area != 0 && cell->x >= 0 ) gray_hline( RAS_VAR_ cell->x, yindex, area, 1 ); x = cell->x + 1; } if ( cover != 0 ) gray_hline( RAS_VAR_ x, yindex, cover * ( ONE_PIXEL * 2 ), ras.count_ex - x ); } if ( ras.render_span && ras.num_gray_spans > 0 ) ras.render_span(ras.num_gray_spans, ras.gray_spans, ras.render_span_data ); } /*************************************************************************/ /* */ /* The following function should only compile in stand-alone mode, */ /* i.e., when building this component without the rest of FreeType. */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* */ /* SW_FT_Outline_Decompose */ /* */ /* */ /* Walk over an outline's structure to decompose it into individual */ /* segments and Bézier arcs. This function is also able to emit */ /* `move to' and `close to' operations to indicate the start and end */ /* of new contours in the outline. */ /* */ /* */ /* outline :: A pointer to the source target. */ /* */ /* func_interface :: A table of `emitters', i.e., function pointers */ /* called during decomposition to indicate path */ /* operations. */ /* */ /* */ /* user :: A typeless pointer which is passed to each */ /* emitter during the decomposition. It can be */ /* used to store the state during the */ /* decomposition. */ /* */ /* */ /* Error code. 0 means success. */ /* */ static int SW_FT_Outline_Decompose( const SW_FT_Outline* outline, const SW_FT_Outline_Funcs* func_interface, void* user ) { #undef SCALED #define SCALED( x ) ( ( (x) << shift ) - delta ) SW_FT_Vector v_last; SW_FT_Vector v_control; SW_FT_Vector v_start; SW_FT_Vector* point; SW_FT_Vector* limit; char* tags; int error; int n; /* index of contour in outline */ int first; /* index of first point in contour */ char tag; /* current point's state */ int shift; TPos delta; if ( !outline || !func_interface ) return SW_FT_THROW( Invalid_Argument ); shift = func_interface->shift; delta = func_interface->delta; first = 0; for ( n = 0; n < outline->n_contours; n++ ) { int last; /* index of last point in contour */ last = outline->contours[n]; if ( last < 0 ) goto Invalid_Outline; limit = outline->points + last; v_start = outline->points[first]; v_start.x = SCALED( v_start.x ); v_start.y = SCALED( v_start.y ); v_last = outline->points[last]; v_last.x = SCALED( v_last.x ); v_last.y = SCALED( v_last.y ); v_control = v_start; point = outline->points + first; tags = outline->tags + first; tag = SW_FT_CURVE_TAG( tags[0] ); /* A contour cannot start with a cubic control point! */ if ( tag == SW_FT_CURVE_TAG_CUBIC ) goto Invalid_Outline; /* check first point to determine origin */ if ( tag == SW_FT_CURVE_TAG_CONIC ) { /* first point is conic control. Yes, this happens. */ if ( SW_FT_CURVE_TAG( outline->tags[last] ) == SW_FT_CURVE_TAG_ON ) { /* start at last point if it is on the curve */ v_start = v_last; limit--; } else { /* if both first and last points are conic, */ /* start at their middle and record its position */ /* for closure */ v_start.x = ( v_start.x + v_last.x ) / 2; v_start.y = ( v_start.y + v_last.y ) / 2; } point--; tags--; } error = func_interface->move_to( &v_start, user ); if ( error ) goto Exit; while ( point < limit ) { point++; tags++; tag = SW_FT_CURVE_TAG( tags[0] ); switch ( tag ) { case SW_FT_CURVE_TAG_ON: /* emit a single line_to */ { SW_FT_Vector vec; vec.x = SCALED( point->x ); vec.y = SCALED( point->y ); error = func_interface->line_to( &vec, user ); if ( error ) goto Exit; continue; } case SW_FT_CURVE_TAG_CONIC: /* consume conic arcs */ v_control.x = SCALED( point->x ); v_control.y = SCALED( point->y ); Do_Conic: if ( point < limit ) { SW_FT_Vector vec; SW_FT_Vector v_middle; point++; tags++; tag = SW_FT_CURVE_TAG( tags[0] ); vec.x = SCALED( point->x ); vec.y = SCALED( point->y ); if ( tag == SW_FT_CURVE_TAG_ON ) { error = func_interface->conic_to( &v_control, &vec, user ); if ( error ) goto Exit; continue; } if ( tag != SW_FT_CURVE_TAG_CONIC ) goto Invalid_Outline; v_middle.x = ( v_control.x + vec.x ) / 2; v_middle.y = ( v_control.y + vec.y ) / 2; error = func_interface->conic_to( &v_control, &v_middle, user ); if ( error ) goto Exit; v_control = vec; goto Do_Conic; } error = func_interface->conic_to( &v_control, &v_start, user ); goto Close; default: /* SW_FT_CURVE_TAG_CUBIC */ { SW_FT_Vector vec1, vec2; if ( point + 1 > limit || SW_FT_CURVE_TAG( tags[1] ) != SW_FT_CURVE_TAG_CUBIC ) goto Invalid_Outline; point += 2; tags += 2; vec1.x = SCALED( point[-2].x ); vec1.y = SCALED( point[-2].y ); vec2.x = SCALED( point[-1].x ); vec2.y = SCALED( point[-1].y ); if ( point <= limit ) { SW_FT_Vector vec; vec.x = SCALED( point->x ); vec.y = SCALED( point->y ); error = func_interface->cubic_to( &vec1, &vec2, &vec, user ); if ( error ) goto Exit; continue; } error = func_interface->cubic_to( &vec1, &vec2, &v_start, user ); goto Close; } } } /* close the contour with a line segment */ error = func_interface->line_to( &v_start, user ); Close: if ( error ) goto Exit; first = last + 1; } return 0; Exit: return error; Invalid_Outline: return SW_FT_THROW( Invalid_Outline ); } typedef struct gray_TBand_ { TPos min, max; } gray_TBand; SW_FT_DEFINE_OUTLINE_FUNCS(func_interface, (SW_FT_Outline_MoveTo_Func) gray_move_to, (SW_FT_Outline_LineTo_Func) gray_line_to, (SW_FT_Outline_ConicTo_Func)gray_conic_to, (SW_FT_Outline_CubicTo_Func)gray_cubic_to, 0, 0 ) static int gray_convert_glyph_inner( RAS_ARG ) { volatile int error = 0; if ( ft_setjmp( ras.jump_buffer ) == 0 ) { error = SW_FT_Outline_Decompose( &ras.outline, &func_interface, &ras ); if ( !ras.invalid ) gray_record_cell( RAS_VAR ); } else error = SW_FT_THROW( Memory_Overflow ); return error; } static int gray_convert_glyph( RAS_ARG ) { gray_TBand bands[40]; gray_TBand* volatile band; int volatile n, num_bands; TPos volatile min, max, max_y; SW_FT_BBox* clip; /* Set up state in the raster object */ gray_compute_cbox( RAS_VAR ); /* clip to target bitmap, exit if nothing to do */ clip = &ras.clip_box; if ( ras.max_ex <= clip->xMin || ras.min_ex >= clip->xMax || ras.max_ey <= clip->yMin || ras.min_ey >= clip->yMax ) return 0; if ( ras.min_ex < clip->xMin ) ras.min_ex = clip->xMin; if ( ras.min_ey < clip->yMin ) ras.min_ey = clip->yMin; if ( ras.max_ex > clip->xMax ) ras.max_ex = clip->xMax; if ( ras.max_ey > clip->yMax ) ras.max_ey = clip->yMax; ras.count_ex = ras.max_ex - ras.min_ex; ras.count_ey = ras.max_ey - ras.min_ey; /* set up vertical bands */ num_bands = (int)( ( ras.max_ey - ras.min_ey ) / ras.band_size ); if ( num_bands == 0 ) num_bands = 1; if ( num_bands >= 39 ) num_bands = 39; ras.band_shoot = 0; min = ras.min_ey; max_y = ras.max_ey; for ( n = 0; n < num_bands; n++, min = max ) { max = min + ras.band_size; if ( n == num_bands - 1 || max > max_y ) max = max_y; bands[0].min = min; bands[0].max = max; band = bands; while ( band >= bands ) { TPos bottom, top, middle; int error; { PCell cells_max; int yindex; long cell_start, cell_end, cell_mod; ras.ycells = (PCell*)ras.buffer; ras.ycount = band->max - band->min; cell_start = sizeof ( PCell ) * ras.ycount; cell_mod = cell_start % sizeof ( TCell ); if ( cell_mod > 0 ) cell_start += sizeof ( TCell ) - cell_mod; cell_end = ras.buffer_size; cell_end -= cell_end % sizeof ( TCell ); cells_max = (PCell)( (char*)ras.buffer + cell_end ); ras.cells = (PCell)( (char*)ras.buffer + cell_start ); if ( ras.cells >= cells_max ) goto ReduceBands; ras.max_cells = cells_max - ras.cells; if ( ras.max_cells < 2 ) goto ReduceBands; for ( yindex = 0; yindex < ras.ycount; yindex++ ) ras.ycells[yindex] = NULL; } ras.num_cells = 0; ras.invalid = 1; ras.min_ey = band->min; ras.max_ey = band->max; ras.count_ey = band->max - band->min; error = gray_convert_glyph_inner( RAS_VAR ); if ( !error ) { gray_sweep( RAS_VAR); band--; continue; } else if ( error != ErrRaster_Memory_Overflow ) return 1; ReduceBands: /* render pool overflow; we will reduce the render band by half */ bottom = band->min; top = band->max; middle = bottom + ( ( top - bottom ) >> 1 ); /* This is too complex for a single scanline; there must */ /* be some problems. */ if ( middle == bottom ) { return 1; } if ( bottom-top >= ras.band_size ) ras.band_shoot++; band[1].min = bottom; band[1].max = middle; band[0].min = middle; band[0].max = top; band++; } } if ( ras.band_shoot > 8 && ras.band_size > 16 ) ras.band_size = ras.band_size / 2; return 0; } static int gray_raster_render( gray_PRaster raster, const SW_FT_Raster_Params* params ) { const SW_FT_Outline* outline = (const SW_FT_Outline*)params->source; gray_TWorker worker[1]; TCell buffer[SW_FT_RENDER_POOL_SIZE / sizeof ( TCell )]; long buffer_size = sizeof ( buffer ); int band_size = (int)( buffer_size / (long)( sizeof ( TCell ) * 8 ) ); if ( !raster) return SW_FT_THROW( Invalid_Argument ); if ( !outline ) return SW_FT_THROW( Invalid_Outline ); /* return immediately if the outline is empty */ if ( outline->n_points == 0 || outline->n_contours <= 0 ) return 0; if ( !outline->contours || !outline->points ) return SW_FT_THROW( Invalid_Outline ); if ( outline->n_points != outline->contours[outline->n_contours - 1] + 1 ) return SW_FT_THROW( Invalid_Outline ); /* this version does not support monochrome rendering */ if ( !( params->flags & SW_FT_RASTER_FLAG_AA ) ) return SW_FT_THROW( Invalid_Mode ); if ( params->flags & SW_FT_RASTER_FLAG_CLIP ) ras.clip_box = params->clip_box; else { ras.clip_box.xMin = -32768L; ras.clip_box.yMin = -32768L; ras.clip_box.xMax = 32767L; ras.clip_box.yMax = 32767L; } gray_init_cells( RAS_VAR_ buffer, buffer_size ); ras.outline = *outline; ras.num_cells = 0; ras.invalid = 1; ras.band_size = band_size; ras.num_gray_spans = 0; ras.span_y = 0; ras.render_span = (SW_FT_Raster_Span_Func)params->gray_spans; ras.render_span_data = params->user; return gray_convert_glyph( RAS_VAR ); } /**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/ /**** a static object. *****/ static int gray_raster_new(SW_FT_Raster* araster ) { static gray_TRaster the_raster; *araster = (SW_FT_Raster)&the_raster; SW_FT_MEM_ZERO( &the_raster, sizeof ( the_raster ) ); return 0; } static void gray_raster_done( SW_FT_Raster raster ) { /* nothing */ SW_FT_UNUSED( raster ); } static void gray_raster_reset( SW_FT_Raster raster, char* pool_base, long pool_size ) { SW_FT_UNUSED( raster ); SW_FT_UNUSED( pool_base ); SW_FT_UNUSED( pool_size ); } SW_FT_DEFINE_RASTER_FUNCS(sw_ft_grays_raster, (SW_FT_Raster_New_Func) gray_raster_new, (SW_FT_Raster_Reset_Func) gray_raster_reset, (SW_FT_Raster_Render_Func) gray_raster_render, (SW_FT_Raster_Done_Func) gray_raster_done ) /* END */