/***************************************************************************/ /* */ /* 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; int bound_left; int bound_top; int bound_right; int bound_bottom; 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 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; ras.bound_left = INT_MAX; ras.bound_top = INT_MAX; ras.bound_right = INT_MIN; ras.bound_bottom = INT_MIN; } /*************************************************************************/ /* */ /* 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; a = base[0].x + base[1].x; b = base[1].x + base[2].x; base[3].x = b >> 1; base[2].x = ( a + b ) >> 2; base[1].x = a >> 1; base[4].y = base[2].y; a = base[0].y + base[1].y; b = base[1].y + base[2].y; base[3].y = b >> 1; base[2].y = ( a + b ) >> 2; base[1].y = a >> 1; } 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; base[6].x = base[3].x; a = base[0].x + base[1].x; b = base[1].x + base[2].x; c = base[2].x + base[3].x; base[5].x = c >> 1; c += b; base[4].x = c >> 2; base[1].x = a >> 1; a += b; base[2].x = a >> 2; base[3].x = ( a + c ) >> 3; base[6].y = base[3].y; a = base[0].y + base[1].y; b = base[1].y + base[2].y; c = base[2].y + base[3].y; base[5].y = c >> 1; c += b; base[4].y = c >> 2; base[1].y = a >> 1; a += b; base[2].y = a >> 2; base[3].y = ( a + c ) >> 3; } 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 = 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 */ if ( ( TRUNC( arc[0].y ) >= ras.max_ey && TRUNC( arc[1].y ) >= ras.max_ey && TRUNC( arc[2].y ) >= ras.max_ey && TRUNC( arc[3].y ) >= ras.max_ey ) || ( TRUNC( arc[0].y ) < ras.min_ey && TRUNC( arc[1].y ) < ras.min_ey && TRUNC( arc[2].y ) < ras.min_ey && TRUNC( arc[3].y ) < ras.min_ey ) ) { ras.x = arc[0].x; ras.y = arc[0].y; return; } for (;;) { /* with each split, control points quickly converge towards */ /* chord trisection points and the vanishing distances below */ /* indicate when the segment is flat enough to draw */ if ( SW_FT_ABS( 2 * arc[0].x - 3 * arc[1].x + arc[3].x ) > ONE_PIXEL / 2 || SW_FT_ABS( 2 * arc[0].y - 3 * arc[1].y + arc[3].y ) > ONE_PIXEL / 2 || SW_FT_ABS( arc[0].x - 3 * arc[2].x + 2 * arc[3].x ) > ONE_PIXEL / 2 || SW_FT_ABS( arc[0].y - 3 * arc[2].y + 2 * arc[3].y ) > ONE_PIXEL / 2 ) goto Split; gray_render_line( RAS_VAR_ arc[0].x, arc[0].y ); if ( arc == ras.bez_stack ) return; arc -= 3; continue; Split: gray_split_cubic( arc ); 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; // update bounding box. if (x < ras.bound_left) ras.bound_left = x; if (y < ras.bound_top) ras.bound_top = y; if (y > ras.bound_bottom) ras.bound_bottom = y; if (x + acount > ras.bound_right) ras.bound_right = x + acount; /* 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 && 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; 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) { SW_FT_UNUSED(raster); 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 (!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.render_span = (SW_FT_Raster_Span_Func)params->gray_spans; ras.render_span_data = params->user; gray_convert_glyph(RAS_VAR); params->bbox_cb(ras.bound_left, ras.bound_top, ras.bound_right - ras.bound_left, ras.bound_bottom - ras.bound_top + 1, params->user); return 1; } /**** 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 */