Edit
kc3-lang/freetype/src/smooth/ftgrays.c
Werner Lemberg
- src/smooth/ftgrays.c
-
/***************************************************************************/ /* */ /* ftgrays.c */ /* */ /* A new `perfect' anti-aliasing renderer (body). */ /* */ /* Copyright 2000-2001, 2002, 2003, 2005, 2006, 2007 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 file can be compiled without the rest of the FreeType engine, by */ /* defining the _STANDALONE_ macro when compiling it. You also need to */ /* put the files `ftgrays.h' and `ftimage.h' into the current */ /* compilation directory. Typically, you could do something like */ /* */ /* - copy `src/smooth/ftgrays.c' (this file) to your current directory */ /* */ /* - copy `include/freetype/ftimage.h' and `src/smooth/ftgrays.h' to the */ /* same directory */ /* */ /* - compile `ftgrays' with the _STANDALONE_ macro defined, as in */ /* */ /* cc -c -D_STANDALONE_ ftgrays.c */ /* */ /* The renderer can be initialized with a call to */ /* `ft_gray_raster.raster_new'; an anti-aliased bitmap can be generated */ /* with a call to `ft_gray_raster.raster_render'. */ /* */ /* See the comments and documentation in the file `ftimage.h' for more */ /* details on how the raster works. */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* 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. */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ /* messages during execution. */ /* */ #undef FT_COMPONENT #define FT_COMPONENT trace_smooth #ifdef _STANDALONE_ #include <string.h> /* for ft_memcpy() */ #include <setjmp.h> #include <limits.h> #define FT_UINT_MAX UINT_MAX #define ft_memset memset #define ft_setjmp setjmp #define ft_longjmp longjmp #define ft_jmp_buf jmp_buf #define ErrRaster_Invalid_Mode -2 #define ErrRaster_Invalid_Outline -1 #define ErrRaster_Invalid_Argument -3 #define ErrRaster_Memory_Overflow -4 #define FT_BEGIN_HEADER #define FT_END_HEADER #include "ftimage.h" #include "ftgrays.h" /* 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 FT_UNUSED( x ) (x) = (x) /* Disable the tracing mechanism for simplicity -- developers can */ /* activate it easily by redefining these two macros. */ #ifndef FT_ERROR #define FT_ERROR( x ) do ; while ( 0 ) /* nothing */ #endif #ifndef FT_TRACE #define FT_TRACE( x ) do ; while ( 0 ) /* nothing */ #endif #else /* !_STANDALONE_ */ #include <ft2build.h> #include "ftgrays.h" #include FT_INTERNAL_OBJECTS_H #include FT_INTERNAL_DEBUG_H #include FT_OUTLINE_H #include "ftsmerrs.h" #define ErrRaster_Invalid_Mode Smooth_Err_Cannot_Render_Glyph #define ErrRaster_Invalid_Outline Smooth_Err_Invalid_Outline #define ErrRaster_Memory_Overflow Smooth_Err_Out_Of_Memory #define ErrRaster_Invalid_Argument Smooth_Err_Bad_Argument #endif /* !_STANDALONE_ */ #ifndef FT_MEM_SET #define FT_MEM_SET( d, s, c ) ft_memset( d, s, c ) #endif #ifndef FT_MEM_ZERO #define FT_MEM_ZERO( dest, count ) FT_MEM_SET( dest, 0, count ) #endif /* define this to dump debugging information */ #define xxxDEBUG_GRAYS /* as usual, for the speed hungry :-) */ #ifndef FT_STATIC_RASTER #define RAS_ARG PWorker worker #define RAS_ARG_ PWorker worker, #define RAS_VAR worker #define RAS_VAR_ worker, #define ras (*worker) #else /* FT_STATIC_RASTER */ #define RAS_ARG /* empty */ #define RAS_ARG_ /* empty */ #define RAS_VAR /* empty */ #define RAS_VAR_ /* empty */ static TWorker ras; #endif /* FT_STATIC_RASTER */ /* must be at least 6 bits! */ #define PIXEL_BITS 8 #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 /*************************************************************************/ /* */ /* TYPE DEFINITIONS */ /* */ /* don't change the following types to FT_Int or FT_Pos, since we might */ /* need to define them to "float" or "double" when experimenting with */ /* new algorithms */ typedef int 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 FT_UINT_MAX == 0xFFFFU typedef long TArea; #else typedef int TArea; #endif #endif /* PIXEL_BITS >= 8 */ /* maximal number of gray spans in a call to the span callback */ #define FT_MAX_GRAY_SPANS 32 typedef struct TCell_* PCell; typedef struct TCell_ { int x; int cover; TArea area; PCell next; } TCell; typedef struct TWorker_ { TCoord ex, ey; TPos min_ex, max_ex; TPos min_ey, max_ey; TPos count_ex, count_ey; TArea area; int cover; int invalid; PCell cells; int max_cells; int num_cells; TCoord cx, cy; TPos x, y; TPos last_ey; FT_Vector bez_stack[32 * 3 + 1]; int lev_stack[32]; FT_Outline outline; FT_Bitmap target; FT_BBox clip_box; FT_Span gray_spans[FT_MAX_GRAY_SPANS]; int num_gray_spans; FT_Raster_Span_Func render_span; void* render_span_data; int span_y; int band_size; int band_shoot; int conic_level; int cubic_level; ft_jmp_buf jump_buffer; void* buffer; long buffer_size; PCell* ycells; int ycount; } TWorker, *PWorker; typedef struct TRaster_ { void* buffer; long buffer_size; int band_size; void* memory; PWorker worker; } TRaster, *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 ) { FT_Outline* outline = &ras.outline; FT_Vector* vec = outline->points; 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; int x = ras.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.invalid && ( 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; 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.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.last_ey = SUBPIXELS( ey ); ras.invalid = 0; gray_set_cell( RAS_VAR_ ex, ey ); } /*************************************************************************/ /* */ /* Render a scanline as one or more cells. */ /* */ static void gray_render_scanline( RAS_ARG_ TCoord ey, TPos x1, TCoord y1, TPos x2, TCoord y2 ) { TCoord ex1, ex2, fx1, fx2, delta; long p, first, dx; int incr, lift, mod, rem; dx = x2 - x1; ex1 = TRUNC( x1 ); ex2 = TRUNC( x2 ); fx1 = (TCoord)( x1 - SUBPIXELS( ex1 ) ); fx2 = (TCoord)( x2 - SUBPIXELS( ex2 ) ); /* trivial case. Happens often */ if ( y1 == y2 ) { gray_set_cell( RAS_VAR_ ex2, ey ); return; } /* everything is located in a single cell. That is easy! */ /* */ if ( ex1 == ex2 ) { delta = y2 - y1; ras.area += (TArea)( fx1 + fx2 ) * delta; ras.cover += delta; return; } /* ok, we'll have to render a run of adjacent cells on the same */ /* scanline... */ /* */ p = ( ONE_PIXEL - fx1 ) * ( y2 - y1 ); first = ONE_PIXEL; incr = 1; if ( dx < 0 ) { p = fx1 * ( y2 - y1 ); first = 0; incr = -1; dx = -dx; } delta = (TCoord)( p / dx ); mod = (TCoord)( p % dx ); if ( mod < 0 ) { delta--; mod += (TCoord)dx; } ras.area += (TArea)( fx1 + first ) * delta; ras.cover += delta; ex1 += incr; gray_set_cell( RAS_VAR_ ex1, ey ); y1 += delta; if ( ex1 != ex2 ) { p = ONE_PIXEL * ( y2 - y1 + delta ); lift = (TCoord)( p / dx ); rem = (TCoord)( p % dx ); if ( rem < 0 ) { lift--; rem += (TCoord)dx; } mod -= (int)dx; while ( ex1 != ex2 ) { delta = lift; mod += rem; if ( mod >= 0 ) { mod -= (TCoord)dx; delta++; } ras.area += (TArea)ONE_PIXEL * delta; ras.cover += delta; y1 += delta; ex1 += incr; gray_set_cell( RAS_VAR_ ex1, ey ); } } delta = y2 - y1; ras.area += (TArea)( fx2 + ONE_PIXEL - first ) * delta; ras.cover += delta; } /*************************************************************************/ /* */ /* Render a given line as a series of scanlines. */ /* */ static void gray_render_line( RAS_ARG_ TPos to_x, TPos to_y ) { TCoord ey1, ey2, fy1, fy2; TPos dx, dy, x, x2; long p, first; int delta, rem, mod, lift, incr; ey1 = TRUNC( ras.last_ey ); ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */ fy1 = (TCoord)( ras.y - ras.last_ey ); fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) ); dx = to_x - ras.x; dy = to_y - ras.y; /* XXX: we should do something about the trivial case where dx == 0, */ /* as it happens very often! */ /* perform vertical clipping */ { TCoord min, max; min = ey1; max = ey2; if ( ey1 > ey2 ) { min = ey2; max = ey1; } if ( min >= ras.max_ey || max < ras.min_ey ) goto End; } /* everything is on a single scanline */ if ( ey1 == ey2 ) { gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 ); goto End; } /* vertical line - avoid calling gray_render_scanline */ incr = 1; if ( dx == 0 ) { TCoord ex = TRUNC( ras.x ); TCoord two_fx = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 ); TPos area; first = ONE_PIXEL; if ( dy < 0 ) { first = 0; incr = -1; } delta = (int)( first - fy1 ); ras.area += (TArea)two_fx * delta; ras.cover += delta; ey1 += incr; gray_set_cell( &ras, ex, ey1 ); delta = (int)( first + first - ONE_PIXEL ); area = (TArea)two_fx * delta; while ( ey1 != ey2 ) { ras.area += area; ras.cover += delta; ey1 += incr; gray_set_cell( &ras, ex, ey1 ); } delta = (int)( fy2 - ONE_PIXEL + first ); ras.area += (TArea)two_fx * delta; ras.cover += delta; goto End; } /* ok, we have to render several scanlines */ p = ( ONE_PIXEL - fy1 ) * dx; first = ONE_PIXEL; incr = 1; if ( dy < 0 ) { p = fy1 * dx; first = 0; incr = -1; dy = -dy; } delta = (int)( p / dy ); mod = (int)( p % dy ); if ( mod < 0 ) { delta--; mod += (TCoord)dy; } x = ras.x + delta; gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, (TCoord)first ); ey1 += incr; gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 ); if ( ey1 != ey2 ) { p = ONE_PIXEL * dx; lift = (int)( p / dy ); rem = (int)( p % dy ); if ( rem < 0 ) { lift--; rem += (int)dy; } mod -= (int)dy; while ( ey1 != ey2 ) { delta = lift; mod += rem; if ( mod >= 0 ) { mod -= (int)dy; delta++; } x2 = x + delta; gray_render_scanline( RAS_VAR_ ey1, x, (TCoord)( ONE_PIXEL - first ), x2, (TCoord)first ); x = x2; ey1 += incr; gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 ); } } gray_render_scanline( RAS_VAR_ ey1, x, (TCoord)( ONE_PIXEL - first ), to_x, fy2 ); End: ras.x = to_x; ras.y = to_y; ras.last_ey = SUBPIXELS( ey2 ); } static void gray_split_conic( 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 FT_Vector* control, const FT_Vector* to ) { TPos dx, dy; int top, level; int* levels; FT_Vector* arc; dx = DOWNSCALE( ras.x ) + to->x - ( control->x << 1 ); if ( dx < 0 ) dx = -dx; dy = DOWNSCALE( ras.y ) + to->y - ( control->y << 1 ); if ( dy < 0 ) dy = -dy; if ( dx < dy ) dx = dy; level = 1; dx = dx / ras.conic_level; while ( dx > 0 ) { dx >>= 2; level++; } /* a shortcut to speed things up */ if ( level <= 1 ) { /* we compute the mid-point directly in order to avoid */ /* calling gray_split_conic() */ TPos to_x, to_y, mid_x, mid_y; to_x = UPSCALE( to->x ); to_y = UPSCALE( to->y ); mid_x = ( ras.x + to_x + 2 * UPSCALE( control->x ) ) / 4; mid_y = ( ras.y + to_y + 2 * UPSCALE( control->y ) ) / 4; gray_render_line( RAS_VAR_ mid_x, mid_y ); gray_render_line( RAS_VAR_ to_x, to_y ); return; } arc = ras.bez_stack; levels = ras.lev_stack; top = 0; levels[0] = level; 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; while ( top >= 0 ) { level = levels[top]; if ( level > 1 ) { /* check that the arc crosses the current band */ TPos min, max, y; 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; gray_split_conic( arc ); arc += 2; top++; levels[top] = levels[top - 1] = level - 1; continue; } Draw: { TPos to_x, to_y, mid_x, mid_y; to_x = arc[0].x; to_y = arc[0].y; mid_x = ( ras.x + to_x + 2 * arc[1].x ) / 4; mid_y = ( ras.y + to_y + 2 * arc[1].y ) / 4; gray_render_line( RAS_VAR_ mid_x, mid_y ); gray_render_line( RAS_VAR_ to_x, to_y ); top--; arc -= 2; } } return; } static void gray_split_cubic( 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 FT_Vector* control1, const FT_Vector* control2, const FT_Vector* to ) { TPos dx, dy, da, db; int top, level; int* levels; FT_Vector* arc; dx = DOWNSCALE( ras.x ) + to->x - ( control1->x << 1 ); if ( dx < 0 ) dx = -dx; dy = DOWNSCALE( ras.y ) + to->y - ( control1->y << 1 ); if ( dy < 0 ) dy = -dy; if ( dx < dy ) dx = dy; da = dx; dx = DOWNSCALE( ras.x ) + to->x - 3 * ( control1->x + control2->x ); if ( dx < 0 ) dx = -dx; dy = DOWNSCALE( ras.y ) + to->y - 3 * ( control1->x + control2->y ); if ( dy < 0 ) dy = -dy; if ( dx < dy ) dx = dy; db = dx; level = 1; da = da / ras.cubic_level; db = db / ras.conic_level; while ( da > 0 || db > 0 ) { da >>= 2; db >>= 3; level++; } if ( level <= 1 ) { TPos to_x, to_y, mid_x, mid_y; to_x = UPSCALE( to->x ); to_y = UPSCALE( to->y ); mid_x = ( ras.x + to_x + 3 * UPSCALE( control1->x + control2->x ) ) / 8; mid_y = ( ras.y + to_y + 3 * UPSCALE( control1->y + control2->y ) ) / 8; gray_render_line( RAS_VAR_ mid_x, mid_y ); gray_render_line( RAS_VAR_ to_x, to_y ); return; } 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; levels = ras.lev_stack; top = 0; levels[0] = level; while ( top >= 0 ) { level = levels[top]; if ( level > 1 ) { /* check that the arc crosses the current band */ TPos min, max, y; 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 ) < 0 ) goto Draw; gray_split_cubic( arc ); arc += 3; top ++; levels[top] = levels[top - 1] = level - 1; continue; } Draw: { TPos to_x, to_y, mid_x, mid_y; to_x = arc[0].x; to_y = arc[0].y; mid_x = ( ras.x + to_x + 3 * ( arc[1].x + arc[2].x ) ) / 8; mid_y = ( ras.y + to_y + 3 * ( arc[1].y + arc[2].y ) ) / 8; gray_render_line( RAS_VAR_ mid_x, mid_y ); gray_render_line( RAS_VAR_ to_x, to_y ); top --; arc -= 3; } } return; } static int gray_move_to( const FT_Vector* to, PWorker worker ) { TPos x, y; /* record current cell, if any */ gray_record_cell( worker ); /* start to a new position */ x = UPSCALE( to->x ); y = UPSCALE( to->y ); gray_start_cell( worker, TRUNC( x ), TRUNC( y ) ); worker->x = x; worker->y = y; return 0; } static int gray_line_to( const FT_Vector* to, PWorker worker ) { gray_render_line( worker, UPSCALE( to->x ), UPSCALE( to->y ) ); return 0; } static int gray_conic_to( const FT_Vector* control, const FT_Vector* to, PWorker worker ) { gray_render_conic( worker, control, to ); return 0; } static int gray_cubic_to( const FT_Vector* control1, const FT_Vector* control2, const FT_Vector* to, PWorker worker ) { gray_render_cubic( worker, control1, control2, to ); return 0; } static void gray_render_span( int y, int count, const FT_Span* spans, PWorker worker ) { unsigned char* p; FT_Bitmap* map = &worker->target; /* first of all, compute the scanline offset */ p = (unsigned char*)map->buffer - y * map->pitch; if ( map->pitch >= 0 ) p += ( map->rows - 1 ) * map->pitch; for ( ; count > 0; count--, spans++ ) { unsigned char coverage = spans->coverage; if ( coverage ) { /* For small-spans it is faster to do it by ourselves than * calling `memset'. This is mainly due to the cost of the * function call. */ if ( spans->len >= 8 ) FT_MEM_SET( p + spans->x, (unsigned char)coverage, spans->len ); else { unsigned char* q = p + spans->x; switch ( spans->len ) { case 7: *q++ = (unsigned char)coverage; case 6: *q++ = (unsigned char)coverage; case 5: *q++ = (unsigned char)coverage; case 4: *q++ = (unsigned char)coverage; case 3: *q++ = (unsigned char)coverage; case 2: *q++ = (unsigned char)coverage; case 1: *q = (unsigned char)coverage; default: ; } } } } } static void gray_hline( RAS_ARG_ TCoord x, TCoord y, TPos area, int acount ) { FT_Span* span; int count; 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 & 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; if ( coverage ) { /* 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 ( ras.span_y != y || count >= FT_MAX_GRAY_SPANS ) { if ( ras.render_span && count > 0 ) ras.render_span( ras.span_y, count, ras.gray_spans, ras.render_span_data ); /* ras.render_span( span->y, ras.gray_spans, count ); */ #ifdef DEBUG_GRAYS if ( ras.span_y >= 0 ) { int n; fprintf( stderr, "y=%3d ", ras.span_y ); span = ras.gray_spans; for ( n = 0; n < count; n++, span++ ) fprintf( stderr, "[%d..%d]:%02x ", span->x, span->x + span->len - 1, span->coverage ); fprintf( stderr, "\n" ); } #endif /* DEBUG_GRAYS */ ras.num_gray_spans = 0; ras.span_y = y; count = 0; span = ras.gray_spans; } else span++; /* add a gray span to the current list */ span->x = (short)x; span->len = (unsigned short)acount; span->coverage = (unsigned char)coverage; ras.num_gray_spans++; } } #ifdef DEBUG_GRAYS /* to be called while in the debugger */ gray_dump_cells( RAS_ARG ) { int yindex; for ( yindex = 0; yindex < ras.ycount; yindex++ ) { PCell cell; printf( "%3d:", yindex ); for ( cell = ras.ycells[yindex]; cell != NULL; cell = cell->next ) printf( " (%3d, c:%4d, a:%6d)", cell->x, cell->cover, cell->area ); printf( "\n" ); } } #endif /* DEBUG_GRAYS */ static void gray_sweep( RAS_ARG_ const FT_Bitmap* target ) { int yindex; FT_UNUSED( target ); 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 ) { TArea 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.span_y, ras.num_gray_spans, ras.gray_spans, ras.render_span_data ); } #ifdef _STANDALONE_ /*************************************************************************/ /* */ /* The following function should only compile in stand_alone mode, */ /* i.e., when building this component without the rest of FreeType. */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* <Function> */ /* FT_Outline_Decompose */ /* */ /* <Description> */ /* Walks over an outline's structure to decompose it into individual */ /* segments and Bezier 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. */ /* */ /* <Input> */ /* 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. */ /* */ /* <Return> */ /* Error code. 0 means success. */ /* */ static int FT_Outline_Decompose( const FT_Outline* outline, const FT_Outline_Funcs* func_interface, void* user ) { #undef SCALED #if 0 #define SCALED( x ) ( ( (x) << shift ) - delta ) #else #define SCALED( x ) (x) #endif FT_Vector v_last; FT_Vector v_control; FT_Vector v_start; FT_Vector* point; FT_Vector* limit; char* tags; int n; /* index of contour in outline */ int first; /* index of first point in contour */ int error; char tag; /* current point's state */ #if 0 int shift = func_interface->shift; TPos delta = func_interface->delta; #endif first = 0; for ( n = 0; n < outline->n_contours; n++ ) { int last; /* index of last point in contour */ last = outline->contours[n]; limit = outline->points + last; v_start = outline->points[first]; v_last = outline->points[last]; v_start.x = SCALED( v_start.x ); v_start.y = SCALED( v_start.y ); 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 = FT_CURVE_TAG( tags[0] ); /* A contour cannot start with a cubic control point! */ if ( tag == FT_CURVE_TAG_CUBIC ) goto Invalid_Outline; /* check first point to determine origin */ if ( tag == FT_CURVE_TAG_CONIC ) { /* first point is conic control. Yes, this happens. */ if ( FT_CURVE_TAG( outline->tags[last] ) == 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; v_last = v_start; } point--; tags--; } error = func_interface->move_to( &v_start, user ); if ( error ) goto Exit; while ( point < limit ) { point++; tags++; tag = FT_CURVE_TAG( tags[0] ); switch ( tag ) { case FT_CURVE_TAG_ON: /* emit a single line_to */ { 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 FT_CURVE_TAG_CONIC: /* consume conic arcs */ { v_control.x = SCALED( point->x ); v_control.y = SCALED( point->y ); Do_Conic: if ( point < limit ) { FT_Vector vec; FT_Vector v_middle; point++; tags++; tag = FT_CURVE_TAG( tags[0] ); vec.x = SCALED( point->x ); vec.y = SCALED( point->y ); if ( tag == FT_CURVE_TAG_ON ) { error = func_interface->conic_to( &v_control, &vec, user ); if ( error ) goto Exit; continue; } if ( tag != 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: /* FT_CURVE_TAG_CUBIC */ { FT_Vector vec1, vec2; if ( point + 1 > limit || FT_CURVE_TAG( tags[1] ) != 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 ) { 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 ErrRaster_Invalid_Outline; } #endif /* _STANDALONE_ */ typedef struct TBand_ { TPos min, max; } TBand; static int gray_convert_glyph_inner( RAS_ARG ) { static const FT_Outline_Funcs func_interface = { (FT_Outline_MoveTo_Func) gray_move_to, (FT_Outline_LineTo_Func) gray_line_to, (FT_Outline_ConicTo_Func)gray_conic_to, (FT_Outline_CubicTo_Func)gray_cubic_to, 0, 0 }; volatile int error = 0; if ( ft_setjmp( ras.jump_buffer ) == 0 ) { error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras ); gray_record_cell( RAS_VAR ); } else { error = ErrRaster_Memory_Overflow; } return error; } static int gray_convert_glyph( RAS_ARG ) { TBand bands[40]; TBand* volatile band; int volatile n, num_bands; TPos volatile min, max, max_y; 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; /* simple heuristic used to speed-up the bezier decomposition -- see */ /* the code in gray_render_conic() and gray_render_cubic() for more */ /* details */ ras.conic_level = 32; ras.cubic_level = 16; { int level = 0; if ( ras.count_ex > 24 || ras.count_ey > 24 ) level++; if ( ras.count_ex > 120 || ras.count_ey > 120 ) level++; ras.conic_level <<= level; ras.cubic_level <<= level; } /* setup 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_ &ras.target ); 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 ) { #ifdef DEBUG_GRAYS fprintf( stderr, "Rotten glyph!\n" ); #endif 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( PRaster raster, const FT_Raster_Params* params ) { const FT_Outline* outline = (const FT_Outline*)params->source; const FT_Bitmap* target_map = params->target; PWorker worker; if ( !raster || !raster->buffer || !raster->buffer_size ) return ErrRaster_Invalid_Argument; /* return immediately if the outline is empty */ if ( outline->n_points == 0 || outline->n_contours <= 0 ) return 0; if ( !outline || !outline->contours || !outline->points ) return ErrRaster_Invalid_Outline; if ( outline->n_points != outline->contours[outline->n_contours - 1] + 1 ) return ErrRaster_Invalid_Outline; worker = raster->worker; /* if direct mode is not set, we must have a target bitmap */ if ( ( params->flags & FT_RASTER_FLAG_DIRECT ) == 0 ) { if ( !target_map ) return ErrRaster_Invalid_Argument; /* nothing to do */ if ( !target_map->width || !target_map->rows ) return 0; if ( !target_map->buffer ) return ErrRaster_Invalid_Argument; } /* this version does not support monochrome rendering */ if ( !( params->flags & FT_RASTER_FLAG_AA ) ) return ErrRaster_Invalid_Mode; /* compute clipping box */ if ( ( params->flags & FT_RASTER_FLAG_DIRECT ) == 0 ) { /* compute clip box from target pixmap */ ras.clip_box.xMin = 0; ras.clip_box.yMin = 0; ras.clip_box.xMax = target_map->width; ras.clip_box.yMax = target_map->rows; } else if ( params->flags & 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( worker, raster->buffer, raster->buffer_size ); ras.outline = *outline; ras.num_cells = 0; ras.invalid = 1; ras.band_size = raster->band_size; ras.num_gray_spans = 0; if ( target_map ) ras.target = *target_map; ras.render_span = (FT_Raster_Span_Func)gray_render_span; ras.render_span_data = &ras; if ( params->flags & FT_RASTER_FLAG_DIRECT ) { ras.render_span = (FT_Raster_Span_Func)params->gray_spans; ras.render_span_data = params->user; } return gray_convert_glyph( worker ); } /**** RASTER OBJECT CREATION: In standalone mode, we simply use *****/ /**** a static object. *****/ #ifdef _STANDALONE_ static int gray_raster_new( void* memory, FT_Raster* araster ) { static TRaster the_raster; FT_UNUSED( memory ); *araster = (FT_Raster)&the_raster; FT_MEM_ZERO( &the_raster, sizeof ( the_raster ) ); return 0; } static void gray_raster_done( FT_Raster raster ) { /* nothing */ FT_UNUSED( raster ); } #else /* _STANDALONE_ */ static int gray_raster_new( FT_Memory memory, FT_Raster* araster ) { FT_Error error; PRaster raster; *araster = 0; if ( !FT_ALLOC( raster, sizeof ( TRaster ) ) ) { raster->memory = memory; *araster = (FT_Raster)raster; } return error; } static void gray_raster_done( FT_Raster raster ) { FT_Memory memory = (FT_Memory)((PRaster)raster)->memory; FT_FREE( raster ); } #endif /* _STANDALONE_ */ static void gray_raster_reset( FT_Raster raster, char* pool_base, long pool_size ) { PRaster rast = (PRaster)raster; if ( raster ) { if ( pool_base && pool_size >= (long)sizeof ( TWorker ) + 2048 ) { PWorker worker = (PWorker)pool_base; rast->worker = worker; rast->buffer = pool_base + ( ( sizeof ( TWorker ) + sizeof ( TCell ) - 1 ) & ~( sizeof ( TCell ) - 1 ) ); rast->buffer_size = (long)( ( pool_base + pool_size ) - (char*)rast->buffer ) & ~( sizeof ( TCell ) - 1 ); rast->band_size = (int)( rast->buffer_size / ( sizeof ( TCell ) * 8 ) ); } else { rast->buffer = NULL; rast->buffer_size = 0; rast->worker = NULL; } } } const FT_Raster_Funcs ft_grays_raster = { FT_GLYPH_FORMAT_OUTLINE, (FT_Raster_New_Func) gray_raster_new, (FT_Raster_Reset_Func) gray_raster_reset, (FT_Raster_Set_Mode_Func)0, (FT_Raster_Render_Func) gray_raster_render, (FT_Raster_Done_Func) gray_raster_done }; /* END */