/**************************************************************************** * * ftgrays.c * * A new `perfect' anti-aliasing renderer (body). * * Copyright (C) 2000-2023 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 -DSTANDALONE_ 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 by straight segments. * * It is based on ideas that I initially found in Raph Levien's * excellent LibArt graphics library (see https://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. * * Bézier segments are flattened by splitting them until their deviation * from straight line becomes much smaller than a pixel. Therefore, the * pixel coverage by a Bézier curve is calculated approximately. To * estimate the deviation, we use the distance from the control point * to the conic chord centre or the cubic chord trisection. These * distances vanish fast after each split. In the conic case, they vanish * predictably and the number of necessary splits can be calculated. * * 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 by straight segments. * * - 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 (< 80) 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 … #ifdef STANDALONE_ /* The size in bytes of the render pool used by the scan-line converter */ /* to do all of its work. */ #define FT_RENDER_POOL_SIZE … /* Auxiliary macros for token concatenation. */ #define FT_ERR_XCAT … #define FT_ERR_CAT … #define FT_BEGIN_STMNT … #define FT_END_STMNT … #define FT_MIN … #define FT_MAX … #define FT_ABS … /* * Approximate sqrt(x*x+y*y) using the `alpha max plus beta min' * algorithm. We use alpha = 1, beta = 3/8, giving us results with a * largest error less than 7% compared to the exact value. */ #define FT_HYPOT … /* define this to dump debugging information */ /* #define FT_DEBUG_LEVEL_TRACE */ #ifdef FT_DEBUG_LEVEL_TRACE #include <stdio.h> #include <stdarg.h> #endif #include <stddef.h> #include <string.h> #include <setjmp.h> #include <limits.h> #define FT_CHAR_BIT … #define FT_UINT_MAX … #define FT_INT_MAX … #define FT_ULONG_MAX … #define ADD_INT … #define FT_STATIC_BYTE_CAST … #define ft_memset … #define ft_setjmp … #define ft_longjmp … #define ft_jmp_buf … typedef ptrdiff_t FT_PtrDist; #define Smooth_Err_Ok … #define Smooth_Err_Invalid_Outline … #define Smooth_Err_Cannot_Render_Glyph … #define Smooth_Err_Invalid_Argument … #define Smooth_Err_Raster_Overflow … #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 … /* we only use level 5 & 7 tracing messages; cf. ftdebug.h */ #ifdef FT_DEBUG_LEVEL_TRACE void FT_Message( const char* fmt, ... ) { va_list ap; va_start( ap, fmt ); vfprintf( stderr, fmt, ap ); va_end( ap ); } /* empty function useful for setting a breakpoint to catch errors */ int FT_Throw( int error, int line, const char* file ) { FT_UNUSED( error ); FT_UNUSED( line ); FT_UNUSED( file ); return 0; } /* we don't handle tracing levels in stand-alone mode; */ #ifndef FT_TRACE5 #define FT_TRACE5 … #endif #ifndef FT_TRACE7 #define FT_TRACE7 … #endif #ifndef FT_ERROR #define FT_ERROR … #endif #define FT_THROW … #else /* !FT_DEBUG_LEVEL_TRACE */ #define FT_TRACE5 … #define FT_TRACE7 … #define FT_ERROR … #define FT_THROW … #endif /* !FT_DEBUG_LEVEL_TRACE */ #define FT_Trace_Enable … #define FT_Trace_Disable … #define FT_DEFINE_OUTLINE_FUNCS … #define FT_DEFINE_RASTER_FUNCS … #else /* !STANDALONE_ */ #include <ft2build.h> #include FT_CONFIG_CONFIG_H #include "ftgrays.h" #include <freetype/internal/ftobjs.h> #include <freetype/internal/ftdebug.h> #include <freetype/internal/ftcalc.h> #include <freetype/ftoutln.h> #include "ftsmerrs.h" #endif /* !STANDALONE_ */ #ifndef FT_MEM_SET #define FT_MEM_SET … #endif #ifndef FT_MEM_ZERO #define FT_MEM_ZERO … #endif #ifndef FT_ZERO #define FT_ZERO … #endif /* as usual, for the speed hungry :-) */ #undef RAS_ARG #undef RAS_ARG_ #undef RAS_VAR #undef RAS_VAR_ #ifndef FT_STATIC_RASTER #define RAS_ARG … #define RAS_ARG_ … #define RAS_VAR … #define RAS_VAR_ … #else /* FT_STATIC_RASTER */ #define RAS_ARG … #define RAS_ARG_ … #define RAS_VAR … #define RAS_VAR_ … #endif /* FT_STATIC_RASTER */ /* must be at least 6 bits! */ #define PIXEL_BITS … #define ONE_PIXEL … #undef TRUNC #define TRUNC( x ) … #undef FRACT #define FRACT( x ) … #if PIXEL_BITS >= 6 #define UPSCALE( x ) … #define DOWNSCALE( x ) … #else #define UPSCALE … #define DOWNSCALE … #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. We use the remainder to keep */ /* track of accumulating errors and compensate for them. */ #define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) … #if defined( __GNUC__ ) && __GNUC__ < 7 && defined( __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 */ /* */ /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43721 */ #undef FT_DIV_MOD #define FT_DIV_MOD … #endif /* __arm__ */ /* Calculating coverages for a slanted line requires a division each */ /* time the line crosses from cell to cell. These macros speed up */ /* the repetitive divisions by replacing them with multiplications */ /* and right shifts so that at most two divisions are performed for */ /* each slanted line. Nevertheless, these divisions are noticeable */ /* in the overall performance because flattened curves produce a */ /* very large number of slanted lines. */ /* */ /* The division results here are always within ONE_PIXEL. Therefore */ /* the shift magnitude should be at least PIXEL_BITS wider than the */ /* divisors to provide sufficient accuracy of the multiply-shift. */ /* It should not exceed (64 - PIXEL_BITS) to prevent overflowing and */ /* leave enough room for 64-bit unsigned multiplication however. */ #define FT_UDIVPREP( c, b ) … #define FT_UDIV( a, b ) … /* Scale area and apply fill rule to calculate the coverage byte. */ /* The top fill bit is used for the non-zero rule. The eighth */ /* fill bit is used for the even-odd rule. The higher coverage */ /* bytes are either clamped for the non-zero-rule or discarded */ /* later for the even-odd rule. */ #define FT_FILL_RULE( coverage, area, fill ) … /* It is faster to write small spans byte-by-byte than calling */ /* `memset'. This is mainly due to the cost of the function call. */ #define FT_GRAY_SET( d, s, count ) … /************************************************************************** * * 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 */ TPos; /* subpixel coordinate */ TCoord; /* integer scanline/pixel coordinate */ TArea; /* cell areas, coordinate products */ PCell; TCell; TPixmap; /* maximum number of gray cells in the buffer */ #if FT_RENDER_POOL_SIZE > 2048 #define FT_MAX_GRAY_POOL … #else #define FT_MAX_GRAY_POOL … #endif /* FT_Span buffer size for direct rendering only */ #define FT_MAX_GRAY_SPANS … #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 */ gray_PWorker; #if defined( _MSC_VER ) #pragma warning( pop ) #endif #ifndef FT_STATIC_RASTER #define ras … #else static gray_TWorker ras; #endif /* The |x| value of the null cell. Must be the largest possible */ /* integer value stored in a `TCell.x` field. */ #define CELL_MAX_X_VALUE … #define FT_INTEGRATE( ras, a, b ) … gray_PRaster; #ifdef FT_DEBUG_LEVEL_TRACE /* to be called while in the debugger -- */ /* this function causes a compiler warning since it is unused otherwise */ static void gray_dump_cells( RAS_ARG ) { int y; for ( y = ras.min_ey; y < ras.max_ey; y++ ) { PCell cell = ras.ycells[y - ras.min_ey]; printf( "%3d:", y ); for ( ; cell != ras.cell_null; cell = cell->next ) printf( " (%3d, c:%4d, a:%6d)", cell->x, cell->cover, cell->area ); printf( "\n" ); } } #endif /* FT_DEBUG_LEVEL_TRACE */ /************************************************************************** * * Set the current cell to a new position. */ static void gray_set_cell( RAS_ARG_ TCoord ex, TCoord ey ) { … } #ifndef FT_INT64 /************************************************************************** * * 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, first, dy, delta, mod; TPos p, dx; int incr; ex1 = TRUNC( x1 ); ex2 = TRUNC( x2 ); /* trivial case. Happens often */ if ( y1 == y2 ) { gray_set_cell( RAS_VAR_ ex2, ey ); return; } fx1 = FRACT( x1 ); fx2 = FRACT( x2 ); /* everything is located in a single cell. That is easy! */ /* */ if ( ex1 == ex2 ) goto End; /* ok, we'll have to render a run of adjacent cells on the same */ /* scanline... */ /* */ dx = x2 - x1; dy = y2 - y1; if ( dx > 0 ) { p = ( ONE_PIXEL - fx1 ) * dy; first = ONE_PIXEL; incr = 1; } else { p = fx1 * dy; first = 0; incr = -1; dx = -dx; } /* the fractional part of y-delta is mod/dx. It is essential to */ /* keep track of its accumulation for accurate rendering. */ /* XXX: y-delta and x-delta below should be related. */ FT_DIV_MOD( TCoord, p, dx, delta, mod ); FT_INTEGRATE( ras, delta, fx1 + first ); y1 += delta; ex1 += incr; gray_set_cell( RAS_VAR_ ex1, ey ); if ( ex1 != ex2 ) { TCoord lift, rem; p = ONE_PIXEL * dy; FT_DIV_MOD( TCoord, p, dx, lift, rem ); do { delta = lift; mod += rem; if ( mod >= (TCoord)dx ) { mod -= (TCoord)dx; delta++; } FT_INTEGRATE( ras, delta, ONE_PIXEL ); y1 += delta; ex1 += incr; gray_set_cell( RAS_VAR_ ex1, ey ); } while ( ex1 != ex2 ); } fx1 = ONE_PIXEL - first; End: FT_INTEGRATE( ras, y2 - y1, fx1 + fx2 ); } /************************************************************************** * * 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, first, delta, mod; TPos p, dx, dy, x, x2; int incr; ey1 = TRUNC( ras.y ); ey2 = TRUNC( to_y ); /* if (ey2 >= ras.max_ey) ey2 = ras.max_ey-1; */ /* perform vertical clipping */ if ( ( ey1 >= ras.max_ey && ey2 >= ras.max_ey ) || ( ey1 < ras.min_ey && ey2 < ras.min_ey ) ) goto End; fy1 = FRACT( ras.y ); fy2 = FRACT( to_y ); /* everything is on a single scanline */ if ( ey1 == ey2 ) { gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, to_x, fy2 ); goto End; } dx = to_x - ras.x; dy = to_y - ras.y; /* vertical line - avoid calling gray_render_scanline */ if ( dx == 0 ) { TCoord ex = TRUNC( ras.x ); TCoord two_fx = FRACT( ras.x ) << 1; if ( dy > 0) { first = ONE_PIXEL; incr = 1; } else { first = 0; incr = -1; } delta = first - fy1; FT_INTEGRATE( ras, delta, two_fx); ey1 += incr; gray_set_cell( RAS_VAR_ ex, ey1 ); delta = first + first - ONE_PIXEL; while ( ey1 != ey2 ) { FT_INTEGRATE( ras, delta, two_fx); ey1 += incr; gray_set_cell( RAS_VAR_ ex, ey1 ); } delta = fy2 - ONE_PIXEL + first; FT_INTEGRATE( ras, delta, two_fx); goto End; } /* ok, we have to render several scanlines */ if ( dy > 0) { p = ( ONE_PIXEL - fy1 ) * dx; first = ONE_PIXEL; incr = 1; } else { p = fy1 * dx; first = 0; incr = -1; dy = -dy; } /* the fractional part of x-delta is mod/dy. It is essential to */ /* keep track of its accumulation for accurate rendering. */ FT_DIV_MOD( TCoord, p, dy, delta, mod ); x = ras.x + delta; gray_render_scanline( RAS_VAR_ ey1, ras.x, fy1, x, first ); ey1 += incr; gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 ); if ( ey1 != ey2 ) { TCoord lift, rem; p = ONE_PIXEL * dx; FT_DIV_MOD( TCoord, p, dy, lift, rem ); do { delta = lift; mod += rem; if ( mod >= (TCoord)dy ) { mod -= (TCoord)dy; delta++; } x2 = x + delta; gray_render_scanline( RAS_VAR_ ey1, x, ONE_PIXEL - first, x2, first ); x = x2; ey1 += incr; gray_set_cell( RAS_VAR_ TRUNC( x ), ey1 ); } while ( ey1 != ey2 ); } gray_render_scanline( RAS_VAR_ ey1, x, ONE_PIXEL - first, to_x, fy2 ); End: ras.x = to_x; ras.y = to_y; } #else /************************************************************************** * * Render a straight line across multiple cells in any direction. */ static void gray_render_line( RAS_ARG_ TPos to_x, TPos to_y ) { … } #endif /* * Benchmarking shows that using DDA to flatten the quadratic Bézier arcs * is slightly faster in the following cases: * * - When the host CPU is 64-bit. * - When SSE2 SIMD registers and instructions are available (even on * x86). * * For other cases, using binary splits is actually slightly faster. */ #if ( defined( __SSE2__ ) || \ defined( __x86_64__ ) || \ defined( _M_AMD64 ) || \ ( defined( _M_IX86_FP ) && _M_IX86_FP >= 2 ) ) && \ !defined( __VMS ) #define FT_SSE2 … #else #define FT_SSE2 … #endif #if FT_SSE2 || \ defined( __aarch64__ ) || \ defined( _M_ARM64 ) #define BEZIER_USE_DDA … #else #define BEZIER_USE_DDA … #endif /* * For now, the code that depends on `BEZIER_USE_DDA` requires `FT_Int64` * to be defined. If `FT_INT64` is not defined, meaning there is no * 64-bit type available, disable it to avoid compilation errors. See for * example https://gitlab.freedesktop.org/freetype/freetype/-/issues/1071. */ #if !defined( FT_INT64 ) # undef BEZIER_USE_DDA #define BEZIER_USE_DDA … #endif #if BEZIER_USE_DDA #if FT_SSE2 # include <emmintrin.h> #endif #define LEFT_SHIFT( a, b ) … static void gray_render_conic( RAS_ARG_ const FT_Vector* control, const FT_Vector* to ) { … } #else /* !BEZIER_USE_DDA */ /* * Note that multiple attempts to speed up the function below * with SSE2 intrinsics, using various data layouts, have turned * out to be slower than the non-SIMD code below. */ static void gray_split_conic( 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 FT_Vector* control, const FT_Vector* to ) { FT_Vector bez_stack[16 * 2 + 1]; /* enough to accommodate bisections */ FT_Vector* arc = bez_stack; TPos dx, dy; int draw; 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; /* 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[0].y ) < ras.min_ey && TRUNC( arc[1].y ) < ras.min_ey && TRUNC( arc[2].y ) < ras.min_ey ) ) { ras.x = arc[0].x; ras.y = arc[0].y; return; } dx = FT_ABS( arc[2].x + arc[0].x - 2 * arc[1].x ); dy = FT_ABS( arc[2].y + arc[0].y - 2 * arc[1].y ); if ( dx < dy ) dx = dy; /* We can calculate the number of necessary bisections because */ /* each bisection predictably reduces deviation exactly 4-fold. */ /* Even 32-bit deviation would vanish after 16 bisections. */ draw = 1; while ( dx > ONE_PIXEL / 4 ) { dx >>= 2; draw <<= 1; } /* We use decrement counter to count the total number of segments */ /* to draw starting from 2^level. Before each draw we split as */ /* many times as there are trailing zeros in the counter. */ do { int split = draw & ( -draw ); /* isolate the rightmost 1-bit */ while ( ( split >>= 1 ) ) { gray_split_conic( arc ); arc += 2; } gray_render_line( RAS_VAR_ arc[0].x, arc[0].y ); arc -= 2; } while ( --draw ); } #endif /* !BEZIER_USE_DDA */ /* * For cubic Bézier, binary splits are still faster than DDA * because the splits are adaptive to how quickly each sub-arc * approaches their chord trisection points. * * It might be useful to experiment with SSE2 to speed up * `gray_split_cubic`, though. */ static void gray_split_cubic( FT_Vector* base ) { … } static void gray_render_cubic( RAS_ARG_ const FT_Vector* control1, const FT_Vector* control2, const FT_Vector* to ) { … } static int gray_move_to( const FT_Vector* to, void* worker_ ) /* gray_PWorker */ { … } static int gray_line_to( const FT_Vector* to, void* worker_ ) /* gray_PWorker */ { … } static int gray_conic_to( const FT_Vector* control, const FT_Vector* to, void* worker_ ) /* gray_PWorker */ { … } static int gray_cubic_to( const FT_Vector* control1, const FT_Vector* control2, const FT_Vector* to, void* worker_ ) /* gray_PWorker */ { … } static void gray_sweep( RAS_ARG ) { … } static void gray_sweep_direct( RAS_ARG ) { … } #ifdef STANDALONE_ /************************************************************************** * * The following functions should only compile in stand-alone mode, * i.e., when building this component without the rest of FreeType. * */ /************************************************************************** * * @Function: * FT_Outline_Decompose * * @Description: * 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. * * @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. * * @InOut: * 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 #define SCALED … FT_Vector v_last; FT_Vector v_control; FT_Vector v_start; FT_Vector* point; FT_Vector* limit; char* tags; int error; int n; /* index of contour in outline */ int first; /* index of first point in contour */ int last; /* index of last point in contour */ char tag; /* current point's state */ int shift; TPos delta; if ( !outline ) return FT_THROW( Invalid_Outline ); if ( !func_interface ) return FT_THROW( Invalid_Argument ); shift = func_interface->shift; delta = func_interface->delta; last = -1; for ( n = 0; n < outline->n_contours; n++ ) { FT_TRACE5(( "FT_Outline_Decompose: Contour %d\n", n )); first = last + 1; last = outline->contours[n]; if ( last < first ) 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 = 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--; } FT_TRACE5(( " move to (%.2f, %.2f)\n", v_start.x / 64.0, v_start.y / 64.0 )); 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 ); FT_TRACE5(( " line to (%.2f, %.2f)\n", vec.x / 64.0, vec.y / 64.0 )); 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 ) { FT_TRACE5(( " conic to (%.2f, %.2f)" " with control (%.2f, %.2f)\n", vec.x / 64.0, vec.y / 64.0, v_control.x / 64.0, v_control.y / 64.0 )); 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; FT_TRACE5(( " conic to (%.2f, %.2f)" " with control (%.2f, %.2f)\n", v_middle.x / 64.0, v_middle.y / 64.0, v_control.x / 64.0, v_control.y / 64.0 )); error = func_interface->conic_to( &v_control, &v_middle, user ); if ( error ) goto Exit; v_control = vec; goto Do_Conic; } FT_TRACE5(( " conic to (%.2f, %.2f)" " with control (%.2f, %.2f)\n", v_start.x / 64.0, v_start.y / 64.0, v_control.x / 64.0, v_control.y / 64.0 )); 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 ); FT_TRACE5(( " cubic to (%.2f, %.2f)" " with controls (%.2f, %.2f) and (%.2f, %.2f)\n", vec.x / 64.0, vec.y / 64.0, vec1.x / 64.0, vec1.y / 64.0, vec2.x / 64.0, vec2.y / 64.0 )); error = func_interface->cubic_to( &vec1, &vec2, &vec, user ); if ( error ) goto Exit; continue; } FT_TRACE5(( " cubic to (%.2f, %.2f)" " with controls (%.2f, %.2f) and (%.2f, %.2f)\n", v_start.x / 64.0, v_start.y / 64.0, vec1.x / 64.0, vec1.y / 64.0, vec2.x / 64.0, vec2.y / 64.0 )); error = func_interface->cubic_to( &vec1, &vec2, &v_start, user ); goto Close; } } } /* close the contour with a line segment */ FT_TRACE5(( " line to (%.2f, %.2f)\n", v_start.x / 64.0, v_start.y / 64.0 )); error = func_interface->line_to( &v_start, user ); Close: if ( error ) goto Exit; } FT_TRACE5(( "FT_Outline_Decompose: Done\n", n )); return Smooth_Err_Ok; Exit: FT_TRACE5(( "FT_Outline_Decompose: Error 0x%x\n", error )); return error; Invalid_Outline: return FT_THROW( Invalid_Outline ); } #endif /* STANDALONE_ */ FT_DEFINE_OUTLINE_FUNCS( func_interface, (FT_Outline_MoveTo_Func) gray_move_to, /* move_to */ (FT_Outline_LineTo_Func) gray_line_to, /* line_to */ (FT_Outline_ConicTo_Func)gray_conic_to, /* conic_to */ (FT_Outline_CubicTo_Func)gray_cubic_to, /* cubic_to */ 0, /* shift */ 0 /* delta */ ) static int gray_convert_glyph_inner( RAS_ARG_ int continued ) { … } static int gray_convert_glyph( RAS_ARG ) { … } static int gray_raster_render( FT_Raster raster, const FT_Raster_Params* params ) { … } /**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/ /**** a static object. *****/ #ifdef STANDALONE_ static int gray_raster_new( void* memory, FT_Raster* araster ) { static gray_TRaster the_raster; FT_UNUSED( memory ); *araster = (FT_Raster)&the_raster; FT_ZERO( &the_raster ); return 0; } static void gray_raster_done( FT_Raster raster ) { /* nothing */ FT_UNUSED( raster ); } #else /* !STANDALONE_ */ static int gray_raster_new( void* memory_, FT_Raster* araster_ ) { … } static void gray_raster_done( FT_Raster raster ) { … } #endif /* !STANDALONE_ */ static void gray_raster_reset( FT_Raster raster, unsigned char* pool_base, unsigned long pool_size ) { … } static int gray_raster_set_mode( FT_Raster raster, unsigned long mode, void* args ) { … } FT_DEFINE_RASTER_FUNCS( ft_grays_raster, FT_GLYPH_FORMAT_OUTLINE, (FT_Raster_New_Func) gray_raster_new, /* raster_new */ (FT_Raster_Reset_Func) gray_raster_reset, /* raster_reset */ (FT_Raster_Set_Mode_Func)gray_raster_set_mode, /* raster_set_mode */ (FT_Raster_Render_Func) gray_raster_render, /* raster_render */ (FT_Raster_Done_Func) gray_raster_done /* raster_done */ ) /* END */ /* Local Variables: */ /* coding: utf-8 */ /* End: */
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