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Diffstat (limited to 'modules/freetype2/src/smooth/ftgrays.c')
| -rw-r--r-- | modules/freetype2/src/smooth/ftgrays.c | 2230 |
1 files changed, 2230 insertions, 0 deletions
diff --git a/modules/freetype2/src/smooth/ftgrays.c b/modules/freetype2/src/smooth/ftgrays.c new file mode 100644 index 0000000000..d9f20eef13 --- /dev/null +++ b/modules/freetype2/src/smooth/ftgrays.c @@ -0,0 +1,2230 @@ +/**************************************************************************** + * + * 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 smooth + + +#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 16384L + + + /* Auxiliary macros for token concatenation. */ +#define FT_ERR_XCAT( x, y ) x ## y +#define FT_ERR_CAT( x, y ) FT_ERR_XCAT( x, y ) + +#define FT_BEGIN_STMNT do { +#define FT_END_STMNT } while ( 0 ) + +#define FT_MIN( a, b ) ( (a) < (b) ? (a) : (b) ) +#define FT_MAX( a, b ) ( (a) > (b) ? (a) : (b) ) +#define FT_ABS( a ) ( (a) < 0 ? -(a) : (a) ) + + + /* + * 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( x, y ) \ + ( x = FT_ABS( x ), \ + y = FT_ABS( y ), \ + x > y ? x + ( 3 * y >> 3 ) \ + : y + ( 3 * x >> 3 ) ) + + + /* 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 CHAR_BIT +#define FT_UINT_MAX UINT_MAX +#define FT_INT_MAX INT_MAX +#define FT_ULONG_MAX ULONG_MAX + +#define ADD_INT( a, b ) \ + (int)( (unsigned int)(a) + (unsigned int)(b) ) + +#define FT_STATIC_BYTE_CAST( type, var ) (type)(unsigned char)(var) + + +#define ft_memset memset + +#define ft_setjmp setjmp +#define ft_longjmp longjmp +#define ft_jmp_buf jmp_buf + +typedef ptrdiff_t FT_PtrDist; + + +#define Smooth_Err_Ok 0 +#define Smooth_Err_Invalid_Outline -1 +#define Smooth_Err_Cannot_Render_Glyph -2 +#define Smooth_Err_Invalid_Argument -3 +#define Smooth_Err_Raster_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) + + + /* 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( varformat ) FT_Message varformat +#endif +#ifndef FT_TRACE7 +#define FT_TRACE7( varformat ) FT_Message varformat +#endif +#ifndef FT_ERROR +#define FT_ERROR( varformat ) FT_Message varformat +#endif + +#define FT_THROW( e ) \ + ( FT_Throw( FT_ERR_CAT( Smooth_Err_, e ), \ + __LINE__, \ + __FILE__ ) | \ + FT_ERR_CAT( Smooth_Err_, e ) ) + +#else /* !FT_DEBUG_LEVEL_TRACE */ + +#define FT_TRACE5( x ) do { } while ( 0 ) /* nothing */ +#define FT_TRACE7( x ) do { } while ( 0 ) /* nothing */ +#define FT_ERROR( x ) do { } while ( 0 ) /* nothing */ +#define FT_THROW( e ) FT_ERR_CAT( Smooth_Err_, e ) + +#endif /* !FT_DEBUG_LEVEL_TRACE */ + + +#define FT_Trace_Enable() do { } while ( 0 ) /* nothing */ +#define FT_Trace_Disable() do { } while ( 0 ) /* nothing */ + + +#define FT_DEFINE_OUTLINE_FUNCS( class_, \ + move_to_, line_to_, \ + conic_to_, cubic_to_, \ + shift_, delta_ ) \ + static const FT_Outline_Funcs class_ = \ + { \ + move_to_, \ + line_to_, \ + conic_to_, \ + cubic_to_, \ + shift_, \ + delta_ \ + }; + +#define FT_DEFINE_RASTER_FUNCS( class_, glyph_format_, \ + raster_new_, raster_reset_, \ + raster_set_mode_, raster_render_, \ + raster_done_ ) \ + const FT_Raster_Funcs class_ = \ + { \ + glyph_format_, \ + raster_new_, \ + raster_reset_, \ + raster_set_mode_, \ + raster_render_, \ + raster_done_ \ + }; + + +#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( 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 + +#ifndef FT_ZERO +#define FT_ZERO( p ) FT_MEM_ZERO( p, sizeof ( *(p) ) ) +#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 gray_PWorker worker +#define RAS_ARG_ gray_PWorker worker, + +#define RAS_VAR worker +#define RAS_VAR_ worker, + +#else /* FT_STATIC_RASTER */ + +#define RAS_ARG void +#define RAS_ARG_ /* empty */ +#define RAS_VAR /* empty */ +#define RAS_VAR_ /* empty */ + +#endif /* FT_STATIC_RASTER */ + + + /* must be at least 6 bits! */ +#define PIXEL_BITS 8 + +#define ONE_PIXEL ( 1 << PIXEL_BITS ) +#undef TRUNC +#define TRUNC( x ) (TCoord)( (x) >> PIXEL_BITS ) +#undef FRACT +#define FRACT( x ) (TCoord)( (x) & ( ONE_PIXEL - 1 ) ) + +#if PIXEL_BITS >= 6 +#define UPSCALE( x ) ( (x) * ( ONE_PIXEL >> 6 ) ) +#define DOWNSCALE( x ) ( (x) >> ( PIXEL_BITS - 6 ) ) +#else +#define UPSCALE( x ) ( (x) >> ( 6 - PIXEL_BITS ) ) +#define DOWNSCALE( x ) ( (x) * ( 64 >> 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. We use the remainder to keep */ + /* track of accumulating errors and compensate for them. */ +#define FT_DIV_MOD( type, dividend, divisor, quotient, remainder ) \ + FT_BEGIN_STMNT \ + (quotient) = (type)( (dividend) / (divisor) ); \ + (remainder) = (type)( (dividend) % (divisor) ); \ + if ( (remainder) < 0 ) \ + { \ + (quotient)--; \ + (remainder) += (type)(divisor); \ + } \ + FT_END_STMNT + +#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( type, dividend, divisor, quotient, remainder ) \ + FT_BEGIN_STMNT \ + (quotient) = (type)( (dividend) / (divisor) ); \ + (remainder) = (type)( (dividend) - (quotient) * (divisor) ); \ + if ( (remainder) < 0 ) \ + { \ + (quotient)--; \ + (remainder) += (type)(divisor); \ + } \ + FT_END_STMNT +#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 ) \ + FT_Int64 b ## _r = c ? (FT_Int64)0xFFFFFFFF / ( b ) : 0 +#define FT_UDIV( a, b ) \ + (TCoord)( ( (FT_UInt64)( a ) * (FT_UInt64)( b ## _r ) ) >> 32 ) + + + /* 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 ) \ + FT_BEGIN_STMNT \ + coverage = (int)( area >> ( PIXEL_BITS * 2 + 1 - 8 ) ); \ + if ( coverage & fill ) \ + coverage = ~coverage; \ + if ( coverage > 255 && fill & INT_MIN ) \ + coverage = 255; \ + FT_END_STMNT + + + /* 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 ) \ + FT_BEGIN_STMNT \ + unsigned char* q = d; \ + switch ( count ) \ + { \ + case 7: *q++ = (unsigned char)s; FALL_THROUGH; \ + case 6: *q++ = (unsigned char)s; FALL_THROUGH; \ + case 5: *q++ = (unsigned char)s; FALL_THROUGH; \ + case 4: *q++ = (unsigned char)s; FALL_THROUGH; \ + case 3: *q++ = (unsigned char)s; FALL_THROUGH; \ + case 2: *q++ = (unsigned char)s; FALL_THROUGH; \ + case 1: *q = (unsigned char)s; FALL_THROUGH; \ + case 0: break; \ + default: FT_MEM_SET( d, s, count ); \ + } \ + FT_END_STMNT + + + /************************************************************************** + * + * 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 long TPos; /* subpixel coordinate */ + typedef int TCoord; /* integer scanline/pixel coordinate */ + typedef int TArea; /* cell areas, coordinate products */ + + + typedef struct TCell_* PCell; + + typedef struct TCell_ + { + TCoord x; /* same with gray_TWorker.ex */ + TCoord cover; /* same with gray_TWorker.cover */ + TArea area; + PCell next; + + } TCell; + + typedef struct TPixmap_ + { + unsigned char* origin; /* pixmap origin at the bottom-left */ + int pitch; /* pitch to go down one row */ + + } TPixmap; + + /* maximum number of gray cells in the buffer */ +#if FT_RENDER_POOL_SIZE > 2048 +#define FT_MAX_GRAY_POOL ( FT_RENDER_POOL_SIZE / sizeof ( TCell ) ) +#else +#define FT_MAX_GRAY_POOL ( 2048 / sizeof ( TCell ) ) +#endif + + /* FT_Span buffer size for direct rendering only */ +#define FT_MAX_GRAY_SPANS 16 + + +#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_ + { + ft_jmp_buf jump_buffer; + + TCoord min_ex, max_ex; /* min and max integer pixel coordinates */ + TCoord min_ey, max_ey; + TCoord count_ey; /* same as (max_ey - min_ey) */ + + PCell cell; /* current cell */ + PCell cell_free; /* call allocation next free slot */ + PCell cell_null; /* last cell, used as dumpster and limit */ + + PCell* ycells; /* array of cell linked-lists; one per */ + /* vertical coordinate in the current band */ + + TPos x, y; /* last point position */ + + FT_Outline outline; /* input outline */ + TPixmap target; /* target pixmap */ + + FT_Raster_Span_Func render_span; + void* render_span_data; + + } gray_TWorker, *gray_PWorker; + +#if defined( _MSC_VER ) +#pragma warning( pop ) +#endif + +#ifndef FT_STATIC_RASTER +#define ras (*worker) +#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 INT_MAX + + +#define FT_INTEGRATE( ras, a, b ) \ + ras.cell->cover = ADD_INT( ras.cell->cover, a ), \ + ras.cell->area = ADD_INT( ras.cell->area, (a) * (TArea)(b) ) + + + typedef struct gray_TRaster_ + { + void* memory; + + } gray_TRaster, *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 ) + { + /* Move the cell pointer to a new position in the linked list. We use */ + /* a dumpster null cell for everything outside of the clipping region */ + /* 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. */ + + TCoord ey_index = ey - ras.min_ey; + + + if ( ey_index < 0 || ey_index >= ras.count_ey || ex >= ras.max_ex ) + ras.cell = ras.cell_null; + else + { + PCell* pcell = ras.ycells + ey_index; + PCell cell; + + + ex = FT_MAX( ex, ras.min_ex - 1 ); + + while ( 1 ) + { + cell = *pcell; + + if ( cell->x > ex ) + break; + + if ( cell->x == ex ) + goto Found; + + pcell = &cell->next; + } + + /* insert new cell */ + cell = ras.cell_free++; + if ( cell >= ras.cell_null ) + ft_longjmp( ras.jump_buffer, 1 ); + + cell->x = ex; + cell->area = 0; + cell->cover = 0; + + cell->next = *pcell; + *pcell = cell; + + Found: + ras.cell = cell; + } + } + + +#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 ) + { + TPos dx, dy; + TCoord fx1, fy1, fx2, fy2; + TCoord ex1, ey1, ex2, ey2; + + + 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; + + ex1 = TRUNC( ras.x ); + ex2 = TRUNC( to_x ); + + fx1 = FRACT( ras.x ); + fy1 = FRACT( ras.y ); + + dx = to_x - ras.x; + dy = to_y - ras.y; + + if ( ex1 == ex2 && ey1 == ey2 ) /* inside one cell */ + ; + else if ( dy == 0 ) /* ex1 != ex2 */ /* any horizontal line */ + { + gray_set_cell( RAS_VAR_ ex2, ey2 ); + goto End; + } + else if ( dx == 0 ) + { + if ( dy > 0 ) /* vertical line up */ + do + { + fy2 = ONE_PIXEL; + FT_INTEGRATE( ras, fy2 - fy1, fx1 * 2 ); + fy1 = 0; + ey1++; + gray_set_cell( RAS_VAR_ ex1, ey1 ); + } while ( ey1 != ey2 ); + else /* vertical line down */ + do + { + fy2 = 0; + FT_INTEGRATE( ras, fy2 - fy1, fx1 * 2 ); + fy1 = ONE_PIXEL; + ey1--; + gray_set_cell( RAS_VAR_ ex1, ey1 ); + } while ( ey1 != ey2 ); + } + else /* any other line */ + { + FT_Int64 prod = dx * (FT_Int64)fy1 - dy * (FT_Int64)fx1; + FT_UDIVPREP( ex1 != ex2, dx ); + FT_UDIVPREP( ey1 != ey2, 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 - dx * ONE_PIXEL > 0 && + prod <= 0 ) /* left */ + { + fx2 = 0; + fy2 = FT_UDIV( -prod, -dx ); + prod -= dy * ONE_PIXEL; + FT_INTEGRATE( ras, fy2 - fy1, fx1 + fx2 ); + fx1 = ONE_PIXEL; + fy1 = fy2; + ex1--; + } + else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 && + prod - dx * ONE_PIXEL <= 0 ) /* up */ + { + prod -= dx * ONE_PIXEL; + fx2 = FT_UDIV( -prod, dy ); + fy2 = ONE_PIXEL; + FT_INTEGRATE( ras, fy2 - fy1, fx1 + fx2 ); + fx1 = fx2; + fy1 = 0; + ey1++; + } + else if ( prod + dy * ONE_PIXEL >= 0 && + prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 ) /* right */ + { + prod += dy * ONE_PIXEL; + fx2 = ONE_PIXEL; + fy2 = FT_UDIV( prod, dx ); + FT_INTEGRATE( ras, fy2 - fy1, fx1 + fx2 ); + fx1 = 0; + fy1 = fy2; + ex1++; + } + else /* ( prod > 0 && + prod + dy * ONE_PIXEL < 0 ) down */ + { + fx2 = FT_UDIV( prod, -dy ); + fy2 = 0; + prod += dx * ONE_PIXEL; + FT_INTEGRATE( ras, fy2 - fy1, fx1 + fx2 ); + fx1 = fx2; + fy1 = ONE_PIXEL; + ey1--; + } + + gray_set_cell( RAS_VAR_ ex1, ey1 ); + + } while ( ex1 != ex2 || ey1 != ey2 ); + } + + fx2 = FRACT( to_x ); + fy2 = FRACT( to_y ); + + FT_INTEGRATE( ras, fy2 - fy1, fx1 + fx2 ); + + End: + ras.x = to_x; + ras.y = 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 ) +# define FT_SSE2 1 +#else +# define FT_SSE2 0 +#endif + +#if FT_SSE2 || \ + defined( __aarch64__ ) || \ + defined( _M_ARM64 ) +# define BEZIER_USE_DDA 1 +#else +# define BEZIER_USE_DDA 0 +#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 0 +#endif + +#if BEZIER_USE_DDA + +#if FT_SSE2 +# include <emmintrin.h> +#endif + +#define LEFT_SHIFT( a, b ) (FT_Int64)( (FT_UInt64)(a) << (b) ) + + + static void + gray_render_conic( RAS_ARG_ const FT_Vector* control, + const FT_Vector* to ) + { + FT_Vector p0, p1, p2; + TPos ax, ay, bx, by, dx, dy; + int shift; + + FT_Int64 rx, ry; + FT_Int64 qx, qy; + FT_Int64 px, py; + + FT_UInt count; + + + p0.x = ras.x; + p0.y = ras.y; + p1.x = UPSCALE( control->x ); + p1.y = UPSCALE( control->y ); + p2.x = UPSCALE( to->x ); + p2.y = UPSCALE( to->y ); + + /* short-cut the arc that crosses the current band */ + if ( ( TRUNC( p0.y ) >= ras.max_ey && + TRUNC( p1.y ) >= ras.max_ey && + TRUNC( p2.y ) >= ras.max_ey ) || + ( TRUNC( p0.y ) < ras.min_ey && + TRUNC( p1.y ) < ras.min_ey && + TRUNC( p2.y ) < ras.min_ey ) ) + { + ras.x = p2.x; + ras.y = p2.y; + return; + } + + bx = p1.x - p0.x; + by = p1.y - p0.y; + ax = p2.x - p1.x - bx; /* p0.x + p2.x - 2 * p1.x */ + ay = p2.y - p1.y - by; /* p0.y + p2.y - 2 * p1.y */ + + dx = FT_ABS( ax ); + dy = FT_ABS( ay ); + if ( dx < dy ) + dx = dy; + + if ( dx <= ONE_PIXEL / 4 ) + { + gray_render_line( RAS_VAR_ p2.x, p2.y ); + return; + } + + /* 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. */ + shift = 0; + do + { + dx >>= 2; + shift += 1; + + } while ( dx > ONE_PIXEL / 4 ); + + /* + * The (P0,P1,P2) arc equation, for t in [0,1] range: + * + * P(t) = P0*(1-t)^2 + P1*2*t*(1-t) + P2*t^2 + * + * P(t) = P0 + 2*(P1-P0)*t + (P0+P2-2*P1)*t^2 + * = P0 + 2*B*t + A*t^2 + * + * for A = P0 + P2 - 2*P1 + * and B = P1 - P0 + * + * Let's consider the difference when advancing by a small + * parameter h: + * + * Q(h,t) = P(t+h) - P(t) = 2*B*h + A*h^2 + 2*A*h*t + * + * And then its own difference: + * + * R(h,t) = Q(h,t+h) - Q(h,t) = 2*A*h*h = R (constant) + * + * Since R is always a constant, it is possible to compute + * successive positions with: + * + * P = P0 + * Q = Q(h,0) = 2*B*h + A*h*h + * R = 2*A*h*h + * + * loop: + * P += Q + * Q += R + * EMIT(P) + * + * To ensure accurate results, perform computations on 64-bit + * values, after scaling them by 2^32. + * + * h = 1 / 2^N + * + * R << 32 = 2 * A << (32 - N - N) + * = A << (33 - 2*N) + * + * Q << 32 = (2 * B << (32 - N)) + (A << (32 - N - N)) + * = (B << (33 - N)) + (A << (32 - 2*N)) + */ + +#if FT_SSE2 + /* Experience shows that for small shift values, */ + /* SSE2 is actually slower. */ + if ( shift > 2 ) + { + union + { + struct { FT_Int64 ax, ay, bx, by; } i; + struct { __m128i a, b; } vec; + + } u; + + union + { + struct { FT_Int32 px_lo, px_hi, py_lo, py_hi; } i; + __m128i vec; + + } v; + + __m128i a, b; + __m128i r, q, q2; + __m128i p; + + + u.i.ax = ax; + u.i.ay = ay; + u.i.bx = bx; + u.i.by = by; + + a = _mm_load_si128( &u.vec.a ); + b = _mm_load_si128( &u.vec.b ); + + r = _mm_slli_epi64( a, 33 - 2 * shift ); + q = _mm_slli_epi64( b, 33 - shift ); + q2 = _mm_slli_epi64( a, 32 - 2 * shift ); + + q = _mm_add_epi64( q2, q ); + + v.i.px_lo = 0; + v.i.px_hi = p0.x; + v.i.py_lo = 0; + v.i.py_hi = p0.y; + + p = _mm_load_si128( &v.vec ); + + for ( count = 1U << shift; count > 0; count-- ) + { + p = _mm_add_epi64( p, q ); + q = _mm_add_epi64( q, r ); + + _mm_store_si128( &v.vec, p ); + + gray_render_line( RAS_VAR_ v.i.px_hi, v.i.py_hi ); + } + + return; + } +#endif /* FT_SSE2 */ + + rx = LEFT_SHIFT( ax, 33 - 2 * shift ); + ry = LEFT_SHIFT( ay, 33 - 2 * shift ); + + qx = LEFT_SHIFT( bx, 33 - shift ) + LEFT_SHIFT( ax, 32 - 2 * shift ); + qy = LEFT_SHIFT( by, 33 - shift ) + LEFT_SHIFT( ay, 32 - 2 * shift ); + + px = LEFT_SHIFT( p0.x, 32 ); + py = LEFT_SHIFT( p0.y, 32 ); + + for ( count = 1U << shift; count > 0; count-- ) + { + px += qx; + py += qy; + qx += rx; + qy += ry; + + gray_render_line( RAS_VAR_ (FT_Pos)( px >> 32 ), + (FT_Pos)( py >> 32 ) ); + } + } + +#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 ) + { + 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 FT_Vector* control1, + const FT_Vector* control2, + const FT_Vector* to ) + { + FT_Vector bez_stack[16 * 3 + 1]; /* enough to accommodate bisections */ + FT_Vector* arc = 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 ( FT_ABS( 2 * arc[0].x - 3 * arc[1].x + arc[3].x ) > ONE_PIXEL / 2 || + FT_ABS( 2 * arc[0].y - 3 * arc[1].y + arc[3].y ) > ONE_PIXEL / 2 || + FT_ABS( arc[0].x - 3 * arc[2].x + 2 * arc[3].x ) > ONE_PIXEL / 2 || + 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 == bez_stack ) + return; + + arc -= 3; + continue; + + Split: + gray_split_cubic( arc ); + arc += 3; + } + } + + + static int + gray_move_to( const FT_Vector* to, + gray_PWorker worker ) + { + TPos x, y; + + + /* start to a new position */ + x = UPSCALE( to->x ); + y = UPSCALE( to->y ); + + gray_set_cell( RAS_VAR_ TRUNC( x ), TRUNC( y ) ); + + ras.x = x; + ras.y = y; + return 0; + } + + + static int + gray_line_to( const 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 FT_Vector* control, + const FT_Vector* to, + gray_PWorker worker ) + { + gray_render_conic( RAS_VAR_ control, to ); + return 0; + } + + + static int + gray_cubic_to( const FT_Vector* control1, + const FT_Vector* control2, + const FT_Vector* to, + gray_PWorker worker ) + { + gray_render_cubic( RAS_VAR_ control1, control2, to ); + return 0; + } + + + static void + gray_sweep( RAS_ARG ) + { + int fill = ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL ) ? 0x100 + : INT_MIN; + int coverage; + int y; + + + for ( y = ras.min_ey; y < ras.max_ey; y++ ) + { + PCell cell = ras.ycells[y - ras.min_ey]; + TCoord x = ras.min_ex; + TArea cover = 0; + + unsigned char* line = ras.target.origin - ras.target.pitch * y; + + + for ( ; cell != ras.cell_null; cell = cell->next ) + { + TArea area; + + + if ( cover != 0 && cell->x > x ) + { + FT_FILL_RULE( coverage, cover, fill ); + FT_GRAY_SET( line + x, coverage, cell->x - x ); + } + + cover += (TArea)cell->cover * ( ONE_PIXEL * 2 ); + area = cover - cell->area; + + if ( area != 0 && cell->x >= ras.min_ex ) + { + FT_FILL_RULE( coverage, area, fill ); + line[cell->x] = (unsigned char)coverage; + } + + x = cell->x + 1; + } + + if ( cover != 0 ) /* only if cropped */ + { + FT_FILL_RULE( coverage, cover, fill ); + FT_GRAY_SET( line + x, coverage, ras.max_ex - x ); + } + } + } + + + static void + gray_sweep_direct( RAS_ARG ) + { + int fill = ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL ) ? 0x100 + : INT_MIN; + int coverage; + int y; + + FT_Span span[FT_MAX_GRAY_SPANS]; + int n = 0; + + + for ( y = ras.min_ey; y < ras.max_ey; y++ ) + { + PCell cell = ras.ycells[y - ras.min_ey]; + TCoord x = ras.min_ex; + TArea cover = 0; + + + for ( ; cell != ras.cell_null; cell = cell->next ) + { + TArea area; + + + if ( cover != 0 && cell->x > x ) + { + FT_FILL_RULE( coverage, cover, fill ); + + span[n].coverage = (unsigned char)coverage; + span[n].x = (short)x; + span[n].len = (unsigned short)( cell->x - x ); + + if ( ++n == FT_MAX_GRAY_SPANS ) + { + /* flush the span buffer and reset the count */ + ras.render_span( y, n, span, ras.render_span_data ); + n = 0; + } + } + + cover += (TArea)cell->cover * ( ONE_PIXEL * 2 ); + area = cover - cell->area; + + if ( area != 0 && cell->x >= ras.min_ex ) + { + FT_FILL_RULE( coverage, area, fill ); + + span[n].coverage = (unsigned char)coverage; + span[n].x = (short)cell->x; + span[n].len = 1; + + if ( ++n == FT_MAX_GRAY_SPANS ) + { + /* flush the span buffer and reset the count */ + ras.render_span( y, n, span, ras.render_span_data ); + n = 0; + } + } + + x = cell->x + 1; + } + + if ( cover != 0 ) /* only if cropped */ + { + FT_FILL_RULE( coverage, cover, fill ); + + span[n].coverage = (unsigned char)coverage; + span[n].x = (short)x; + span[n].len = (unsigned short)( ras.max_ex - x ); + + ++n; + } + + if ( n ) + { + /* flush the span buffer and reset the count */ + ras.render_span( y, n, span, ras.render_span_data ); + n = 0; + } + } + } + + +#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( x ) ( (x) * ( 1L << shift ) - delta ) + + 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 */ + 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; + first = 0; + + for ( n = 0; n < outline->n_contours; n++ ) + { + int last; /* index of last point in contour */ + + + FT_TRACE5(( "FT_Outline_Decompose: Outline %d\n", n )); + + 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 = 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; + + first = last + 1; + } + + 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 ) + { + volatile int error; + + + if ( ft_setjmp( ras.jump_buffer ) == 0 ) + { + if ( continued ) + FT_Trace_Disable(); + error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras ); + if ( continued ) + FT_Trace_Enable(); + + FT_TRACE7(( "band [%d..%d]: %ld cell%s remaining/\n", + ras.min_ey, + ras.max_ey, + ras.cell_null - ras.cell_free, + ras.cell_null - ras.cell_free == 1 ? "" : "s" )); + } + else + { + error = FT_THROW( Raster_Overflow ); + + FT_TRACE7(( "band [%d..%d]: to be bisected\n", + ras.min_ey, ras.max_ey )); + } + + return error; + } + + + static int + gray_convert_glyph( RAS_ARG ) + { + const TCoord yMin = ras.min_ey; + const TCoord yMax = ras.max_ey; + + TCell buffer[FT_MAX_GRAY_POOL]; + size_t height = (size_t)( yMax - yMin ); + size_t n = FT_MAX_GRAY_POOL / 8; + TCoord y; + TCoord bands[32]; /* enough to accommodate bisections */ + TCoord* band; + + int continued = 0; + + + /* Initialize the null cell at the end of the poll. */ + ras.cell_null = buffer + FT_MAX_GRAY_POOL - 1; + ras.cell_null->x = CELL_MAX_X_VALUE; + ras.cell_null->area = 0; + ras.cell_null->cover = 0; + ras.cell_null->next = NULL; + + /* set up vertical bands */ + ras.ycells = (PCell*)buffer; + + if ( height > n ) + { + /* two divisions rounded up */ + n = ( height + n - 1 ) / n; + height = ( height + n - 1 ) / n; + } + + for ( y = yMin; y < yMax; ) + { + ras.min_ey = y; + y += height; + ras.max_ey = FT_MIN( y, yMax ); + + band = bands; + band[1] = ras.min_ey; + band[0] = ras.max_ey; + + do + { + TCoord width = band[0] - band[1]; + TCoord w; + int error; + + + for ( w = 0; w < width; ++w ) + ras.ycells[w] = ras.cell_null; + + /* memory management: skip ycells */ + n = ( (size_t)width * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) / + sizeof ( TCell ); + + ras.cell_free = buffer + n; + ras.cell = ras.cell_null; + ras.min_ey = band[1]; + ras.max_ey = band[0]; + ras.count_ey = width; + + error = gray_convert_glyph_inner( RAS_VAR_ continued ); + continued = 1; + + if ( !error ) + { + if ( ras.render_span ) /* for FT_RASTER_FLAG_DIRECT only */ + gray_sweep_direct( RAS_VAR ); + else + gray_sweep( RAS_VAR ); + band--; + continue; + } + else if ( error != Smooth_Err_Raster_Overflow ) + return error; + + /* render pool overflow; we will reduce the render band by half */ + width >>= 1; + + /* this should never happen even with tiny rendering pool */ + if ( width == 0 ) + { + FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" )); + return FT_THROW( Raster_Overflow ); + } + + band++; + band[1] = band[0]; + band[0] += width; + } while ( band >= bands ); + } + + return Smooth_Err_Ok; + } + + + static int + gray_raster_render( FT_Raster raster, + const FT_Raster_Params* params ) + { + const FT_Outline* outline = (const FT_Outline*)params->source; + const FT_Bitmap* target_map = params->target; + +#ifndef FT_STATIC_RASTER + gray_TWorker worker[1]; +#endif + + + if ( !raster ) + return FT_THROW( Invalid_Argument ); + + /* this version does not support monochrome rendering */ + if ( !( params->flags & FT_RASTER_FLAG_AA ) ) + return FT_THROW( Cannot_Render_Glyph ); + + if ( !outline ) + return FT_THROW( Invalid_Outline ); + + /* return immediately if the outline is empty */ + if ( outline->n_points == 0 || outline->n_contours <= 0 ) + return Smooth_Err_Ok; + + if ( !outline->contours || !outline->points ) + return FT_THROW( Invalid_Outline ); + + if ( outline->n_points != + outline->contours[outline->n_contours - 1] + 1 ) + return FT_THROW( Invalid_Outline ); + + ras.outline = *outline; + + if ( params->flags & FT_RASTER_FLAG_DIRECT ) + { + if ( !params->gray_spans ) + return Smooth_Err_Ok; + + ras.render_span = (FT_Raster_Span_Func)params->gray_spans; + ras.render_span_data = params->user; + + ras.min_ex = params->clip_box.xMin; + ras.min_ey = params->clip_box.yMin; + ras.max_ex = params->clip_box.xMax; + ras.max_ey = params->clip_box.yMax; + } + else + { + /* if direct mode is not set, we must have a target bitmap */ + if ( !target_map ) + return FT_THROW( Invalid_Argument ); + + /* nothing to do */ + if ( !target_map->width || !target_map->rows ) + return Smooth_Err_Ok; + + if ( !target_map->buffer ) + return FT_THROW( Invalid_Argument ); + + if ( target_map->pitch < 0 ) + ras.target.origin = target_map->buffer; + else + ras.target.origin = target_map->buffer + + ( target_map->rows - 1 ) * (unsigned int)target_map->pitch; + + ras.target.pitch = target_map->pitch; + + ras.render_span = (FT_Raster_Span_Func)NULL; + ras.render_span_data = NULL; + + ras.min_ex = 0; + ras.min_ey = 0; + ras.max_ex = (FT_Pos)target_map->width; + ras.max_ey = (FT_Pos)target_map->rows; + } + + /* exit if nothing to do */ + if ( ras.max_ex <= ras.min_ex || ras.max_ey <= ras.min_ey ) + return Smooth_Err_Ok; + + return gray_convert_glyph( RAS_VAR ); + } + + + /**** 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( FT_Memory memory, + gray_PRaster* araster ) + { + FT_Error error; + gray_PRaster raster = NULL; + + + if ( !FT_NEW( raster ) ) + raster->memory = memory; + + *araster = raster; + + return error; + } + + + static void + gray_raster_done( FT_Raster raster ) + { + FT_Memory memory = (FT_Memory)((gray_PRaster)raster)->memory; + + + FT_FREE( raster ); + } + +#endif /* !STANDALONE_ */ + + + static void + gray_raster_reset( FT_Raster raster, + unsigned char* pool_base, + unsigned long pool_size ) + { + FT_UNUSED( raster ); + FT_UNUSED( pool_base ); + FT_UNUSED( pool_size ); + } + + + static int + gray_raster_set_mode( FT_Raster raster, + unsigned long mode, + void* args ) + { + FT_UNUSED( raster ); + FT_UNUSED( mode ); + FT_UNUSED( args ); + + + return 0; /* nothing to do */ + } + + + 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: */ |