| /**************************************************************************** |
| * |
| * ftgrays.c |
| * |
| * A new `perfect' anti-aliasing renderer (body). |
| * |
| * Copyright (C) 2000-2022 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 ) |
| { |
| 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: */ |