ref: 34010f7c473330907b39bd7d55e985f407d7f87c
dir: /src/smooth/ftgrays.c/
/***************************************************************************/
/* */
/* ftgrays.c */
/* */
/* A new `perfect' anti-aliasing renderer (body). */
/* */
/* Copyright 2000-2017 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. */
/* */
/* It is based on ideas that I initially found in Raph Levien's */
/* excellent LibArt graphics library (see http://www.levien.com/libart */
/* for more information, though the web pages do not tell anything */
/* about the renderer; you'll have to dive into the source code to */
/* understand how it works). */
/* */
/* Note, however, that this is a _very_ different implementation */
/* compared to Raph's. Coverage information is stored in a very */
/* different way, and I don't use sorted vector paths. Also, it doesn't */
/* use floating point values. */
/* */
/* This renderer has the following advantages: */
/* */
/* - It doesn't need an intermediate bitmap. Instead, one can supply a */
/* callback function that will be called by the renderer to draw gray */
/* spans on any target surface. You can thus do direct composition on */
/* any kind of bitmap, provided that you give the renderer the right */
/* callback. */
/* */
/* - A perfect anti-aliaser, i.e., it computes the _exact_ coverage on */
/* each pixel cell. */
/* */
/* - It performs a single pass on the outline (the `standard' FT2 */
/* renderer makes two passes). */
/* */
/* - It can easily be modified to render to _any_ number of gray levels */
/* cheaply. */
/* */
/* - For small (< 20) pixel sizes, it is faster than the standard */
/* renderer. */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* The macro FT_COMPONENT is used in trace mode. It is an implicit */
/* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */
/* messages during execution. */
/* */
#undef FT_COMPONENT
#define FT_COMPONENT trace_smooth
#ifdef STANDALONE_
/* 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 ft_memset memset
#define ft_setjmp setjmp
#define ft_longjmp longjmp
#define ft_jmp_buf jmp_buf
typedef ptrdiff_t FT_PtrDist;
#define ErrRaster_Invalid_Mode -2
#define ErrRaster_Invalid_Outline -1
#define ErrRaster_Invalid_Argument -3
#define ErrRaster_Memory_Overflow -4
#define FT_BEGIN_HEADER
#define FT_END_HEADER
#include "ftimage.h"
#include "ftgrays.h"
/* This macro is used to indicate that a function parameter is unused. */
/* Its purpose is simply to reduce compiler warnings. Note also that */
/* simply defining it as `(void)x' doesn't avoid warnings with certain */
/* ANSI compilers (e.g. LCC). */
#define FT_UNUSED( x ) (x) = (x)
/* 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( ErrRaster, e ), \
__LINE__, \
__FILE__ ) | \
FT_ERR_CAT( ErrRaster, 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( ErrRaster_, e )
#endif /* !FT_DEBUG_LEVEL_TRACE */
#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 "ftgrays.h"
#include FT_INTERNAL_OBJECTS_H
#include FT_INTERNAL_DEBUG_H
#include FT_OUTLINE_H
#include "ftsmerrs.h"
#include "ftspic.h"
#define Smooth_Err_Invalid_Mode Smooth_Err_Cannot_Render_Glyph
#define Smooth_Err_Memory_Overflow Smooth_Err_Out_Of_Memory
#define ErrRaster_Memory_Overflow Smooth_Err_Out_Of_Memory
#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
#undef FLOOR
#undef CEILING
#undef TRUNC
#undef SCALED
#define ONE_PIXEL ( 1 << PIXEL_BITS )
#define TRUNC( x ) ( (TCoord)( (x) >> PIXEL_BITS ) )
#define SUBPIXELS( x ) ( (TPos)(x) * ONE_PIXEL )
#define FLOOR( x ) ( (x) & -ONE_PIXEL )
#define CEILING( x ) ( ( (x) + ONE_PIXEL - 1 ) & -ONE_PIXEL )
#define ROUND( x ) ( ( (x) + ONE_PIXEL / 2 ) & -ONE_PIXEL )
#if PIXEL_BITS >= 6
#define UPSCALE( x ) ( (x) * ( 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
#ifdef __arm__
/* Work around a bug specific to GCC which make the compiler fail to */
/* optimize a division and modulo operation on the same parameters */
/* into a single call to `__aeabi_idivmod'. See */
/* */
/* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43721 */
#undef 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__ */
/* These macros speed up repetitive divisions by replacing them */
/* with multiplications and right shifts. */
#define FT_UDIVPREP( c, b ) \
long b ## _r = c ? (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) \
: 0
#define FT_UDIV( a, b ) \
( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >> \
( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )
/*************************************************************************/
/* */
/* 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; /* sub-pixel 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
#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 ex, ey;
TCoord min_ex, max_ex;
TCoord min_ey, max_ey;
TArea area;
TCoord cover;
int invalid;
PCell* ycells;
PCell cells;
FT_PtrDist max_cells;
FT_PtrDist num_cells;
TPos x, y;
FT_Outline outline;
TPixmap target;
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
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 != NULL; cell = cell->next )
printf( " (%3d, c:%4d, a:%6d)",
cell->x, cell->cover, cell->area );
printf( "\n" );
}
}
#endif /* FT_DEBUG_LEVEL_TRACE */
/*************************************************************************/
/* */
/* Record the current cell in the table. */
/* */
static void
gray_record_cell( RAS_ARG )
{
PCell *pcell, cell;
TCoord x = ras.ex;
pcell = &ras.ycells[ras.ey - ras.min_ey];
for (;;)
{
cell = *pcell;
if ( !cell || cell->x > x )
break;
if ( cell->x == x )
goto Found;
pcell = &cell->next;
}
if ( ras.num_cells >= ras.max_cells )
ft_longjmp( ras.jump_buffer, 1 );
/* insert new cell */
cell = ras.cells + ras.num_cells++;
cell->x = x;
cell->area = ras.area;
cell->cover = ras.cover;
cell->next = *pcell;
*pcell = cell;
return;
Found:
/* update old cell */
cell->area += ras.area;
cell->cover += ras.cover;
}
/*************************************************************************/
/* */
/* Set the current cell to a new position. */
/* */
static void
gray_set_cell( RAS_ARG_ TCoord ex,
TCoord ey )
{
/* Move the cell pointer to a new position. We set the `invalid' */
/* flag to indicate that the cell isn't part of those we're interested */
/* in during the render phase. This means that: */
/* */
/* . the new vertical position must be within min_ey..max_ey-1. */
/* . the new horizontal position must be strictly less than max_ex */
/* */
/* Note that if a cell is to the left of the clipping region, it is */
/* actually set to the (min_ex-1) horizontal position. */
if ( ex < ras.min_ex )
ex = ras.min_ex - 1;
/* record the current one if it is valid */
if ( !ras.invalid )
gray_record_cell( RAS_VAR );
ras.area = 0;
ras.cover = 0;
ras.ex = ex;
ras.ey = ey;
ras.invalid = ( ey >= ras.max_ey || ey < ras.min_ey ||
ex >= ras.max_ex );
}
#ifndef FT_LONG64
/*************************************************************************/
/* */
/* 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 = (TCoord)( x1 - SUBPIXELS( ex1 ) );
fx2 = (TCoord)( x2 - SUBPIXELS( ex2 ) );
/* 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;
}
FT_DIV_MOD( TCoord, p, dx, delta, mod );
ras.area += (TArea)( ( fx1 + first ) * delta );
ras.cover += delta;
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++;
}
ras.area += (TArea)( ONE_PIXEL * delta );
ras.cover += delta;
y1 += delta;
ex1 += incr;
gray_set_cell( RAS_VAR_ ex1, ey );
} while ( ex1 != ex2 );
}
fx1 = ONE_PIXEL - first;
End:
dy = y2 - y1;
ras.area += (TArea)( ( fx1 + fx2 ) * dy );
ras.cover += dy;
}
/*************************************************************************/
/* */
/* 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 = (TCoord)( ras.y - SUBPIXELS( ey1 ) );
fy2 = (TCoord)( to_y - SUBPIXELS( ey2 ) );
/* 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 = (TCoord)( ( ras.x - SUBPIXELS( ex ) ) << 1 );
TArea area;
if ( dy > 0)
{
first = ONE_PIXEL;
incr = 1;
}
else
{
first = 0;
incr = -1;
}
delta = first - fy1;
ras.area += (TArea)two_fx * delta;
ras.cover += delta;
ey1 += incr;
gray_set_cell( RAS_VAR_ ex, ey1 );
delta = first + first - ONE_PIXEL;
area = (TArea)two_fx * delta;
while ( ey1 != ey2 )
{
ras.area += area;
ras.cover += delta;
ey1 += incr;
gray_set_cell( RAS_VAR_ ex, ey1 );
}
delta = fy2 - ONE_PIXEL + first;
ras.area += (TArea)two_fx * delta;
ras.cover += delta;
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;
}
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, fx1, fy1, fx2, fy2;
TCoord ex1, ex2, ey1, 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 = ras.x - SUBPIXELS( ex1 );
fy1 = ras.y - SUBPIXELS( ey1 );
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 */
{
ex1 = ex2;
gray_set_cell( RAS_VAR_ ex1, ey1 );
}
else if ( dx == 0 )
{
if ( dy > 0 ) /* vertical line up */
do
{
fy2 = ONE_PIXEL;
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * fx1 * 2;
fy1 = 0;
ey1++;
gray_set_cell( RAS_VAR_ ex1, ey1 );
} while ( ey1 != ey2 );
else /* vertical line down */
do
{
fy2 = 0;
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * fx1 * 2;
fy1 = ONE_PIXEL;
ey1--;
gray_set_cell( RAS_VAR_ ex1, ey1 );
} while ( ey1 != ey2 );
}
else /* any other line */
{
TPos prod = dx * fy1 - dy * 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 <= 0 &&
prod - dx * ONE_PIXEL > 0 ) /* left */
{
fx2 = 0;
fy2 = (TPos)FT_UDIV( -prod, -dx );
prod -= dy * ONE_PIXEL;
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
fx1 = ONE_PIXEL;
fy1 = fy2;
ex1--;
}
else if ( prod - dx * ONE_PIXEL <= 0 &&
prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0 ) /* up */
{
prod -= dx * ONE_PIXEL;
fx2 = (TPos)FT_UDIV( -prod, dy );
fy2 = ONE_PIXEL;
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
fx1 = fx2;
fy1 = 0;
ey1++;
}
else if ( prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 &&
prod + dy * ONE_PIXEL >= 0 ) /* right */
{
prod += dy * ONE_PIXEL;
fx2 = ONE_PIXEL;
fy2 = (TPos)FT_UDIV( prod, dx );
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
fx1 = 0;
fy1 = fy2;
ex1++;
}
else /* ( prod + dy * ONE_PIXEL < 0 &&
prod > 0 ) down */
{
fx2 = (TPos)FT_UDIV( prod, -dy );
fy2 = 0;
prod += dx * ONE_PIXEL;
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
fx1 = fx2;
fy1 = ONE_PIXEL;
ey1--;
}
gray_set_cell( RAS_VAR_ ex1, ey1 );
} while ( ex1 != ex2 || ey1 != ey2 );
}
fx2 = to_x - SUBPIXELS( ex2 );
fy2 = to_y - SUBPIXELS( ey2 );
ras.cover += ( fy2 - fy1 );
ras.area += ( fy2 - fy1 ) * ( fx1 + fx2 );
End:
ras.x = to_x;
ras.y = to_y;
}
#endif
static void
gray_split_conic( FT_Vector* base )
{
TPos a, b;
base[4].x = base[2].x;
b = base[1].x;
a = base[3].x = ( base[2].x + b ) / 2;
b = base[1].x = ( base[0].x + b ) / 2;
base[2].x = ( a + b ) / 2;
base[4].y = base[2].y;
b = base[1].y;
a = base[3].y = ( base[2].y + b ) / 2;
b = base[1].y = ( base[0].y + b ) / 2;
base[2].y = ( a + b ) / 2;
}
static void
gray_render_conic( RAS_ARG_ const FT_Vector* control,
const FT_Vector* to )
{
FT_Vector bez_stack[16 * 2 + 1]; /* enough to accommodate bisections */
FT_Vector* arc = bez_stack;
TPos dx, dy;
int draw, split;
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
{
split = 1;
while ( ( draw & split ) == 0 )
{
gray_split_conic( arc );
arc += 2;
split <<= 1;
}
gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
arc -= 2;
} while ( --draw );
}
static void
gray_split_cubic( FT_Vector* base )
{
TPos a, b, c, d;
base[6].x = base[3].x;
c = base[1].x;
d = base[2].x;
base[1].x = a = ( base[0].x + c ) / 2;
base[5].x = b = ( base[3].x + d ) / 2;
c = ( c + d ) / 2;
base[2].x = a = ( a + c ) / 2;
base[4].x = b = ( b + c ) / 2;
base[3].x = ( a + b ) / 2;
base[6].y = base[3].y;
c = base[1].y;
d = base[2].y;
base[1].y = a = ( base[0].y + c ) / 2;
base[5].y = b = ( base[3].y + d ) / 2;
c = ( c + d ) / 2;
base[2].y = a = ( a + c ) / 2;
base[4].y = b = ( b + c ) / 2;
base[3].y = ( a + b ) / 2;
}
static void
gray_render_cubic( RAS_ARG_ const FT_Vector* control1,
const FT_Vector* control2,
const FT_Vector* to )
{
FT_Vector bez_stack[16 * 3 + 1]; /* enough to accommodate bisections */
FT_Vector* arc = bez_stack;
TPos dx, dy, dx_, dy_;
TPos dx1, dy1, dx2, dy2;
TPos L, s, s_limit;
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 (;;)
{
/* Decide whether to split or draw. See `Rapid Termination */
/* Evaluation for Recursive Subdivision of Bezier Curves' by Thomas */
/* F. Hain, at */
/* http://www.cis.southalabama.edu/~hain/general/Publications/Bezier/Camera-ready%20CISST02%202.pdf */
/* dx and dy are x and y components of the P0-P3 chord vector. */
dx = dx_ = arc[3].x - arc[0].x;
dy = dy_ = arc[3].y - arc[0].y;
L = FT_HYPOT( dx_, dy_ );
/* Avoid possible arithmetic overflow below by splitting. */
if ( L > 32767 )
goto Split;
/* Max deviation may be as much as (s/L) * 3/4 (if Hain's v = 1). */
s_limit = L * (TPos)( ONE_PIXEL / 6 );
/* s is L * the perpendicular distance from P1 to the line P0-P3. */
dx1 = arc[1].x - arc[0].x;
dy1 = arc[1].y - arc[0].y;
s = FT_ABS( dy * dx1 - dx * dy1 );
if ( s > s_limit )
goto Split;
/* s is L * the perpendicular distance from P2 to the line P0-P3. */
dx2 = arc[2].x - arc[0].x;
dy2 = arc[2].y - arc[0].y;
s = FT_ABS( dy * dx2 - dx * dy2 );
if ( s > s_limit )
goto Split;
/* Split super curvy segments where the off points are so far
from the chord that the angles P0-P1-P3 or P0-P2-P3 become
acute as detected by appropriate dot products. */
if ( dx1 * ( dx1 - dx ) + dy1 * ( dy1 - dy ) > 0 ||
dx2 * ( dx2 - dx ) + dy2 * ( dy2 - dy ) > 0 )
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_hline( RAS_ARG_ TCoord x,
TCoord y,
TArea coverage,
TCoord acount )
{
/* scale the coverage from 0..(ONE_PIXEL*ONE_PIXEL*2) to 0..256 */
coverage >>= PIXEL_BITS * 2 + 1 - 8;
if ( coverage < 0 )
coverage = -coverage - 1;
/* compute the line's coverage depending on the outline fill rule */
if ( ras.outline.flags & FT_OUTLINE_EVEN_ODD_FILL )
{
coverage &= 511;
if ( coverage >= 256 )
coverage = 511 - coverage;
}
else
{
/* normal non-zero winding rule */
if ( coverage >= 256 )
coverage = 255;
}
if ( ras.render_span ) /* for FT_RASTER_FLAG_DIRECT only */
{
FT_Span span;
span.x = (short)x;
span.len = (unsigned short)acount;
span.coverage = (unsigned char)coverage;
ras.render_span( y, 1, &span, ras.render_span_data );
}
else
{
unsigned char* q = ras.target.origin - ras.target.pitch * y + x;
unsigned char c = (unsigned char)coverage;
/* For small-spans it is faster to do it by ourselves than
* calling `memset'. This is mainly due to the cost of the
* function call.
*/
switch ( acount )
{
case 7: *q++ = c;
case 6: *q++ = c;
case 5: *q++ = c;
case 4: *q++ = c;
case 3: *q++ = c;
case 2: *q++ = c;
case 1: *q = c;
case 0: break;
default:
FT_MEM_SET( q, c, acount );
}
}
}
static void
gray_sweep( RAS_ARG )
{
int y;
FT_TRACE7(( "gray_sweep: start\n" ));
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;
TArea area;
for ( ; cell != NULL; cell = cell->next )
{
if ( cover != 0 && cell->x > x )
gray_hline( RAS_VAR_ x, y, cover, cell->x - x );
cover += (TArea)cell->cover * ( ONE_PIXEL * 2 );
area = cover - cell->area;
if ( area != 0 && cell->x >= ras.min_ex )
gray_hline( RAS_VAR_ cell->x, y, area, 1 );
x = cell->x + 1;
}
if ( cover != 0 )
gray_hline( RAS_VAR_ x, y, cover, ras.max_ex - x );
}
FT_TRACE7(( "gray_sweep: end\n" ));
}
#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) << 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 0;
Exit:
FT_TRACE5(( "FT_Outline_Decompose: Error 0x%x\n", error ));
return error;
Invalid_Outline:
return FT_THROW( Invalid_Outline );
}
/*************************************************************************/
/* */
/* <Function> */
/* FT_Outline_Get_CBox */
/* */
/* <Description> */
/* Return an outline's `control box'. The control box encloses all */
/* the outline's points, including Bézier control points. Though it */
/* coincides with the exact bounding box for most glyphs, it can be */
/* slightly larger in some situations (like when rotating an outline */
/* that contains Bézier outside arcs). */
/* */
/* Computing the control box is very fast, while getting the bounding */
/* box can take much more time as it needs to walk over all segments */
/* and arcs in the outline. To get the latter, you can use the */
/* `ftbbox' component, which is dedicated to this single task. */
/* */
/* <Input> */
/* outline :: A pointer to the source outline descriptor. */
/* */
/* <Output> */
/* acbox :: The outline's control box. */
/* */
/* <Note> */
/* See @FT_Glyph_Get_CBox for a discussion of tricky fonts. */
/* */
static void
FT_Outline_Get_CBox( const FT_Outline* outline,
FT_BBox *acbox )
{
TPos xMin, yMin, xMax, yMax;
if ( outline && acbox )
{
if ( outline->n_points == 0 )
{
xMin = 0;
yMin = 0;
xMax = 0;
yMax = 0;
}
else
{
FT_Vector* vec = outline->points;
FT_Vector* limit = vec + outline->n_points;
xMin = xMax = vec->x;
yMin = yMax = vec->y;
vec++;
for ( ; vec < limit; vec++ )
{
TPos x, y;
x = vec->x;
if ( x < xMin ) xMin = x;
if ( x > xMax ) xMax = x;
y = vec->y;
if ( y < yMin ) yMin = y;
if ( y > yMax ) yMax = y;
}
}
acbox->xMin = xMin;
acbox->xMax = xMax;
acbox->yMin = yMin;
acbox->yMax = yMax;
}
}
#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 )
{
volatile int error = 0;
#ifdef FT_CONFIG_OPTION_PIC
FT_Outline_Funcs func_interface;
Init_Class_func_interface(&func_interface);
#endif
if ( ft_setjmp( ras.jump_buffer ) == 0 )
{
error = FT_Outline_Decompose( &ras.outline, &func_interface, &ras );
if ( !ras.invalid )
gray_record_cell( RAS_VAR );
FT_TRACE7(( "band [%d..%d]: %d cells\n",
ras.min_ey, ras.max_ey, ras.num_cells ));
}
else
{
error = FT_THROW( Memory_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 )
{
TCell buffer[FT_MAX_GRAY_POOL];
TCoord band_size = FT_MAX_GRAY_POOL / 8;
TCoord count = ras.max_ey - ras.min_ey;
int num_bands;
TCoord min, max, max_y;
TCoord bands[32]; /* enough to accommodate bisections */
TCoord* band;
/* set up vertical bands */
if ( count > band_size )
{
/* two divisions rounded up */
num_bands = (int)( ( count + band_size - 1) / band_size );
band_size = ( count + num_bands - 1 ) / num_bands;
}
min = ras.min_ey;
max_y = ras.max_ey;
for ( ; min < max_y; min = max )
{
max = min + band_size;
if ( max > max_y )
max = max_y;
band = bands;
band[1] = min;
band[0] = max;
do
{
TCoord width = band[0] - band[1];
int error;
/* memory management */
{
size_t ycount = (size_t)width;
size_t cell_start;
cell_start = ( ycount * sizeof ( PCell ) + sizeof ( TCell ) - 1 ) /
sizeof ( TCell );
ras.cells = buffer + cell_start;
ras.max_cells = (FT_PtrDist)( FT_MAX_GRAY_POOL - cell_start );
ras.num_cells = 0;
ras.ycells = (PCell*)buffer;
while ( ycount )
ras.ycells[--ycount] = NULL;
}
ras.invalid = 1;
ras.min_ey = band[1];
ras.max_ey = band[0];
error = gray_convert_glyph_inner( RAS_VAR );
if ( !error )
{
gray_sweep( RAS_VAR );
band--;
continue;
}
else if ( error != ErrRaster_Memory_Overflow )
return 1;
/* render pool overflow; we will reduce the render band by half */
width >>= 1;
/* This is too complex for a single scanline; there must */
/* be some problems. */
if ( width == 0 )
{
FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" ));
return 1;
}
band++;
band[1] = band[0];
band[0] += width;
} while ( band >= bands );
}
return 0;
}
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;
FT_BBox cbox, clip;
#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( Invalid_Mode );
if ( !outline )
return FT_THROW( Invalid_Outline );
/* return immediately if the outline is empty */
if ( outline->n_points == 0 || outline->n_contours <= 0 )
return 0;
if ( !outline->contours || !outline->points )
return 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 0;
ras.render_span = (FT_Raster_Span_Func)params->gray_spans;
ras.render_span_data = params->user;
}
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 0;
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;
}
FT_Outline_Get_CBox( outline, &cbox );
/* reject too large outline coordinates */
if ( cbox.xMin < -0x1000000L || cbox.xMax > 0x1000000L ||
cbox.yMin < -0x1000000L || cbox.yMax > 0x1000000L )
return FT_THROW( Invalid_Outline );
/* truncate the bounding box to integer pixels */
cbox.xMin = cbox.xMin >> 6;
cbox.yMin = cbox.yMin >> 6;
cbox.xMax = ( cbox.xMax + 63 ) >> 6;
cbox.yMax = ( cbox.yMax + 63 ) >> 6;
/* compute clipping box */
if ( !( params->flags & FT_RASTER_FLAG_DIRECT ) )
{
/* compute clip box from target pixmap */
clip.xMin = 0;
clip.yMin = 0;
clip.xMax = (FT_Pos)target_map->width;
clip.yMax = (FT_Pos)target_map->rows;
}
else if ( params->flags & FT_RASTER_FLAG_CLIP )
clip = params->clip_box;
else
{
clip.xMin = -32768L;
clip.yMin = -32768L;
clip.xMax = 32767L;
clip.yMax = 32767L;
}
/* clip to target bitmap, exit if nothing to do */
ras.min_ex = FT_MAX( cbox.xMin, clip.xMin );
ras.min_ey = FT_MAX( cbox.yMin, clip.yMin );
ras.max_ex = FT_MIN( cbox.xMax, clip.xMax );
ras.max_ey = FT_MIN( cbox.yMax, clip.yMax );
if ( ras.max_ex <= ras.min_ex || ras.max_ey <= ras.min_ey )
return 0;
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,
FT_Raster* araster )
{
FT_Error error;
gray_PRaster raster = NULL;
*araster = 0;
if ( !FT_ALLOC( raster, sizeof ( gray_TRaster ) ) )
{
raster->memory = memory;
*araster = (FT_Raster)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: */