ref: 488cd71e4ba08cd5b1d6076401323e9bb6ee25fd
dir: /src/base/ftraster.c/
/***************************************************************************/
/* */
/* ftraster.c */
/* */
/* The FreeType glyph rasterizer (body). */
/* */
/* Copyright 1996-2000 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. */
/* */
/***************************************************************************/
/*************************************************************************/
/* */
/* The `raster' component implements FreeType's scan-line converter, the */
/* one used to generate bitmaps and pixmaps from vectorial outline */
/* descriptions. */
/* */
/* It has been rewritten entirely for FreeType 2.0, in order to become */
/* completely independent of the rest of the library. It should now be */
/* possible to include it more easily in all kinds of libraries and */
/* applications, which do not necessarily need the font engines and API. */
/* */
/* This version contains the following features: */
/* */
/* - Support for third-order Bezier arcs. */
/* */
/* - Improved performance of the 5-levels anti-aliasing algorithm. */
/* */
/* - 17-levels anti-aliasing for smoother curves, though the difference */
/* isn't always noticeable, depending on your palette. */
/* */
/* - An API to decompose a raster outline into a path (i.e., into a */
/* a series of segments and arcs). */
/* */
/* Planned additions: */
/* */
/* - Getting rid of the second pass for horizontal drop-out detection. */
/* I've got a few ideas, but I'll have to experiment in Pascal with */
/* them. to avoid damaging of the rendering of glyphs at small sizes. */
/* */
/* - Adding a `composition' callback, which should be invoked during */
/* anti-aliased rendering. In short, it will allow line-by-line */
/* composition (i.e., transparencies, etc.) of the output in a fairly */
/* portable way. Of course, a single sweep is required there. */
/* */
/*************************************************************************/
#include <ftraster.h>
#ifndef _STANDALONE_
#include <ftconfig.h>
#endif
#ifndef EXPORT_FUNC
#define EXPORT_FUNC /* nothing */
#endif
#undef FT_COMPONENT
#define FT_COMPONENT trace_raster
#ifdef _STANDALONE_
/*************************************************************************/
/* */
/* The following defines are used when the raster is compiled as a */
/* stand-alone object. Each of them is commented, and you're free to */
/* toggle them to suit your needs. */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* FT_RASTER_INT_IS_32 */
/* */
/* Set this configuration macro to the unsigned type which has 32 */
/* bits. */
/* */
#define FT_RASTER_INT_IS_32
/*************************************************************************/
/* */
/* FT_RASTER_OPTION_ANTI_ALIAS */
/* */
/* Define this configuration macro if you want to support */
/* anti-aliasing. */
/* */
#undef FT_RASTER_OPTION_ANTI_ALIAS
/*************************************************************************/
/* */
/* FT_RASTER_OPTION_CONIC_BEZIERS */
/* */
/* Define this configuration macro if your source outlines contain */
/* second-order Bezier arcs. Typically, these are TrueType outlines. */
/* */
#define FT_RASTER_CONIC_BEZIERS
/*************************************************************************/
/* */
/* FT_RASTER_OPTION_CUBIC_BEZIERS */
/* */
/* Define this configuration macro if your source outlines contain */
/* third-order Bezier arcs. Typically, these are Type1 outlines. */
/* */
#define FT_RASTER_CUBIC_BEZIERS
/*************************************************************************/
/* */
/* FT_RASTER_ANTI_ALIAS_5 */
/* */
/* Define this configuration macro if you want to enable the 5-grays */
/* anti-aliasing mode. Ignored if FT_RASTER_OPTION_ANTI_ALIAS isn't */
/* defined. */
/* */
#define FT_RASTER_ANTI_ALIAS_5
/*************************************************************************/
/* */
/* FT_RASTER_ANTI_ALIAS_17 */
/* */
/* Define this configuration macro if you want to enable the 17-grays */
/* anti-aliasing mode. Ignored if FT_RASTER_OPTION_ANTI_ALIAS isn't */
/* defined. */
/* */
/* #define FT_RASTER_ANTI_ALIAS_17 */
/*************************************************************************/
/* */
/* FT_RASTER_LITTLE_ENDIAN */
/* FT_RASTER_BIG_ENDIAN */
/* */
/* The default anti-alias routines are processor-independent, but */
/* slow. Define one of these macros to suit your own system, and */
/* enjoy greatly improved rendering speed. */
/* */
/* #define FT_RASTER_LITTLE_ENDIAN */
/* #define FT_RASTER_BIG_ENDIAN */
/*************************************************************************/
/* */
/* FT_RASTER_CONSTANT_PRECISION */
/* */
/* Define this configuration macro if you want to use a constant */
/* precision for the internal sub-pixel coordinates. Otherwise, the */
/* precision is either 64 or 1024 units per pixel, depending on the */
/* outline's "high_precision" flag.. */
/* */
/* This results in a speed boost, but the macro can be undefined if */
/* it results in rendering errors (mainly changed drop-outs).. */
/* */
#define FT_RASTER_CONSTANT_PRECISION
/*************************************************************************/
/* */
/* FT_PRECISION_BITS */
/* */
/* When the macro FT_RASTER_CONSTANT_PRECISION is defined, this */
/* constant holds the number of bits used for the internal sub-pixels */
/* */
/* This number should be at least 6, but use at least 8 if you */
/* intend to generate small glyph images (use 6 for a printer, for */
/* example..) */
/* */
#define FT_PRECISION_BITS 8
/*************************************************************************/
/* */
/* FT_DYNAMIC_BEZIER_STEPS */
/* */
/* Set this macro to enable the bezier decomposition to be */
/* dynamically computed. This is interesting when the precision is */
/* constant, as it speeds things a bit while keeping a very good */
/* accuracy on the bezier intersections.. */
/* */
#define FT_DYNAMIC_BEZIER_STEPS
#else /* _STANDALONE_ */
#include <freetype.h>
#include <ftconfig.h>
/*************************************************************************/
/* */
/* The following defines are used when the raster is compiled within the */
/* FreeType base layer. Don't change these unless you really know what */
/* you're doing. */
/* */
/*************************************************************************/
#ifdef FT_CONFIG_OPTION_ANTI_ALIAS
#define FT_RASTER_OPTION_ANTI_ALIAS
#endif
#define FT_RASTER_CONIC_BEZIERS
#define FT_RASTER_CUBIC_BEZIERS
#define FT_RASTER_ANTI_ALIAS_5
/* #define FT_RASTER_ANTI_ALIAS_17 */
#ifdef FT_CONFIG_OPTION_LITTLE_ENDIAN
#define FT_RASTER_LITTLE_ENDIAN
#endif
#ifdef FT_CONFIG_OPTION_BIG_ENDIAN
#define FT_RASTER_BIG_ENDIAN
#endif
#define FT_RASTER_CONSTANT_PRECISION
#define FT_DYNAMIC_BEZIER_STEPS
#define FT_PRECISION_BITS 8
#endif /* _STANDALONE_ */
/* to keep the compiler happy */
#ifndef PTRACE2
#define PTRACE2(x) /*void*/
#endif
/*************************************************************************/
/* */
/* FT_RASTER_ANY_ENDIAN indicates that no endianess was defined by one */
/* of the configuration macros. */
/* */
#if !defined( FT_RASTER_LITTLE_ENDIAN ) && !defined( FT_RASTER_BIG_ENDIAN )
#define FT_RASTER_ANY_ENDIAN
#endif
/*************************************************************************/
/* */
/* The rasterizer is a very general purpose component. Please leave the */
/* following redefinitions here (you never know your target */
/* environment). */
/* */
/*************************************************************************/
#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif
#ifndef NULL
#define NULL (void*)0
#endif
#ifndef UNUSED
#define UNUSED( arg ) ( (void)(arg) )
#endif
#undef FAILURE
#define FAILURE TRUE
#undef SUCCESS
#define SUCCESS FALSE
#ifndef ABS
#define ABS(x) ( (x) < 0 ? -(x) : (x) )
#endif
/*************************************************************************/
/* */
/* Please don't touch the following macros. Their importance is */
/* historical to FreeType, but they have some nice effects, like getting */
/* rid of all `->' symbols when accessing the raster object (replacing */
/* them with a simple `.'). */
/* */
/*************************************************************************/
/* used in function signatures to define the _first_ argument */
#define RAS_ARG_ FT_Raster raster,
#define RAS_ARG FT_Raster raster
/* used to call a function within this component, first parameter */
#define RAS_VAR_ raster,
#define RAS_VAR raster
/* used to access the current raster object, with a `.' instead of a */
/* `->' */
#define ras (*raster)
/*************************************************************************/
/* */
/* Error codes returned by the scan-line converter/raster. */
/* */
#define ErrRaster_Ok 0
#define ErrRaster_Uninitialized_Object 1
#define ErrRaster_Overflow 2
#define ErrRaster_Negative_Height 3
#define ErrRaster_Invalid_Outline 4
#define ErrRaster_Invalid_Map 5
#define ErrRaster_AntiAlias_Unsupported 6
#define ErrRaster_Invalid_Pool 7
#define ErrRaster_Unimplemented 8
#define ErrRaster_Bad_Palette_Count 9
#define Flow_Up 1
#define Flow_Down -1
#define SET_High_Precision( p ) Set_High_Precision( RAS_VAR_ p )
/*************************************************************************/
/* */
/* Fast MulDiv, as `b' is always < 64. Don't use intermediate */
/* precision. */
/* */
#define FMulDiv( a, b, c ) ( (a) * (b) / (c) )
/*************************************************************************/
/* */
/* Define DEBUG_RASTER if you want to generate a debug version of the */
/* rasterizer. This will progressively draw the glyphs while all the */
/* computation are done directly on the graphics screen (the glyphs will */
/* will be shown inverted). */
/* */
/* Note that DEBUG_RASTER should only be used for debugging with b/w */
/* rendering, not with gray levels. */
/* */
/* The definition of DEBUG_RASTER should appear in the file */
/* `ftconfig.h'. */
/* */
#ifdef DEBUG_RASTER
extern char* vio; /* A pointer to VRAM or display buffer */
#endif
/*************************************************************************/
/* */
/* The maximum number of stacked Bezier curves. Setting this constant */
/* to more than 32 is a pure waste of space. */
/* */
#define MaxBezier 32
/*************************************************************************/
/* */
/* The number fractional bits of *input* coordinates. We always use the */
/* 26.6 format (i.e, 6 bits for the fractional part), but hackers are */
/* free to experiment with different values. */
/* */
#define INPUT_BITS 6
/*************************************************************************/
/* */
/* An unsigned type that is exactly 32 bits on your platform. This */
/* means `unsigned long' on 16-bit machines, and `unsigned int' on */
/* others. */
/* */
#ifdef _STANDALONE_
#if defined( FT_RASTER_INT_IS_32 )
typedef unsigned int FT_Word32;
#elif defined( FT_RASTER_LONG_IS_32 )
typedef unsigned long FT_Word32;
#else
#error "no 32bit type found - please check your configuration"
#endif
#endif
/*************************************************************************/
/* */
/* A pointer to an unsigned char. */
/* */
typedef unsigned char Byte, *PByte;
typedef int TResult;
/*************************************************************************/
/* */
/* The type of the pixel coordinates used within the render pool during */
/* scan-line conversion. We use longs to store either 26.6 or 22.10 */
/* fixed float values, depending on the `precision' we want to use */
/* (i.e., low resp. high precision). These are ideals in order to */
/* subdivise Bezier arcs in halves by simple additions and shifts. */
/* */
/* Note that this is an 8-bytes integer on 64 bits systems. */
/* */
typedef long TPos, *PPos;
/*************************************************************************/
/* */
/* The type of a scanline position/coordinate within a map. */
/* */
typedef int TScan, *PScan;
/*************************************************************************/
/* */
/* States and directions of each line, arc, and profile. */
/* */
typedef enum _TDirection
{
Unknown,
Ascending,
Descending,
Flat
} TDirection;
struct _TProfile;
typedef struct _TProfile TProfile;
typedef TProfile* PProfile;
/*************************************************************************/
/* */
/* The `master' structure used for decomposing outlines. */
/* */
struct _TProfile
{
TPos X; /* current coordinate during sweep */
PProfile link; /* link to next profile - various purpose */
PPos offset; /* start of profile's data in render pool */
int flow; /* Profile orientation: Asc/Descending */
TScan height; /* profile's height in scanlines */
TScan start; /* profile's starting scanline */
TScan countL; /* number of lines to step before this */
/* profile becomes drawable */
PProfile next; /* next profile in same contour, used */
/* during drop-out control */
};
typedef PProfile TProfileList;
typedef PProfile* PProfileList;
/*************************************************************************/
/* */
/* A simple record used to implement a stack of bands, required by the */
/* sub-banding mechanism. */
/* */
typedef struct _TBand
{
TScan y_min; /* band's minimum */
TScan y_max; /* band's maximum */
} TBand;
/*************************************************************************/
/* */
/* The size in _TPos_ of a profile record in the render pool. */
/* */
#define AlignProfileSize \
( (sizeof ( TProfile ) + sizeof ( TPos ) - 1) / sizeof ( TPos ) )
/*************************************************************************/
/* */
/* Prototypes used for sweep function dispatch. */
/* */
typedef void (*Function_Sweep_Init)( RAS_ARG_ int* min,
int* max );
typedef void (*Function_Sweep_Span)( RAS_ARG_ TScan y,
TPos x1,
TPos x2 );
typedef int (*Function_Test_Pixel)( RAS_ARG_ TScan y,
int x );
typedef void (*Function_Set_Pixel)( RAS_ARG_ TScan y,
int x,
int color );
typedef void (*Function_Sweep_Step)( RAS_ARG );
typedef struct Raster_Render_
{
Function_Sweep_Init init;
Function_Sweep_Span span;
Function_Sweep_Step step;
Function_Test_Pixel test_pixel;
Function_Set_Pixel set_pixel;
} Raster_Render;
#ifdef FT_RASTER_CONSTANT_PRECISION
#define PRECISION_BITS FT_PRECISION_BITS
#define PRECISION (1 << PRECISION_BITS)
#define PRECISION_MASK (-1L << PRECISION_BITS)
#define PRECISION_HALF (PRECISION >> 1)
#define PRECISION_JITTER (PRECISION >> 5)
#define PRECISION_STEP PRECISION_HALF
#else
#define PRECISION_BITS ras.precision_bits
#define PRECISION ras.precision
#define PRECISION_MASK ras.precision_mask
#define PRECISION_HALF ras.precision_half
#define PRECISION_JITTER ras.precision_jitter
#define PRECISION_STEP ras.precision_step
#endif
/*************************************************************************/
/* */
/* Compute lowest integer coordinate below a given value. */
/* */
#define FLOOR( x ) ( (x) & PRECISION_MASK )
/*************************************************************************/
/* */
/* Compute highest integer coordinate above a given value. */
/* */
#define CEILING( x ) ( ((x) + PRECISION - 1) & PRECISION_MASK )
/*************************************************************************/
/* */
/* Get integer coordinate of a given 26.6 or 22.10 `x' coordinate -- no */
/* rounding. */
/* */
#define TRUNC( x ) ( (signed long)(x) >> PRECISION_BITS )
/*************************************************************************/
/* */
/* Get the fractional part of a given coordinate. */
/* */
#define FRAC( x ) ( (x) & (PRECISION-1) )
/*************************************************************************/
/* */
/* Scale an `input coordinate' (as found in FT_Outline structures) into */
/* a `work coordinate' which depends on current resolution and render */
/* mode. */
/* */
#define SCALED( x ) ( ((x) << ras.scale_shift) - ras.scale_delta )
/*************************************************************************/
/* */
/* DEBUG_PSET is used to plot a single pixel in VRam during debug mode. */
/* */
#ifdef DEBUG_RASTER
#define DEBUG_PSET Pset()
#else
#define DEBUG_PSET
#endif
/*************************************************************************/
/* */
/* This structure defines a point in a plane. */
/* */
typedef struct _TPoint
{
TPos x, y;
} TPoint;
/*************************************************************************/
/* */
/* The most used variables are at the beginning of the structure. Thus, */
/* their offset can be coded with less opcodes which results in a */
/* smaller executable. */
/* */
struct FT_RasterRec_
{
PPos cursor; /* Current cursor in render pool */
PPos pool; /* The render pool base address */
PPos pool_size; /* The render pool's size */
PPos pool_limit; /* Limit of profiles zone in pool */
int bit_width; /* target bitmap width */
PByte bit_buffer; /* target bitmap buffer */
PByte pix_buffer; /* target pixmap buffer */
TPoint last;
long minY, maxY;
int error;
#ifndef FT_RASTER_CONSTANT_PRECISION
int precision_bits; /* precision related variables */
int precision;
int precision_half;
long precision_mask;
int precision_shift;
int precision_step;
int precision_jitter;
#endif
FT_Outline* outline;
int n_points; /* number of points in current glyph */
int n_contours; /* number of contours in current glyph */
int n_extrema; /* number of `extrema' scanlines */
TPoint* arc; /* current Bezier arc pointer */
int num_profs; /* current number of profiles */
char fresh; /* signals a fresh new profile which */
/* `start' field must be completed */
char joint; /* signals that the last arc ended */
/* exactly on a scanline. Allows */
/* removal of doublets */
PProfile cur_prof; /* current profile */
PProfile start_prof; /* head of linked list of profiles */
PProfile first_prof; /* contour's first profile in case */
/* of impact */
TDirection state; /* rendering state */
FT_Bitmap target; /* description of target bit/pixmap */
void* memory;
int trace_bit; /* current offset in target bitmap */
int trace_pix; /* current offset in target pixmap */
int trace_incr; /* sweep's increment in target bitmap */
/* dispatch variables */
Raster_Render render;
int scale_shift; /* == 0 for bitmaps */
/* == 1 for 5-levels pixmaps */
/* == 2 for 17-levels pixmaps */
int scale_delta; /* ras.precision_half for bitmaps */
/* 0 for pixmaps */
char dropout_mode; /* current drop_out control method */
char second_pass; /* indicates whether a horizontal pass */
/* should be performed to control drop-out */
/* accurately when calling Render_Glyph. */
/* Note that there is no horizontal pass */
/* during gray rendering. */
char flipped; /* this flag is set during the rendering to */
/* indicate the second pass. */
TBand band_stack[16]; /* band stack used for sub-banding */
int band_top; /* band stack top */
TPoint arcs[2 * MaxBezier + 1]; /* The Bezier stack */
};
#ifdef DEBUG_RASTER
/*************************************************************************/
/* */
/* <Function> */
/* Pset */
/* */
/* <Description> */
/* Used for debugging only. Plots a point in VRAM during rendering */
/* (not afterwards). */
/* */
/* <Note> */
/* This procedure relies on the value of cProfile->start, which may */
/* not be set when Pset() is called sometimes. This will usually */
/* result in a dot plotted on the first screen scanline (far away */
/* from its original position). */
/* */
/* This `feature' reflects nothing wrong in the current */
/* implementation, and the bitmap is rendered correctly, so don't */
/* panic if you see `flying' dots in debugging mode. */
/* */
static
void Pset( RAS_ARG )
{
long o;
long x;
x = ras.cursor[-1];
switch ( ras.cur_prof->flow )
{
case FT_Flow_Up:
o = Vio_ScanLineWidth *
( ras.cursor - ras.cur_prof->offset + ras.cur_prof->start ) +
( x / (PRECISION * 8) );
break;
case FT_Flow_Down:
o = Vio_ScanLineWidth *
( ras.cur_prof->start - ras.cursor + ras.cur_prof->offset ) +
( x / (PRECISION * 8) );
break;
}
if ( o > 0 )
Vio[o] |= (unsigned)0x80 >> ( (x/PRECISION) & 7 );
}
static
void Clear_Band( RAS_ARG_ TScan y1,
TScan y2 )
{
MEM_Set( Vio + y1*Vio_ScanLineWidth, (y2-y1+1)*Vio_ScanLineWidth, 0 );
}
#endif /* DEBUG_RASTER */
/*************************************************************************/
/* */
/* <Function> */
/* Set_High_Precision */
/* */
/* <Description> */
/* Sets precision variables according to the parameter flag. */
/* */
/* <Input> */
/* High :: Set to True for high precision (typically for ppem < 18), */
/* false otherwise. */
/* */
static
void Set_High_Precision( RAS_ARG_ char High )
{
#ifdef FT_RASTER_CONSTANT_PRECISION
(void)High;
(void)&ras;
#else
if ( High )
{
ras.precision_bits = 10;
ras.precision_step = 128;
ras.precision_jitter = 24;
}
else
{
ras.precision_bits = 6;
ras.precision_step = 32;
ras.precision_jitter = 2;
}
ras.precision = 1L << ras.precision_bits;
ras.precision_half = ras.precision / 2;
ras.precision_shift = ras.precision_bits - INPUT_BITS;
ras.precision_mask = -ras.precision;
#endif
}
/*************************************************************************/
/* */
/* A simple technical note on how the raster works: */
/* */
/* Converting an outline into a bitmap is achieved in several steps */
/* which are: */
/* */
/* 1 - Decomposing the outline into successive `profiles'. Each */
/* profile is simply an array of scanline intersections on a given */
/* dimension. A profile's main attributes are */
/* */
/* o its scanline position boundaries, i.e. `Ymin' and `Ymax'. */
/* */
/* o an array of intersection coordinates for each scanline */
/* between `Ymin' and `Ymax'. */
/* */
/* o a direction, indicating wether is was built going `up' or */
/* `down', as this is very important for filling rules. */
/* */
/* 2 - Sweeping the target map's scanlines in order to compute segment */
/* `spans' which are then filled. Additionaly, this pass performs */
/* drop-out control. */
/* */
/* The outline data is parsed during step 1 only. The profiles are */
/* built from the bottom of the render pool, used as a stack. The */
/* following graphics shows the profile list under construction: */
/* */
/* ____________________________________________________________ _ _ */
/* | | | | | */
/* | profile | coordinates for | profile | coordinates for |--> */
/* | 1 | profile 1 | 2 | profile 2 |--> */
/* |_________|___________________|_________|_________________|__ _ _ */
/* */
/* ^ ^ */
/* | | */
/* start of render pool cursor */
/* */
/* The top of the profile stack is kept in the `cursor' variable. */
/* */
/* As you can see, a profile record is pushed on top of the render */
/* pool, which is then followed by its coordinates/intersections. If */
/* a change of direction is detected in the outline, a new profile is */
/* generated until the end of the outline. */
/* */
/* Note that when all profiles have been generated, the function */
/* Finalize_Profile_Table() is used to record, for each profile, its */
/* bottom-most scanline as well as the scanline above its upmost */
/* boundary. These positions are called `extrema' because they (sort */
/* of) correspond to local extrema. They are stored in a sorted list */
/* built from the top of the render pool as a downwards stack: */
/* */
/* _ _ _______________________________________ */
/* | | */
/* <--| sorted list of | */
/* <--| extrema scanlines | */
/* _ _ __________________|____________________| */
/* */
/* ^ ^ */
/* | | */
/* pool_limit end of render pool */
/* */
/* This list is later used during the sweep phase in order to */
/* optimize performance (see technical note on the sweep below). */
/* */
/* Of course, the raster detects whether the two stacks collide and */
/* handles the situation propertly. */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* New_Profile */
/* */
/* <Description> */
/* Creates a new Profile in the render pool. */
/* */
/* <Input> */
/* aState :: The state/orientation of the new profile. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult New_Profile( RAS_ARG_ TDirection direction )
{
if ( ras.start_prof == NULL )
{
ras.cur_prof = (PProfile)ras.cursor; /* current profile */
ras.start_prof = ras.cur_prof; /* first profile in pool */
ras.cursor += AlignProfileSize; /* record profile in buffer */
}
/* check for overflow */
if ( ras.cursor >= ras.pool_limit )
{
ras.error = ErrRaster_Overflow;
return FAILURE;
}
/* record profile direction */
switch ( direction )
{
case Ascending:
ras.cur_prof->flow = Flow_Up;
break;
case Descending:
ras.cur_prof->flow = Flow_Down;
break;
default:
ras.error = ErrRaster_Invalid_Map;
return FAILURE;
}
/* initialize a few fields */
{
PProfile cur = ras.cur_prof;
cur->start = 0; /* current start scanline */
cur->height = 0; /* current height */
cur->offset = ras.cursor; /* address of first coordinate */
cur->link = (PProfile)0; /* link to next profile in pool */
cur->next = (PProfile)0; /* link to next profile in contour */
}
/* record the first profile in a contour */
if ( ras.first_prof == NULL )
ras.first_prof = ras.cur_prof;
ras.state = direction;
ras.fresh = TRUE; /* this profile has no coordinates yet */
ras.joint = FALSE;
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* End_Profile */
/* */
/* <Description> */
/* Finalizes the current Profile and computes its height. If it is */
/* not 0, the profile's fields are updated and a new profile is */
/* pushed on top of its coordinates. Otherwise the current profile */
/* is kept and the recording of intersections is restarted. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult End_Profile( RAS_ARG )
{
int h;
h = ras.cursor - ras.cur_prof->offset;
if ( h < 0 )
{
/* This error should _never_ occur unless the raster is buggy */
ras.error = ErrRaster_Negative_Height;
return FAILURE;
}
if ( h > 0 )
{
PProfile old, new;
/* record scanline height in current profile, create a new one */
/* and set a link from the old one to it */
old = ras.cur_prof;
old->height = h;
ras.cur_prof = new = (PProfile)ras.cursor;
ras.cursor += AlignProfileSize;
new->height = 0;
new->offset = ras.cursor;
old->next = new;
ras.num_profs++;
}
/* check for overflow */
if ( ras.cursor >= ras.pool_limit )
{
ras.error = ErrRaster_Overflow;
return FAILURE;
}
ras.joint = FALSE;
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* Insert_Extrema */
/* */
/* <Description> */
/* Records that a given scanline contains at least one local */
/* extremum. The table of extrema is placed at the end of the render */
/* pool and grows downwards. It is used during the sweep phase. */
/* */
/* <Input> */
/* y :: The coordinate of the scanline containing an extremum. */
/* */
static
TResult Insert_Extrema( RAS_ARG_ TScan y )
{
PPos extrema;
TScan y2;
int n;
PTRACE2(( "EXTREMA += %d", y ));
n = ras.n_extrema - 1;
extrema = ras.pool_size - ras.n_extrema;
/* look for first y extremum that is <= */
while ( n >= 0 && y < extrema[n] )
n--;
/* if it is <, simply insert it, ignore if == */
if ( n >= 0 && y > extrema[n] )
while ( n >= 0 )
{
y2 = extrema[n];
extrema[n] = y;
y = y2;
n--;
}
if ( n < 0 )
{
ras.pool_limit--;
ras.n_extrema++;
ras.pool_size[-ras.n_extrema] = y;
if ( ras.pool_limit <= ras.cursor )
{
ras.error = ErrRaster_Overflow;
return FAILURE;
}
}
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* Finalize_Profile_Table */
/* */
/* <Description> */
/* Adjusts all links in the profiles list. Called when the outline */
/* parsing is done. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult Finalize_Profile_Table( RAS_ARG )
{
int n, bottom, top;
PProfile p;
n = ras.num_profs;
if ( n > 1 )
{
p = ras.start_prof;
while ( n > 0 )
{
if ( n > 1 )
p->link = (PProfile)( p->offset + p->height );
else
p->link = NULL;
switch ( p->flow )
{
case Flow_Down:
PTRACE2(( "FLOW DOWN (start = %d, height = %d)",
p->start, p->height ));
bottom = p->start - p->height+1;
top = p->start;
p->start = bottom;
p->offset += p->height-1;
break;
case Flow_Up:
default:
PTRACE2(( "FLOW UP (start = %d, height = %d)",
p->start, p->height ));
bottom = p->start;
top = p->start + p->height-1;
}
if ( Insert_Extrema( RAS_VAR_ bottom ) ||
Insert_Extrema( RAS_VAR_ top+1 ) )
return FAILURE;
p = p->link;
n--;
}
}
else
ras.start_prof = NULL;
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* Line_Up */
/* */
/* <Description> */
/* Computes the scan-line intersections of an ascending line segment */
/* and stores them in the render pool. */
/* */
/* <Input> */
/* x1 :: The start x coordinate. */
/* y1 :: The start y coordinate. */
/* x2 :: The end x coordinate. */
/* y2 :: The end y coordinate. */
/* miny :: The minimum vertical grid coordinate. */
/* maxy :: The maximum vertical grid coordinate. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult Line_Up( RAS_ARG_ TPos x1, TPos y1,
TPos x2, TPos y2,
TPos miny, TPos maxy )
{
TPos Dx, Dy;
int e1, e2, f1, f2, size;
TPos Ix, Rx, Ax;
PPos top;
Dx = x2 - x1;
Dy = y2 - y1;
if ( Dy <= 0 || y2 < miny || y1 > maxy )
return SUCCESS;
/* clip to higher scanline when necessary */
if ( y2 > maxy )
{
/* x2 += FMulDiv( Dx, maxy-y2, Dy ); UNNECESSARY */
e2 = TRUNC( maxy );
f2 = 0;
}
else
{
e2 = TRUNC( y2 );
f2 = FRAC( y2 );
}
/* clip to lower scanline when necessary */
if ( y1 < miny )
{
TPos x, y;
/* we use a binary search to compute the lower
// clipping intersection. That's because we don't
// want to use an external function like FT_MulDiv
// to compute it directly.
*/
if ( y2 == miny ) goto Exit;
do
{
x = (x1 + x2) >> 1;
y = (y1 + y2) >> 1;
if (y <= miny)
{
x1 = x;
y1 = y;
}
else
{
x2 = x;
y2 = y;
}
}
while ( y1 < miny );
e1 = TRUNC( miny );
f1 = 0;
}
else
{
e1 = TRUNC( y1 );
f1 = FRAC( y1 );
}
/* adjust start point so that we begin on an integer scanline position */
if ( f1 > 0 )
{
if ( e1 == e2 ) goto Exit;
else
{
x1 += FMulDiv( Dx, PRECISION - f1, Dy );
e1 += 1;
}
}
else
if ( ras.joint )
{
ras.cursor--;
ras.joint = FALSE;
}
ras.joint = ( f2 == 0 );
/* if this is a `fresh' profile, record its starting scanline */
if ( ras.fresh )
{
ras.cur_prof->start = e1;
ras.fresh = FALSE;
}
/* check for overflow */
size = e2 - e1 + 1;
if ( ras.cursor + size >= ras.pool_limit )
{
ras.error = ErrRaster_Overflow;
return FAILURE;
}
/* compute decision variables and push the intersections on top */
/* of the render pool */
Dx <<= PRECISION_BITS;
Ix = Dx / Dy;
Rx = Dx % Dy;
if (Rx < 0)
{
Ix --;
Rx += Dy;
}
Ax = -Dy;
Rx <<= 1;
Dy <<= 1;
top = ras.cursor;
while ( size > 0 )
{
*top++ = x1;
DEBUG_PSET;
x1 += Ix;
Ax += Rx;
if ( Ax >= 0 )
{
Ax -= Dy;
x1 ++;
}
size--;
}
ras.cursor = top;
Exit:
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* Line_Down */
/* */
/* <Description> */
/* Computes the scan-line intersections of a descending line segment */
/* and stores them in the render pool. */
/* */
/* <Input> */
/* x1 :: The start x coordinate. */
/* y1 :: The start y coordinate. */
/* x2 :: The end x coordinate. */
/* y2 :: The end y coordinate. */
/* miny :: The minimum vertical grid coordinate. */
/* maxy :: The maximum vertical grid coordinate. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult Line_Down( RAS_ARG_ TPos x1, TPos y1,
TPos x2, TPos y2,
TPos miny, TPos maxy )
{
TResult result, fresh;
/* simply invert the coordinates and call Line_Up */
fresh = ras.fresh;
result = Line_Up( RAS_VAR_ x1, -y1, x2, -y2, -maxy, -miny );
/* if this was a fresh profile, invert the recorded start position */
if ( fresh && !ras.fresh )
ras.cur_prof->start = -ras.cur_prof->start;
return result;
}
/* A function type describing the functions used to split bezier arcs */
typedef void (*TSplitter)( TPoint* base );
#ifdef FT_DYNAMIC_BEZIER_STEPS
static
TPos Dynamic_Bezier_Threshold( RAS_ARG_ int degree, TPoint* arc )
{
TPos min_x, max_x, min_y, max_y, A, B;
TPos wide_x, wide_y, threshold;
TPoint* cur = arc;
TPoint* limit = cur + degree;
/* first of all, set the threshold to the maximum x or y extent */
min_x = max_x = arc[0].x;
min_y = max_y = arc[0].y;
cur++;
for ( ; cur < limit; cur++ )
{
TPos x = cur->x;
TPos y = cur->y;
if ( x < min_x ) min_x = x;
if ( x > max_x ) max_x = x;
if ( y < min_y ) min_y = y;
if ( y > max_y ) max_y = y;
}
wide_x = (max_x - min_x) << 4;
wide_y = (max_y - min_y) << 4;
threshold = wide_x;
if (threshold < wide_y) threshold = wide_y;
/* now compute the second and third order error values */
wide_x = arc[0].x + arc[1].x - arc[2].x*2;
wide_y = arc[0].y + arc[1].y - arc[2].y*2;
if (wide_x < 0) wide_x = -wide_x;
if (wide_y < 0) wide_y = -wide_y;
A = wide_x; if ( A < wide_y ) A = wide_y;
if (degree >= 3)
{
wide_x = arc[3].x - arc[0].x + 3*(arc[2].x - arc[3].x);
wide_y = arc[3].y - arc[0].y + 3*(arc[2].y - arc[3].y);
if (wide_x < 0) wide_x = -wide_x;
if (wide_y < 0) wide_y = -wide_y;
B = wide_x; if ( B < wide_y ) B = wide_y;
}
else
B = 0;
while ( A > 0 || B > 0 )
{
threshold >>= 1;
A >>= 2;
B >>= 3;
}
if (threshold < PRECISION_STEP)
threshold = PRECISION_STEP;
return threshold;
}
#endif
/*************************************************************************/
/* */
/* <Function> */
/* Bezier_Up */
/* */
/* <Description> */
/* Computes the scan-line intersections of an ascending second-order */
/* Bezier arc and stores them in the render pool. The arc is taken */
/* from the top of the stack. */
/* */
/* <Input> */
/* miny :: The minimum vertical grid coordinate. */
/* maxy :: The maximum vertical grid coordinate. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult Bezier_Up( RAS_ARG_ int degree,
TSplitter splitter,
TPos miny,
TPos maxy )
{
TPos y1, y2, e, e2, e0, threshold;
int f1;
TPoint* arc;
TPoint* start_arc;
PPos top;
arc = ras.arc;
y1 = arc[degree].y;
y2 = arc[0].y;
top = ras.cursor;
if ( y2 < miny || y1 > maxy )
goto Fin;
e2 = FLOOR( y2 ); /* integer end y */
if ( e2 > maxy )
e2 = FLOOR(maxy);
e0 = CEILING(miny);
if ( y1 < miny )
{
e = e0; /* integer start y == current scanline */
}
else
{
e = CEILING( y1 ); /* integer start y == current scanline */
f1 = FRAC( y1 ); /* fractional shift of start y */
e0 = e; /* first integer scanline to be pushed */
if ( f1 == 0 ) /* do we start on an integer scanline? */
{
if ( ras.joint )
{
top--;
ras.joint = FALSE;
}
*top++ = arc[degree].x; /* write directly start position */
DEBUG_PSET;
e += PRECISION; /* go to next scanline */
}
}
/* record start position if necessary */
if ( ras.fresh )
{
ras.cur_prof->start = TRUNC( e0 );
ras.fresh = FALSE;
}
/* exit if the current scanline is already above the max scanline */
if ( e2 < e )
goto Fin;
/* check for overflow */
if ( ( top + TRUNC( e2 - e ) + 1 ) >= ras.pool_limit )
{
ras.cursor = top;
ras.error = ErrRaster_Overflow;
return FAILURE;
}
#ifdef FT_DYNAMIC_BEZIER_STEPS
/* compute dynamic bezier step threshold */
threshold = Dynamic_Bezier_Threshold( RAS_VAR_ degree, arc );
#else
threshold = PRECISION_STEP;
#endif
start_arc = arc;
/* loop while there is still an arc on the bezier stack */
/* and the current scan line is below y max == e2 */
while ( arc >= start_arc && e <= e2 )
{
ras.joint = FALSE;
y2 = arc[0].y; /* final y of the top-most arc */
if ( y2 > e ) /* the arc intercepts the current scanline */
{
y1 = arc[degree].y; /* start y of top-most arc */
if ( y2 >= e + PRECISION || y2 - y1 >= threshold )
{
/* if the arc's height is too great, split it */
splitter( arc );
arc += degree;
}
else
{
/* otherwise, approximate it as a segment and compute */
/* its intersection with the current scanline */
*top++ = arc[degree].x +
FMulDiv( arc[0].x-arc[degree].x,
e - y1,
y2 - y1 );
DEBUG_PSET;
arc -= degree; /* pop the arc */
e += PRECISION; /* go to next scanline */
}
}
else
{
if ( y2 == e ) /* if the arc falls on the scanline */
{ /* record its _joint_ intersection */
ras.joint = TRUE;
*top++ = arc[0].x;
DEBUG_PSET;
e += PRECISION; /* go to next scanline */
}
arc -= degree; /* pop the arc */
}
}
Fin:
ras.cursor = top;
ras.arc -= degree;
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* Bezier_Down */
/* */
/* <Description> */
/* Computes the scan-line intersections of a descending second-order */
/* Bezier arc and stores them in the render pool. The arc is taken */
/* from the top of the stack. */
/* */
/* <Input> */
/* miny :: The minimum vertical grid coordinate. */
/* maxy :: The maximum vertical grid coordinate. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult Bezier_Down( RAS_ARG_ int degree,
TSplitter splitter,
TPos miny,
TPos maxy )
{
TPoint* arc = ras.arc;
TResult result, fresh;
arc[0].y = -arc[0].y;
arc[1].y = -arc[1].y;
arc[2].y = -arc[2].y;
if (degree > 2)
arc[3].y = -arc[3].y;
fresh = ras.fresh;
result = Bezier_Up( RAS_VAR_ degree, splitter, -maxy, -miny );
if ( fresh && !ras.fresh )
ras.cur_prof->start = -ras.cur_prof->start;
arc[0].y = -arc[0].y;
return result;
}
#ifdef FT_RASTER_CONIC_BEZIERS
/*************************************************************************/
/* */
/* <Function> */
/* Split_Conic */
/* */
/* <Description> */
/* Subdivides one second-order Bezier arc into two joint sub-arcs in */
/* the Bezier stack. */
/* */
/* <Note> */
/* This routine is the `beef' of the component. It is one of _the_ */
/* inner loops that should be optimized like hell to get the best */
/* performance. */
/* */
static
void Split_Conic( TPoint* base )
{
TPos a, b;
base[4].x = base[2].x;
b = base[1].x;
a = base[3].x = ( base[2].x + b + 1 ) >> 1;
b = base[1].x = ( base[0].x + b + 1 ) >> 1;
base[2].x = ( a + b + 1 ) >> 1;
base[4].y = base[2].y;
b = base[1].y;
a = base[3].y = ( base[2].y + b + 1 ) >> 1;
b = base[1].y = ( base[0].y + b + 1 ) >> 1;
base[2].y = ( a + b ) / 2;
}
/*************************************************************************/
/* */
/* <Function> */
/* Push_Conic */
/* */
/* <Description> */
/* Clears the Bezier stack and pushes a new arc on top of it. */
/* */
/* <Input> */
/* p2 :: A pointer to the second (control) point. */
/* p3 :: A pointer to the third (end) point. */
/* */
/* <Note> */
/* The first point is taken as `raster->last', so it doesn't appear */
/* in the signature. */
/* */
static
void Push_Conic( RAS_ARG_ FT_Vector* p2,
FT_Vector* p3 )
{
#undef STORE
#define STORE( _arc, point ) \
{ \
TPos x = SCALED( point->x ); \
TPos y = SCALED( point->y ); \
\
\
if ( ras.flipped ) \
{ \
_arc.x = y; \
_arc.y = x; \
} \
else \
{ \
_arc.x = x; \
_arc.y = y; \
} \
}
TPoint* arc;
ras.arc = arc = ras.arcs;
arc[2] = ras.last;
STORE( arc[1], p2 );
STORE( arc[0], p3 );
#undef STORE
}
#endif /* FT_RASTER_CONIC_BEZIERS */
#ifdef FT_RASTER_CUBIC_BEZIERS
/*************************************************************************/
/* */
/* <Function> Split_Cubic */
/* */
/* <Description> */
/* Subdivides a third-order Bezier arc into two joint sub-arcs in */
/* the Bezier stack. */
/* */
/* <Note> */
/* This routine is the `beef' of the component. It is one of _the_ */
/* inner loops that should be optimized like hell to get the best */
/* performance. */
/* */
static
void Split_Cubic( TPoint* 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 + 1 ) >> 1;
base[5].x = b = ( base[3].x + d + 1 ) >> 1;
c = ( c + d + 1 ) >> 1;
base[2].x = a = ( a + c + 1 ) >> 1;
base[4].x = b = ( b + c + 1 ) >> 1;
base[3].x = ( a + b + 1 ) >> 1;
base[6].y = base[3].y;
c = base[1].y;
d = base[2].y;
base[1].y = a = ( base[0].y + c + 1 ) >> 1;
base[5].y = b = ( base[3].y + d + 1 ) >> 1;
c = ( c + d + 1 ) >> 1;
base[2].y = a = ( a + c + 1 ) >> 1;
base[4].y = b = ( b + c + 1 ) >> 1;
base[3].y = ( a + b + 1 ) >> 1;
}
/*************************************************************************/
/* */
/* <Function> */
/* Push_Cubic */
/* */
/* <Description> */
/* Clears the Bezier stack and pushes a new third-order Bezier arc on */
/* top of it. */
/* */
/* <Input> */
/* p2 :: A pointer to the second (control) point. */
/* p3 :: A pointer to the third (control) point. */
/* p4 :: A pointer to the fourth (end) point. */
/* */
/* <Note> */
/* The first point is taken as `raster->last', so it doesn't appear */
/* in the signature. */
/* */
/* This is the same as Push_Conic(), except that it deals with */
/* third-order Beziers. */
/* */
static
void Push_Cubic( RAS_ARG_ FT_Vector* p2,
FT_Vector* p3,
FT_Vector* p4 )
{
#undef STORE
#define STORE( _arc, point ) \
{ \
TPos x = SCALED( point->x ); \
TPos y = SCALED( point->y ); \
\
if ( ras.flipped ) \
{ \
_arc.x = y; \
_arc.y = x; \
} \
else \
{ \
_arc.x = x; \
_arc.y = y; \
} \
}
TPoint* arc;
ras.arc = arc = ras.arcs;
arc[3] = ras.last;
STORE( arc[2], p2 );
STORE( arc[1], p3 );
STORE( arc[0], p4 );
#undef STORE
}
#endif /* FT_RASTER_CUBIC_BEZIERS */
/*************************************************************************/
/* */
/* <Function> */
/* Check_Contour */
/* */
/* <Description> */
/* Performs some checks at contour closure. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult Check_Contour( RAS_ARG )
{
PProfile lastProfile;
/* Sometimes, the first and last profile in a contour join on */
/* an integer scan-line; we must then remove the last intersection */
/* from the last profile to get rid of doublets */
if ( ( FRAC( ras.last.y ) == 0 &&
ras.last.y >= ras.minY &&
ras.last.y <= ras.maxY ) )
{
if ( ras.first_prof && ras.first_prof->flow == ras.cur_prof->flow )
ras.cursor--;
}
lastProfile = ras.cur_prof;
if ( End_Profile( RAS_VAR ) )
return FAILURE;
/* close the `next profile in contour' linked list */
lastProfile->next = ras.first_prof;
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* Move_To */
/* */
/* <Description> */
/* This function injects a new contour in the render pool. */
/* */
/* <Input> */
/* to :: A pointer to the contour's first point. */
/* raster :: A pointer to the current raster object. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
/* <Note> */
/* This function is used as a `FTRasterMoveTo_Func' by the outline */
/* decomposer. */
/* */
static
int Move_To( FT_Vector* to,
FT_Raster raster )
{
TPos scaled_x, scaled_y;
/* if there was already a contour being built, perform some checks */
if ( ras.start_prof )
if ( Check_Contour( RAS_VAR ) )
return FAILURE;
/* set the `current last point' */
scaled_x = SCALED( to->x );
scaled_y = SCALED( to->y );
if ( ras.flipped )
{
ras.last.x = scaled_y;
ras.last.y = scaled_x;
}
else
{
ras.last.x = scaled_x;
ras.last.y = scaled_y;
}
ras.state = Unknown;
ras.first_prof = NULL;
return SUCCESS;
}
/*************************************************************************/
/* */
/* <Function> */
/* Line_To */
/* */
/* <Description> */
/* This function injects a new line segment in the render pool and */
/* adjusts the profiles list accordingly. */
/* */
/* <Input> */
/* to :: A pointer to the target position. */
/* raster :: A pointer to the current raster object. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
/* <Note> */
/* This function is used as a `FTRasterLineTo_Func' by the outline */
/* decomposer. */
/* */
static
int Line_To( FT_Vector* to,
FT_Raster raster )
{
TPos x, scaled_x;
TPos y, scaled_y;
scaled_x = SCALED( to->x );
scaled_y = SCALED( to->y );
if ( ras.flipped )
{
x = scaled_y;
y = scaled_x;
}
else
{
x = scaled_x;
y = scaled_y;
}
/* First, detect a change of direction */
if ( y != ras.last.y )
{
TDirection new_state = ( (y > ras.last.y) ? Ascending : Descending );
if ( ras.state != new_state )
{
if ( ras.state != Unknown &&
End_Profile( RAS_VAR ) )
goto Fail;
if ( New_Profile( RAS_VAR_ new_state ) )
goto Fail;
}
}
/* Then compute the lines */
switch ( ras.state )
{
case Ascending:
if ( Line_Up ( RAS_VAR_ ras.last.x, ras.last.y,
x, y, ras.minY, ras.maxY ) )
goto Fail;
break;
case Descending:
if ( Line_Down( RAS_VAR_ ras.last.x, ras.last.y,
x, y, ras.minY, ras.maxY ) )
goto Fail;
break;
default:
;
}
ras.last.x = x;
ras.last.y = y;
return SUCCESS;
Fail:
return FAILURE;
}
#ifdef FT_RASTER_CONIC_BEZIERS
/*************************************************************************/
/* */
/* <Function> */
/* Conic_To */
/* */
/* <Description> */
/* Injects a new conic Bezier arc and adjusts the profile list */
/* accordingly. */
/* */
/* <Input> */
/* control :: A pointer to an intermediate control point. */
/* to :: A pointer to the end point. */
/* raster :: A handle to the current raster object. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
/* <Note> */
/* This function is used as a `FTRasterConicTo_Func' by the outline */
/* decomposer. */
/* */
static
int Conic_To( FT_Vector* control,
FT_Vector* to,
FT_Raster raster )
{
TPos y1, y2, y3, x3, ymin, ymax;
TDirection state_bez;
Push_Conic( RAS_VAR_ control, to );
do
{
y1 = ras.arc[2].y;
y2 = ras.arc[1].y;
y3 = ras.arc[0].y;
x3 = ras.arc[0].x;
/* first, categorize the Bezier arc */
if ( y1 <= y3 )
{
ymin = y1;
ymax = y3;
}
else
{
ymin = y3;
ymax = y1;
}
if ( y2 < ymin || y2 > ymax )
{
/* this arc has no given direction, split it !! */
Split_Conic( ras.arc );
ras.arc += 2;
}
else if ( y1 == y3 )
{
/* this arc is flat, ignore it and pop it from the bezier stack */
ras.arc -= 2;
}
else
{
/* the arc is y-monotonous, either ascending or descending */
/* detect a change of direction */
state_bez = y1 < y3 ? Ascending : Descending;
if ( ras.state != state_bez )
{
/* finalize current profile if any */
if ( ras.state != Unknown &&
End_Profile( RAS_VAR ) )
goto Fail;
/* create a new profile */
if ( New_Profile( RAS_VAR_ state_bez ) )
goto Fail;
}
/* now call the appropriate routine */
if ( state_bez == Ascending )
{
if ( Bezier_Up( RAS_VAR_ 2, Split_Conic, ras.minY, ras.maxY ) )
goto Fail;
}
else
if ( Bezier_Down( RAS_VAR_ 2, Split_Conic, ras.minY, ras.maxY ) )
goto Fail;
}
} while ( ras.arc >= ras.arcs );
ras.last.x = x3;
ras.last.y = y3;
return SUCCESS;
Fail:
return FAILURE;
}
#else /* FT_RASTER_CONIC_BEZIERS */
static
int Conic_To( FT_Vector* control,
FT_Vector* to,
FT_Raster raster )
{
UNUSED( control );
UNUSED( to );
UNUSED( raster );
return ErrRaster_Invalid_Outline;
}
#endif /* FT_RASTER_CONIC_BEZIERS */
#ifdef FT_RASTER_CUBIC_BEZIERS
/*************************************************************************/
/* */
/* <Function> */
/* Cubic_To */
/* */
/* <Description> */
/* Injects a new cubic Bezier arc and adjusts the profile list */
/* accordingly. */
/* */
/* <Input> */
/* control1 :: A pointer to the first control point. */
/* control2 :: A pointer to the second control point. */
/* to :: A pointer to the end point. */
/* raster :: A handle to the current raster object. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
/* <Note> */
/* This function is used as a `FTRasterCubicTo_Func' by the outline */
/* decomposer. */
/* */
static
int Cubic_To( FT_Vector* control1,
FT_Vector* control2,
FT_Vector* to,
FT_Raster raster )
{
TPos y1, y2, y3, y4, x4, ymin1, ymax1, ymin2, ymax2;
TDirection state_bez;
Push_Cubic( RAS_VAR_ control1, control2, to );
do
{
y1 = ras.arc[3].y;
y2 = ras.arc[2].y;
y3 = ras.arc[1].y;
y4 = ras.arc[0].y;
x4 = ras.arc[0].x;
/* first, categorize the Bezier arc */
if ( y1 <= y4 )
{
ymin1 = y1;
ymax1 = y4;
}
else
{
ymin1 = y4;
ymax1 = y1;
}
if ( y2 <= y3 )
{
ymin2 = y2;
ymax2 = y3;
}
else
{
ymin2 = y3;
ymax2 = y2;
}
if ( ymin2 < ymin1 || ymax2 > ymax1 )
{
/* this arc has no given direction, split it! */
Split_Cubic( ras.arc );
ras.arc += 3;
}
else if ( y1 == y4 )
{
/* this arc is flat, ignore it and pop it from the bezier stack */
ras.arc -= 3;
}
else
{
state_bez = ( y1 <= y4 ) ? Ascending : Descending;
/* detect a change of direction */
if ( ras.state != state_bez )
{
if ( ras.state != Unknown &&
End_Profile( RAS_VAR ) )
goto Fail;
if ( New_Profile( RAS_VAR_ state_bez ) )
goto Fail;
}
/* compute intersections */
if ( state_bez == Ascending )
{
if ( Bezier_Up ( RAS_VAR_ 3, Split_Cubic, ras.minY, ras.maxY ) )
goto Fail;
}
else
if ( Bezier_Down ( RAS_VAR_ 3, Split_Cubic, ras.minY, ras.maxY ) )
goto Fail;
}
} while ( ras.arc >= ras.arcs );
ras.last.x = x4;
ras.last.y = y4;
return SUCCESS;
Fail:
return FAILURE;
}
#else /* FT_RASTER_CUBIC_BEZIERS */
int Cubic_To( FT_Vector* control1,
FT_Vector* control2,
FT_Vector* to,
FT_Raster raster )
{
UNUSED( control1 );
UNUSED( control2 );
UNUSED( to );
UNUSED( raster );
return ErrRaster_Invalid_Outline;
}
#endif /* FT_RASTER_CUBIC_BEZIERS */
/*************************************************************************/
/* */
/* <Function> */
/* Convert_Glyph */
/* */
/* <Description> */
/* Converts a glyph into a series of segments and arcs and makes a */
/* profiles list with them. */
/* */
/* <InOut> */
/* outline :: The glyph outline. */
/* */
/* <Return> */
/* SUCCESS or FAILURE. */
/* */
static
TResult Convert_Glyph( RAS_ARG_ FT_Outline* outline )
{
static
FT_Outline_Funcs interface =
{
(FT_Outline_MoveTo_Func)Move_To,
(FT_Outline_LineTo_Func)Line_To,
(FT_Outline_ConicTo_Func)Conic_To,
(FT_Outline_CubicTo_Func)Cubic_To
};
/* Set up state in the raster object */
ras.start_prof = NULL;
ras.joint = FALSE;
ras.fresh = FALSE;
ras.pool_limit = ras.pool_size - AlignProfileSize;
ras.n_extrema = 0;
ras.cur_prof = (PProfile)ras.cursor;
ras.cur_prof->offset = ras.cursor;
ras.num_profs = 0;
/* Now decompose curve */
if ( FT_Outline_Decompose( outline, &interface, &ras ) )
return FAILURE;
/* XXX: the error condition is in ras.error */
/* Check the last contour if needed */
if ( Check_Contour( RAS_VAR ) )
return FAILURE;
/* Finalize profiles list */
return Finalize_Profile_Table( RAS_VAR );
}
/*************************************************************************/
/* */
/* Init_Linked */
/* */
/* Inits an empty linked list. */
/* */
static
void Init_Linked( TProfileList* l )
{
*l = NULL;
}
/*************************************************************************/
/* */
/* InsNew */
/* */
/* Inserts a new Profile in a linked list. */
/* */
static
void InsNew( PProfileList list,
PProfile profile )
{
PProfile *old, current;
TPos x;
old = list;
current = *old;
x = profile->X;
while ( current )
{
if ( x < current->X )
break;
old = ¤t->link;
current = *old;
}
profile->link = current;
*old = profile;
}
/*************************************************************************/
/* */
/* DelOld */
/* */
/* Removes an old Profile from a linked list. */
/* */
static
void DelOld( PProfileList list,
PProfile profile )
{
PProfile *old, current;
old = list;
current = *old;
while ( current )
{
if ( current == profile )
{
*old = current->link;
return;
}
old = ¤t->link;
current = *old;
}
/* We should never reach this place, unless the Profile was not */
/* part of the list. */
}
/*************************************************************************/
/* */
/* Update */
/* */
/* Updates all X offsets of a drawing list. */
/* */
static
void Update( PProfile first )
{
PProfile current = first;
while ( current )
{
current->X = *current->offset;
current->offset += current->flow;
current->height--;
current = current->link;
}
}
/*************************************************************************/
/* */
/* Sort */
/* */
/* Sorts a trace list. In 95%, the list is already sorted. We need */
/* an algorithm which is fast in this case. Bubble sort is enough */
/* and simple to implement. */
/* */
static
void Sort( PProfileList list )
{
PProfile *old, current, next;
/* First, set the new X coordinate of each profile */
Update( *list );
/* Then sort them */
old = list;
current = *old;
if ( !current )
return;
next = current->link;
while ( next )
{
if ( current->X <= next->X )
{
old = ¤t->link;
current = *old;
if ( !current )
return;
}
else
{
*old = next;
current->link = next->link;
next->link = current;
old = list;
current = *old;
}
next = current->link;
}
}
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/******** ********/
/******** Vertical Bitmap Sweep Routines ********/
/******** ********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Sweep_Init */
/* */
/* <Description> */
/* Initializes the vertical bitmap sweep. Called by the generic */
/* sweep/draw routine before its loop. */
/* */
/* <Input> */
/* min :: The address of the current minimum scanline. */
/* max :: The address of the current maximum scanline. */
/* */
static
void Vertical_Sweep_Init( RAS_ARG_ int* min, int* max )
{
long pitch;
UNUSED( max );
pitch = ras.target.pitch;
/* start from the bottom line, going up !! */
ras.trace_bit = - *min * pitch;
ras.trace_incr = -pitch;
if (pitch > 0)
ras.trace_bit += pitch*(ras.target.rows-1);
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Sweep_Span */
/* */
/* <Description> */
/* Draws a single horizontal bitmap span during the vertical bitmap */
/* sweep. */
/* */
/* <Input> */
/* y :: The current scanline. */
/* x1 :: The left span edge. */
/* x2 :: The right span edge. */
/* */
static
void Vertical_Sweep_Span( RAS_ARG_ TScan y,
TPos x1,
TPos x2 )
{
TPos e1, e2;
int c1, c2;
Byte f1, f2;
PByte target;
UNUSED( y );
/* Drop-out control */
e1 = TRUNC( CEILING( x1 ) );
if ( x2 - x1 - PRECISION <= PRECISION_JITTER )
e2 = e1;
else
e2 = TRUNC( FLOOR( x2 ) );
if ( e1 <= e2 && e2 >= 0 && e1 < ras.bit_width )
{
if ( e1 < 0 ) e1 = 0;
if ( e2 >= ras.bit_width ) e2 = ras.bit_width - 1;
c1 = e1 >> 3;
c2 = e2 >> 3;
f1 = ((unsigned char)0xFF >> (e1 & 7));
f2 = ~((unsigned char)0x7F >> (e2 & 7));
target = ras.bit_buffer + ras.trace_bit + c1;
c2 -= c1;
if ( c2 > 0 )
{
target[0] |= f1;
/* memset() is slower than the following code on many platforms. */
/* This is due to the fact that, in the vast majority of cases, */
/* the span length in bytes is relatively small. */
c2--;
while ( c2 > 0 )
{
*(++target) = 0xFF;
c2--;
}
target[1] |= f2;
}
else
*target |= ( f1 & f2 );
}
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Test_Pixel */
/* */
/* <Description> */
/* Tests a pixel `light' during the vertical bitmap sweep. Used */
/* during drop-out control only. */
/* */
/* <Input> */
/* y :: The current scanline. */
/* x :: The current x coordinate. */
/* */
static
int Vertical_Test_Pixel( RAS_ARG_ TScan y,
int x )
{
int c1 = x >> 3;
UNUSED( y );
return ( x >= 0 && x < ras.bit_width &&
ras.bit_buffer[ras.trace_bit + c1] & (0x80 >> (x & 7)) );
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Set_Pixel */
/* */
/* <Description> */
/* Sets a single pixel in a bitmap during the vertical sweep. Used */
/* during drop-out control. */
/* */
/* <Input> */
/* y :: The current scanline. */
/* x :: The current x coordinate. */
/* color :: Ignored by this function. */
/* */
static
void Vertical_Set_Pixel( RAS_ARG_ int y,
int x,
int color )
{
UNUSED( color );
UNUSED( y );
if ( x >= 0 && x < ras.bit_width )
ras.bit_buffer[ras.trace_bit+(x >> 3)] |= (char)(0x80 >> (x & 7));
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Sweep_Step */
/* */
/* <Description> */
/* Called whenever the sweep jumps to another scanline. Only updates */
/* the pointers in the vertical bitmap sweep. */
/* */
static
void Vertical_Sweep_Step( RAS_ARG )
{
ras.trace_bit += ras.trace_incr;
}
static
const Raster_Render vertical_render_mono =
{
&Vertical_Sweep_Init,
&Vertical_Sweep_Span,
&Vertical_Sweep_Step,
&Vertical_Test_Pixel,
&Vertical_Set_Pixel
};
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/******** ********/
/******** Horizontal Bitmap Sweep Routines ********/
/******** ********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Sweep_Init */
/* */
/* <Description> */
/* Initializes the horizontal bitmap sweep. Called by the generic */
/* sweep/draw routine before its loop. */
/* */
/* <Input> */
/* min :: The address of the current minimum pixel column. */
/* max :: The address of the current maximum pixel column. */
/* */
static
void Horizontal_Sweep_Init( RAS_ARG_ int* min,
int* max )
{
UNUSED( ras );
UNUSED( min );
UNUSED( max );
/* nothing, really */
}
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Sweep_Span */
/* */
/* <Description> */
/* Draws a single vertical bitmap span during the horizontal bitmap */
/* sweep. Actually, this function is only used to check for weird */
/* drop-out cases. */
/* */
/* <Input> */
/* y :: The current pixel column. */
/* x1 :: The top span edge. */
/* x2 :: The bottom span edge. */
/* */
static
void Horizontal_Sweep_Span( RAS_ARG_ TScan y,
TPos x1,
TPos x2 )
{
TPos e1, e2;
PByte bits;
Byte f1;
UNUSED( y );
/* During the horizontal sweep, we only take care of drop-outs */
if ( x2 - x1 < PRECISION )
{
e1 = CEILING( x1 );
e2 = FLOOR( x2 );
if ( e1 == e2 )
{
bits = ras.bit_buffer + (y >> 3);
f1 = (Byte)(0x80 >> (y & 7));
e1 = TRUNC( e1 );
if ( e1 >= 0 && e1 < ras.target.rows )
{
long pitch = ras.target.pitch;
long offset = - pitch * e1;
if (pitch > 0)
offset += (ras.target.rows-1)*pitch;
bits[offset] |= f1;
}
}
}
}
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Test_Pixel */
/* */
/* <Description> */
/* Tests a pixel `light' during the horizontal bitmap sweep. Used */
/* during drop-out control only. */
/* */
/* <Input> */
/* y :: The current pixel column. */
/* x :: The current row/scanline. */
/* */
static
int Horizontal_Test_Pixel( RAS_ARG_ int y,
int x )
{
char* bits = (char*)ras.bit_buffer + (y >> 3);
int f1 = (Byte)(0x80 >> (y & 7));
long pitch = ras.target.pitch;
long offset = - pitch * x;
if (pitch > 0)
offset += (ras.target.rows-1)*pitch;
return ( x >= 0 && x < ras.target.rows && (bits[0] & f1) );
}
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Set_Pixel */
/* */
/* <Description> */
/* Sets a single pixel in a bitmap during the horizontal sweep. Used */
/* during drop-out control. */
/* */
/* <Input> */
/* y :: The current pixel column. */
/* x :: The current row/scanline. */
/* color :: Ignored by this function. */
/* */
static
void Horizontal_Set_Pixel( RAS_ARG_ int y,
int x,
int color )
{
char* bits = (char*)ras.bit_buffer + (y >> 3);
int f1 = (Byte)(0x80 >> (y & 7));
UNUSED( color );
if ( x >= 0 && x < ras.target.rows )
{
long pitch = ras.target.pitch;
long offset = - x*pitch;
if (pitch > 0)
offset += (ras.target.rows-1)*pitch;
bits[offset] |= f1;
}
}
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Sweep_Step */
/* */
/* <Description> */
/* Called whenever the sweep jumps to another pixel column. */
/* */
static
void Horizontal_Sweep_Step( RAS_ARG )
{
UNUSED( ras.target );
/* Nothing, really */
}
static
const Raster_Render horizontal_render_mono =
{
&Horizontal_Sweep_Init,
&Horizontal_Sweep_Span,
&Horizontal_Sweep_Step,
&Horizontal_Test_Pixel,
&Horizontal_Set_Pixel
};
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/******** ********/
/******** Anti-Aliased Vertical Bitmap Sweep Routines ********/
/******** ********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
#ifdef FT_RASTER_OPTION_ANTI_ALIAS
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Gray_Sweep_Init */
/* */
/* <Description> */
/* Initializes the vertical bitmap sweep. Called by the generic */
/* sweep/draw routine before its loop. */
/* */
/* <Input> */
/* min :: The address of the current minimum scanline. */
/* max :: The address of the current maximum scanline. */
/* */
static
void Vertical_Gray_Sweep_Init( RAS_ARG_ int* min, int* max )
{
long pitch;
UNUSED( max );
pitch = ras.target.pitch;
/* start from the bottom line, going up */
ras.trace_incr = -pitch;
ras.trace_bit = - *min * pitch;
if (pitch > 0)
ras.trace_bit += (ras.target.rows-1)*pitch;
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Gray_Sweep_Span */
/* */
/* <Description> */
/* Draws a single horizontal bitmap span during the vertical bitmap */
/* sweep. */
/* */
/* <Input> */
/* y :: The current scanline. */
/* x1 :: The left span edge. */
/* x2 :: The right span edge. */
/* */
static
void Vertical_Gray_Sweep_Span( RAS_ARG_ TScan y,
TPos x1,
TPos x2 )
{
TPos e1, e2;
int shift = PRECISION_BITS - 6;
PByte target;
UNUSED( y );
x1 += PRECISION_HALF;
x2 += PRECISION_HALF;
e1 = TRUNC( x1 );
e2 = TRUNC( x2 );
if ( e1 <= e2 && e2 >= 0 && e1 < ras.bit_width )
{
x1 = FRAC(x1) >> shift;
x2 = FRAC(x2) >> shift;
if ( e1 < 0 )
{
e1 = 0;
x1 = 0;
}
if ( e2 > ras.bit_width )
{
e2 = ras.bit_width-1;
x2 = 0;
}
target = ras.bit_buffer + ras.trace_bit + e1;
e2 -= e1;
if ( e2 > 0 )
{
if (x1 > 0) target[0] += (Byte)(64-x1) << 1;
else target[0] = 127;
e2--;
while (e2 > 0)
{
*(++target) = 127;
e2--;
}
if (x2)
target[1] += (Byte)x2 << 1;
}
else
{
target[0] += (Byte)(x2-x1) << 1;
}
}
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Gray_Test_Pixel */
/* */
/* <Description> */
/* Tests a pixel `light' during the vertical bitmap sweep. Used */
/* during drop-out control only. */
/* */
/* <Input> */
/* y :: The current scanline. */
/* x :: The current x coordinate. */
/* */
static
int Vertical_Gray_Test_Pixel( RAS_ARG_ TScan y,
int x )
{
UNUSED( y );
#if 0
/* as a rule of thumb, do not add a drop-out if the current */
/* gray level is over 0.5 */
return ( x >= 0 && x < ras.bit_width &&
ras.bit_buffer[ras.trace_bit + x] >= 64 );
#else
UNUSED(x);
return 0;
#endif
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Gray_Set_Pixel */
/* */
/* <Description> */
/* Sets a single pixel in a bitmap during the vertical sweep. Used */
/* during drop-out control. */
/* */
/* <Input> */
/* y :: The current scanline. */
/* x :: The current x coordinate. */
/* color :: Ignored by this function. */
/* */
static
void Vertical_Gray_Set_Pixel( RAS_ARG_ int y,
int x,
int color )
{
UNUSED( y );
if ( x >= 0 && x < ras.bit_width )
{
unsigned char* pixel;
pixel = ras.bit_buffer + ras.trace_bit + x;
/* do not add too much to the pixel gray level */
color += *pixel;
if (color < 64)
color = 64;
*pixel = ( color >= 127 ? 127 : (unsigned char)color );
}
}
/*************************************************************************/
/* */
/* <Function> */
/* Vertical_Sweep_Step */
/* */
/* <Description> */
/* Called whenever the sweep jumps to another scanline. Only updates */
/* the pointers in the vertical bitmap sweep. */
/* */
static
void Vertical_Gray_Sweep_Step( RAS_ARG )
{
ras.trace_bit += ras.trace_incr;
}
static
const Raster_Render vertical_render_gray =
{
&Vertical_Gray_Sweep_Init,
&Vertical_Gray_Sweep_Span,
&Vertical_Gray_Sweep_Step,
&Vertical_Gray_Test_Pixel,
&Vertical_Gray_Set_Pixel
};
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/******** ********/
/******** Horizontal Bitmap Sweep Routines ********/
/******** ********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Sweep_Init */
/* */
/* <Description> */
/* Initializes the horizontal bitmap sweep. Called by the generic */
/* sweep/draw routine before its loop. */
/* */
/* <Input> */
/* min :: The address of the current minimum pixel column. */
/* max :: The address of the current maximum pixel column. */
/* */
static
void Horizontal_Gray_Sweep_Init( RAS_ARG_ int* min,
int* max )
{
UNUSED( ras );
UNUSED( min );
UNUSED( max );
/* nothing, really */
}
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Gray_Sweep_Span */
/* */
/* <Description> */
/* Draws a single vertical bitmap span during the horizontal bitmap */
/* sweep. */
/* */
/* <Input> */
/* y :: The current scanline. */
/* x1 :: The left span edge. */
/* x2 :: The right span edge. */
/* */
static
void Horizontal_Gray_Sweep_Span( RAS_ARG_ TScan y,
TPos x1,
TPos x2 )
{
TPos e1, e2;
int shift = PRECISION_BITS - 6;
int incr;
PByte bits;
Byte b;
UNUSED( y );
x1 += PRECISION_HALF;
x2 += PRECISION_HALF;
e1 = TRUNC( x1 );
e2 = TRUNC( x2 );
if ( e1 <= e2 && e2 >= 0 && e1 < ras.bit_width )
{
x1 = FRAC(x1) >> shift;
x2 = FRAC(x2) >> shift;
if ( e1 < 0 )
{
e1 = 0;
x1 = 0;
}
if ( e2 >= ras.bit_width )
{
e2 = ras.bit_width;
x2 = 0;
}
incr = -ras.target.pitch;
bits = ras.bit_buffer + y;
bits += incr * e1;
if (incr < 0)
bits -= incr*(ras.target.rows-1);
e2 -= e1;
if ( e2 > 0 )
{
b = bits[0];
if (b < 127) b++;
b = (Byte)((64-x1) + (b >> 1));
bits[0] = b;
if ( e2 < 24 )
{
e2--;
while (e2 > 0)
{
bits += incr;
b = bits[0];
if (b < 127)
bits[0] = (Byte)(63+((b+1) >> 1));
e2--;
}
}
else
bits += incr*(e2-1);
if (x2)
{
bits += incr;
b = bits[0];
if (b < 127) b++;
b = (Byte)(x2 + (b >> 1));
bits[0] = b;
}
}
else
{
b = bits[0];
if (b < 127) b++;
b = (Byte)((b >> 1)+(x2-x1));
bits[0] = b;
}
}
}
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Gray_Test_Pixel */
/* */
/* <Description> */
/* Tests a pixel `light' during the horizontal bitmap sweep. Used */
/* during drop-out control only. */
/* */
/* <Input> */
/* y :: The current pixel column. */
/* x :: The current row/scanline. */
/* */
static
int Horizontal_Gray_Test_Pixel( RAS_ARG_ int y,
int x )
{
#if 0
unsigned char* pixel = (unsigned char*)ras.bit_buffer + y;
if ( ras.target.flow == Flow_Down )
pixel += (ras.target.rows-1 - x) * ras.target.cols;
else
pixel += x * ras.target.cols;
return ( x >= 0 && x < ras.target.rows &&
*pixel >= 64 );
#else
UNUSED(y);
UNUSED(x);
return 0;
#endif
}
/*************************************************************************/
/* */
/* <Function> */
/* Horizontal_Set_Pixel */
/* */
/* <Description> */
/* Sets a single pixel in a bitmap during the horizontal sweep. Used */
/* during drop-out control. */
/* */
/* <Input> */
/* y :: The current pixel column. */
/* x :: The current row/scanline. */
/* color :: Ignored by this function. */
/* */
static
void Horizontal_Gray_Set_Pixel( RAS_ARG_ int y,
int x,
int color )
{
unsigned char* pixel = (unsigned char*)ras.bit_buffer + y;
if ( x >= 0 && x < ras.target.rows )
{
long pitch = ras.target.pitch;
pixel -= pitch*x;
if (pitch > 0)
pixel += pitch*(ras.target.rows-1);
color += *pixel;
if (color < 64)
color = 64;
*pixel = (color >= 127 ? 127 : (unsigned char)color );
}
}
static
void Gray_Ignore( void )
{
;
}
static
const Raster_Render horizontal_render_gray =
{
&Horizontal_Gray_Sweep_Init,
&Horizontal_Gray_Sweep_Span,
(Function_Sweep_Step) &Gray_Ignore,
&Horizontal_Gray_Test_Pixel,
&Horizontal_Gray_Set_Pixel,
};
#endif /* FT_RASTER_OPTION_ANTI_ALIAS */
/*************************************************************************/
/* */
/* A technical note to explain how the scanline sweep is performed: */
/* */
/* The function Draw_Sweep() is used to sweep the scanlines of the */
/* target bitmap or pixmap. For each scanline, it must do the */
/* following: */
/* */
/* - Get the set of all outline intersections for the current */
/* scanline. */
/* */
/* - Sort these intersections (in increasing order). */
/* */
/* - Pair intersections to create spans (horizontal pixel segments) */
/* that are then `drawn' by calling a `sweep_span' function. */
/* */
/* - Check for dropouts: If a span is too small to be drawn, it must */
/* be re-adjusted in order to make it visible again. */
/* */
/* The sweep starts from the bottom of the outline (ymin) and goes */
/* upwards (to ymax). Thus, the function manages the following: */
/* */
/* - A linked list of the profiles which are above the current */
/* scanline. It is called the `wait' list as it contains all the */
/* profiles waiting to be `activated' during the sweep. It contains */
/* all profiles initially. */
/* */
/* - A linked list of the profiles covering the current scanline, */
/* i.e., all the profiles that contain an intersection for the */
/* current scanline. It is called the `draw' list. */
/* */
/* A profile travels from the wait list to the draw list if the */
/* current scanline reaches its bottom border (its ymin). It is also */
/* removed from the draw list (and becomes unlisted) when the current */
/* scanline reaches the scanline above its upper border (its ymax). */
/* */
/* These positions correspond to the `extrema' table built by */
/* Finalize_Profile_Table(). */
/* */
/* The draw list is always sorted in increasing order of the X */
/* coordinates. We use a bubble sort because it is easy to implement */
/* on a linked list, and because in 95% cases, the list is already */
/* correctly sorted when going from one scanline to the other. */
/* */
/* The extrema table gives the scanline coordinates at which at least */
/* one profile must be removed from the `draw' list, or another one */
/* must be moved from the `wait' to `draw' lists. */
/* */
/* Note that when a dropout is detected, the corresponding span is not */
/* drawn immediately but kept on a temporary list. All dropout spans */
/* are drawn after the regular spans on a given scanline. This is a */
/* requirement of the TrueType specification to properly implement */
/* some drop-out control modes -- yes, it's weird! */
/* */
/* Finally, the parser contains four function pointers that are called */
/* by Draw_Sweep(). Each rendering mode (monochrome, anti-aliased-5, */
/* and anti-aliased-17) provide its own set of such functions. These */
/* are: */
/* */
/* sweep_init: Called only when the sweep starts. Used to set */
/* up some variables. */
/* */
/* sweep_span: Used to draw a horizontal span on the current */
/* scanline. */
/* */
/* sweep_test_pixel: Used to test a pixel's intensity, as it is */
/* required for drop-out control. */
/* */
/* sweep_put_pixel: Used to write a single pixel when a drop-out */
/* needs to be lighted/drawn. */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* Generic Sweep Drawing routine */
/* */
static
TResult Draw_Sweep( RAS_ARG )
{
TScan y, y_change, y_height;
PProfile P, Q, P_Left, P_Right;
TScan min_Y, max_Y, top, bottom, dropouts;
TPos x1, x2, e1, e2;
TProfileList wait;
TProfileList draw;
/* Init empty linked lists */
Init_Linked( &wait );
Init_Linked( &draw );
/* first, compute min and max Y -- and add profiles to the wait list */
P = ras.start_prof;
max_Y = TRUNC( ras.minY );
min_Y = TRUNC( ras.maxY );
while ( P )
{
Q = P->link;
bottom = P->start;
top = P->start + P->height-1;
if ( min_Y > bottom ) min_Y = bottom;
if ( max_Y < top ) max_Y = top;
P->X = 0;
InsNew( &wait, P );
P = Q;
}
/* Check the extrema table */
if ( ras.n_extrema == 0 )
{
ras.error = ErrRaster_Invalid_Outline;
return FAILURE;
}
/* Now inits the sweep */
PTRACE2(( "draw_sweep: initialize sweep\n" ));
ras.render.init( RAS_VAR_ &min_Y, &max_Y );
PTRACE2(( " init min_y = %d, max_y = %d\n", min_Y, max_Y ));
/* Then compute the distance of each profile from min_Y */
P = wait;
while ( P )
{
P->countL = P->start - min_Y;
P = P->link;
}
/* Let's go */
y = min_Y;
y_height = 0;
if ( ras.n_extrema > 0 &&
ras.pool_size[-ras.n_extrema] == min_Y )
ras.n_extrema--;
PTRACE2(( "starting loop with n_extrema = %d", ras.n_extrema ));
while ( ras.n_extrema > 0 )
{
PProfile prof = wait;
/* look in the wait list for new activations */
while ( prof )
{
PProfile next = prof->link;
prof->countL -= y_height;
if ( prof->countL == 0 )
{
/* move the profile from the wait list to the draw list */
DelOld( &wait, prof );
InsNew( &draw, prof );
}
prof = next;
}
/* Sort the draw list */
Sort( &draw );
/* compute next y extremum scanline; we won't change the */
/* elements of the wait and draw lists until there */
y_change = ras.pool_size[-ras.n_extrema--];
y_height = y_change - y;
PTRACE2(( ">>> y = %d, y_change = %d, y_height = %d",
y, y_change, y_height ));
while ( y < y_change )
{
int window;
PProfile left;
/* Let's trace */
dropouts = 0;
/* skip to next line if there is no active profile there */
if ( !draw ) goto Next_Line;
left = draw;
window = left->flow;
prof = left->link;
PTRACE2(( ">>> line y = %d", y ));
while ( prof )
{
PProfile next = prof->link;
window += prof->flow;
if ( window == 0 )
{
x1 = left->X;
x2 = prof->X;
if ( x1 > x2 )
{
TPos xs = x1;
x1 = x2;
x2 = xs;
}
if ( x2 - x1 <= PRECISION && ras.dropout_mode )
{
e1 = CEILING( x1 );
e2 = FLOOR( x2 );
if ( e1 > e2 || e2 == e1 + PRECISION )
{
/* a drop out was detected */
left->X = x1;
prof->X = x2;
/* mark profiles for drop-out processing */
left->countL = 1;
prof->countL = 2;
dropouts++;
goto Skip_To_Next;
}
}
PTRACE2(( "drawing span ( y=%d, x1=%d, x2=%d )", y, x1, x2 ));
ras.render.span( RAS_VAR_ y, x1, x2 );
Skip_To_Next:
left = next;
}
prof = next;
}
/* now perform the dropouts _after_ the span drawing */
/* drop-outs processing has been moved out of the loop */
/* for performance tuning */
if ( dropouts > 0 )
goto Scan_DropOuts;
Next_Line:
ras.render.step( RAS_VAR );
y++;
if ( y < y_change )
Sort( &draw );
PTRACE2(( "line sorted for next operation" ));
}
/* Now finalize the profiles that needs it */
PTRACE2(( "finalizing profiles..." ));
{
PProfile prof, next;
prof = draw;
while ( prof )
{
next = prof->link;
if (prof->height == 0)
DelOld( &draw, prof );
prof = next;
}
}
PTRACE2(( "profiles finalized for this run" ));
}
/* for gray-scaling, flushes the bitmap scanline cache */
while ( y <= max_Y )
{
ras.render.step( RAS_VAR );
y++;
}
return SUCCESS;
Scan_DropOuts :
P_Left = draw;
while ( dropouts > 0 )
{
TPos e1, e2;
PProfile left, right;
while ( P_Left->countL != 1 )
P_Left = P_Left->link;
P_Right = P_Left->link;
while ( P_Right->countL != 2 )
P_Right = P_Right->link;
P_Left->countL = 0;
P_Right->countL = 0;
/* Now perform the dropout control */
x1 = P_Left->X;
x2 = P_Right->X;
left = ( ras.flipped ? P_Right : P_Left );
right = ( ras.flipped ? P_Left : P_Right );
PTRACE2(( "performing drop-out control ( x1= %d, x2 = %d )",
x1, x2 ));
e1 = CEILING( x1 );
e2 = FLOOR ( x2 );
if ( e1 > e2 )
{
if ( e1 == e2 + PRECISION )
{
switch ( ras.dropout_mode )
{
case 1:
e1 = e2;
break;
case 4:
e1 = CEILING( (x1 + x2 + 1) / 2 );
break;
case 2:
case 5:
/* Drop-out Control Rule #4 */
/* The spec is not very clear regarding rule #4. It */
/* presents a method that is way too costly to implement */
/* while the general idea seems to get rid of `stubs'. */
/* */
/* Here, we only get rid of stubs recognized when: */
/* */
/* upper stub: */
/* */
/* - P_Left and P_Right are in the same contour */
/* - P_Right is the successor of P_Left in that contour */
/* - y is the top of P_Left and P_Right */
/* */
/* lower stub: */
/* */
/* - P_Left and P_Right are in the same contour */
/* - P_Left is the successor of P_Right in that contour */
/* - y is the bottom of P_Left */
/* */
/* upper stub test */
if ( ( left->next == right && left->height <= 0 ) ||
/* lower stub test */
( right->next == left && left->start == y ) ||
/* check that the rightmost pixel isn't set */
ras.render.test_pixel( RAS_VAR_ y, TRUNC(e1)) )
goto Next_Dropout;
if ( ras.dropout_mode == 2 )
e1 = e2;
else
e1 = CEILING( (x1 + x2 + 1)/2 );
break;
default:
goto Next_Dropout; /* Unsupported mode */
}
}
else
goto Next_Dropout;
}
PTRACE2(( " -> setting pixel" ));
ras.render.set_pixel( RAS_VAR_ y,
TRUNC( e1 ),
(x2 - x1) >> ras.scale_shift );
Next_Dropout:
dropouts--;
}
goto Next_Line;
}
/*************************************************************************/
/* */
/* <Function> */
/* Render_Single_Pass */
/* */
/* <Description> */
/* Performs one sweep with sub-banding. */
/* */
/* <Input> */
/* flipped :: whether or not we have to flip. */
/* */
/* <Returns> */
/* Error code. 0 means success. */
/* */
static
int Render_Single_Pass( RAS_ARG_ int flipped )
{
TBand* band;
ras.flipped = flipped;
band = ras.band_stack;
PTRACE2(( "raster: entering render_single_pass (flipped = %d)\n",
flipped ));
while ( band >= ras.band_stack )
{
ras.maxY = ((long)band[0].y_max << PRECISION_BITS) - 1;
ras.minY = (long)band[0].y_min << PRECISION_BITS;
ras.cursor = ras.pool;
ras.error = 0;
PTRACE2(( "raster: band = [ %d, %d ]\n",
band[0].y_min,
band[0].y_max ));
if ( Convert_Glyph( RAS_VAR_ ras.outline ) )
{
int bottom, top, half;
if ( ras.error != ErrRaster_Overflow )
return FAILURE;
ras.error = ErrRaster_Ok;
PTRACE2(( "conversion failure, performing sub-banding\n" ));
/* sub-banding */
#ifdef DEBUG_RASTER
ClearBand( RAS_VAR_ TRUNC( ras.minY ), TRUNC( ras.maxY ) );
#endif
bottom = band[0].y_min;
top = band[0].y_max;
half = ( top - bottom ) >> 1;
if ( band >= ras.band_stack + 7 || half == 0 )
{
ras.band_top = 0;
ras.error = ErrRaster_Invalid_Outline;
return ras.error;
}
band[1].y_min = bottom + half;
band[1].y_max = top;
band[0].y_max = bottom + half;
band ++;
}
else
{
PTRACE2(( "conversion succeeded, span drawing sweep\n" ));
#if 1 /* for debugging */
if ( ras.start_prof )
if ( Draw_Sweep( RAS_VAR ) )
return ras.error;
#endif
band --;
}
}
PTRACE2(( "raster: exiting render_single_pass\n" ));
return SUCCESS; /* success */
}
static
int Raster_Render1( FT_Raster raster )
{
int error;
if ( ras.target.width > ABS(ras.target.pitch)*8 )
return ErrRaster_Invalid_Map;
ras.scale_shift = PRECISION_BITS - INPUT_BITS;
ras.scale_delta = PRECISION_HALF;
/* Vertical Sweep */
ras.band_top = 0;
ras.band_stack[0].y_min = 0;
ras.band_stack[0].y_max = ras.target.rows;
ras.render = vertical_render_mono;
ras.bit_width = ras.target.width;
ras.bit_buffer = (unsigned char*)ras.target.buffer;
if ( (error = Render_Single_Pass( RAS_VAR_ 0 )) != 0 )
return error;
/* Horizontal Sweep */
if ( ras.second_pass && ras.dropout_mode != 0 )
{
ras.render = horizontal_render_mono;
ras.band_top = 0;
ras.band_stack[0].y_min = 0;
ras.band_stack[0].y_max = ras.target.width;
if ( (error = Render_Single_Pass( RAS_VAR_ 1 )) != 0 )
return error;
}
return ErrRaster_Ok;
}
#ifdef FT_RASTER_OPTION_ANTI_ALIAS
static
int Raster_Render8( FT_Raster raster )
{
int error;
if ( ras.target.width > ABS(ras.target.pitch) )
return ErrRaster_Invalid_Map;
/* Vertical Sweep */
ras.band_top = 0;
ras.band_stack[0].y_min = 0;
ras.band_stack[0].y_max = ras.target.rows;
ras.scale_shift = PRECISION_BITS - INPUT_BITS;
ras.scale_delta = PRECISION_HALF;
ras.dropout_mode = 2;
ras.render = vertical_render_gray;
ras.bit_width = ras.target.width;
ras.bit_buffer = (unsigned char*)ras.target.buffer;
ras.pix_buffer = (unsigned char*)ras.target.buffer;
error = Render_Single_Pass( RAS_VAR_ 0 );
if ( error )
return error;
#if 1
/* Horizontal Sweep */
ras.render = horizontal_render_gray;
ras.band_top = 0;
ras.bit_width = ras.target.rows;
ras.band_stack[0].y_min = 0;
ras.band_stack[0].y_max = ras.target.width;
return Render_Single_Pass( RAS_VAR_ 1 );
#else
return 0;
#endif
}
#else /* FT_RASTER_OPTION_ANTI_ALIAS */
static
int Raster_Render8( FT_Raster raster )
{
return ErrRaster_Unimplemented;
}
#endif /* FT_RASTER_OPTION_ANTI_ALIAS */
/**** RASTER OBJECT CREATION : in standalone mode, we simply use *****/
/**** a static object .. *****/
#ifdef _STANDALONE_
static
int ft_raster_new( void* memory, FT_Raster *araster )
{
static FT_RasterRec_ the_raster;
*araster = &the_raster;
memset( &the_raster, sizeof(the_raster), 0 );
return 0;
}
static
void ft_raster_done( FT_Raster raster )
{
/* nothing */
raster->init = 0;
}
#else
#include "ftobjs.h"
static
int ft_raster_new( FT_Memory memory, FT_Raster* araster )
{
FT_Error error;
FT_Raster raster;
*araster = 0;
if ( !ALLOC( raster, sizeof(*raster) ))
{
raster->memory = memory;
*araster = raster;
}
return error;
}
static
void ft_raster_done( FT_Raster raster )
{
FT_Memory memory = (FT_Memory)raster->memory;
FREE( raster );
}
#endif
static void ft_raster_reset( FT_Raster raster,
const char* pool_base,
long pool_size )
{
if ( raster && pool_base && pool_size >= 4096 )
{
/* save the pool */
raster->pool = (PPos)pool_base;
raster->pool_size = raster->pool + pool_size / sizeof ( TPos );
}
}
static
int ft_raster_render( FT_Raster raster,
FT_Raster_Params* params )
{
FT_Outline* outline = (FT_Outline*)params->source;
FT_Bitmap* target_map = params->target;
if ( !raster || !raster->pool || !raster->pool_size )
return ErrRaster_Uninitialized_Object;
if ( !outline || !outline->contours || !outline->points )
return ErrRaster_Invalid_Outline;
/* return immediately if the outline is empty */
if ( outline->n_points == 0 || outline->n_contours <= 0 )
return ErrRaster_Ok;
if ( outline->n_points != outline->contours[outline->n_contours - 1] + 1 )
return ErrRaster_Invalid_Outline;
if ( !target_map || !target_map->buffer )
return ErrRaster_Invalid_Map;
ras.outline = outline;
ras.target = *target_map;
/* Note that we always use drop-out mode 2, because it seems that */
/* it's the only way to do to get results consistent with Windows */
/* rendering.. */
ras.dropout_mode = 2;
ras.second_pass = (outline->flags & ft_outline_single_pass) == 0;
SET_High_Precision( (char)((outline->flags & ft_outline_high_precision)!= 0) );
/* this version of the raster does not support direct rendering, sorry */
if ( params->flags & ft_raster_flag_direct )
return ErrRaster_Unimplemented;
return ( params->flags & ft_raster_flag_aa
? Raster_Render8( raster )
: Raster_Render1( raster ) );
}
FT_Raster_Funcs ft_default_raster =
{
ft_glyph_format_outline,
(FT_Raster_New_Func) ft_raster_new,
(FT_Raster_Reset_Func) ft_raster_reset,
(FT_Raster_Set_Mode_Func) 0,
(FT_Raster_Render_Func) ft_raster_render,
(FT_Raster_Done_Func) ft_raster_done
};
/* END */