ref: f373e2d9bc5856925c6df82e6022e3e88881947a
dir: /include/freetype/ftimage.h/
/***************************************************************************/
/* */
/* ftimage.h */
/* */
/* FreeType glyph image formats and default raster interface */
/* (specification). */
/* */
/* Copyright 1996-2001 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. */
/* */
/***************************************************************************/
/*************************************************************************/
/* */
/* Note: A `raster' is simply a scan-line converter, used to render */
/* FT_Outlines into FT_Bitmaps. */
/* */
/*************************************************************************/
#ifndef __FTIMAGE_H__
#define __FTIMAGE_H__
#include <ft2build.h>
FT_BEGIN_HEADER
/*************************************************************************/
/* */
/* <Section> */
/* basic_types */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Type> */
/* FT_Pos */
/* */
/* <Description> */
/* The type FT_Pos is a 32-bit integer used to store vectorial */
/* coordinates. Depending on the context, these can represent */
/* distances in integer font units, or 26.6 fixed float pixel */
/* coordinates. */
/* */
typedef signed long FT_Pos;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_Vector */
/* */
/* <Description> */
/* A simple structure used to store a 2D vector; coordinates are of */
/* the FT_Pos type. */
/* */
/* <Fields> */
/* x :: The horizontal coordinate. */
/* y :: The vertical coordinate. */
/* */
typedef struct FT_Vector_
{
FT_Pos x;
FT_Pos y;
} FT_Vector;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_BBox */
/* */
/* <Description> */
/* A structure used to hold an outline's bounding box, i.e., the */
/* coordinates of its extrema in the horizontal and vertical */
/* directions. */
/* */
/* <Fields> */
/* xMin :: The horizontal minimum (left-most). */
/* */
/* yMin :: The vertical minimum (bottom-most). */
/* */
/* xMax :: The horizontal maximum (right-most). */
/* */
/* yMax :: The vertical maximum (top-most). */
/* */
typedef struct FT_BBox_
{
FT_Pos xMin, yMin;
FT_Pos xMax, yMax;
} FT_BBox;
/*************************************************************************/
/* */
/* <Enum> */
/* FT_Pixel_Mode */
/* */
/* <Description> */
/* An enumeration type used to describe the format of pixels in a */
/* given bitmap. Note that additional formats may be added in the */
/* future. */
/* */
/* <Fields> */
/* ft_pixel_mode_mono :: A monochrome bitmap (1 bit/pixel). */
/* */
/* ft_pixel_mode_grays :: An 8-bit gray-levels bitmap. Note that the */
/* total number of gray levels is given in the */
/* `num_grays' field of the FT_Bitmap */
/* structure. */
/* */
/* ft_pixel_mode_pal2 :: A 2-bit paletted bitmap. */
/* Currently unused by FreeType. */
/* */
/* ft_pixel_mode_pal4 :: A 4-bit paletted bitmap. */
/* Currently unused by FreeType. */
/* */
/* ft_pixel_mode_pal8 :: An 8-bit paletted bitmap. */
/* Currently unused by FreeType. */
/* */
/* ft_pixel_mode_rgb15 :: A 15-bit RGB bitmap. Uses 5:5:5 encoding. */
/* Currently unused by FreeType. */
/* */
/* ft_pixel_mode_rgb16 :: A 16-bit RGB bitmap. Uses 5:6:5 encoding. */
/* Currently unused by FreeType. */
/* */
/* ft_pixel_mode_rgb24 :: A 24-bit RGB bitmap. */
/* Currently unused by FreeType. */
/* */
/* ft_pixel_mode_rgb32 :: A 32-bit RGB bitmap. */
/* Currently unused by FreeType. */
/* */
/* <Note> */
/* Some anti-aliased bitmaps might be embedded in TrueType fonts */
/* using formats pal2 or pal4, though no fonts presenting those have */
/* been found to date. */
/* */
typedef enum FT_Pixel_Mode_
{
ft_pixel_mode_none = 0,
ft_pixel_mode_mono,
ft_pixel_mode_grays,
ft_pixel_mode_pal2,
ft_pixel_mode_pal4,
ft_pixel_mode_pal8,
ft_pixel_mode_rgb15,
ft_pixel_mode_rgb16,
ft_pixel_mode_rgb24,
ft_pixel_mode_rgb32,
ft_pixel_mode_max /* do not remove */
} FT_Pixel_Mode;
/*************************************************************************/
/* */
/* <Enum> */
/* FT_Palette_Mode */
/* */
/* <Description> */
/* An enumeration type used to describe the format of a bitmap */
/* palette, used with ft_pixel_mode_pal4 and ft_pixel_mode_pal8. */
/* */
/* <Fields> */
/* ft_palette_mode_rgb :: The palette is an array of 3-bytes RGB */
/* records. */
/* */
/* ft_palette_mode_rgba :: The palette is an array of 4-bytes RGBA */
/* records. */
/* */
/* <Note> */
/* As ft_pixel_mode_pal2, pal4 and pal8 are currently unused by */
/* FreeType, these types are not handled by the library itself. */
/* */
typedef enum FT_Palette_Mode_
{
ft_palette_mode_rgb = 0,
ft_palette_mode_rgba,
ft_palettte_mode_max /* do not remove */
} FT_Palette_Mode;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_Bitmap */
/* */
/* <Description> */
/* A structure used to describe a bitmap or pixmap to the raster. */
/* Note that we now manage pixmaps of various depths through the */
/* `pixel_mode' field. */
/* */
/* <Fields> */
/* rows :: The number of bitmap rows. */
/* */
/* width :: The number of pixels in bitmap row. */
/* */
/* pitch :: The pitch's absolute value is the number of bytes */
/* taken by one bitmap row, including padding. */
/* However, the pitch is positive when the bitmap has */
/* a `down' flow, and negative when it has an `up' */
/* flow. In all cases, the pitch is an offset to add */
/* to a bitmap pointer in order to go down one row. */
/* */
/* buffer :: A typeless pointer to the bitmap buffer. This */
/* value should be aligned on 32-bit boundaries in */
/* most cases. */
/* */
/* num_grays :: This field is only used with */
/* `ft_pixel_mode_grays'; it gives the number of gray */
/* levels used in the bitmap. */
/* */
/* pixel_mode :: The pixel_mode, i.e., how pixel bits are stored. */
/* */
/* palette_mode :: This field is only used with paletted pixel modes; */
/* it indicates how the palette is stored. */
/* */
/* palette :: A typeless pointer to the bitmap palette; only */
/* used for paletted pixel modes. */
/* */
/* <Note> */
/* For now, the only pixel mode supported by FreeType are mono and */
/* grays. However, drivers might be added in the future to support */
/* more `colorful' options. */
/* */
/* When using pixel modes pal2, pal4 and pal8 with a void `palette' */
/* field, a gray pixmap with respectively 4, 16, and 256 levels of */
/* gray is assumed. This, in order to be compatible with some */
/* embedded bitmap formats defined in the TrueType specification. */
/* */
/* Note that no font was found presenting such embedded bitmaps, so */
/* this is currently completely unhandled by the library. */
/* */
typedef struct FT_Bitmap_
{
int rows;
int width;
int pitch;
unsigned char* buffer;
short num_grays;
char pixel_mode;
char palette_mode;
void* palette;
} FT_Bitmap;
/*************************************************************************/
/* */
/* <Section> */
/* outline_processing */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Struct> */
/* FT_Outline */
/* */
/* <Description> */
/* This structure is used to describe an outline to the scan-line */
/* converter. */
/* */
/* <Fields> */
/* n_contours :: The number of contours in the outline. */
/* */
/* n_points :: The number of points in the outline. */
/* */
/* points :: A pointer to an array of `n_points' FT_Vector */
/* elements, giving the outline's point coordinates. */
/* */
/* tags :: A pointer to an array of `n_points' chars, giving */
/* each outline point's type. If bit 0 is unset, the */
/* point is `off' the curve, i.e. a Bezier control */
/* point, while it is `on' when set. */
/* */
/* Bit 1 is meaningful for `off' points only. If set, */
/* it indicates a third-order Bezier arc control point; */
/* and a second-order control point if unset. */
/* */
/* contours :: An array of `n_contours' shorts, giving the end */
/* point of each contour within the outline. For */
/* example, the first contour is defined by the points */
/* `0' to `contours[0]', the second one is defined by */
/* the points `contours[0]+1' to `contours[1]', etc. */
/* */
/* flags :: A set of bit flags used to characterize the outline */
/* and give hints to the scan-converter and hinter on */
/* how to convert/grid-fit it. See FT_Outline_Flags. */
/* */
typedef struct FT_Outline_
{
short n_contours; /* number of contours in glyph */
short n_points; /* number of points in the glyph */
FT_Vector* points; /* the outline's points */
char* tags; /* the points flags */
short* contours; /* the contour end points */
int flags; /* outline masks */
} FT_Outline;
/*************************************************************************/
/* */
/* <Enum> */
/* FT_Outline_Flags */
/* */
/* <Description> */
/* A simple type used to enumerates the flags in an outline's */
/* `outline_flags' field. */
/* */
/* <Fields> */
/* ft_outline_owner :: If set, this flag indicates that the */
/* outline's field arrays (i.e. */
/* `points', `flags' & `contours') are */
/* `owned' by the outline object, and */
/* should thus be freed when it is */
/* destroyed. */
/* */
/* ft_outline_even_odd_fill :: By default, outlines are filled using */
/* the non-zero winding rule. If set to */
/* 1, the outline will be filled using */
/* the even-odd fill rule (only works */
/* with the smooth raster). */
/* */
/* ft_outline_reverse_fill :: By default, outside contours of an */
/* outline are oriented in clock-wise */
/* direction, as defined in the TrueType */
/* specification. This flag is set if */
/* the outline uses the opposite */
/* direction (typically for Type 1 */
/* fonts). This flag is ignored by the */
/* scan-converter. However, it is very */
/* important for the auto-hinter. */
/* */
/* ft_outline_ignore_dropouts :: By default, the scan converter will */
/* try to detect drop-outs in an outline */
/* and correct the glyph bitmap to */
/* ensure consistent shape continuity. */
/* If set, this flag hints the scan-line */
/* converter to ignore such cases. */
/* */
/* ft_outline_high_precision :: This flag indicates that the */
/* scan-line converter should try to */
/* convert this outline to bitmaps with */
/* the highest possible quality. It is */
/* typically set for small character */
/* sizes. Note that this is only a */
/* hint, that might be completely */
/* ignored by a given scan-converter. */
/* */
/* ft_outline_single_pass :: This flag is set to force a given */
/* scan-converter to only use a single */
/* pass over the outline to render a */
/* bitmap glyph image. Normally, it is */
/* set for very large character sizes. */
/* It is only a hint, that might be */
/* completely ignored by a given */
/* scan-converter. */
/* */
typedef enum FT_Outline_Flags_
{
ft_outline_none = 0,
ft_outline_owner = 1,
ft_outline_even_odd_fill = 2,
ft_outline_reverse_fill = 4,
ft_outline_ignore_dropouts = 8,
ft_outline_high_precision = 256,
ft_outline_single_pass = 512
} FT_Outline_Flags;
/* */
#define FT_CURVE_TAG( flag ) ( flag & 3 )
#define FT_Curve_Tag_On 1
#define FT_Curve_Tag_Conic 0
#define FT_Curve_Tag_Cubic 2
#define FT_Curve_Tag_Touch_X 8 /* reserved for the TrueType hinter */
#define FT_Curve_Tag_Touch_Y 16 /* reserved for the TrueType hinter */
#define FT_Curve_Tag_Touch_Both ( FT_Curve_Tag_Touch_X | \
FT_Curve_Tag_Touch_Y )
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Outline_MoveTo_Func */
/* */
/* <Description> */
/* A function pointer type used to describe the signature of a `move */
/* to' function during outline walking/decomposition. */
/* */
/* A `move to' is emitted to start a new contour in an outline. */
/* */
/* <Input> */
/* to :: A pointer to the target point of the `move to'. */
/* */
/* user :: A typeless pointer which is passed from the caller of the */
/* decomposition function. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
typedef int
(*FT_Outline_MoveTo_Func)( FT_Vector* to,
void* user );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Outline_LineTo_Func */
/* */
/* <Description> */
/* A function pointer type used to describe the signature of a `line */
/* to' function during outline walking/decomposition. */
/* */
/* A `line to' is emitted to indicate a segment in the outline. */
/* */
/* <Input> */
/* to :: A pointer to the target point of the `line to'. */
/* */
/* user :: A typeless pointer which is passed from the caller of the */
/* decomposition function. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
typedef int
(*FT_Outline_LineTo_Func)( FT_Vector* to,
void* user );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Outline_ConicTo_Func */
/* */
/* <Description> */
/* A function pointer type use to describe the signature of a `conic */
/* to' function during outline walking/decomposition. */
/* */
/* A `conic to' is emitted to indicate a second-order Bezier arc in */
/* the outline. */
/* */
/* <Input> */
/* control :: An intermediate control point between the last position */
/* and the new target in `to'. */
/* */
/* to :: A pointer to the target end point of the conic arc. */
/* */
/* user :: A typeless pointer which is passed from the caller of */
/* the decomposition function. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
typedef int
(*FT_Outline_ConicTo_Func)( FT_Vector* control,
FT_Vector* to,
void* user );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Outline_CubicTo_Func */
/* */
/* <Description> */
/* A function pointer type used to describe the signature of a `cubic */
/* to' function during outline walking/decomposition. */
/* */
/* A `cubic to' is emitted to indicate a third-order Bezier arc. */
/* */
/* <Input> */
/* control1 :: A pointer to the first Bezier control point. */
/* */
/* control2 :: A pointer to the second Bezier control point. */
/* */
/* to :: A pointer to the target end point. */
/* */
/* user :: A typeless pointer which is passed from the caller of */
/* the decomposition function. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
typedef int
(*FT_Outline_CubicTo_Func)( FT_Vector* control1,
FT_Vector* control2,
FT_Vector* to,
void* user );
/*************************************************************************/
/* */
/* <Struct> */
/* FT_Outline_Funcs */
/* */
/* <Description> */
/* A structure to hold various function pointers used during outline */
/* decomposition in order to emit segments, conic, and cubic Beziers, */
/* as well as `move to' and `close to' operations. */
/* */
/* <Fields> */
/* move_to :: The `move to' emitter. */
/* */
/* line_to :: The segment emitter. */
/* */
/* conic_to :: The second-order Bezier arc emitter. */
/* */
/* cubic_to :: The third-order Bezier arc emitter. */
/* */
/* shift :: The shift that is applied to coordinates before they */
/* are sent to the emitter. */
/* */
/* delta :: The delta that is applied to coordinates before they */
/* are sent to the emitter, but after the shift. */
/* */
/* <Note> */
/* The point coordinates sent to the emitters are the transformed */
/* version of the original coordinates (this is important for high */
/* accuracy during scan-conversion). The transformation is simple: */
/* */
/* x' = (x << shift) - delta */
/* y' = (x << shift) - delta */
/* */
/* Set the value of `shift' and `delta' to 0 to get the original */
/* point coordinates. */
/* */
typedef struct FT_Outline_Funcs_
{
FT_Outline_MoveTo_Func move_to;
FT_Outline_LineTo_Func line_to;
FT_Outline_ConicTo_Func conic_to;
FT_Outline_CubicTo_Func cubic_to;
int shift;
FT_Pos delta;
} FT_Outline_Funcs;
/*************************************************************************/
/* */
/* <Section> */
/* basic_types */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Macro> */
/* FT_IMAGE_TAG */
/* */
/* <Description> */
/* This macro converts four letter tags into an unsigned long. */
/* */
#ifndef FT_IMAGE_TAG
#define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) \
value = ( ( (unsigned long)_x1 << 24 ) | \
( (unsigned long)_x2 << 16 ) | \
( (unsigned long)_x3 << 8 ) | \
(unsigned long)_x4 )
#endif /* FT_IMAGE_TAG */
/*************************************************************************/
/* */
/* <Enum> */
/* FT_Glyph_Format */
/* */
/* <Description> */
/* An enumeration type used to describe the format of a given glyph */
/* image. Note that this version of FreeType only supports two image */
/* formats, even though future font drivers will be able to register */
/* their own format. */
/* */
/* <Fields> */
/* ft_glyph_format_composite :: The glyph image is a composite of */
/* several other images. This glyph */
/* format is _only_ used with the */
/* FT_LOAD_FLAG_NO_RECURSE flag (XXX: */
/* Which is currently unimplemented). */
/* */
/* ft_glyph_format_bitmap :: The glyph image is a bitmap, and can */
/* be described as a FT_Bitmap. */
/* */
/* ft_glyph_format_outline :: The glyph image is a vectorial image */
/* made of bezier control points, and */
/* can be described as a FT_Outline. */
/* */
/* ft_glyph_format_plotter :: The glyph image is a vectorial image */
/* made of plotter lines (some T1 fonts */
/* like Hershey contain glyph in this */
/* format). */
/* */
typedef enum FT_Glyph_Format_
{
FT_IMAGE_TAG( ft_glyph_format_none, 0, 0, 0, 0 ),
FT_IMAGE_TAG( ft_glyph_format_composite, 'c', 'o', 'm', 'p' ),
FT_IMAGE_TAG( ft_glyph_format_bitmap, 'b', 'i', 't', 's' ),
FT_IMAGE_TAG( ft_glyph_format_outline, 'o', 'u', 't', 'l' ),
FT_IMAGE_TAG( ft_glyph_format_plotter, 'p', 'l', 'o', 't' )
} FT_Glyph_Format;
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** R A S T E R D E F I N I T I O N S *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* A raster is a scan converter, in charge of rendering an outline into */
/* a a bitmap. This section contains the public API for rasters. */
/* */
/* Note that in FreeType 2, all rasters are now encapsulated within */
/* specific modules called `renderers'. See `freetype/ftrender.h' for */
/* more details on renderers. */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Section> */
/* Raster */
/* */
/* <Title> */
/* Scanline converter */
/* */
/* <Abstract> */
/* How vectorial outlines are converted into bitmaps and pixmaps. */
/* */
/* <Description> */
/* This section contains technical definitions. */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Type> */
/* FT_Raster */
/* */
/* <Description> */
/* A handle (pointer) to a raster object. Each object can be used */
/* independently to convert an outline into a bitmap or pixmap. */
/* */
typedef struct FT_RasterRec_* FT_Raster;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_Span */
/* */
/* <Description> */
/* A structure used to model a single span of gray (or black) pixels */
/* when rendering a monochrome or anti-aliased bitmap. */
/* */
/* <Fields> */
/* x :: The span's horizontal start position. */
/* */
/* len :: The span's length in pixels. */
/* */
/* coverage :: The span color/coverage, ranging from 0 (background) */
/* to 255 (foreground). Only used for anti-aliased */
/* rendering. */
/* */
/* <Note> */
/* This structure is used by the span drawing callback type named */
/* FT_Raster_Span_Func(), which takes the y-coordinate of the span as */
/* a parameter. */
/* */
/* The coverage value is always between 0 and 255, even if the number */
/* of gray levels have been set through FT_Set_Gray_Levels(). */
/* */
typedef struct FT_Span_
{
short x;
unsigned short len;
unsigned char coverage;
} FT_Span;
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_Span_Func */
/* */
/* <Description> */
/* A function used as a call-back by the anti-aliased renderer in */
/* order to let client applications draw themselves the gray pixel */
/* spans on each scan line. */
/* */
/* <Input> */
/* y :: The scanline's y-coordinate. */
/* */
/* count :: The number of spans to draw on this scanline. */
/* */
/* spans :: A table of `count' spans to draw on the scanline. */
/* */
/* user :: User-supplied data that is passed to the callback. */
/* */
/* <Note> */
/* This callback allows client applications to directly render the */
/* gray spans of the anti-aliased bitmap to any kind of surfaces. */
/* */
/* This can be used to write anti-aliased outlines directly to a */
/* given background bitmap, and even perform translucency. */
/* */
/* Note that the `count' field cannot be greater than a fixed value */
/* defined by the FT_MAX_GRAY_SPANS configuration macro in */
/* ftoption.h. By default, this value is set to 32, which means that */
/* if there are more than 32 spans on a given scanline, the callback */
/* will be called several times with the same `y' parameter in order */
/* to draw all callbacks. */
/* */
/* Otherwise, the callback is only called once per scan-line, and */
/* only for those scanlines that do have `gray' pixels on them. */
/* */
typedef void
(*FT_Raster_Span_Func)( int y,
int count,
FT_Span* spans,
void* user );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_BitTest_Func */
/* */
/* <Description> */
/* A function used as a call-back by the monochrome scan-converter */
/* to test whether a given target pixel is already set to the drawing */
/* `color'. These tests are crucial to implement drop-out control */
/* per-se the TrueType spec. */
/* */
/* <Input> */
/* y :: The pixel's y-coordinate. */
/* */
/* x :: The pixel's x-coordinate. */
/* */
/* user :: User-supplied data that is passed to the callback. */
/* */
/* <Return> */
/* 1 if the pixel is `set', 0 otherwise. */
/* */
typedef int
(*FT_Raster_BitTest_Func)( int y,
int x,
void* user );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_BitSet_Func */
/* */
/* <Description> */
/* A function used as a call-back by the monochrome scan-converter */
/* to set an individual target pixel. This is crucial to implement */
/* drop-out control according to the TrueType specification. */
/* */
/* <Input> */
/* y :: The pixel's y-coordinate. */
/* */
/* x :: The pixel's x-coordinate. */
/* */
/* user :: User-supplied data that is passed to the callback. */
/* */
/* <Return> */
/* 1 if the pixel is `set', 0 otherwise. */
/* */
typedef void
(*FT_Raster_BitSet_Func)( int y,
int x,
void* user );
/*************************************************************************/
/* */
/* <Enum> */
/* FT_Raster_Flag */
/* */
/* <Description> */
/* An enumeration to list the bit flags as used in the `flags' field */
/* of a FT_Raster_Params structure. */
/* */
/* <Fields> */
/* ft_raster_flag_default :: This value is 0. */
/* */
/* ft_raster_flag_aa :: This flag is set to indicate that an */
/* anti-aliased glyph image should be */
/* generated. Otherwise, it will be */
/* monochrome (1-bit) */
/* */
/* ft_raster_flag_direct :: This flag is set to indicate direct */
/* rendering. In this mode, client */
/* applications must provide their own span */
/* callback. This lets them directly */
/* draw or compose over an existing bitmap. */
/* If this bit is not set, the target */
/* pixmap's buffer _must_ be zeroed before */
/* rendering. */
/* */
/* Note that for now, direct rendering is */
/* only possible with anti-aliased glyphs. */
/* */
/* ft_raster_flag_clip :: This flag is only used in direct */
/* rendering mode. If set, the output will */
/* be clipped to a box specified in the */
/* "clip_box" field of the FT_Raster_Params */
/* structure. */
/* */
/* Note that by default, the glyph bitmap */
/* is clipped to the target pixmap, except */
/* in direct rendering mode where all spans */
/* are generated if no clipping box is set. */
/* */
typedef enum
{
ft_raster_flag_default = 0,
ft_raster_flag_aa = 1,
ft_raster_flag_direct = 2,
ft_raster_flag_clip = 4
} FT_Raster_Flag;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_Raster_Params */
/* */
/* <Description> */
/* A structure to hold the arguments used by a raster's render */
/* function. */
/* */
/* <Fields> */
/* target :: The target bitmap. */
/* */
/* source :: A pointer to the source glyph image (e.g. an */
/* FT_Outline). */
/* */
/* flags :: The rendering flags. */
/* */
/* gray_spans :: The gray span drawing callback. */
/* */
/* black_spans :: The black span drawing callback. */
/* */
/* bit_test :: The bit test callback. */
/* */
/* bit_set :: The bit set callback. */
/* */
/* user :: User-supplied data that is passed to each drawing */
/* callback. */
/* */
/* clip_box :: an optional clipping box. It is only used in */
/* direct rendering mode */
/* */
/* <Note> */
/* An anti-aliased glyph bitmap is drawn if the ft_raster_flag_aa bit */
/* flag is set in the `flags' field, otherwise a monochrome bitmap */
/* will be generated. */
/* */
/* If the ft_raster_flag_direct bit flag is set in `flags', the */
/* raster will call the `gray_spans' callback to draw gray pixel */
/* spans, in the case of an aa glyph bitmap, it will call */
/* `black_spans', and `bit_test' and `bit_set' in the case of a */
/* monochrome bitmap. This allows direct composition over a */
/* pre-existing bitmap through user-provided callbacks to perform the */
/* span drawing/composition. */
/* */
/* Note that the `bit_test' and `bit_set' callbacks are required when */
/* rendering a monochrome bitmap, as they are crucial to implement */
/* correct drop-out control as defined in the TrueType specification. */
/* */
typedef struct FT_Raster_Params_
{
FT_Bitmap* target;
void* source;
int flags;
FT_Raster_Span_Func gray_spans;
FT_Raster_Span_Func black_spans;
FT_Raster_BitTest_Func bit_test;
FT_Raster_BitSet_Func bit_set;
void* user;
FT_BBox clip_box;
} FT_Raster_Params;
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_New_Func */
/* */
/* <Description> */
/* A function used to create a new raster object. */
/* */
/* <Input> */
/* memory :: A handle to the memory allocator. */
/* */
/* <Output> */
/* raster :: A handle to the new raster object. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
/* <Note> */
/* The `memory' parameter is a typeless pointer in order to avoid */
/* un-wanted dependencies on the rest of the FreeType code. In */
/* practice, it is a FT_Memory, i.e., a handle to the standard */
/* FreeType memory allocator. However, this field can be completely */
/* ignored by a given raster implementation. */
/* */
typedef int
(*FT_Raster_New_Func)( void* memory,
FT_Raster* raster );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_Done_Func */
/* */
/* <Description> */
/* A function used to destroy a given raster object. */
/* */
/* <Input> */
/* raster :: A handle to the raster object. */
/* */
typedef void
(*FT_Raster_Done_Func)( FT_Raster raster );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_Reset_Func */
/* */
/* <Description> */
/* FreeType provides an area of memory called the `render pool', */
/* available to all registered rasters. This pool can be freely used */
/* during a given scan-conversion but is shared by all rasters. Its */
/* content is thus transient. */
/* */
/* This function is called each time the render pool changes, or just */
/* after a new raster object is created. */
/* */
/* <Input> */
/* raster :: A handle to the new raster object. */
/* */
/* pool_base :: The address in memory of the render pool. */
/* */
/* pool_size :: The size in bytes of the render pool. */
/* */
/* <Note> */
/* Rasters can ignore the render pool and rely on dynamic memory */
/* allocation if they want to (a handle to the memory allocator is */
/* passed to the raster constructor). However, this is not */
/* recommended for efficiency purposes. */
/* */
typedef void
(*FT_Raster_Reset_Func)( FT_Raster raster,
unsigned char* pool_base,
unsigned long pool_size );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_Set_Mode_Func */
/* */
/* <Description> */
/* This function is a generic facility to change modes or attributes */
/* in a given raster. This can be used for debugging purposes, or */
/* simply to allow implementation-specific `features' in a given */
/* raster module. */
/* */
/* <Input> */
/* raster :: A handle to the new raster object. */
/* */
/* mode :: A 4-byte tag used to name the mode or property. */
/* */
/* args :: A pointer to the new mode/property to use. */
/* */
typedef int
(*FT_Raster_Set_Mode_Func)( FT_Raster raster,
unsigned long mode,
void* args );
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_Render_Func */
/* */
/* <Description> */
/* Invokes a given raster to scan-convert a given glyph image into a */
/* target bitmap. */
/* */
/* <Input> */
/* raster :: A handle to the raster object. */
/* */
/* params :: A pointer to a FT_Raster_Params structure used to store */
/* the rendering parameters. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
/* <Note> */
/* The exact format of the source image depends on the raster's glyph */
/* format defined in its FT_Raster_Funcs structure. It can be an */
/* FT_Outline or anything else in order to support a large array of */
/* glyph formats. */
/* */
/* Note also that the render function can fail and return a */
/* FT_Err_Unimplemented_Feature error code if the raster used does */
/* not support direct composition. */
/* */
/* XXX: For now, the standard raster doesn't support direct */
/* composition but this should change for the final release (see */
/* the files demos/src/ftgrays.c and demos/src/ftgrays2.c for */
/* examples of distinct implementations which support direct */
/* composition). */
/* */
typedef int
(*FT_Raster_Render_Func)( FT_Raster raster,
FT_Raster_Params* params );
/*************************************************************************/
/* */
/* <Struct> */
/* FT_Raster_Funcs */
/* */
/* <Description> */
/* A structure used to describe a given raster class to the library. */
/* */
/* <Fields> */
/* glyph_format :: The supported glyph format for this raster. */
/* */
/* raster_new :: The raster constructor. */
/* */
/* raster_reset :: Used to reset the render pool within the raster. */
/* */
/* raster_render :: A function to render a glyph into a given bitmap. */
/* */
/* raster_done :: The raster destructor. */
/* */
typedef struct FT_Raster_Funcs_
{
FT_Glyph_Format glyph_format;
FT_Raster_New_Func raster_new;
FT_Raster_Reset_Func raster_reset;
FT_Raster_Set_Mode_Func raster_set_mode;
FT_Raster_Render_Func raster_render;
FT_Raster_Done_Func raster_done;
} FT_Raster_Funcs;
/* */
FT_END_HEADER
#endif /* __FTIMAGE_H__ */
/* END */