ref: c6a92202c23b916536903921401e6289f8b66ca2
dir: /include/freetype/ftimage.h/
/***************************************************************************/
/* */
/* ftimage.h */
/* */
/* This file defines the glyph image formats recognized by FreeType, as */
/* well as the default raster interface. */
/* */
/* Note: a "raster" is simply a scan-line converter, used to render */
/* FT_Outlines into FT_Bitmaps */
/* */
/* 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. */
/* */
/***************************************************************************/
#ifndef FTIMAGE_H
#define FTIMAGE_H
/*************************************************************************/
/* */
/* <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;
/*************************************************************************
*
* <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 spec.
*
* 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;
void* buffer;
short num_grays;
char pixel_mode;
char palette_mode;
void* palette;
} FT_Bitmap;
/*************************************************************************/
/* */
/* <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 */
/* unset. */
/* */
/* 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 :: */
/* when 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. When 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 when 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. When 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're sent to the emmiter */
/* */
/* delta :: the delta that is applied to coordinates before */
/* they're 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 transform is simply: */
/* */
/* 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;
/*************************************************************************/
/* */
/* <Macro> */
/* FT_IMAGE_TAG */
/* */
/* <Description> */
/* This macro converts four letter tags into unsigned longs.. */
/* */
#define FT_IMAGE_TAG( _x1, _x2, _x3, _x4 ) \
(((unsigned long)_x1 << 24) | \
((unsigned long)_x2 << 16) | \
((unsigned long)_x3 << 8) | \
(unsigned long)_x4)
/***********************************************************************
*
* <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 iunimplemented)
*
* 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_glyph_format_none = 0,
ft_glyph_format_composite = FT_IMAGE_TAG('c','o','m','p'),
ft_glyph_format_bitmap = FT_IMAGE_TAG('b','i','t','s'),
ft_glyph_format_outline = FT_IMAGE_TAG('o','u','t','l'),
ft_glyph_format_plotter = FT_IMAGE_TAG('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/internal/ftrender.h>
* for more details on renderers..
*
**************************************************************************/
/*************************************************************************/
/* */
/* <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 monocrhome 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 paremeter.. */
/* */
/* 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 wether 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 */
/* used to set an individual target pixel. This is 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 void (*FT_Raster_BitSet_Func)( int y,
int x,
void* user );
/**************************************************************************
*
* <Enum>
* FT_Raster_Flag
*
* <Description>
* An enumeration used to list the bit flags used in the "flags"
* field of a FT_Raster_Params function.
*
* <Fields>
* ft_raster_flag_default :: this value is 0
*
* ft_raster_flag_aa :: resquests the rendering of an anti-aliased
* glyph bitmap. If unset, a monchrome bitmap
* will be rendered.
*
* ft_raster_flag_direct :: requests direct rendering over the target
* bitmap. Direct rendering uses user-provided
* callbacks in order to perform direct
* drawing or composition over an existing
* bitmap. If this bit is unset, the content
* of the target bitmap **must be zeroed** !
*
**************************************************************************/
typedef enum {
ft_raster_flag_default = 0,
ft_raster_flag_aa = 1,
ft_raster_flag_direct = 2
} FT_Raster_Flag;
/**************************************************************************
*
* <Struct>
* FT_Raster_Params
*
* <Description>
* A structure used to hold the arguments used by a raster's render
* function.
*
* <Fields>
* target :: the target bitmap
* source :: pointer to the source glyph image (e.g. a FT_Outline)
* flags :: rendering flags
* gray_spans :: gray span drawing callback
* black_spans :: black span drawing callback
* bit_test :: bit test callback
* bit_set :: bit set callback
* user :: user-supplied data that is passed to each drawing
* callback..
*
* <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.
*
* When the ft_raster_flag_direct bit flag is set in "flags", the raster
* will call the "gray_spans" callback to drawn gray pixel spans, in the
* case of an aa glyph bitmap, or "black_spans", "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 per-se 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_Raster_Params;
/**************************************************************************
* <FuncType>
* FT_Raster_New_Func
*
* <Description>
* A function used to create a new raster object.
*
* <Input>
* memory :: handle to memory allocator.
*
* <Output>
* raster :: handle to 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 :: handle to new 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 :: handle to new raster object
* pool_base :: address in memory of render pool
* pool_size :: size in bytes of 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,
const char* pool_base,
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 :: handle to 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 :: handle to raster object
* params :: 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 when 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 :: renders 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;
#endif /* FTIMAGE_H */