kc3-lang/freetype/include/freetype/ftimage.h
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Hash : 415235df
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Date : 2001-06-28T17:49:10
finishing function header formatting updating copyrights
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include/freetype/ftimage.h
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/***************************************************************************/ /* */ /* 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 */ /* 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 */