| /***************************************************************************/ |
| /* */ |
| /* ftimage.h */ |
| /* */ |
| /* FreeType glyph image formats and default raster interface */ |
| /* (specification). */ |
| /* */ |
| /* 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. */ |
| /* */ |
| /***************************************************************************/ |
| |
| /*************************************************************************/ |
| /* */ |
| /* Note: A `raster' is simply a scan-line converter, used to render */ |
| /* FT_Outlines into FT_Bitmaps. */ |
| /* */ |
| /*************************************************************************/ |
| |
| |
| #ifndef FTIMAGE_H |
| #define FTIMAGE_H |
| |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <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 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; |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <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; |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* <Macro> */ |
| /* FT_IMAGE_TAG */ |
| /* */ |
| /* <Description> */ |
| /* This macro converts four letter tags into an unsigned long. */ |
| /* */ |
| #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 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_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/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 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 :: Requests 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 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. */ |
| /* */ |
| /* <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_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; |
| |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| |
| #endif /* FTIMAGE_H */ |
| |
| |
| /* END */ |
