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Edit File: ftimage.h

/***************************************************************************/ /* */ /* ftimage.h */ /* */ /* FreeType glyph image formats and default raster interface */ /* (specification). */ /* */ /* Copyright 1996-2017 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_ /* STANDALONE_ is from ftgrays.c */ #ifndef STANDALONE_ #include <ft2build.h> #endif FT_BEGIN_HEADER /*************************************************************************/ /* */ /* <Section> */ /* basic_types */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* <Type> */ /* FT_Pos */ /* */ /* <Description> */ /* The type FT_Pos is used to store vectorial coordinates. Depending */ /* on the context, these can represent distances in integer font */ /* units, or 16.16, or 26.6 fixed-point 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). */ /* */ /* <Note> */ /* The bounding box is specified with the coordinates of the lower */ /* left and the upper right corner. In PostScript, those values are */ /* often called (llx,lly) and (urx,ury), respectively. */ /* */ /* If `yMin' is negative, this value gives the glyph's descender. */ /* Otherwise, the glyph doesn't descend below the baseline. */ /* Similarly, if `ymax' is positive, this value gives the glyph's */ /* ascender. */ /* */ /* `xMin' gives the horizontal distance from the glyph's origin to */ /* the left edge of the glyph's bounding box. If `xMin' is negative, */ /* the glyph extends to the left of the origin. */ /* */ 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. */ /* */ /* <Values> */ /* FT_PIXEL_MODE_NONE :: */ /* Value~0 is reserved. */ /* */ /* FT_PIXEL_MODE_MONO :: */ /* A monochrome bitmap, using 1~bit per pixel. Note that pixels */ /* are stored in most-significant order (MSB), which means that */ /* the left-most pixel in a byte has value 128. */ /* */ /* FT_PIXEL_MODE_GRAY :: */ /* An 8-bit bitmap, generally used to represent anti-aliased glyph */ /* images. Each pixel is stored in one byte. Note that the number */ /* of `gray' levels is stored in the `num_grays' field of the */ /* @FT_Bitmap structure (it generally is 256). */ /* */ /* FT_PIXEL_MODE_GRAY2 :: */ /* A 2-bit per pixel bitmap, used to represent embedded */ /* anti-aliased bitmaps in font files according to the OpenType */ /* specification. We haven't found a single font using this */ /* format, however. */ /* */ /* FT_PIXEL_MODE_GRAY4 :: */ /* A 4-bit per pixel bitmap, representing embedded anti-aliased */ /* bitmaps in font files according to the OpenType specification. */ /* We haven't found a single font using this format, however. */ /* */ /* FT_PIXEL_MODE_LCD :: */ /* An 8-bit bitmap, representing RGB or BGR decimated glyph images */ /* used for display on LCD displays; the bitmap is three times */ /* wider than the original glyph image. See also */ /* @FT_RENDER_MODE_LCD. */ /* */ /* FT_PIXEL_MODE_LCD_V :: */ /* An 8-bit bitmap, representing RGB or BGR decimated glyph images */ /* used for display on rotated LCD displays; the bitmap is three */ /* times taller than the original glyph image. See also */ /* @FT_RENDER_MODE_LCD_V. */ /* */ /* FT_PIXEL_MODE_BGRA :: */ /* An image with four 8-bit channels per pixel, representing a */ /* color image (such as emoticons) with alpha channel. For each */ /* pixel, the format is BGRA, which means, the blue channel comes */ /* first in memory. The color channels are pre-multiplied and in */ /* the sRGB colorspace. For example, full red at half-translucent */ /* opacity will be represented as `00,00,80,80', not `00,00,FF,80'. */ /* See also @FT_LOAD_COLOR. */ /* */ typedef enum FT_Pixel_Mode_ { FT_PIXEL_MODE_NONE = 0, FT_PIXEL_MODE_MONO, FT_PIXEL_MODE_GRAY, FT_PIXEL_MODE_GRAY2, FT_PIXEL_MODE_GRAY4, FT_PIXEL_MODE_LCD, FT_PIXEL_MODE_LCD_V, FT_PIXEL_MODE_BGRA, FT_PIXEL_MODE_MAX /* do not remove */ } FT_Pixel_Mode; /* these constants are deprecated; use the corresponding `FT_Pixel_Mode' */ /* values instead. */ #define ft_pixel_mode_none FT_PIXEL_MODE_NONE #define ft_pixel_mode_mono FT_PIXEL_MODE_MONO #define ft_pixel_mode_grays FT_PIXEL_MODE_GRAY #define ft_pixel_mode_pal2 FT_PIXEL_MODE_GRAY2 #define ft_pixel_mode_pal4 FT_PIXEL_MODE_GRAY4 /*************************************************************************/ /* */ /* <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. */ /* */ /* Note that `padding' means the alignment of a */ /* bitmap to a byte border, and FreeType functions */ /* normally align to the smallest possible integer */ /* value. */ /* */ /* For the B/W rasterizer, `pitch' is always an even */ /* number. */ /* */ /* To change the pitch of a bitmap (say, to make it a */ /* multiple of 4), use @FT_Bitmap_Convert. */ /* Alternatively, you might use callback functions to */ /* directly render to the application's surface; see */ /* the file `example2.cpp' in the tutorial for a */ /* demonstration. */ /* */ /* 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_GRAY; it gives the number of gray */ /* levels used in the bitmap. */ /* */ /* pixel_mode :: The pixel mode, i.e., how pixel bits are stored. */ /* See @FT_Pixel_Mode for possible values. */ /* */ /* palette_mode :: This field is intended for paletted pixel modes; */ /* it indicates how the palette is stored. Not */ /* used currently. */ /* */ /* palette :: A typeless pointer to the bitmap palette; this */ /* field is intended for paletted pixel modes. Not */ /* used currently. */ /* */ typedef struct FT_Bitmap_ { int rows; int width; int pitch; unsigned char* buffer; short num_grays; char pixel_mode; char palette_mode; void* palette; } FT_Bitmap; /*************************************************************************/ /* */ /* <Section> */ /* outline_processing */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* <Struct> */ /* FT_Outline */ /* */ /* <Description> */ /* This structure is used to describe an outline to the scan-line */ /* converter. */ /* */ /* <Fields> */ /* n_contours :: The number of contours in the outline. */ /* */ /* n_points :: The number of points in the outline. */ /* */ /* points :: A pointer to an array of `n_points' @FT_Vector */ /* elements, giving the outline's point coordinates. */ /* */ /* tags :: A pointer to an array of `n_points' chars, giving */ /* each outline point's type. */ /* */ /* If bit~0 is unset, the point is `off' the curve, */ /* i.e., a Bézier control point, while it is `on' if */ /* set. */ /* */ /* Bit~1 is meaningful for `off' points only. If set, */ /* it indicates a third-order Bézier arc control point; */ /* and a second-order control point if unset. */ /* */ /* If bit~2 is set, bits 5-7 contain the drop-out mode */ /* (as defined in the OpenType specification; the value */ /* is the same as the argument to the SCANMODE */ /* instruction). */ /* */ /* Bits 3 and~4 are reserved for internal purposes. */ /* */ /* 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_XXX. */ /* */ /* <Note> */ /* The B/W rasterizer only checks bit~2 in the `tags' array for the */ /* first point of each contour. The drop-out mode as given with */ /* @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, and */ /* @FT_OUTLINE_INCLUDE_STUBS in `flags' is then overridden. */ /* */ 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; /* */ /* Following limits must be consistent with */ /* FT_Outline.{n_contours,n_points} */ #define FT_OUTLINE_CONTOURS_MAX SHRT_MAX #define FT_OUTLINE_POINTS_MAX SHRT_MAX /*************************************************************************/ /* */ /* <Enum> */ /* FT_OUTLINE_XXX */ /* */ /* <Description> */ /* A list of bit-field constants use for the flags in an outline's */ /* `flags' field. */ /* */ /* <Values> */ /* FT_OUTLINE_NONE :: */ /* Value~0 is reserved. */ /* */ /* FT_OUTLINE_OWNER :: */ /* If set, this flag indicates that the outline's field arrays */ /* (i.e., `points', `flags', and `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 rasterizer). */ /* */ /* 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. */ /* */ /* 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. See below for more information. */ /* */ /* FT_OUTLINE_SMART_DROPOUTS :: */ /* Select smart dropout control. If unset, use simple dropout */ /* control. Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See */ /* below for more information. */ /* */ /* FT_OUTLINE_INCLUDE_STUBS :: */ /* If set, turn pixels on for `stubs', otherwise exclude them. */ /* Ignored if @FT_OUTLINE_IGNORE_DROPOUTS is set. See below for */ /* more information. */ /* */ /* 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. */ /* */ /* <Note> */ /* The flags @FT_OUTLINE_IGNORE_DROPOUTS, @FT_OUTLINE_SMART_DROPOUTS, */ /* and @FT_OUTLINE_INCLUDE_STUBS are ignored by the smooth */ /* rasterizer. */ /* */ /* There exists a second mechanism to pass the drop-out mode to the */ /* B/W rasterizer; see the `tags' field in @FT_Outline. */ /* */ /* Please refer to the description of the `SCANTYPE' instruction in */ /* the OpenType specification (in file `ttinst1.doc') how simple */ /* drop-outs, smart drop-outs, and stubs are defined. */ /* */ #define FT_OUTLINE_NONE 0x0 #define FT_OUTLINE_OWNER 0x1 #define FT_OUTLINE_EVEN_ODD_FILL 0x2 #define FT_OUTLINE_REVERSE_FILL 0x4 #define FT_OUTLINE_IGNORE_DROPOUTS 0x8 #define FT_OUTLINE_SMART_DROPOUTS 0x10 #define FT_OUTLINE_INCLUDE_STUBS 0x20 #define FT_OUTLINE_HIGH_PRECISION 0x100 #define FT_OUTLINE_SINGLE_PASS 0x200 /* these constants are deprecated; use the corresponding */ /* `FT_OUTLINE_XXX' values instead */ #define ft_outline_none FT_OUTLINE_NONE #define ft_outline_owner FT_OUTLINE_OWNER #define ft_outline_even_odd_fill FT_OUTLINE_EVEN_ODD_FILL #define ft_outline_reverse_fill FT_OUTLINE_REVERSE_FILL #define ft_outline_ignore_dropouts FT_OUTLINE_IGNORE_DROPOUTS #define ft_outline_high_precision FT_OUTLINE_HIGH_PRECISION #define ft_outline_single_pass FT_OUTLINE_SINGLE_PASS /* */ #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_HAS_SCANMODE 4 #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 ) #define FT_Curve_Tag_On FT_CURVE_TAG_ON #define FT_Curve_Tag_Conic FT_CURVE_TAG_CONIC #define FT_Curve_Tag_Cubic FT_CURVE_TAG_CUBIC #define FT_Curve_Tag_Touch_X FT_CURVE_TAG_TOUCH_X #define FT_Curve_Tag_Touch_Y FT_CURVE_TAG_TOUCH_Y /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Outline_MoveToFunc */ /* */ /* <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_MoveToFunc)( const FT_Vector* to, void* user ); #define FT_Outline_MoveTo_Func FT_Outline_MoveToFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Outline_LineToFunc */ /* */ /* <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_LineToFunc)( const FT_Vector* to, void* user ); #define FT_Outline_LineTo_Func FT_Outline_LineToFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Outline_ConicToFunc */ /* */ /* <Description> */ /* A function pointer type used to describe the signature of a `conic */ /* to' function during outline walking or decomposition. */ /* */ /* A `conic to' is emitted to indicate a second-order Bézier 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_ConicToFunc)( const FT_Vector* control, const FT_Vector* to, void* user ); #define FT_Outline_ConicTo_Func FT_Outline_ConicToFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Outline_CubicToFunc */ /* */ /* <Description> */ /* A function pointer type used to describe the signature of a `cubic */ /* to' function during outline walking or decomposition. */ /* */ /* A `cubic to' is emitted to indicate a third-order Bézier arc. */ /* */ /* <Input> */ /* control1 :: A pointer to the first Bézier control point. */ /* */ /* control2 :: A pointer to the second Bézier 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_CubicToFunc)( const FT_Vector* control1, const FT_Vector* control2, const FT_Vector* to, void* user ); #define FT_Outline_CubicTo_Func FT_Outline_CubicToFunc /*************************************************************************/ /* */ /* <Struct> */ /* FT_Outline_Funcs */ /* */ /* <Description> */ /* A structure to hold various function pointers used during outline */ /* decomposition in order to emit segments, conic, and cubic Béziers. */ /* */ /* <Fields> */ /* move_to :: The `move to' emitter. */ /* */ /* line_to :: The segment emitter. */ /* */ /* conic_to :: The second-order Bézier arc emitter. */ /* */ /* cubic_to :: The third-order Bézier 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' = (y << shift) - delta */ /* } */ /* */ /* Set the values of `shift' and `delta' to~0 to get the original */ /* point coordinates. */ /* */ typedef struct FT_Outline_Funcs_ { FT_Outline_MoveToFunc move_to; FT_Outline_LineToFunc line_to; FT_Outline_ConicToFunc conic_to; FT_Outline_CubicToFunc cubic_to; int shift; FT_Pos delta; } FT_Outline_Funcs; /*************************************************************************/ /* */ /* <Section> */ /* basic_types */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* <Macro> */ /* FT_IMAGE_TAG */ /* */ /* <Description> */ /* This macro converts four-letter tags to an unsigned long type. */ /* */ /* <Note> */ /* Since many 16-bit compilers don't like 32-bit enumerations, you */ /* should redefine this macro in case of problems to something like */ /* this: */ /* */ /* { */ /* #define FT_IMAGE_TAG( value, _x1, _x2, _x3, _x4 ) value */ /* } */ /* */ /* to get a simple enumeration without assigning special numbers. */ /* */ #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. */ /* */ /* <Values> */ /* FT_GLYPH_FORMAT_NONE :: */ /* The value~0 is reserved. */ /* */ /* FT_GLYPH_FORMAT_COMPOSITE :: */ /* The glyph image is a composite of several other images. This */ /* format is _only_ used with @FT_LOAD_NO_RECURSE, and is used to */ /* report compound glyphs (like accented characters). */ /* */ /* FT_GLYPH_FORMAT_BITMAP :: */ /* The glyph image is a bitmap, and can be described as an */ /* @FT_Bitmap. You generally need to access the `bitmap' field of */ /* the @FT_GlyphSlotRec structure to read it. */ /* */ /* FT_GLYPH_FORMAT_OUTLINE :: */ /* The glyph image is a vectorial outline made of line segments */ /* and Bézier arcs; it can be described as an @FT_Outline; you */ /* generally want to access the `outline' field of the */ /* @FT_GlyphSlotRec structure to read it. */ /* */ /* FT_GLYPH_FORMAT_PLOTTER :: */ /* The glyph image is a vectorial path with no inside and outside */ /* contours. Some Type~1 fonts, like those in the Hershey family, */ /* contain glyphs in this format. These are described as */ /* @FT_Outline, but FreeType isn't currently capable of rendering */ /* them correctly. */ /* */ 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; /* these constants are deprecated; use the corresponding */ /* `FT_Glyph_Format' values instead. */ #define ft_glyph_format_none FT_GLYPH_FORMAT_NONE #define ft_glyph_format_composite FT_GLYPH_FORMAT_COMPOSITE #define ft_glyph_format_bitmap FT_GLYPH_FORMAT_BITMAP #define ft_glyph_format_outline FT_GLYPH_FORMAT_OUTLINE #define ft_glyph_format_plotter FT_GLYPH_FORMAT_PLOTTER /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** 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 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 `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. */ /* */ /* <Order> */ /* FT_Raster */ /* FT_Span */ /* FT_SpanFunc */ /* */ /* FT_Raster_Params */ /* FT_RASTER_FLAG_XXX */ /* */ /* FT_Raster_NewFunc */ /* FT_Raster_DoneFunc */ /* FT_Raster_ResetFunc */ /* FT_Raster_SetModeFunc */ /* FT_Raster_RenderFunc */ /* FT_Raster_Funcs */ /* */ /*************************************************************************/ /*************************************************************************/ /* */ /* <Type> */ /* FT_Raster */ /* */ /* <Description> */ /* An opaque 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 pixels when */ /* rendering an 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). */ /* */ /* <Note> */ /* This structure is used by the span drawing callback type named */ /* @FT_SpanFunc that takes the y~coordinate of the span as a */ /* parameter. */ /* */ /* The coverage value is always between 0 and 255. If you want less */ /* gray values, the callback function has to reduce them. */ /* */ typedef struct FT_Span_ { short x; unsigned short len; unsigned char coverage; } FT_Span; /*************************************************************************/ /* */ /* <FuncType> */ /* FT_SpanFunc */ /* */ /* <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. */ /* */ typedef void (*FT_SpanFunc)( int y, int count, const FT_Span* spans, void* user ); #define FT_Raster_Span_Func FT_SpanFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Raster_BitTest_Func */ /* */ /* <Description> */ /* Deprecated, unimplemented. */ /* */ typedef int (*FT_Raster_BitTest_Func)( int y, int x, void* user ); /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Raster_BitSet_Func */ /* */ /* <Description> */ /* Deprecated, unimplemented. */ /* */ typedef void (*FT_Raster_BitSet_Func)( int y, int x, void* user ); /*************************************************************************/ /* */ /* <Enum> */ /* FT_RASTER_FLAG_XXX */ /* */ /* <Description> */ /* A list of bit flag constants as used in the `flags' field of a */ /* @FT_Raster_Params structure. */ /* */ /* <Values> */ /* 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. */ /* */ /* 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. */ /* */ #define FT_RASTER_FLAG_DEFAULT 0x0 #define FT_RASTER_FLAG_AA 0x1 #define FT_RASTER_FLAG_DIRECT 0x2 #define FT_RASTER_FLAG_CLIP 0x4 /* these constants are deprecated; use the corresponding */ /* `FT_RASTER_FLAG_XXX' values instead */ #define ft_raster_flag_default FT_RASTER_FLAG_DEFAULT #define ft_raster_flag_aa FT_RASTER_FLAG_AA #define ft_raster_flag_direct FT_RASTER_FLAG_DIRECT #define ft_raster_flag_clip FT_RASTER_FLAG_CLIP /*************************************************************************/ /* */ /* <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 :: Unused. */ /* */ /* bit_test :: Unused. */ /* */ /* bit_set :: Unused. */ /* */ /* 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 that coordinates here */ /* should be expressed in _integer_ pixels (and not in */ /* 26.6 fixed-point units). */ /* */ /* <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 is 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. This allows direct composition over a pre-existing bitmap */ /* through user-provided callbacks to perform the span drawing and */ /* composition. Not supported by the monochrome rasterizer. */ /* */ typedef struct FT_Raster_Params_ { const FT_Bitmap* target; const void* source; int flags; FT_SpanFunc gray_spans; FT_SpanFunc black_spans; /* unused */ FT_Raster_BitTest_Func bit_test; /* unused */ FT_Raster_BitSet_Func bit_set; /* unused */ void* user; FT_BBox clip_box; } FT_Raster_Params; /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Raster_NewFunc */ /* */ /* <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 an @FT_Memory object, 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_NewFunc)( void* memory, FT_Raster* raster ); #define FT_Raster_New_Func FT_Raster_NewFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Raster_DoneFunc */ /* */ /* <Description> */ /* A function used to destroy a given raster object. */ /* */ /* <Input> */ /* raster :: A handle to the raster object. */ /* */ typedef void (*FT_Raster_DoneFunc)( FT_Raster raster ); #define FT_Raster_Done_Func FT_Raster_DoneFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Raster_ResetFunc */ /* */ /* <Description> */ /* FreeType used to provide an area of memory called the `render */ /* pool' available to all registered rasters. This was not thread */ /* safe however and now FreeType never allocates this pool. NULL */ /* is always passed in as pool_base. */ /* */ /* 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 should ignore the render pool and rely on dynamic or stack */ /* allocation if they want to (a handle to the memory allocator is */ /* passed to the raster constructor). */ /* */ typedef void (*FT_Raster_ResetFunc)( FT_Raster raster, unsigned char* pool_base, unsigned long pool_size ); #define FT_Raster_Reset_Func FT_Raster_ResetFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Raster_SetModeFunc */ /* */ /* <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_SetModeFunc)( FT_Raster raster, unsigned long mode, void* args ); #define FT_Raster_Set_Mode_Func FT_Raster_SetModeFunc /*************************************************************************/ /* */ /* <FuncType> */ /* FT_Raster_RenderFunc */ /* */ /* <Description> */ /* Invoke 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 an @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 that support direct */ /* composition). */ /* */ typedef int (*FT_Raster_RenderFunc)( FT_Raster raster, const FT_Raster_Params* params ); #define FT_Raster_Render_Func FT_Raster_RenderFunc /*************************************************************************/ /* */ /* <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_NewFunc raster_new; FT_Raster_ResetFunc raster_reset; FT_Raster_SetModeFunc raster_set_mode; FT_Raster_RenderFunc raster_render; FT_Raster_DoneFunc raster_done; } FT_Raster_Funcs; /* */ FT_END_HEADER #endif /* FTIMAGE_H_ */ /* END */ /* Local Variables: */ /* coding: utf-8 */ /* End: */