📄 ftimage.h
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/* a parameter. */
/* */
/* The coverage value is always between 0 and 255. */
/* */
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. */
/* */
/* 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 is 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_SpanFunc)( int y,
int count,
const FT_Span* spans,
void* user );
#define FT_Raster_Span_Func FT_SpanFunc
/*************************************************************************/
/* */
/* <FuncType> */
/* FT_Raster_BitTest_Func */
/* */
/* <Description> */
/* THIS TYPE IS DEPRECATED. DO NOT USE IT. */
/* */
/* 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> */
/* THIS TYPE IS DEPRECATED. DO NOT USE IT. */
/* */
/* 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_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. */
/* */
/* 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. */
/* */
#define FT_RASTER_FLAG_DEFAULT 0x0
#define FT_RASTER_FLAG_AA 0x1
#define FT_RASTER_FLAG_DIRECT 0x2
#define FT_RASTER_FLAG_CLIP 0x4
/* deprecated */
#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 :: The black span drawing callback. */
/* */
/* bit_test :: The bit test callback. UNIMPLEMENTED! */
/* */
/* bit_set :: The bit set callback. UNIMPLEMENTED! */
/* */
/* 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 */
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