/***************************************************************************/
/* */
/* ftimage.h */
/* */
/* FreeType glyph image formats and default raster interface */
/* (specification). */
/* */
/* Copyright 1996-2010, 2013 by */
/* David Turner, Robert Wilhelm, and Werner Lemberg. */
/* */
/* This file is part of the FreeType project, and may only be used, */
/* modified, and distributed under the terms of the FreeType project */
/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
/* this file you indicate that you have read the license and */
/* understand and accept it fully. */
/* */
/***************************************************************************/
#ifndef PLUTOVG_FT_RASTER_H
#define PLUTOVG_FT_RASTER_H
#include "plutovg-ft-types.h"
/*************************************************************************/
/* */
/* <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 PVG_FT_BBox_
{
PVG_FT_Pos xMin, yMin;
PVG_FT_Pos xMax, yMax;
} PVG_FT_BBox;
/*************************************************************************/
/* */
/* <Struct> */
/* PVG_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' @PVG_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 @PVG_FT_OUTLINE_FLAGS.*/
/* */
typedef struct PVG_FT_Outline_
{
int n_contours; /* number of contours in glyph */
int n_points; /* number of points in the glyph */
PVG_FT_Vector* points; /* the outline's points */
char* tags; /* the points flags */
int* contours; /* the contour end points */
char* contours_flag; /* the contour open flags */
int flags; /* outline masks */
} PVG_FT_Outline;
/*************************************************************************/
/* */
/* <Enum> */
/* PVG_FT_OUTLINE_FLAGS */
/* */
/* <Description> */
/* A list of bit-field constants use for the flags in an outline's */
/* `flags' field. */
/* */
/* <Values> */
/* PVG_FT_OUTLINE_NONE :: */
/* Value~0 is reserved. */
/* */
/* PVG_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. */
/* */
/* PVG_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). */
/* */
/* PVG_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. */
/* */
/* */
/* */
/* There exists a second mechanism to pass the drop-out mode to the */
/* B/W rasterizer; see the `tags' field in @PVG_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 PVG_FT_OUTLINE_NONE 0x0
#define PVG_FT_OUTLINE_OWNER 0x1
#define PVG_FT_OUTLINE_EVEN_ODD_FILL 0x2
#define PVG_FT_OUTLINE_REVERSE_FILL 0x4
/* */
#define PVG_FT_CURVE_TAG( flag ) ( flag & 3 )
#define PVG_FT_CURVE_TAG_ON 1
#define PVG_FT_CURVE_TAG_CONIC 0
#define PVG_FT_CURVE_TAG_CUBIC 2
#define PVG_FT_Curve_Tag_On PVG_FT_CURVE_TAG_ON
#define PVG_FT_Curve_Tag_Conic PVG_FT_CURVE_TAG_CONIC
#define PVG_FT_Curve_Tag_Cubic PVG_FT_CURVE_TAG_CUBIC
/*************************************************************************/
/* */
/* <Function> */
/* PVG_FT_Outline_Check */
/* */
/* <Description> */
/* Check the contents of an outline descriptor. */
/* */
/* <Input> */
/* outline :: A handle to a source outline. */
/* */
/* <Return> */
/* FreeType error code. 0~means success. */
/* */
PVG_FT_Error
PVG_FT_Outline_Check( PVG_FT_Outline* outline );
/*************************************************************************/
/* */
/* <Function> */
/* PVG_FT_Outline_Get_CBox */
/* */
/* <Description> */
/* Return an outline's `control box'. The control box encloses all */
/* the outline's points, including Bézier control points. Though it */
/* coincides with the exact bounding box for most glyphs, it can be */
/* slightly larger in some situations (like when rotating an outline */
/* that contains Bézier outside arcs). */
/* */
/* Computing the control box is very fast, while getting the bounding */
/* box can take much more time as it needs to walk over all segments */
/* and arcs in the outline. To get the latter, you can use the */
/* `ftbbox' component, which is dedicated to this single task. */
/* */
/* <Input> */
/* outline :: A pointer to the source outline descriptor. */
/* */
/* <Output> */
/* acbox :: The outline's control box. */
/* */
/* <Note> */
/* See @PVG_FT_Glyph_Get_CBox for a discussion of tricky fonts. */
/* */
void
PVG_FT_Outline_Get_CBox( const PVG_FT_Outline* outline,
PVG_FT_BBox *acbox );
/*************************************************************************/
/* */
/* <Struct> */
/* PVG_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 */
/* @PVG_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 PVG_FT_Span_
{
int x;
int len;
int y;
unsigned char coverage;
} PVG_FT_Span;
/*************************************************************************/
/* */
/* <FuncType> */
/* PVG_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 `PVG_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
(*PVG_FT_SpanFunc)( int count,
const PVG_FT_Span* spans,
void* user );
#define PVG_FT_Raster_Span_Func PVG_FT_SpanFunc
/*************************************************************************/
/* */
/* <Enum> */
/* PVG_FT_RASTER_FLAG_XXX */
/* */
/* <Description> */
/* A list of bit flag constants as used in the `flags' field of a */
/* @PVG_FT_Raster_Params structure. */
/* */
/* <Values> */
/* PVG_FT_RASTER_FLAG_DEFAULT :: This value is 0. */
/* */
/* PVG_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). */
/* */
/* PVG_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. */
/* */
/* PVG_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 */
/* @PVG_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 PVG_FT_RASTER_FLAG_DEFAULT 0x0
#define PVG_FT_RASTER_FLAG_AA 0x1
#define PVG_FT_RASTER_FLAG_DIRECT 0x2
#define PVG_FT_RASTER_FLAG_CLIP 0x4
/*************************************************************************/
/* */
/* <Struct> */
/* PVG_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 */
/* @PVG_FT_Outline). */
/* */
/* flags :: The rendering flags. */
/* */
/* gray_spans :: The gray span drawing callback. */
/* */
/* black_spans :: The black span drawing callback. UNIMPLEMENTED! */
/* */
/* 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 @PVG_FT_RASTER_FLAG_AA */
/* bit flag is set in the `flags' field, otherwise a monochrome */
/* bitmap is generated. */
/* */
/* If the @PVG_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 PVG_FT_Raster_Params_
{
const void* source;
int flags;
PVG_FT_SpanFunc gray_spans;
void* user;
PVG_FT_BBox clip_box;
} PVG_FT_Raster_Params;
void
PVG_FT_Raster_Render(const PVG_FT_Raster_Params *params);
#endif // PLUTOVG_FT_RASTER_H