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https://github.com/RetroDECK/ES-DE.git
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421 lines
26 KiB
C
421 lines
26 KiB
C
/***************************************************************************/
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/* */
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/* ftimage.h */
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/* */
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/* FreeType glyph image formats and default raster interface */
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/* (specification). */
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/* */
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/* Copyright 1996-2010, 2013 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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/* */
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/* This file is part of the FreeType project, and may only be used, */
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/* modified, and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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#ifndef PLUTOVG_FT_RASTER_H
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#define PLUTOVG_FT_RASTER_H
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#include "plutovg-ft-types.h"
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* FT_BBox */
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/* */
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/* <Description> */
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/* A structure used to hold an outline's bounding box, i.e., the */
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/* coordinates of its extrema in the horizontal and vertical */
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/* directions. */
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/* */
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/* <Fields> */
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/* xMin :: The horizontal minimum (left-most). */
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/* */
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/* yMin :: The vertical minimum (bottom-most). */
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/* */
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/* xMax :: The horizontal maximum (right-most). */
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/* */
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/* yMax :: The vertical maximum (top-most). */
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/* */
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/* <Note> */
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/* The bounding box is specified with the coordinates of the lower */
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/* left and the upper right corner. In PostScript, those values are */
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/* often called (llx,lly) and (urx,ury), respectively. */
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/* */
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/* If `yMin' is negative, this value gives the glyph's descender. */
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/* Otherwise, the glyph doesn't descend below the baseline. */
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/* Similarly, if `ymax' is positive, this value gives the glyph's */
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/* ascender. */
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/* */
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/* `xMin' gives the horizontal distance from the glyph's origin to */
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/* the left edge of the glyph's bounding box. If `xMin' is negative, */
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/* the glyph extends to the left of the origin. */
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/* */
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typedef struct PVG_FT_BBox_
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{
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PVG_FT_Pos xMin, yMin;
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PVG_FT_Pos xMax, yMax;
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} PVG_FT_BBox;
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* PVG_FT_Outline */
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/* */
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/* <Description> */
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/* This structure is used to describe an outline to the scan-line */
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/* converter. */
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/* */
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/* <Fields> */
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/* n_contours :: The number of contours in the outline. */
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/* */
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/* n_points :: The number of points in the outline. */
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/* */
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/* points :: A pointer to an array of `n_points' @PVG_FT_Vector */
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/* elements, giving the outline's point coordinates. */
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/* */
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/* tags :: A pointer to an array of `n_points' chars, giving */
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/* each outline point's type. */
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/* */
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/* If bit~0 is unset, the point is `off' the curve, */
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/* i.e., a Bézier control point, while it is `on' if */
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/* set. */
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/* */
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/* Bit~1 is meaningful for `off' points only. If set, */
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/* it indicates a third-order Bézier arc control point; */
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/* and a second-order control point if unset. */
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/* */
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/* If bit~2 is set, bits 5-7 contain the drop-out mode */
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/* (as defined in the OpenType specification; the value */
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/* is the same as the argument to the SCANMODE */
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/* instruction). */
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/* */
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/* Bits 3 and~4 are reserved for internal purposes. */
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/* */
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/* contours :: An array of `n_contours' shorts, giving the end */
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/* point of each contour within the outline. For */
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/* example, the first contour is defined by the points */
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/* `0' to `contours[0]', the second one is defined by */
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/* the points `contours[0]+1' to `contours[1]', etc. */
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/* */
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/* flags :: A set of bit flags used to characterize the outline */
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/* and give hints to the scan-converter and hinter on */
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/* how to convert/grid-fit it. See @PVG_FT_OUTLINE_FLAGS.*/
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/* */
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typedef struct PVG_FT_Outline_
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{
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int n_contours; /* number of contours in glyph */
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int n_points; /* number of points in the glyph */
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PVG_FT_Vector* points; /* the outline's points */
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char* tags; /* the points flags */
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int* contours; /* the contour end points */
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char* contours_flag; /* the contour open flags */
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int flags; /* outline masks */
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} PVG_FT_Outline;
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/*************************************************************************/
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/* */
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/* <Enum> */
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/* PVG_FT_OUTLINE_FLAGS */
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/* */
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/* <Description> */
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/* A list of bit-field constants use for the flags in an outline's */
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/* `flags' field. */
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/* */
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/* <Values> */
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/* PVG_FT_OUTLINE_NONE :: */
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/* Value~0 is reserved. */
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/* */
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/* PVG_FT_OUTLINE_OWNER :: */
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/* If set, this flag indicates that the outline's field arrays */
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/* (i.e., `points', `flags', and `contours') are `owned' by the */
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/* outline object, and should thus be freed when it is destroyed. */
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/* */
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/* PVG_FT_OUTLINE_EVEN_ODD_FILL :: */
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/* By default, outlines are filled using the non-zero winding rule. */
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/* If set to 1, the outline will be filled using the even-odd fill */
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/* rule (only works with the smooth rasterizer). */
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/* */
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/* PVG_FT_OUTLINE_REVERSE_FILL :: */
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/* By default, outside contours of an outline are oriented in */
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/* clock-wise direction, as defined in the TrueType specification. */
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/* This flag is set if the outline uses the opposite direction */
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/* (typically for Type~1 fonts). This flag is ignored by the scan */
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/* converter. */
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/* */
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/* */
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/* */
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/* There exists a second mechanism to pass the drop-out mode to the */
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/* B/W rasterizer; see the `tags' field in @PVG_FT_Outline. */
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/* */
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/* Please refer to the description of the `SCANTYPE' instruction in */
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/* the OpenType specification (in file `ttinst1.doc') how simple */
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/* drop-outs, smart drop-outs, and stubs are defined. */
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/* */
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#define PVG_FT_OUTLINE_NONE 0x0
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#define PVG_FT_OUTLINE_OWNER 0x1
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#define PVG_FT_OUTLINE_EVEN_ODD_FILL 0x2
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#define PVG_FT_OUTLINE_REVERSE_FILL 0x4
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/* */
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#define PVG_FT_CURVE_TAG( flag ) ( flag & 3 )
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#define PVG_FT_CURVE_TAG_ON 1
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#define PVG_FT_CURVE_TAG_CONIC 0
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#define PVG_FT_CURVE_TAG_CUBIC 2
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#define PVG_FT_Curve_Tag_On PVG_FT_CURVE_TAG_ON
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#define PVG_FT_Curve_Tag_Conic PVG_FT_CURVE_TAG_CONIC
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#define PVG_FT_Curve_Tag_Cubic PVG_FT_CURVE_TAG_CUBIC
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/*************************************************************************/
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/* */
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/* <Function> */
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/* PVG_FT_Outline_Check */
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/* */
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/* <Description> */
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/* Check the contents of an outline descriptor. */
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/* */
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/* <Input> */
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/* outline :: A handle to a source outline. */
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/* */
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/* <Return> */
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/* FreeType error code. 0~means success. */
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/* */
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PVG_FT_Error
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PVG_FT_Outline_Check( PVG_FT_Outline* outline );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* PVG_FT_Outline_Get_CBox */
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/* */
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/* <Description> */
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/* Return an outline's `control box'. The control box encloses all */
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/* the outline's points, including Bézier control points. Though it */
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/* coincides with the exact bounding box for most glyphs, it can be */
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/* slightly larger in some situations (like when rotating an outline */
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/* that contains Bézier outside arcs). */
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/* */
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/* Computing the control box is very fast, while getting the bounding */
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/* box can take much more time as it needs to walk over all segments */
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/* and arcs in the outline. To get the latter, you can use the */
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/* `ftbbox' component, which is dedicated to this single task. */
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/* */
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/* <Input> */
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/* outline :: A pointer to the source outline descriptor. */
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/* */
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/* <Output> */
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/* acbox :: The outline's control box. */
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/* */
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/* <Note> */
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/* See @PVG_FT_Glyph_Get_CBox for a discussion of tricky fonts. */
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/* */
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void
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PVG_FT_Outline_Get_CBox( const PVG_FT_Outline* outline,
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PVG_FT_BBox *acbox );
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* PVG_FT_Span */
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/* */
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/* <Description> */
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/* A structure used to model a single span of gray (or black) pixels */
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/* when rendering a monochrome or anti-aliased bitmap. */
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/* */
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/* <Fields> */
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/* x :: The span's horizontal start position. */
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/* */
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/* len :: The span's length in pixels. */
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/* */
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/* coverage :: The span color/coverage, ranging from 0 (background) */
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/* to 255 (foreground). Only used for anti-aliased */
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/* rendering. */
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/* */
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/* <Note> */
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/* This structure is used by the span drawing callback type named */
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/* @PVG_FT_SpanFunc that takes the y~coordinate of the span as a */
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/* parameter. */
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/* */
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/* The coverage value is always between 0 and 255. If you want less */
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/* gray values, the callback function has to reduce them. */
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/* */
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typedef struct PVG_FT_Span_
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{
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int x;
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int len;
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int y;
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unsigned char coverage;
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} PVG_FT_Span;
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/*************************************************************************/
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/* */
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/* <FuncType> */
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/* PVG_FT_SpanFunc */
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/* */
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/* <Description> */
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/* A function used as a call-back by the anti-aliased renderer in */
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/* order to let client applications draw themselves the gray pixel */
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/* spans on each scan line. */
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/* */
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/* <Input> */
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/* y :: The scanline's y~coordinate. */
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/* */
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/* count :: The number of spans to draw on this scanline. */
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/* */
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/* spans :: A table of `count' spans to draw on the scanline. */
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/* */
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/* user :: User-supplied data that is passed to the callback. */
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/* */
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/* <Note> */
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/* This callback allows client applications to directly render the */
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/* gray spans of the anti-aliased bitmap to any kind of surfaces. */
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/* */
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/* This can be used to write anti-aliased outlines directly to a */
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/* given background bitmap, and even perform translucency. */
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/* */
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/* Note that the `count' field cannot be greater than a fixed value */
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/* defined by the `PVG_FT_MAX_GRAY_SPANS' configuration macro in */
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/* `ftoption.h'. By default, this value is set to~32, which means */
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/* that if there are more than 32~spans on a given scanline, the */
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/* callback is called several times with the same `y' parameter in */
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/* order to draw all callbacks. */
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/* */
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/* Otherwise, the callback is only called once per scan-line, and */
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/* only for those scanlines that do have `gray' pixels on them. */
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/* */
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typedef void
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(*PVG_FT_SpanFunc)( int count,
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const PVG_FT_Span* spans,
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void* user );
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#define PVG_FT_Raster_Span_Func PVG_FT_SpanFunc
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/*************************************************************************/
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/* */
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/* <Enum> */
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/* PVG_FT_RASTER_FLAG_XXX */
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/* */
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/* <Description> */
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/* A list of bit flag constants as used in the `flags' field of a */
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/* @PVG_FT_Raster_Params structure. */
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/* */
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/* <Values> */
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/* PVG_FT_RASTER_FLAG_DEFAULT :: This value is 0. */
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/* */
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/* PVG_FT_RASTER_FLAG_AA :: This flag is set to indicate that an */
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/* anti-aliased glyph image should be */
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/* generated. Otherwise, it will be */
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/* monochrome (1-bit). */
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/* */
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/* PVG_FT_RASTER_FLAG_DIRECT :: This flag is set to indicate direct */
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/* rendering. In this mode, client */
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/* applications must provide their own span */
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/* callback. This lets them directly */
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/* draw or compose over an existing bitmap. */
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/* If this bit is not set, the target */
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/* pixmap's buffer _must_ be zeroed before */
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/* rendering. */
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/* */
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/* Note that for now, direct rendering is */
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/* only possible with anti-aliased glyphs. */
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/* */
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/* PVG_FT_RASTER_FLAG_CLIP :: This flag is only used in direct */
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/* rendering mode. If set, the output will */
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/* be clipped to a box specified in the */
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/* `clip_box' field of the */
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/* @PVG_FT_Raster_Params structure. */
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/* */
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/* Note that by default, the glyph bitmap */
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/* is clipped to the target pixmap, except */
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/* in direct rendering mode where all spans */
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/* are generated if no clipping box is set. */
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/* */
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#define PVG_FT_RASTER_FLAG_DEFAULT 0x0
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#define PVG_FT_RASTER_FLAG_AA 0x1
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#define PVG_FT_RASTER_FLAG_DIRECT 0x2
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#define PVG_FT_RASTER_FLAG_CLIP 0x4
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* PVG_FT_Raster_Params */
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/* */
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/* <Description> */
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/* A structure to hold the arguments used by a raster's render */
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/* function. */
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/* */
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/* <Fields> */
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/* target :: The target bitmap. */
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/* */
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/* source :: A pointer to the source glyph image (e.g., an */
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/* @PVG_FT_Outline). */
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/* */
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/* flags :: The rendering flags. */
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/* */
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/* gray_spans :: The gray span drawing callback. */
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/* */
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/* black_spans :: The black span drawing callback. UNIMPLEMENTED! */
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/* */
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/* bit_test :: The bit test callback. UNIMPLEMENTED! */
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/* */
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/* bit_set :: The bit set callback. UNIMPLEMENTED! */
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/* */
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/* user :: User-supplied data that is passed to each drawing */
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/* callback. */
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/* */
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/* clip_box :: An optional clipping box. It is only used in */
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/* direct rendering mode. Note that coordinates here */
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/* should be expressed in _integer_ pixels (and not in */
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/* 26.6 fixed-point units). */
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/* */
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/* <Note> */
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/* An anti-aliased glyph bitmap is drawn if the @PVG_FT_RASTER_FLAG_AA */
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/* bit flag is set in the `flags' field, otherwise a monochrome */
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/* bitmap is generated. */
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/* */
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/* If the @PVG_FT_RASTER_FLAG_DIRECT bit flag is set in `flags', the */
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/* raster will call the `gray_spans' callback to draw gray pixel */
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/* spans, in the case of an aa glyph bitmap, it will call */
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/* `black_spans', and `bit_test' and `bit_set' in the case of a */
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/* monochrome bitmap. This allows direct composition over a */
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/* pre-existing bitmap through user-provided callbacks to perform the */
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/* span drawing/composition. */
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/* */
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/* Note that the `bit_test' and `bit_set' callbacks are required when */
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/* rendering a monochrome bitmap, as they are crucial to implement */
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/* correct drop-out control as defined in the TrueType specification. */
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/* */
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typedef struct PVG_FT_Raster_Params_
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{
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const void* source;
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int flags;
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PVG_FT_SpanFunc gray_spans;
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void* user;
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PVG_FT_BBox clip_box;
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} PVG_FT_Raster_Params;
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void
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PVG_FT_Raster_Render(const PVG_FT_Raster_Params *params);
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#endif // PLUTOVG_FT_RASTER_H
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