561 lines
33 KiB
C
561 lines
33 KiB
C
/***************************************************************************/
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/* */
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/* ftoutln.h */
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/* */
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/* Support for the FT_Outline type used to store glyph shapes of */
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/* most scalable font formats (specification). */
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/* */
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/* Copyright 1996-2003, 2005-2012 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 __FTOUTLN_H__
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#define __FTOUTLN_H__
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#include <ft2build.h>
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#include FT_FREETYPE_H
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#ifdef FREETYPE_H
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#error "freetype.h of FreeType 1 has been loaded!"
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#error "Please fix the directory search order for header files"
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#error "so that freetype.h of FreeType 2 is found first."
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#endif
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FT_BEGIN_HEADER
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/*************************************************************************/
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/* */
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/* <Section> */
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/* outline_processing */
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/* */
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/* <Title> */
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/* Outline Processing */
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/* */
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/* <Abstract> */
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/* Functions to create, transform, and render vectorial glyph images. */
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/* */
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/* <Description> */
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/* This section contains routines used to create and destroy scalable */
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/* glyph images known as `outlines'. These can also be measured, */
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/* transformed, and converted into bitmaps and pixmaps. */
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/* */
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/* <Order> */
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/* FT_Outline */
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/* FT_OUTLINE_FLAGS */
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/* FT_Outline_New */
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/* FT_Outline_Done */
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/* FT_Outline_Copy */
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/* FT_Outline_Translate */
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/* FT_Outline_Transform */
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/* FT_Outline_Embolden */
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/* FT_Outline_EmboldenXY */
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/* FT_Outline_Reverse */
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/* FT_Outline_Check */
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/* */
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/* FT_Outline_Get_CBox */
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/* FT_Outline_Get_BBox */
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/* */
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/* FT_Outline_Get_Bitmap */
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/* FT_Outline_Render */
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/* */
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/* FT_Outline_Decompose */
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/* FT_Outline_Funcs */
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/* FT_Outline_MoveTo_Func */
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/* FT_Outline_LineTo_Func */
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/* FT_Outline_ConicTo_Func */
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/* FT_Outline_CubicTo_Func */
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/* */
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/*************************************************************************/
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Decompose */
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/* */
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/* <Description> */
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/* Walk over an outline's structure to decompose it into individual */
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/* segments and Bézier arcs. This function also emits `move to' */
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/* operations to indicate the start of new contours in the outline. */
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/* */
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/* <Input> */
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/* outline :: A pointer to the source target. */
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/* */
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/* func_interface :: A table of `emitters', i.e., function pointers */
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/* called during decomposition to indicate path */
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/* operations. */
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/* */
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/* <InOut> */
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/* user :: A typeless pointer which is passed to each */
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/* emitter during the decomposition. It can be */
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/* used to store the state during the */
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/* decomposition. */
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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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FT_EXPORT( FT_Error )
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FT_Outline_Decompose( FT_Outline* outline,
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const FT_Outline_Funcs* func_interface,
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void* user );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_New */
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/* */
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/* <Description> */
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/* Create a new outline of a given size. */
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/* */
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/* <Input> */
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/* library :: A handle to the library object from where the */
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/* outline is allocated. Note however that the new */
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/* outline will *not* necessarily be *freed*, when */
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/* destroying the library, by @FT_Done_FreeType. */
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/* */
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/* numPoints :: The maximum number of points within the outline. */
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/* Must be smaller than or equal to 0xFFFF (65535). */
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/* */
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/* numContours :: The maximum number of contours within the outline. */
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/* This value must be in the range 0 to `numPoints'. */
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/* */
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/* <Output> */
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/* anoutline :: A handle to the new 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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/* <Note> */
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/* The reason why this function takes a `library' parameter is simply */
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/* to use the library's memory allocator. */
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/* */
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FT_EXPORT( FT_Error )
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FT_Outline_New( FT_Library library,
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FT_UInt numPoints,
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FT_Int numContours,
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FT_Outline *anoutline );
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FT_EXPORT( FT_Error )
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FT_Outline_New_Internal( FT_Memory memory,
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FT_UInt numPoints,
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FT_Int numContours,
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FT_Outline *anoutline );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Done */
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/* */
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/* <Description> */
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/* Destroy an outline created with @FT_Outline_New. */
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/* */
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/* <Input> */
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/* library :: A handle of the library object used to allocate the */
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/* outline. */
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/* */
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/* outline :: A pointer to the outline object to be discarded. */
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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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/* <Note> */
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/* If the outline's `owner' field is not set, only the outline */
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/* descriptor will be released. */
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/* */
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/* The reason why this function takes an `library' parameter is */
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/* simply to use ft_mem_free(). */
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/* */
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FT_EXPORT( FT_Error )
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FT_Outline_Done( FT_Library library,
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FT_Outline* outline );
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FT_EXPORT( FT_Error )
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FT_Outline_Done_Internal( FT_Memory memory,
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FT_Outline* outline );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* 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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FT_EXPORT( FT_Error )
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FT_Outline_Check( FT_Outline* outline );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* 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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/* which 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 @FT_Glyph_Get_CBox for a discussion of tricky fonts. */
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/* */
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FT_EXPORT( void )
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FT_Outline_Get_CBox( const FT_Outline* outline,
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FT_BBox *acbox );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Translate */
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/* */
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/* <Description> */
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/* Apply a simple translation to the points of an outline. */
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/* */
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/* <InOut> */
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/* outline :: A pointer to the target outline descriptor. */
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/* */
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/* <Input> */
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/* xOffset :: The horizontal offset. */
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/* */
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/* yOffset :: The vertical offset. */
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/* */
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FT_EXPORT( void )
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FT_Outline_Translate( const FT_Outline* outline,
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FT_Pos xOffset,
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FT_Pos yOffset );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Copy */
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/* */
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/* <Description> */
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/* Copy an outline into another one. Both objects must have the */
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/* same sizes (number of points & number of contours) when this */
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/* function is called. */
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/* */
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/* <Input> */
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/* source :: A handle to the source outline. */
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/* */
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/* <Output> */
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/* target :: A handle to the target 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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FT_EXPORT( FT_Error )
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FT_Outline_Copy( const FT_Outline* source,
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FT_Outline *target );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Transform */
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/* */
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/* <Description> */
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/* Apply a simple 2x2 matrix to all of an outline's points. Useful */
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/* for applying rotations, slanting, flipping, etc. */
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/* */
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/* <InOut> */
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/* outline :: A pointer to the target outline descriptor. */
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/* */
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/* <Input> */
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/* matrix :: A pointer to the transformation matrix. */
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/* */
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/* <Note> */
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/* You can use @FT_Outline_Translate if you need to translate the */
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/* outline's points. */
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/* */
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FT_EXPORT( void )
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FT_Outline_Transform( const FT_Outline* outline,
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const FT_Matrix* matrix );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Embolden */
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/* */
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/* <Description> */
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/* Embolden an outline. The new outline will be at most 4~times */
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/* `strength' pixels wider and higher. You may think of the left and */
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/* bottom borders as unchanged. */
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/* */
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/* Negative `strength' values to reduce the outline thickness are */
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/* possible also. */
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/* */
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/* <InOut> */
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/* outline :: A handle to the target outline. */
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/* */
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/* <Input> */
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/* strength :: How strong the glyph is emboldened. Expressed in */
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/* 26.6 pixel format. */
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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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/* <Note> */
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/* The used algorithm to increase or decrease the thickness of the */
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/* glyph doesn't change the number of points; this means that certain */
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/* situations like acute angles or intersections are sometimes */
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/* handled incorrectly. */
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/* */
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/* If you need `better' metrics values you should call */
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/* @FT_Outline_Get_CBox or @FT_Outline_Get_BBox. */
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/* */
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/* Example call: */
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/* */
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/* { */
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/* FT_Load_Glyph( face, index, FT_LOAD_DEFAULT ); */
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/* if ( face->slot->format == FT_GLYPH_FORMAT_OUTLINE ) */
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/* FT_Outline_Embolden( &face->slot->outline, strength ); */
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/* } */
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/* */
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FT_EXPORT( FT_Error )
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FT_Outline_Embolden( FT_Outline* outline,
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FT_Pos strength );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_EmboldenXY */
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/* */
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/* <Description> */
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/* Embolden an outline. The new outline will be `xstrength' pixels */
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/* wider and `ystrength' pixels higher. Otherwise, it is similar to */
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/* @FT_Outline_Embolden, which uses the same strength in both */
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/* directions. */
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/* */
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FT_EXPORT( FT_Error )
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FT_Outline_EmboldenXY( FT_Outline* outline,
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FT_Pos xstrength,
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FT_Pos ystrength );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Reverse */
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/* */
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/* <Description> */
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/* Reverse the drawing direction of an outline. This is used to */
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/* ensure consistent fill conventions for mirrored glyphs. */
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/* */
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/* <InOut> */
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/* outline :: A pointer to the target outline descriptor. */
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/* */
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/* <Note> */
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/* This function toggles the bit flag @FT_OUTLINE_REVERSE_FILL in */
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/* the outline's `flags' field. */
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/* */
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/* It shouldn't be used by a normal client application, unless it */
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/* knows what it is doing. */
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/* */
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FT_EXPORT( void )
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FT_Outline_Reverse( FT_Outline* outline );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Get_Bitmap */
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/* */
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/* <Description> */
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/* Render an outline within a bitmap. The outline's image is simply */
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/* OR-ed to the target bitmap. */
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/* */
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/* <Input> */
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/* library :: A handle to a FreeType library object. */
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/* */
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/* outline :: A pointer to the source outline descriptor. */
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/* */
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/* <InOut> */
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/* abitmap :: A pointer to the target bitmap descriptor. */
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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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/* <Note> */
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/* This function does NOT CREATE the bitmap, it only renders an */
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/* outline image within the one you pass to it! Consequently, the */
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/* various fields in `abitmap' should be set accordingly. */
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/* */
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/* It will use the raster corresponding to the default glyph format. */
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/* */
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/* The value of the `num_grays' field in `abitmap' is ignored. If */
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/* you select the gray-level rasterizer, and you want less than 256 */
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/* gray levels, you have to use @FT_Outline_Render directly. */
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/* */
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FT_EXPORT( FT_Error )
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FT_Outline_Get_Bitmap( FT_Library library,
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FT_Outline* outline,
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const FT_Bitmap *abitmap );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Outline_Render */
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/* */
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/* <Description> */
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/* Render an outline within a bitmap using the current scan-convert. */
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/* This function uses an @FT_Raster_Params structure as an argument, */
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/* allowing advanced features like direct composition, translucency, */
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/* etc. */
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/* */
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/* <Input> */
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/* library :: A handle to a FreeType library object. */
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/* */
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/* outline :: A pointer to the source outline descriptor. */
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/* */
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/* <InOut> */
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/* params :: A pointer to an @FT_Raster_Params structure used to */
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/* describe the rendering operation. */
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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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/* <Note> */
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/* You should know what you are doing and how @FT_Raster_Params works */
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/* to use this function. */
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/* */
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/* The field `params.source' will be set to `outline' before the scan */
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/* converter is called, which means that the value you give to it is */
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/* actually ignored. */
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/* */
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/* The gray-level rasterizer always uses 256 gray levels. If you */
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/* want less gray levels, you have to provide your own span callback. */
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/* See the @FT_RASTER_FLAG_DIRECT value of the `flags' field in the */
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/* @FT_Raster_Params structure for more details. */
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/* */
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FT_EXPORT( FT_Error )
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FT_Outline_Render( FT_Library library,
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FT_Outline* outline,
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FT_Raster_Params* params );
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/**************************************************************************
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*
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* @enum:
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* FT_Orientation
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*
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* @description:
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* A list of values used to describe an outline's contour orientation.
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*
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* The TrueType and PostScript specifications use different conventions
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* to determine whether outline contours should be filled or unfilled.
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*
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* @values:
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* FT_ORIENTATION_TRUETYPE ::
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* According to the TrueType specification, clockwise contours must
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* be filled, and counter-clockwise ones must be unfilled.
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*
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* FT_ORIENTATION_POSTSCRIPT ::
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* According to the PostScript specification, counter-clockwise contours
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* must be filled, and clockwise ones must be unfilled.
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*
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* FT_ORIENTATION_FILL_RIGHT ::
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* This is identical to @FT_ORIENTATION_TRUETYPE, but is used to
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* remember that in TrueType, everything that is to the right of
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* the drawing direction of a contour must be filled.
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*
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* FT_ORIENTATION_FILL_LEFT ::
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* This is identical to @FT_ORIENTATION_POSTSCRIPT, but is used to
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* remember that in PostScript, everything that is to the left of
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* the drawing direction of a contour must be filled.
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*
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* FT_ORIENTATION_NONE ::
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* The orientation cannot be determined. That is, different parts of
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* the glyph have different orientation.
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*
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*/
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typedef enum FT_Orientation_
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{
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FT_ORIENTATION_TRUETYPE = 0,
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FT_ORIENTATION_POSTSCRIPT = 1,
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FT_ORIENTATION_FILL_RIGHT = FT_ORIENTATION_TRUETYPE,
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FT_ORIENTATION_FILL_LEFT = FT_ORIENTATION_POSTSCRIPT,
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FT_ORIENTATION_NONE
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} FT_Orientation;
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/**************************************************************************
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*
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* @function:
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* FT_Outline_Get_Orientation
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*
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* @description:
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* This function analyzes a glyph outline and tries to compute its
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* fill orientation (see @FT_Orientation). This is done by computing
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* the direction of each global horizontal and/or vertical extrema
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* within the outline.
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*
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* Note that this will return @FT_ORIENTATION_TRUETYPE for empty
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* outlines.
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*
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* @input:
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* outline ::
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* A handle to the source outline.
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*
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* @return:
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* The orientation.
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*
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*/
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FT_EXPORT( FT_Orientation )
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FT_Outline_Get_Orientation( FT_Outline* outline );
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/* */
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FT_END_HEADER
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#endif /* __FTOUTLN_H__ */
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/* END */
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/* Local Variables: */
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/* coding: utf-8 */
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/* End: */
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