518 lines
32 KiB
C
518 lines
32 KiB
C
/***************************************************************************/
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/* */
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/* ftglyph.h */
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/* */
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/* FreeType convenience functions to handle glyphs (specification). */
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/* */
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/* Copyright 1996-2001 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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/*************************************************************************/
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/* */
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/* This file contains the definition of several convenience functions */
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/* that can be used by client applications to easily retrieve glyph */
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/* bitmaps and outlines from a given face. */
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/* */
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/* These functions should be optional if you are writing a font server */
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/* or text layout engine on top of FreeType. However, they are pretty */
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/* handy for many other simple uses of the library. */
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/* */
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/*************************************************************************/
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#ifndef __FTGLYPH_H__
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#define __FTGLYPH_H__
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#include <ft2build.h>
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#include FT_FREETYPE_H
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FT_BEGIN_HEADER
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/*************************************************************************/
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/* */
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/* <Section> */
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/* glyph_management */
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/* */
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/* <Title> */
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/* Glyph Management */
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/* */
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/* <Abstract> */
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/* Generic interface to manage individual glyph data. */
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/* */
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/* <Description> */
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/* This section contains definitions used to manage glyph data */
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/* through generic FT_Glyph objects. Each of them can contain a */
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/* bitmap, a vector outline, or even images in other formats. */
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/* */
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/*************************************************************************/
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/* forward declaration to a private type */
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typedef struct FT_Glyph_Class_ FT_Glyph_Class;
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/*************************************************************************/
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/* */
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/* <Type> */
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/* FT_Glyph */
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/* */
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/* <Description> */
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/* Handle to an object used to model generic glyph images. It is a */
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/* pointer to the @FT_GlyphRec structure and can contain a glyph */
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/* bitmap or pointer. */
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/* */
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/* <Note> */
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/* Glyph objects are not owned by the library. You must thus release */
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/* them manually (through @FT_Done_Glyph) _before_ calling */
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/* @FT_Done_FreeType. */
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/* */
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typedef struct FT_GlyphRec_* FT_Glyph;
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* FT_GlyphRec */
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/* */
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/* <Description> */
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/* The root glyph structure contains a given glyph image plus its */
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/* advance width in 16.16 fixed float format. */
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/* */
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/* <Fields> */
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/* library :: A handle to the FreeType library object. */
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/* */
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/* clazz :: A pointer to the glyph's class. Private. */
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/* */
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/* format :: The format of the glyph's image. */
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/* */
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/* advance :: A 16.16 vector that gives the glyph's advance width. */
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/* */
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typedef struct FT_GlyphRec_
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{
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FT_Library library;
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const FT_Glyph_Class* clazz;
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FT_Glyph_Format format;
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FT_Vector advance;
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} FT_GlyphRec;
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/*************************************************************************/
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/* */
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/* <Type> */
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/* FT_BitmapGlyph */
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/* */
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/* <Description> */
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/* A handle to an object used to model a bitmap glyph image. This is */
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/* a sub-class of @FT_Glyph, and a pointer to @FT_BitmapGlyphRec. */
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/* */
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typedef struct FT_BitmapGlyphRec_* FT_BitmapGlyph;
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* FT_BitmapGlyphRec */
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/* */
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/* <Description> */
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/* A structure used for bitmap glyph images. This really is a */
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/* `sub-class' of `FT_GlyphRec'. */
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/* */
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/* <Fields> */
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/* root :: The root FT_Glyph fields. */
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/* */
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/* left :: The left-side bearing, i.e., the horizontal distance */
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/* from the current pen position to the left border of the */
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/* glyph bitmap. */
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/* */
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/* top :: The top-side bearing, i.e., the vertical distance from */
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/* the current pen position to the top border of the glyph */
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/* bitmap. This distance is positive for upwards-y! */
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/* */
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/* bitmap :: A descriptor for the bitmap. */
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/* */
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/* <Note> */
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/* You can typecast FT_Glyph to FT_BitmapGlyph if you have */
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/* glyph->format == FT_GLYPH_FORMAT_BITMAP. This lets you access */
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/* the bitmap's contents easily. */
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/* */
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/* The corresponding pixel buffer is always owned by the BitmapGlyph */
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/* and is thus created and destroyed with it. */
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/* */
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typedef struct FT_BitmapGlyphRec_
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{
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FT_GlyphRec root;
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FT_Int left;
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FT_Int top;
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FT_Bitmap bitmap;
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} FT_BitmapGlyphRec;
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/*************************************************************************/
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/* */
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/* <Type> */
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/* FT_OutlineGlyph */
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/* */
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/* <Description> */
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/* A handle to an object used to model an outline glyph image. This */
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/* is a sub-class of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec. */
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/* */
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typedef struct FT_OutlineGlyphRec_* FT_OutlineGlyph;
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* FT_OutlineGlyphRec */
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/* */
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/* <Description> */
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/* A structure used for outline (vectorial) glyph images. This */
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/* really is a `sub-class' of `FT_GlyphRec'. */
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/* */
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/* <Fields> */
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/* root :: The root FT_Glyph fields. */
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/* */
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/* outline :: A descriptor for the outline. */
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/* */
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/* <Note> */
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/* You can typecast FT_Glyph to FT_OutlineGlyph if you have */
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/* glyph->format == FT_GLYPH_FORMAT_OUTLINE. This lets you access */
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/* the outline's content easily. */
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/* */
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/* As the outline is extracted from a glyph slot, its coordinates are */
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/* expressed normally in 26.6 pixels, unless the flag */
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/* FT_LOAD_NO_SCALE was used in FT_Load_Glyph() or FT_Load_Char(). */
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/* */
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/* The outline's tables are always owned by the object and are */
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/* destroyed with it. */
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/* */
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typedef struct FT_OutlineGlyphRec_
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{
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FT_GlyphRec root;
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FT_Outline outline;
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} FT_OutlineGlyphRec;
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Get_Glyph */
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/* */
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/* <Description> */
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/* A function used to extract a glyph image from a slot. */
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/* */
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/* <Input> */
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/* slot :: A handle to the source glyph slot. */
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/* */
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/* <Output> */
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/* aglyph :: A handle to the glyph object. */
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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_Get_Glyph( FT_GlyphSlot slot,
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FT_Glyph *aglyph );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Glyph_Copy */
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/* */
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/* <Description> */
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/* A function used to copy a glyph image. */
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/* */
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/* <Input> */
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/* source :: A handle to the source glyph object. */
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/* */
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/* <Output> */
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/* target :: A handle to the target glyph object. 0 in case of */
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/* error. */
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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_Glyph_Copy( FT_Glyph source,
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FT_Glyph *target );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Glyph_Transform */
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/* */
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/* <Description> */
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/* Transforms a glyph image if its format is scalable. */
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/* */
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/* <InOut> */
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/* glyph :: A handle to the target glyph object. */
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/* */
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/* <Input> */
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/* matrix :: A pointer to a 2x2 matrix to apply. */
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/* */
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/* delta :: A pointer to a 2d vector to apply. Coordinates are */
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/* expressed in 1/64th of a pixel. */
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/* */
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/* <Return> */
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/* FreeType error code (the glyph format is not scalable if it is */
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/* not zero). */
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/* */
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/* <Note> */
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/* The 2x2 transformation matrix is also applied to the glyph's */
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/* advance vector. */
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/* */
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FT_EXPORT( FT_Error )
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FT_Glyph_Transform( FT_Glyph glyph,
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FT_Matrix* matrix,
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FT_Vector* delta );
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/* */
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Glyph_Get_CBox */
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/* */
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/* <Description> */
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/* Returns a glyph's `control box'. The control box encloses all the */
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/* outline's points, including Bezier 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 Bezier 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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/* glyph :: A handle to the source glyph object. */
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/* */
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/* mode :: The mode which indicates how to interpret the returned */
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/* bounding box values. */
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/* */
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/* <Output> */
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/* acbox :: The glyph coordinate bounding box. Coordinates are */
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/* expressed in 1/64th of pixels if it is grid-fitted. */
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/* */
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/* <Note> */
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/* Coordinates are relative to the glyph origin, using the Y-upwards */
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/* convention. */
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/* */
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/* If the glyph has been loaded with FT_LOAD_NO_SCALE, `bbox_mode' */
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/* must be set to `ft_glyph_bbox_unscaled' to get unscaled font */
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/* units. */
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/* */
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/* If `bbox_mode' is set to `ft_glyph_bbox_subpixels' the bbox */
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/* coordinates are returned in 26.6 pixels (i.e. 1/64th of pixels). */
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/* */
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/* Note that the maximum coordinates are exclusive, which means that */
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/* one can compute the width and height of the glyph image (be it in */
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/* integer or 26.6 pixels) as: */
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/* */
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/* width = bbox.xMax - bbox.xMin; */
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/* height = bbox.yMax - bbox.yMin; */
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/* */
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/* Note also that for 26.6 coordinates, if `bbox_mode' is set to */
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/* `ft_glyph_bbox_gridfit', the coordinates will also be grid-fitted, */
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/* which corresponds to: */
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/* */
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/* bbox.xMin = FLOOR(bbox.xMin); */
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/* bbox.yMin = FLOOR(bbox.yMin); */
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/* bbox.xMax = CEILING(bbox.xMax); */
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/* bbox.yMax = CEILING(bbox.yMax); */
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/* */
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/* To get the bbox in pixel coordinates, set `bbox_mode' to */
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/* `ft_glyph_bbox_truncate'. */
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/* */
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/* To get the bbox in grid-fitted pixel coordinates, set `bbox_mode' */
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/* to `ft_glyph_bbox_pixels'. */
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/* */
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/* The default value for `bbox_mode' is `ft_glyph_bbox_pixels'. */
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/* */
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enum
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{
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ft_glyph_bbox_unscaled = 0, /* return unscaled font units */
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ft_glyph_bbox_subpixels = 0, /* return unfitted 26.6 coordinates */
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ft_glyph_bbox_gridfit = 1, /* return grid-fitted 26.6 coordinates */
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ft_glyph_bbox_truncate = 2, /* return coordinates in integer pixels */
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ft_glyph_bbox_pixels = 3 /* return grid-fitted pixel coordinates */
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};
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FT_EXPORT( void )
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FT_Glyph_Get_CBox( FT_Glyph glyph,
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FT_UInt bbox_mode,
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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_Glyph_To_Bitmap */
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/* */
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/* <Description> */
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/* Converts a given glyph object to a bitmap glyph object. */
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/* */
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/* <InOut> */
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/* the_glyph :: A pointer to a handle to the target glyph. */
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/* */
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/* <Input> */
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/* render_mode :: An enumeration that describe how the data is */
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/* rendered. */
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/* */
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/* origin :: A pointer to a vector used to translate the glyph */
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/* image before rendering. Can be 0 (if no */
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/* translation). The origin is expressed in */
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/* 26.6 pixels. */
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/* */
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/* destroy :: A boolean that indicates that the original glyph */
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/* image should be destroyed by this function. It is */
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/* never destroyed in case of error. */
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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 glyph image is translated with the `origin' vector before */
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/* rendering. In case of error, it it translated back to its */
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/* original position and the glyph is left untouched. */
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/* */
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/* The first parameter is a pointer to a FT_Glyph handle, that will */
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/* be replaced by this function. Typically, you would use (omitting */
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/* error handling): */
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/* */
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/* */
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/* { */
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/* FT_Glyph glyph; */
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/* FT_BitmapGlyph glyph_bitmap; */
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/* */
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/* */
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/* // load glyph */
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/* error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAUT ); */
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/* */
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/* // extract glyph image */
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/* error = FT_Get_Glyph( face->glyph, &glyph ); */
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/* */
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/* // convert to a bitmap (default render mode + destroy old) */
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/* if ( glyph->format != FT_GLYPH_FORMAT_BITMAP ) */
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/* { */
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/* error = FT_Glyph_To_Bitmap( &glyph, ft_render_mode_default, */
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/* 0, 1 ); */
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/* if ( error ) // glyph unchanged */
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/* ... */
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/* } */
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/* */
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/* // access bitmap content by typecasting */
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/* glyph_bitmap = (FT_BitmapGlyph)glyph; */
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/* */
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/* // do funny stuff with it, like blitting/drawing */
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/* ... */
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/* */
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/* // discard glyph image (bitmap or not) */
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/* FT_Done_Glyph( glyph ); */
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/* } */
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/* */
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/* */
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/* This function will always fail if the glyph's format isn't */
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/* scalable. */
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/* */
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FT_EXPORT( FT_Error )
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FT_Glyph_To_Bitmap( FT_Glyph* the_glyph,
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FT_Render_Mode render_mode,
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FT_Vector* origin,
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FT_Bool destroy );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Done_Glyph */
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/* */
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/* <Description> */
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/* Destroys a given glyph. */
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/* */
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/* <Input> */
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/* glyph :: A handle to the target glyph object. */
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/* */
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FT_EXPORT( void )
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FT_Done_Glyph( FT_Glyph glyph );
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/* other helpful functions */
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/*************************************************************************/
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/* */
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/* <Section> */
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/* computations */
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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_Matrix_Multiply */
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/* */
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/* <Description> */
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/* Performs the matrix operation `b = a*b'. */
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/* */
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/* <Input> */
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/* a :: A pointer to matrix `a'. */
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/* */
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/* <InOut> */
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/* b :: A pointer to matrix `b'. */
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/* */
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/* <Note> */
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/* The result is undefined if either `a' or `b' is zero. */
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/* */
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FT_EXPORT( void )
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FT_Matrix_Multiply( FT_Matrix* a,
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FT_Matrix* b );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_Matrix_Invert */
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/* */
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/* <Description> */
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/* Inverts a 2x2 matrix. Returns an error if it can't be inverted. */
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/* */
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/* <InOut> */
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/* matrix :: A pointer to the target matrix. Remains untouched in */
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/* case of error. */
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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_Matrix_Invert( FT_Matrix* matrix );
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/* */
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FT_END_HEADER
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#endif /* __FTGLYPH_H__ */
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/* END */
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