606 lines
38 KiB
C
606 lines
38 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 1996-2017 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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#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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/* 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-point 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 an @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 @FT_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 an @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. Note that */
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/* the created @FT_Glyph object must be released with @FT_Done_Glyph. */
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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. Note that the created */
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/* @FT_Glyph object must be released with @FT_Done_Glyph. */
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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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/* Transform 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 (if not 0, the glyph format is not scalable). */
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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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/* <Enum> */
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/* FT_Glyph_BBox_Mode */
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/* */
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/* <Description> */
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/* The mode how the values of @FT_Glyph_Get_CBox are returned. */
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/* */
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/* <Values> */
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/* FT_GLYPH_BBOX_UNSCALED :: */
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/* Return unscaled font units. */
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/* */
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/* FT_GLYPH_BBOX_SUBPIXELS :: */
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/* Return unfitted 26.6 coordinates. */
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/* */
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/* FT_GLYPH_BBOX_GRIDFIT :: */
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/* Return grid-fitted 26.6 coordinates. */
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/* */
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/* FT_GLYPH_BBOX_TRUNCATE :: */
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/* Return coordinates in integer pixels. */
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/* */
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/* FT_GLYPH_BBOX_PIXELS :: */
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/* Return grid-fitted pixel coordinates. */
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/* */
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typedef enum FT_Glyph_BBox_Mode_
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{
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FT_GLYPH_BBOX_UNSCALED = 0,
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FT_GLYPH_BBOX_SUBPIXELS = 0,
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FT_GLYPH_BBOX_GRIDFIT = 1,
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FT_GLYPH_BBOX_TRUNCATE = 2,
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FT_GLYPH_BBOX_PIXELS = 3
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} FT_Glyph_BBox_Mode;
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/* these constants are deprecated; use the corresponding */
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/* `FT_Glyph_BBox_Mode' values instead */
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#define ft_glyph_bbox_unscaled FT_GLYPH_BBOX_UNSCALED
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#define ft_glyph_bbox_subpixels FT_GLYPH_BBOX_SUBPIXELS
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#define ft_glyph_bbox_gridfit FT_GLYPH_BBOX_GRIDFIT
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#define ft_glyph_bbox_truncate FT_GLYPH_BBOX_TRUNCATE
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#define ft_glyph_bbox_pixels FT_GLYPH_BBOX_PIXELS
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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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/* Return a glyph's `control box'. The control box encloses all the */
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/* 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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/* glyph :: A handle to the source glyph object. */
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/* */
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/* mode :: The mode that 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 in 26.6 pixel format. The value @FT_GLYPH_BBOX_SUBPIXELS */
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/* is another name for this constant. */
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/* */
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/* If the font is tricky and the glyph has been loaded with */
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/* @FT_LOAD_NO_SCALE, the resulting CBox is meaningless. To get */
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/* reasonable values for the CBox it is necessary to load the glyph */
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/* at a large ppem value (so that the hinting instructions can */
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/* properly shift and scale the subglyphs), then extracting the CBox, */
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/* which can be eventually converted back to font units. */
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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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/* { */
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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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/* */
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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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/* { */
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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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/* */
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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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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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/* Convert 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 describes 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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/* This function does nothing if the glyph format isn't scalable. */
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/* */
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/* The glyph image is translated with the `origin' vector before */
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/* rendering. */
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/* */
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/* The first parameter is a pointer to an @FT_Glyph handle, that will */
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/* be _replaced_ by this function (with newly allocated data). */
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/* Typically, you would use (omitting 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_DEFAULT ); */
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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 + destroying 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_NORMAL, */
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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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/* Here another example, again without error handling: */
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/* */
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/* */
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/* { */
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/* FT_Glyph glyphs[MAX_GLYPHS] */
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/* */
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/* */
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/* ... */
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/* */
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/* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
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/* error = FT_Load_Glyph( face, idx, FT_LOAD_DEFAULT ) || */
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/* FT_Get_Glyph ( face->glyph, &glyph[idx] ); */
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/* */
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/* ... */
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/* */
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/* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
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/* { */
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/* FT_Glyph bitmap = glyphs[idx]; */
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/* */
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/* */
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/* ... */
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/* */
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/* // after this call, `bitmap' no longer points into */
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/* // the `glyphs' array (and the old value isn't destroyed) */
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/* FT_Glyph_To_Bitmap( &bitmap, FT_RENDER_MODE_MONO, 0, 0 ); */
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/* */
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/* ... */
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/* */
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/* FT_Done_Glyph( bitmap ); */
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/* } */
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/* */
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/* ... */
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/* */
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/* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
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/* FT_Done_Glyph( glyphs[idx] ); */
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/* } */
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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 );
|
|
|
|
|
|
/*************************************************************************/
|
|
/* */
|
|
/* <Function> */
|
|
/* FT_Done_Glyph */
|
|
/* */
|
|
/* <Description> */
|
|
/* Destroy a given glyph. */
|
|
/* */
|
|
/* <Input> */
|
|
/* glyph :: A handle to the target glyph object. */
|
|
/* */
|
|
FT_EXPORT( void )
|
|
FT_Done_Glyph( FT_Glyph glyph );
|
|
|
|
/* */
|
|
|
|
|
|
/* other helpful functions */
|
|
|
|
/*************************************************************************/
|
|
/* */
|
|
/* <Section> */
|
|
/* computations */
|
|
/* */
|
|
/*************************************************************************/
|
|
|
|
|
|
/*************************************************************************/
|
|
/* */
|
|
/* <Function> */
|
|
/* FT_Matrix_Multiply */
|
|
/* */
|
|
/* <Description> */
|
|
/* Perform the matrix operation `b = a*b'. */
|
|
/* */
|
|
/* <Input> */
|
|
/* a :: A pointer to matrix `a'. */
|
|
/* */
|
|
/* <InOut> */
|
|
/* b :: A pointer to matrix `b'. */
|
|
/* */
|
|
/* <Note> */
|
|
/* The result is undefined if either `a' or `b' is zero. */
|
|
/* */
|
|
FT_EXPORT( void )
|
|
FT_Matrix_Multiply( const FT_Matrix* a,
|
|
FT_Matrix* b );
|
|
|
|
|
|
/*************************************************************************/
|
|
/* */
|
|
/* <Function> */
|
|
/* FT_Matrix_Invert */
|
|
/* */
|
|
/* <Description> */
|
|
/* Invert a 2x2 matrix. Return an error if it can't be inverted. */
|
|
/* */
|
|
/* <InOut> */
|
|
/* matrix :: A pointer to the target matrix. Remains untouched in */
|
|
/* case of error. */
|
|
/* */
|
|
/* <Return> */
|
|
/* FreeType error code. 0~means success. */
|
|
/* */
|
|
FT_EXPORT( FT_Error )
|
|
FT_Matrix_Invert( FT_Matrix* matrix );
|
|
|
|
/* */
|
|
|
|
|
|
FT_END_HEADER
|
|
|
|
#endif /* FTGLYPH_H_ */
|
|
|
|
|
|
/* END */
|
|
|
|
|
|
/* Local Variables: */
|
|
/* coding: utf-8 */
|
|
/* End: */
|