forked from minhngoc25a/freetype2
407 lines
15 KiB
C
407 lines
15 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.. */
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/* */
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/* Copyright 1996-2000 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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/* 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're 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 <freetype/freetype.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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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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* <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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* <Field>
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* library :: a handle to the FreeType library object.
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* clazz :: a pointer to the glyph's class. Private.
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* format :: the format of the glyph's image
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* advance :: a 16.16 vector that gives the glyph's advance width
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*
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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, *FT_Glyph;
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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
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* a "sub-class" of "FT_GlyphRec".
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*
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* <Field>
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* root :: the root FT_Glyph fields
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* left :: left-side bearing, i.e. the horizontal distance from
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* the current pen position to the left border of the glyph
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* bitmap.
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* top :: top-side bearing, i.e. the vertical distance from the
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* current pen position to the top border of the glyph bitmap
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* this distance is positive for upwards-y !!
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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 a FT_Glyph to FT_BitmapGlyph when you have
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* glyph->format == ft_glyph_format_bitmap. This lets you access
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* the bitmap's content 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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***********************************************************************/
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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, *FT_BitmapGlyph;
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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..
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* This really is a "sub-class" of FT_GlyphRec.
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*
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* <Field>
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* root :: the root FT_Glyph fields.
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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 a FT_Glyph to FT_OutlineGlyph when 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
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* are expressed normally in 26.6 pixels, unless the flag
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* FT_LOAD_NO_SCALE was used in FT_Load_Glyph / 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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***********************************************************************/
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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, *FT_OutlineGlyph;
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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 one glyph image from a slot..
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*
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* <Input>
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* slot :: handle to source glyph slot.
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*
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* <Output>
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* aglyph :: handle to the glyph object.
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*
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* <Return>
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* Error code. 0 means success.
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*
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* <Note>
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*
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*
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***********************************************************************/
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FT_EXPORT_DEF(FT_Error) 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 one glyph image.
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*
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* <Input>
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* source :: handle to source glyph object
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*
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* <Output>
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* target :: handle to target glyph object. 0 in case of error
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*
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* <Return>
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* Error code. 0 means success.
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*
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***********************************************************************/
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FT_EXPORT_DEF(FT_Error) 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, when it's format is scalable
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*
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* <Input>
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* glyph :: handle to target glyph object
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*
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* matrix :: pointer to 2x2 matrix to apply
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*
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* delta :: 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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* error code (is not 0, the glyph format is not scalable).
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*
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* <Note>
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* the 2x2 transform matrix is also applied to the glyph's
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* advance vector
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*
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***********************************************************************/
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FT_EXPORT_DEF(FT_Error) 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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* <Function>
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* FT_Glyph_Get_CBox
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*
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* <Description>
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* Returns the glyph image's bounding box.
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*
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* <Input>
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* glyph :: handle to source glyph object
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* mode :: a set of bit flags that indicate how to interpret
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* the meaning of the box's coordinates
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*
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* <Output>
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* box :: the glyph bounding box. Coordinates are expressed in
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* 1/64th of pixels, 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 'ft_glyph_bbox_subpixels' is set in "mode", the bbox coordinates
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* are returned in 26.6 pixels (i.e. 1/64th of pixels).
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*
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* otherwise, coordinates are in integer pixels.
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*
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* note that the maximum coordinates are exclusive, which means that
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* once can compute the width and height of the glyph image (be it
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* in 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 the 'ft_glyph_bbox_gridfit'
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* flag is set in "mode", 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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***********************************************************************/
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enum
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{
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ft_glyph_bbox_pixels = 0,
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ft_glyph_bbox_subpixels = 1,
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ft_glyph_bbox_gridfit = 2
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};
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FT_EXPORT_DEF(void) FT_Glyph_Get_CBox( FT_Glyph glyph,
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FT_UInt bbox_mode,
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FT_BBox *cbox );
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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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* glyph :: pointer to a handle to the target glyph
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*
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* <Input>
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* render_mode :: a set of bit flags that describe how
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*
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* origin :: pointer to a vector used to translate the glyph image
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* before rendering. Can be 0 (for no translation). The
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* origin is expressed in 26.6 pixels..
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*
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* destroy :: a boolean that indicates that the original glyph image
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* should be destroyed by this function. The glyph is
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* never destroyed in case of error..
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*
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* <Return>
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* 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 original
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* position and the glyph is untouched..
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*
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* The first parameter is a pointer to a FT_Glyph handle, that
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* will be replaced by this function. Typically, you would use:
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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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* // 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, 0, 1 );
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* if (error) // glyph unchanged..
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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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* This function will always fail if the glyph's format isn't scalable
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*
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***********************************************************************/
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FT_EXPORT_DEF(FT_Error) FT_Glyph_To_Bitmap( FT_Glyph *the_glyph,
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FT_ULong 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 :: handle to target glyph object
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*
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***********************************************************************/
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FT_EXPORT_DEF(void) 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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/* <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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/* <MT-Note> */
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/* Yes. */
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/* */
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FT_EXPORT_DEF(void) 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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/* <MT-Note> */
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/* Yes. */
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/* */
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FT_EXPORT_DEF(FT_Error) FT_Matrix_Invert( FT_Matrix* matrix );
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#ifdef __cplusplus
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}
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#endif
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#endif /* FTGLYPH_H */
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