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freetype2/include/freetype/ftcache.h

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/***************************************************************************/
/* */
/* ftcache.h */
/* */
/* FreeType Cache subsystem */
/* */
/* Copyright 1996-2000 by */
/* David Turner, Robert Wilhelm, and Werner Lemberg. */
/* */
/* This file is part of the FreeType project, and may only be used, */
/* modified, and distributed under the terms of the FreeType project */
/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
/* this file you indicate that you have read the license and */
/* understand and accept it fully. */
/* */
/***************************************************************************/
#ifndef FTCACHE_H
#define FTCACHE_H
#include <freetype/ftglyph.h>
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/***** *****/
/***** BASIC TYPE DEFINITIONS *****/
/***** *****/
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/**************************************************************************
*
* <Type>
* FTC_FaceID
*
* <Description>
* a generic pointer type that is used to identity face objects.
* the content of such objects is application-dependent
*
**************************************************************************/
typedef FT_Pointer FTC_FaceID;
/**************************************************************************
*
* <FuncType>
* FTC_Face_Requester
*
* <Description>
* a callback function provided by client applications. It is used
* to translate a given FTC_FaceID into a new valid FT_Face object
*
* <Input>
* face_id :: the face id to resolve
* library :: handle to a FreeType library object
* data :: application-provided request data
*
* <Output>
* aface :: a new FT_Face handle
*
* <Return>
* Error code. 0 means success
*
**************************************************************************/
typedef FT_Error (*FTC_Face_Requester)( FTC_FaceID face_id,
FT_Library library,
FT_Pointer request_data,
FT_Face* aface );
/**************************************************************************
*
* <Struct>
* FTC_SizeRec
*
* <Description>
* A simple structure used to describe a given "font size" to the
* cache manager
*
* <Fields>
* face_id :: id of face to use
* pix_width :: character width in integer pixels
* pix_height :: character height in integer pixels
*
**************************************************************************/
typedef struct FTC_SizeRec_
{
FTC_FaceID face_id;
FT_UShort pix_width;
FT_UShort pix_height;
} FTC_SizeRec;
/**************************************************************************
*
* <Type>
* FTC_SizeID
*
* <Description>
* A simple handle to a FTC_SizeRec structure
*
**************************************************************************/
typedef FTC_SizeRec* FTC_SizeID;
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/***** *****/
/***** CACHE MANAGER OBJECT *****/
/***** *****/
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/**************************************************************************
*
* <Type>
* FTC_Manager
*
* <Description>
* This object is used to cache one or more FT_Face object, along with
* corresponding FT_Size objects.
*
**************************************************************************/
typedef struct FTC_ManagerRec_* FTC_Manager;
/**************************************************************************
*
* <Function>
* FTC_Manager_New
*
* <Description>
* Create a new cache manager.
*
* <Input>
* library :: the parent FreeType library handle to use
*
* requester :: an application-provided callback used to translate
* face IDs into real FT_Face objects
*
* req_data :: a generic pointer that is passed to the requester
* each time it is called (see FTC_Face_Requester)
*
* <Output>
* amanager :: handle to new manager object. 0 in case of failure
*
* <Return>
* Error code. 0 means success
*
**************************************************************************/
FT_EXPORT_DEF( FT_Error ) FTC_Manager_New( FT_Library library,
FTC_Face_Requester requester,
FT_Pointer req_data,
FTC_Manager* amanager );
/**************************************************************************
*
* <Function>
* FTC_Manager_Reset
*
* <Description>
* Empty a given cache manager. This simply gets rid of all the
* currently cached FT_Face & FT_Size objects within the manager
*
* <Input>
* manager :: handle to manager
*
**************************************************************************/
FT_EXPORT_DEF( void ) FTC_Manager_Reset( FTC_Manager manager );
/**************************************************************************
*
* <Function>
* FTC_Manager_Done
*
* <Description>
* destroys a given manager after emptying it..
*
* <Input>
* manager :: handle to target cache manager object
*
**************************************************************************/
FT_EXPORT_DEF( void ) FTC_Manager_Done( FTC_Manager manager );
/**************************************************************************
*
* <Function>
* FTC_Manager_Lookup_Face
*
* <Description>
* retrieves the FT_Face that corresponds to a given face ID through
* a cache manager.
*
* <Input>
* manager :: handle to cache manager
* face_id :: ID of face object
*
* <Output>
* aface :: handle to face object
*
* <Return>
* Error code. 0 means success
*
* <Note>
* The returned FT_Face object is always owned by the manager, you
* should never try to discard it yourself..
*
* The FT_Face object doesn't necessarily have a current size object
* (i.e. face->size can be 0). If you need a specific "font size",
* use FTC_Manager_Lookup_Size instead..
*
* Never change the face's transform (i.e. NEVER CALL FT_Set_Transform)
* on a returned face. If you need to transform glyphs, do it yourself
* after glyph loading..
*
**************************************************************************/
FT_EXPORT_DEF( FT_Error ) FTC_Manager_Lookup_Face( FTC_Manager manager,
FTC_FaceID face_id,
FT_Face* aface );
/**************************************************************************
*
* <Function>
* FTC_Manager_Lookup_Size
*
* <Description>
* retrieves the FT_Face & FT_Size that correspond to a given
* FTC_SizeID
*
* <Input>
* manager :: handle to cache manager.
* size_id :: ID of the "font size" to use
*
* <InOut>
* aface :: ptr to handle to face object. Set to 0 if you don't need it
* asize :: ptr to handle to size object. Set to 0 if you don't need it
*
* <Return>
* Error code. 0 means success
*
* <Note>
* The returned FT_Face object is always owned by the manager, you
* should never try to discard it yourself..
*
* Never change the face's transform (i.e. NEVER CALL FT_Set_Transform)
* on a returned face. If you need to transform glyphs, do it yourself
* after glyph loading..
*
* The returned FT_Size object is always owned by the manager, you
* should never try to discard it, NEVER CHANGE ITS SETTINGS THROUGH
* FT_Set_Pixel_Sizes OR FT_Set_Char_Size !!
*
* The returned size object is the face's current size, which means
* that you can call FT_Load_Glyph with the face if you need to..
*
**************************************************************************/
FT_EXPORT_DEF( FT_Error ) FTC_Manager_Lookup_Size( FTC_Manager manager,
FTC_SizeID size_id,
FT_Face* aface,
FT_Size* asize );
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/***** *****/
/***** IMAGE CACHE OBJECT *****/
/***** *****/
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/**************************************************************************
*
* <Enum>
* FTC_Image_Type
*
* <Description>
* An enumeration used to list the types of glyph images found in a
* glyph image cache.
*
* <Fields>
* ftc_image_mono :: monochrome bitmap glyphs
* ftc_image_grays :: anti-aliased bitmap glyphs
* ftc_image_outline :: scaled (and hinted) outline glyphs
* ftc_master_outline :: unscaled original outline glyphs
*
* <Note>
* other types may be defined in the future
*
**************************************************************************/
typedef enum FTC_Image_Type_
{
ftc_image_mono = 0, /* monochrome bitmap */
ftc_image_grays, /* anti-aliased bitmap */
ftc_image_outline, /* scaled outline */
ftc_image_master_outline /* original outline */
} FTC_Image_Type;
/**************************************************************************
*
* <Struct>
* FTC_Image_Desc
*
* <Description>
* A simple structure used to describe a given glyph image category
*
* <Fields>
* size :: a FTC_SizeRec used to describe the glyph's face & size
* image_type :: the glyph image's type
*
**************************************************************************/
typedef struct FTC_Image_Desc_
{
FTC_SizeRec size;
FT_UInt image_type;
} FTC_Image_Desc;
/**************************************************************************
*
* <Type>
* FTC_Image_Cache
*
* <Description>
* A handle to an glyph image cache object.. They are designed to
* hold many distinct glyph images, while not exceeding a certain
* memory threshold..
*
**************************************************************************/
typedef struct FTC_Image_CacheRec_* FTC_Image_Cache;
/**************************************************************************
*
* <Function>
* FTC_Image_Cache_New
*
* <Description>
* Create a new glyph image cache.
*
* <Input>
* manager :: parent manager for the image cache
*
* max_bytes :: the maximum amount of memory that will be used to
* store glyph images
*
* <Output>
* acache :: handle to new glyph image cache object
*
* <Return>
* Error code. 0 means success
*
**************************************************************************/
FT_EXPORT_DEF( FT_Error ) FTC_Image_Cache_New( FTC_Manager manager,
FT_ULong max_bytes,
FTC_Image_Cache* acache );
/**************************************************************************
*
* <Function>
* FTC_Image_Cache_Done
*
* <Description>
* Destroys a given glyph image cache (and all glyphs within it).
*
* <Input>
* manager :: parent manager for the image cache
*
**************************************************************************/
FT_EXPORT_DEF( void ) FTC_Image_Cache_Done( FTC_Image_Cache cache );
/**************************************************************************
*
* <Function>
* FTC_Image_Cache_Lookup
*
* <Description>
* Retrieve a given glyph image from a glyph image cache.
*
* <Input>
* cache :: handle to source glyph image cache
* desc :: pointer to a glyph image descriptor
* gindex :: index of glyph to retrieve
*
* <Output>
* aglyph :: the corresponding FT_Glyph object. 0 in case of failure
*
* <Return>
* Error code. 0 means success
*
* <Note>
* the returned glyph is owned and manager by the glyph image cache,
* never try to transform or discard it manually. You can however
* create a copy with FT_Glyph_Copy and modify the new one at will.
*
* Because the glyph image cache limits the total amount of memory
* taken by the glyphs it holds, the returned glyph might disappear
* on a later invocation of this function !! It's a cache after all ;-)
*
**************************************************************************/
FT_EXPORT_DEF( FT_Error ) FTC_Image_Cache_Lookup(
FTC_Image_Cache cache,
FTC_Image_Desc* desc,
FT_UInt gindex,
FT_Glyph* aglyph );
#endif /* FTCACHE_H */
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