ref: 8b560632d7434a18dcc2639e3173fa653a4c0e6b
dir: /include/freetype/ftcache.h/
/***************************************************************************/
/* */
/* ftcache.h */
/* */
/* FreeType Cache subsystem (specification). */
/* */
/* Copyright 1996-2001, 2002, 2003, 2004, 2005 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. */
/* */
/***************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/********* *********/
/********* WARNING, THIS IS BETA CODE. *********/
/********* *********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
#ifndef __FTCACHE_H__
#define __FTCACHE_H__
#include <ft2build.h>
#include FT_GLYPH_H
FT_BEGIN_HEADER
/*************************************************************************/
/* */
/* <Section> */
/* cache_subsystem */
/* */
/* <Title> */
/* Cache Sub-System */
/* */
/* <Abstract> */
/* How to cache face, size, and glyph data with FreeType 2. */
/* */
/* <Description> */
/* This section describes the FreeType 2 cache sub-system which is */
/* still in beta. */
/* */
/* <Order> */
/* FTC_Manager */
/* FTC_FaceID */
/* FTC_Face_Requester */
/* */
/* FTC_Manager_New */
/* FTC_Manager_Reset */
/* FTC_Manager_Done */
/* FTC_Manager_LookupFace */
/* FTC_Manager_LookupSize */
/* FTC_Manager_RemoveFaceID */
/* */
/* FTC_Node */
/* FTC_Node_Unref */
/* */
/* FTC_Font */
/* FTC_ImageCache */
/* FTC_ImageCache_New */
/* FTC_ImageCache_Lookup */
/* */
/* FTC_SBit */
/* FTC_SBitCache */
/* FTC_SBitCache_New */
/* FTC_SBitCache_Lookup */
/* */
/* FTC_CMapCache */
/* FTC_CMapCache_New */
/* FTC_CMapCache_Lookup */
/* */
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** BASIC TYPE DEFINITIONS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* <Type> */
/* FTC_FaceID */
/* */
/* <Description> */
/* An opaque pointer type that is used to identity face objects. The */
/* contents of such objects is application-dependent. */
/* */
typedef struct FTC_FaceIDRec_* 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 :: A handle to a FreeType library object. */
/* */
/* data :: Application-provided request data. */
/* */
/* <Output> */
/* aface :: A new @FT_Face handle. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* The face requester should not perform funny things on the returned */
/* face object, like creating a new @FT_Size for it, or setting a */
/* transformation through @FT_Set_Transform! */
/* */
typedef FT_Error
(*FTC_Face_Requester)( FTC_FaceID face_id,
FT_Library library,
FT_Pointer request_data,
FT_Face* aface );
/*************************************************************************/
/* */
/* <Struct> */
/* FTC_FontRec */
/* */
/* <Description> */
/* A simple structure used to describe a given `font' to the cache */
/* manager. Note that a `font' is the combination of a given face */
/* with a given character size. */
/* */
/* <Fields> */
/* face_id :: The ID of the face to use. */
/* */
/* pix_width :: The character width in integer pixels. */
/* */
/* pix_height :: The character height in integer pixels. */
/* */
typedef struct FTC_FontRec_
{
FTC_FaceID face_id;
FT_UShort pix_width;
FT_UShort pix_height;
} FTC_FontRec;
/* */
#define FTC_FONT_COMPARE( f1, f2 ) \
( (f1)->face_id == (f2)->face_id && \
(f1)->pix_width == (f2)->pix_width && \
(f1)->pix_height == (f2)->pix_height )
#define FT_POINTER_TO_ULONG( p ) ((FT_ULong)(FT_Pointer)(p))
#define FTC_FACE_ID_HASH( i ) \
((FT_UInt32)(( FT_POINTER_TO_ULONG( i ) >> 3 ) ^ \
( FT_POINTER_TO_ULONG( i ) << 7 ) ) )
#define FTC_FONT_HASH( f ) \
(FT_UInt32)( FTC_FACE_ID_HASH((f)->face_id) ^ \
((f)->pix_width << 8) ^ \
((f)->pix_height) )
/*************************************************************************/
/* */
/* <Type> */
/* FTC_Font */
/* */
/* <Description> */
/* A simple handle to an @FTC_FontRec structure. */
/* */
typedef FTC_FontRec* FTC_Font;
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** CACHE MANAGER OBJECT *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/* */
/* <Type> */
/* FTC_Manager */
/* */
/* <Description> */
/* This object is used to cache one or more @FT_Face objects, along */
/* with corresponding @FT_Size objects. */
/* */
typedef struct FTC_ManagerRec_* FTC_Manager;
/*************************************************************************/
/* */
/* <Type> */
/* FTC_Node */
/* */
/* <Description> */
/* An opaque handle to a cache node object. Each cache node is */
/* reference-counted. A node with a count of 0 might be flushed */
/* out of a full cache whenever a lookup request is performed. */
/* */
/* If you lookup nodes, you have the ability to "acquire" them, i.e., */
/* to increment their reference count. This will prevent the node */
/* from being flushed out of the cache until you explicitly "release" */
/* it (see @FTC_Node_Unref). */
/* */
/* See also @FTC_SBitCache_Lookup and @FTC_ImageCache_Lookup. */
/* */
typedef struct FTC_NodeRec_* FTC_Node;
/*************************************************************************/
/* */
/* <Function> */
/* FTC_Manager_New */
/* */
/* <Description> */
/* Creates a new cache manager. */
/* */
/* <Input> */
/* library :: The parent FreeType library handle to use. */
/* */
/* max_bytes :: Maximum number of bytes to use for cached data */
/* nodes. Use 0 for defaults. Note that this value */
/* does not account for managed FT_Face and FT_Size */
/* objects. */
/* */
/* 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 :: A handle to a new manager object. 0 in case of */
/* failure. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* When you perform a lookup, out-of-memory errors are detected */
/* _within_ the lookup and force incremental flushes of the cache */
/* until enough memory is released for the lookup to succeed. */
/* */
/* If a lookup fails with FT_Err_Out_Of_Memory the cache has already */
/* been completely flushed, and still no memory is available for the */
/* operation. */
/* */
FT_EXPORT( FT_Error )
FTC_Manager_New( FT_Library library,
FT_UInt max_faces,
FT_UInt max_sizes,
FT_ULong max_bytes,
FTC_Face_Requester requester,
FT_Pointer req_data,
FTC_Manager *amanager );
/*************************************************************************/
/* */
/* <Function> */
/* FTC_Manager_Reset */
/* */
/* <Description> */
/* Empties a given cache manager. This simply gets rid of all the */
/* currently cached @FT_Face and @FT_Size objects within the manager. */
/* */
/* <InOut> */
/* manager :: A handle to the manager. */
/* */
FT_EXPORT( void )
FTC_Manager_Reset( FTC_Manager manager );
/*************************************************************************/
/* */
/* <Function> */
/* FTC_Manager_Done */
/* */
/* <Description> */
/* Destroys a given manager after emptying it. */
/* */
/* <Input> */
/* manager :: A handle to the target cache manager object. */
/* */
FT_EXPORT( void )
FTC_Manager_Done( FTC_Manager manager );
/*************************************************************************/
/* */
/* <Function> */
/* FTC_Manager_LookupFace */
/* */
/* <Description> */
/* Retrieves the @FT_Face object that corresponds to a given face ID */
/* through a cache manager. */
/* */
/* <Input> */
/* manager :: A handle to the cache manager. */
/* */
/* face_id :: The ID of the face object. */
/* */
/* <Output> */
/* aface :: A handle to the face object. */
/* */
/* <Return> */
/* FreeType 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_LookupSize instead. */
/* */
/* Never change the face's transformation matrix (i.e., never call */
/* the @FT_Set_Transform function) on a returned face! If you need */
/* to transform glyphs, do it yourself after glyph loading. */
/* */
FT_EXPORT( FT_Error )
FTC_Manager_LookupFace( FTC_Manager manager,
FTC_FaceID face_id,
FT_Face *aface );
/*************************************************************************/
/* */
/* <Struct> */
/* FTC_ScalerRec */
/* */
/* <Description> */
/* A structure used to describe a given character size in either */
/* pixels or points to the cache manager. See */
/* @FTC_Manager_LookupSize. */
/* */
/* <Fields> */
/* face_id :: The source face ID. */
/* */
/* width :: The character width. */
/* */
/* height :: The character height. */
/* */
/* pixel :: A Boolean. If TRUE, the `width' and `height' fields */
/* are interpreted as integer pixel character sizes. */
/* Otherwise, they are expressed as 1/64th of points. */
/* */
/* x_res :: Only used when `pixel' is FALSE to indicate the */
/* horizontal resolution in dpi. */
/* */
/* y_res :: Only used when `pixel' is FALSE to indicate the */
/* vertical resolution in dpi. */
/* */
/* <Note> */
/* This type is mainly used to retrieve @FT_Size objects through the */
/* cache manager. */
/* */
typedef struct FTC_ScalerRec_
{
FTC_FaceID face_id;
FT_UInt width;
FT_UInt height;
FT_Int pixel;
FT_UInt x_res;
FT_UInt y_res;
} FTC_ScalerRec, *FTC_Scaler;
/*************************************************************************/
/* */
/* <Function> */
/* FTC_Manager_LookupSize */
/* */
/* <Description> */
/* Retrieve the @FT_Size object that corresponds to a given */
/* @FTC_Scaler through a cache manager. */
/* */
/* <Input> */
/* manager :: A handle to the cache manager. */
/* */
/* scaler :: A scaler handle. */
/* */
/* <Output> */
/* asize :: A handle to the size object. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* The returned @FT_Size object is always owned by the manager. You */
/* should never try to discard it by yourself. */
/* */
/* You can access the parent @FT_Face object simply as `size->face' */
/* if you need it. Note that this object is also owned by the */
/* manager. */
/* */
FT_EXPORT( FT_Error )
FTC_Manager_LookupSize( FTC_Manager manager,
FTC_Scaler scaler,
FT_Size *asize );
/*************************************************************************/
/* */
/* <Function> */
/* FTC_Node_Unref */
/* */
/* <Description> */
/* Decrement a cache node's internal reference count. When the count */
/* reaches 0, it is not destroyed but becomes eligible for subsequent */
/* cache flushes. */
/* */
/* <Input> */
/* node :: The cache node handle. */
/* */
/* manager :: The cache manager handle. */
/* */
FT_EXPORT( void )
FTC_Node_Unref( FTC_Node node,
FTC_Manager manager );
/* remove all nodes belonging to a given face_id */
FT_EXPORT( void )
FTC_Manager_RemoveFaceID( FTC_Manager manager,
FTC_FaceID face_id );
/*************************************************************************/
/* */
/* <Section> */
/* cache_subsystem */
/* */
/*************************************************************************/
/*************************************************************************
*
* @type:
* FTC_CMapCache
*
* @description:
* An opaque handle used to manager a charmap cache. This cache is to
* hold character codes -> glyph indices mappings.
*
*/
typedef struct FTC_CMapCacheRec_* FTC_CMapCache;
/*************************************************************************
*
* @function:
* FTC_CMapCache_New
*
* @description:
* Create a new charmap cache.
*
* @input:
* manager ::
* A handle to the cache manager.
*
* @output:
* acache ::
* A new cache handle. NULL in case of error.
*
* @return:
* FreeType error code. 0 means success.
*
* @note:
* Like all other caches, this one will be destroyed with the cache
* manager.
*
*/
FT_EXPORT( FT_Error )
FTC_CMapCache_New( FTC_Manager manager,
FTC_CMapCache *acache );
/************************************************************************
*
* @function:
* FTC_CMapCache_Lookup
*
* @description:
* Translate a character code into a glyph index, using the charmap
* cache.
*
* @input:
* cache ::
* A charmap cache handle.
*
* face_id ::
* The source face ID.
*
* cmap_index ::
* The index of the charmap in the source face.
*
* char_code ::
* The character code (in the corresponding charmap).
*
* @return:
* Glyph index. 0 means `no glyph'.
*
*/
FT_EXPORT( FT_UInt )
FTC_CMapCache_Lookup( FTC_CMapCache cache,
FTC_FaceID face_id,
FT_Int cmap_index,
FT_UInt32 char_code );
/*************************************************************************/
/* */
/* <Section> */
/* cache_subsystem */
/* */
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** IMAGE CACHE OBJECT *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
typedef struct FTC_ImageTypeRec_
{
FTC_FaceID face_id;
FT_Int width;
FT_Int height;
FT_Int32 flags;
} FTC_ImageTypeRec;
typedef struct FTC_ImageTypeRec_* FTC_ImageType;
/* */
#define FTC_IMAGE_TYPE_COMPARE( d1, d2 ) \
( FTC_FONT_COMPARE( &(d1)->font, &(d2)->font ) && \
(d1)->flags == (d2)->flags )
#define FTC_IMAGE_TYPE_HASH( d ) \
(FT_UFast)( FTC_FONT_HASH( &(d)->font ) ^ \
( (d)->flags << 4 ) )
/*************************************************************************/
/* */
/* <Type> */
/* FTC_ImageCache */
/* */
/* <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_ImageCacheRec_* FTC_ImageCache;
/*************************************************************************/
/* */
/* <Function> */
/* FTC_ImageCache_New */
/* */
/* <Description> */
/* Creates a new glyph image cache. */
/* */
/* <Input> */
/* manager :: The parent manager for the image cache. */
/* */
/* <Output> */
/* acache :: A handle to the new glyph image cache object. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
FT_EXPORT( FT_Error )
FTC_ImageCache_New( FTC_Manager manager,
FTC_ImageCache *acache );
/*************************************************************************/
/* */
/* <Function> */
/* FTC_ImageCache_Lookup */
/* */
/* <Description> */
/* Retrieves a given glyph image from a glyph image cache. */
/* */
/* <Input> */
/* cache :: A handle to the source glyph image cache. */
/* */
/* type :: A pointer to a glyph image type descriptor. */
/* */
/* gindex :: The glyph index to retrieve. */
/* */
/* <Output> */
/* aglyph :: The corresponding @FT_Glyph object. 0 in case of */
/* failure. */
/* */
/* anode :: Used to return the address of of the corresponding cache */
/* node after incrementing its reference count (see note */
/* below). */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* The returned glyph is owned and managed 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. */
/* */
/* If `anode' is _not_ NULL, it receives the address of the cache */
/* node containing the glyph image, after increasing its reference */
/* count. This ensures that the node (as well as the FT_Glyph) will */
/* always be kept in the cache until you call @FTC_Node_Unref to */
/* `release' it. */
/* */
/* If `anode' is NULL, the cache node is left unchanged, which means */
/* that the FT_Glyph could be flushed out of the cache on the next */
/* call to one of the caching sub-system APIs. Don't assume that it */
/* is persistent! */
/* */
FT_EXPORT( FT_Error )
FTC_ImageCache_Lookup( FTC_ImageCache cache,
FTC_ImageType type,
FT_UInt gindex,
FT_Glyph *aglyph,
FTC_Node *anode );
/*************************************************************************/
/* */
/* <Type> */
/* FTC_SBit */
/* */
/* <Description> */
/* A handle to a small bitmap descriptor. See the @FTC_SBitRec */
/* structure for details. */
/* */
typedef struct FTC_SBitRec_* FTC_SBit;
/*************************************************************************/
/* */
/* <Struct> */
/* FTC_SBitRec */
/* */
/* <Description> */
/* A very compact structure used to describe a small glyph bitmap. */
/* */
/* <Fields> */
/* width :: The bitmap width in pixels. */
/* */
/* height :: The bitmap height in pixels. */
/* */
/* left :: The horizontal distance from the pen position to the */
/* left bitmap border (a.k.a. `left side bearing', or */
/* `lsb'). */
/* */
/* top :: The vertical distance from the pen position (on the */
/* baseline) to the upper bitmap border (a.k.a. `top */
/* side bearing'). The distance is positive for upwards */
/* Y coordinates. */
/* */
/* format :: The format of the glyph bitmap (monochrome or gray). */
/* */
/* max_grays :: Maximum gray level value (in the range 1 to 255). */
/* */
/* pitch :: The number of bytes per bitmap line. May be positive */
/* or negative. */
/* */
/* xadvance :: The horizontal advance width in pixels. */
/* */
/* yadvance :: The vertical advance height in pixels. */
/* */
/* buffer :: A pointer to the bitmap pixels. */
/* */
typedef struct FTC_SBitRec_
{
FT_Byte width;
FT_Byte height;
FT_Char left;
FT_Char top;
FT_Byte format;
FT_Byte max_grays;
FT_Short pitch;
FT_Char xadvance;
FT_Char yadvance;
FT_Byte* buffer;
} FTC_SBitRec;
/*************************************************************************/
/* */
/* <Type> */
/* FTC_SBitCache */
/* */
/* <Description> */
/* A handle to a small bitmap cache. These are special cache objects */
/* used to store small glyph bitmaps (and anti-aliased pixmaps) in a */
/* much more efficient way than the traditional glyph image cache */
/* implemented by @FTC_ImageCache. */
/* */
typedef struct FTC_SBitCacheRec_* FTC_SBitCache;
/*************************************************************************/
/* */
/* <Function> */
/* FTC_SBitCache_New */
/* */
/* <Description> */
/* Creates a new cache to store small glyph bitmaps. */
/* */
/* <Input> */
/* manager :: A handle to the source cache manager. */
/* */
/* <Output> */
/* acache :: A handle to the new sbit cache. NULL in case of error. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
FT_EXPORT( FT_Error )
FTC_SBitCache_New( FTC_Manager manager,
FTC_SBitCache *acache );
/*************************************************************************/
/* */
/* <Function> */
/* FTC_SBitCache_Lookup */
/* */
/* <Description> */
/* Looks up a given small glyph bitmap in a given sbit cache and */
/* `lock' it to prevent its flushing from the cache until needed. */
/* */
/* <Input> */
/* cache :: A handle to the source sbit cache. */
/* */
/* type :: A pointer to the glyph image type descriptor. */
/* */
/* gindex :: The glyph index. */
/* */
/* <Output> */
/* sbit :: A handle to a small bitmap descriptor. */
/* */
/* anode :: Used to return the address of of the corresponding cache */
/* node after incrementing its reference count (see note */
/* below). */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* The small bitmap descriptor and its bit buffer are owned by the */
/* cache and should never be freed by the application. They might */
/* as well disappear from memory on the next cache lookup, so don't */
/* treat them as persistent data. */
/* */
/* The descriptor's `buffer' field is set to 0 to indicate a missing */
/* glyph bitmap. */
/* */
/* If `anode' is _not_ NULL, it receives the address of the cache */
/* node containing the bitmap, after increasing its reference count. */
/* This ensures that the node (as well as the image) will always be */
/* kept in the cache until you call @FTC_Node_Unref to `release' it. */
/* */
/* If `anode' is NULL, the cache node is left unchanged, which means */
/* that the bitmap could be flushed out of the cache on the next */
/* call to one of the caching sub-system APIs. Don't assume that it */
/* is persistent! */
/* */
FT_EXPORT( FT_Error )
FTC_SBitCache_Lookup( FTC_SBitCache cache,
FTC_ImageType type,
FT_UInt gindex,
FTC_SBit *sbit,
FTC_Node *anode );
/* */
FT_END_HEADER
#endif /* __FTCACHE_H__ */
/* END */