1088 lines
33 KiB
C
1088 lines
33 KiB
C
/****************************************************************************
|
|
*
|
|
* ftcache.h
|
|
*
|
|
* FreeType Cache subsystem (specification).
|
|
*
|
|
* Copyright (C) 1996-2021 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>
|
|
|
|
|
|
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 used
|
|
* to limit the number of concurrently opened @FT_Face and @FT_Size
|
|
* objects, as well as caching information like character maps and glyph
|
|
* images while limiting their maximum memory usage.
|
|
*
|
|
* Note that all types and functions begin with the `FTC_` prefix.
|
|
*
|
|
* The cache is highly portable and thus doesn't know anything about the
|
|
* fonts installed on your system, or how to access them. This implies
|
|
* the following scheme:
|
|
*
|
|
* First, available or installed font faces are uniquely identified by
|
|
* @FTC_FaceID values, provided to the cache by the client. Note that
|
|
* the cache only stores and compares these values, and doesn't try to
|
|
* interpret them in any way.
|
|
*
|
|
* Second, the cache calls, only when needed, a client-provided function
|
|
* to convert an @FTC_FaceID into a new @FT_Face object. The latter is
|
|
* then completely managed by the cache, including its termination
|
|
* through @FT_Done_Face. To monitor termination of face objects, the
|
|
* finalizer callback in the `generic` field of the @FT_Face object can
|
|
* be used, which might also be used to store the @FTC_FaceID of the
|
|
* face.
|
|
*
|
|
* Clients are free to map face IDs to anything else. The most simple
|
|
* usage is to associate them to a (pathname,face_index) pair that is
|
|
* used to call @FT_New_Face. However, more complex schemes are also
|
|
* possible.
|
|
*
|
|
* Note that for the cache to work correctly, the face ID values must be
|
|
* **persistent**, which means that the contents they point to should not
|
|
* change at runtime, or that their value should not become invalid.
|
|
*
|
|
* If this is unavoidable (e.g., when a font is uninstalled at runtime),
|
|
* you should call @FTC_Manager_RemoveFaceID as soon as possible, to let
|
|
* the cache get rid of any references to the old @FTC_FaceID it may keep
|
|
* internally. Failure to do so will lead to incorrect behaviour or even
|
|
* crashes.
|
|
*
|
|
* To use the cache, start with calling @FTC_Manager_New to create a new
|
|
* @FTC_Manager object, which models a single cache instance. You can
|
|
* then look up @FT_Face and @FT_Size objects with
|
|
* @FTC_Manager_LookupFace and @FTC_Manager_LookupSize, respectively.
|
|
*
|
|
* If you want to use the charmap caching, call @FTC_CMapCache_New, then
|
|
* later use @FTC_CMapCache_Lookup to perform the equivalent of
|
|
* @FT_Get_Char_Index, only much faster.
|
|
*
|
|
* If you want to use the @FT_Glyph caching, call @FTC_ImageCache_New,
|
|
* then later use @FTC_ImageCache_Lookup to retrieve the corresponding
|
|
* @FT_Glyph objects from the cache.
|
|
*
|
|
* If you need lots of small bitmaps, it is much more memory efficient to
|
|
* call @FTC_SBitCache_New followed by @FTC_SBitCache_Lookup. This
|
|
* returns @FTC_SBitRec structures, which are used to store small bitmaps
|
|
* directly. (A small bitmap is one whose metrics and dimensions all fit
|
|
* into 8-bit integers).
|
|
*
|
|
* We hope to also provide a kerning cache in the near future.
|
|
*
|
|
*
|
|
* @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_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.
|
|
*
|
|
* These pointers are typically used to point to a user-defined structure
|
|
* containing a font file path, and face index.
|
|
*
|
|
* @note:
|
|
* Never use `NULL` as a valid @FTC_FaceID.
|
|
*
|
|
* Face IDs are passed by the client to the cache manager that calls,
|
|
* when needed, the @FTC_Face_Requester to translate them into new
|
|
* @FT_Face objects.
|
|
*
|
|
* If the content of a given face ID changes at runtime, or if the value
|
|
* becomes invalid (e.g., when uninstalling a font), you should
|
|
* immediately call @FTC_Manager_RemoveFaceID before any other cache
|
|
* function.
|
|
*
|
|
* Failure to do so will result in incorrect behaviour or even memory
|
|
* leaks and crashes.
|
|
*/
|
|
typedef FT_Pointer FTC_FaceID;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @functype:
|
|
* FTC_Face_Requester
|
|
*
|
|
* @description:
|
|
* A callback function provided by client applications. It is used by
|
|
* the cache manager to translate a given @FTC_FaceID into a new valid
|
|
* @FT_Face object, on demand.
|
|
*
|
|
* @input:
|
|
* face_id ::
|
|
* The face ID to resolve.
|
|
*
|
|
* library ::
|
|
* A handle to a FreeType library object.
|
|
*
|
|
* req_data ::
|
|
* Application-provided request data (see note below).
|
|
*
|
|
* @output:
|
|
* aface ::
|
|
* A new @FT_Face handle.
|
|
*
|
|
* @return:
|
|
* FreeType error code. 0~means success.
|
|
*
|
|
* @note:
|
|
* The third parameter `req_data` is the same as the one passed by the
|
|
* client when @FTC_Manager_New is called.
|
|
*
|
|
* 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 req_data,
|
|
FT_Face* aface );
|
|
|
|
/* */
|
|
|
|
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/***** *****/
|
|
/***** CACHE MANAGER OBJECT *****/
|
|
/***** *****/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @type:
|
|
* FTC_Manager
|
|
*
|
|
* @description:
|
|
* This object corresponds to one instance of the cache-subsystem. It is
|
|
* used to cache one or more @FT_Face objects, along with corresponding
|
|
* @FT_Size objects.
|
|
*
|
|
* The manager intentionally limits the total number of opened @FT_Face
|
|
* and @FT_Size objects to control memory usage. See the `max_faces` and
|
|
* `max_sizes` parameters of @FTC_Manager_New.
|
|
*
|
|
* The manager is also used to cache 'nodes' of various types while
|
|
* limiting their total memory usage.
|
|
*
|
|
* All limitations are enforced by keeping lists of managed objects in
|
|
* most-recently-used order, and flushing old nodes to make room for new
|
|
* ones.
|
|
*/
|
|
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 look up 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:
|
|
* Create a new cache manager.
|
|
*
|
|
* @input:
|
|
* library ::
|
|
* The parent FreeType library handle to use.
|
|
*
|
|
* max_faces ::
|
|
* Maximum number of opened @FT_Face objects managed by this cache
|
|
* instance. Use~0 for defaults.
|
|
*
|
|
* max_sizes ::
|
|
* Maximum number of opened @FT_Size objects managed by this cache
|
|
* instance. Use~0 for defaults.
|
|
*
|
|
* 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.
|
|
*/
|
|
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:
|
|
* Empty 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:
|
|
* Destroy 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:
|
|
* Retrieve 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.
|
|
*
|
|
* 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 was available for the
|
|
* operation.
|
|
*/
|
|
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 1, 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 value~0 to indicate the horizontal
|
|
* resolution in dpi.
|
|
*
|
|
* y_res ::
|
|
* Only used when `pixel` is value~0 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;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @struct:
|
|
* FTC_Scaler
|
|
*
|
|
* @description:
|
|
* A handle to an @FTC_ScalerRec structure.
|
|
*/
|
|
typedef struct FTC_ScalerRec_* FTC_Scaler;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @function:
|
|
* FTC_Manager_LookupSize
|
|
*
|
|
* @description:
|
|
* Retrieve the @FT_Size object that corresponds to a given
|
|
* @FTC_ScalerRec pointer 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.
|
|
*
|
|
* @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_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 );
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @function:
|
|
* FTC_Manager_RemoveFaceID
|
|
*
|
|
* @description:
|
|
* A special function used to indicate to the cache manager that a given
|
|
* @FTC_FaceID is no longer valid, either because its content changed, or
|
|
* because it was deallocated or uninstalled.
|
|
*
|
|
* @input:
|
|
* manager ::
|
|
* The cache manager handle.
|
|
*
|
|
* face_id ::
|
|
* The @FTC_FaceID to be removed.
|
|
*
|
|
* @note:
|
|
* This function flushes all nodes from the cache corresponding to this
|
|
* `face_id`, with the exception of nodes with a non-null reference
|
|
* count.
|
|
*
|
|
* Such nodes are however modified internally so as to never appear in
|
|
* later lookups with the same `face_id` value, and to be immediately
|
|
* destroyed when released by all their users.
|
|
*
|
|
*/
|
|
FT_EXPORT( void )
|
|
FTC_Manager_RemoveFaceID( FTC_Manager manager,
|
|
FTC_FaceID face_id );
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @type:
|
|
* FTC_CMapCache
|
|
*
|
|
* @description:
|
|
* An opaque handle used to model 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. Any negative value
|
|
* means to use the cache @FT_Face's default charmap.
|
|
*
|
|
* 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 );
|
|
|
|
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/***** *****/
|
|
/***** IMAGE CACHE OBJECT *****/
|
|
/***** *****/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @struct:
|
|
* FTC_ImageTypeRec
|
|
*
|
|
* @description:
|
|
* A structure used to model the type of images in a glyph cache.
|
|
*
|
|
* @fields:
|
|
* face_id ::
|
|
* The face ID.
|
|
*
|
|
* width ::
|
|
* The width in pixels.
|
|
*
|
|
* height ::
|
|
* The height in pixels.
|
|
*
|
|
* flags ::
|
|
* The load flags, as in @FT_Load_Glyph.
|
|
*
|
|
*/
|
|
typedef struct FTC_ImageTypeRec_
|
|
{
|
|
FTC_FaceID face_id;
|
|
FT_UInt width;
|
|
FT_UInt height;
|
|
FT_Int32 flags;
|
|
|
|
} FTC_ImageTypeRec;
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @type:
|
|
* FTC_ImageType
|
|
*
|
|
* @description:
|
|
* A handle to an @FTC_ImageTypeRec structure.
|
|
*
|
|
*/
|
|
typedef struct FTC_ImageTypeRec_* FTC_ImageType;
|
|
|
|
|
|
/* */
|
|
|
|
|
|
#define FTC_IMAGE_TYPE_COMPARE( d1, d2 ) \
|
|
( (d1)->face_id == (d2)->face_id && \
|
|
(d1)->width == (d2)->width && \
|
|
(d1)->flags == (d2)->flags )
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @type:
|
|
* FTC_ImageCache
|
|
*
|
|
* @description:
|
|
* A handle to a 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:
|
|
* Create 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:
|
|
* Retrieve 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 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 );
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @function:
|
|
* FTC_ImageCache_LookupScaler
|
|
*
|
|
* @description:
|
|
* A variant of @FTC_ImageCache_Lookup that uses an @FTC_ScalerRec to
|
|
* specify the face ID and its size.
|
|
*
|
|
* @input:
|
|
* cache ::
|
|
* A handle to the source glyph image cache.
|
|
*
|
|
* scaler ::
|
|
* A pointer to a scaler descriptor.
|
|
*
|
|
* load_flags ::
|
|
* The corresponding load flags.
|
|
*
|
|
* 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 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!
|
|
*
|
|
* Calls to @FT_Set_Char_Size and friends have no effect on cached
|
|
* glyphs; you should always use the FreeType cache API instead.
|
|
*/
|
|
FT_EXPORT( FT_Error )
|
|
FTC_ImageCache_LookupScaler( FTC_ImageCache cache,
|
|
FTC_Scaler scaler,
|
|
FT_ULong load_flags,
|
|
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:
|
|
* Create 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:
|
|
* Look 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 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 );
|
|
|
|
|
|
/**************************************************************************
|
|
*
|
|
* @function:
|
|
* FTC_SBitCache_LookupScaler
|
|
*
|
|
* @description:
|
|
* A variant of @FTC_SBitCache_Lookup that uses an @FTC_ScalerRec to
|
|
* specify the face ID and its size.
|
|
*
|
|
* @input:
|
|
* cache ::
|
|
* A handle to the source sbit cache.
|
|
*
|
|
* scaler ::
|
|
* A pointer to the scaler descriptor.
|
|
*
|
|
* load_flags ::
|
|
* The corresponding load flags.
|
|
*
|
|
* gindex ::
|
|
* The glyph index.
|
|
*
|
|
* @output:
|
|
* sbit ::
|
|
* A handle to a small bitmap descriptor.
|
|
*
|
|
* anode ::
|
|
* Used to return the address 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_LookupScaler( FTC_SBitCache cache,
|
|
FTC_Scaler scaler,
|
|
FT_ULong load_flags,
|
|
FT_UInt gindex,
|
|
FTC_SBit *sbit,
|
|
FTC_Node *anode );
|
|
|
|
/* */
|
|
|
|
|
|
FT_END_HEADER
|
|
|
|
#endif /* FTCACHE_H_ */
|
|
|
|
|
|
/* END */
|