1058 lines
56 KiB
C
1058 lines
56 KiB
C
/***************************************************************************/
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/* */
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/* ftcache.h */
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/* */
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/* FreeType Cache subsystem (specification). */
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/* */
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/* Copyright 1996-2017 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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/* */
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/* This file is part of the FreeType project, and may only be used, */
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/* modified, and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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#ifndef FTCACHE_H_
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#define FTCACHE_H_
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#include <ft2build.h>
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#include FT_GLYPH_H
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FT_BEGIN_HEADER
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/*************************************************************************
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*
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* <Section>
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* cache_subsystem
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*
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* <Title>
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* Cache Sub-System
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*
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* <Abstract>
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* How to cache face, size, and glyph data with FreeType~2.
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*
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* <Description>
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* This section describes the FreeType~2 cache sub-system, which is used
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* to limit the number of concurrently opened @FT_Face and @FT_Size
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* objects, as well as caching information like character maps and glyph
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* images while limiting their maximum memory usage.
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*
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* Note that all types and functions begin with the `FTC_' prefix.
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*
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* The cache is highly portable and thus doesn't know anything about the
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* fonts installed on your system, or how to access them. This implies
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* the following scheme:
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*
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* First, available or installed font faces are uniquely identified by
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* @FTC_FaceID values, provided to the cache by the client. Note that
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* the cache only stores and compares these values, and doesn't try to
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* interpret them in any way.
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*
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* Second, the cache calls, only when needed, a client-provided function
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* to convert an @FTC_FaceID into a new @FT_Face object. The latter is
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* then completely managed by the cache, including its termination
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* through @FT_Done_Face. To monitor termination of face objects, the
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* finalizer callback in the `generic' field of the @FT_Face object can
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* be used, which might also be used to store the @FTC_FaceID of the
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* face.
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*
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* Clients are free to map face IDs to anything else. The most simple
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* usage is to associate them to a (pathname,face_index) pair that is
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* used to call @FT_New_Face. However, more complex schemes are also
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* possible.
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*
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* Note that for the cache to work correctly, the face ID values must be
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* *persistent*, which means that the contents they point to should not
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* change at runtime, or that their value should not become invalid.
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*
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* If this is unavoidable (e.g., when a font is uninstalled at runtime),
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* you should call @FTC_Manager_RemoveFaceID as soon as possible, to let
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* the cache get rid of any references to the old @FTC_FaceID it may
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* keep internally. Failure to do so will lead to incorrect behaviour
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* or even crashes.
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*
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* To use the cache, start with calling @FTC_Manager_New to create a new
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* @FTC_Manager object, which models a single cache instance. You can
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* then look up @FT_Face and @FT_Size objects with
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* @FTC_Manager_LookupFace and @FTC_Manager_LookupSize, respectively.
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*
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* If you want to use the charmap caching, call @FTC_CMapCache_New, then
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* later use @FTC_CMapCache_Lookup to perform the equivalent of
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* @FT_Get_Char_Index, only much faster.
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*
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* If you want to use the @FT_Glyph caching, call @FTC_ImageCache, then
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* later use @FTC_ImageCache_Lookup to retrieve the corresponding
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* @FT_Glyph objects from the cache.
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*
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* If you need lots of small bitmaps, it is much more memory efficient
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* to call @FTC_SBitCache_New followed by @FTC_SBitCache_Lookup. This
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* returns @FTC_SBitRec structures, which are used to store small
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* bitmaps directly. (A small bitmap is one whose metrics and
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* dimensions all fit into 8-bit integers).
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*
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* We hope to also provide a kerning cache in the near future.
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*
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*
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* <Order>
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* FTC_Manager
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* FTC_FaceID
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* FTC_Face_Requester
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*
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* FTC_Manager_New
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* FTC_Manager_Reset
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* FTC_Manager_Done
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* FTC_Manager_LookupFace
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* FTC_Manager_LookupSize
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* FTC_Manager_RemoveFaceID
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*
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* FTC_Node
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* FTC_Node_Unref
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*
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* FTC_ImageCache
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* FTC_ImageCache_New
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* FTC_ImageCache_Lookup
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*
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* FTC_SBit
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* FTC_SBitCache
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* FTC_SBitCache_New
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* FTC_SBitCache_Lookup
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*
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* FTC_CMapCache
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* FTC_CMapCache_New
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* FTC_CMapCache_Lookup
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*
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*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/***** *****/
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/***** BASIC TYPE DEFINITIONS *****/
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/***** *****/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************
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*
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* @type: FTC_FaceID
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*
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* @description:
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* An opaque pointer type that is used to identity face objects. The
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* contents of such objects is application-dependent.
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*
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* These pointers are typically used to point to a user-defined
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* structure containing a font file path, and face index.
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*
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* @note:
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* Never use NULL as a valid @FTC_FaceID.
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*
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* Face IDs are passed by the client to the cache manager that calls,
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* when needed, the @FTC_Face_Requester to translate them into new
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* @FT_Face objects.
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*
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* If the content of a given face ID changes at runtime, or if the value
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* becomes invalid (e.g., when uninstalling a font), you should
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* immediately call @FTC_Manager_RemoveFaceID before any other cache
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* function.
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*
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* Failure to do so will result in incorrect behaviour or even
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* memory leaks and crashes.
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*/
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typedef FT_Pointer FTC_FaceID;
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/************************************************************************
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*
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* @functype:
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* FTC_Face_Requester
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*
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* @description:
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* A callback function provided by client applications. It is used by
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* the cache manager to translate a given @FTC_FaceID into a new valid
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* @FT_Face object, on demand.
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*
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* <Input>
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* face_id ::
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* The face ID to resolve.
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*
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* library ::
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* A handle to a FreeType library object.
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*
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* req_data ::
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* Application-provided request data (see note below).
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*
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* <Output>
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* aface ::
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* A new @FT_Face handle.
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*
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* <Return>
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* FreeType error code. 0~means success.
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*
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* <Note>
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* The third parameter `req_data' is the same as the one passed by the
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* client when @FTC_Manager_New is called.
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*
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* The face requester should not perform funny things on the returned
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* face object, like creating a new @FT_Size for it, or setting a
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* transformation through @FT_Set_Transform!
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*/
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typedef FT_Error
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(*FTC_Face_Requester)( FTC_FaceID face_id,
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FT_Library library,
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FT_Pointer req_data,
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FT_Face* aface );
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/* */
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/***** *****/
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/***** CACHE MANAGER OBJECT *****/
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/***** *****/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/*************************************************************************/
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/* */
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/* <Type> */
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/* FTC_Manager */
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/* */
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/* <Description> */
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/* This object corresponds to one instance of the cache-subsystem. */
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/* It is used to cache one or more @FT_Face objects, along with */
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/* corresponding @FT_Size objects. */
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/* */
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/* The manager intentionally limits the total number of opened */
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/* @FT_Face and @FT_Size objects to control memory usage. See the */
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/* `max_faces' and `max_sizes' parameters of @FTC_Manager_New. */
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/* */
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/* The manager is also used to cache `nodes' of various types while */
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/* limiting their total memory usage. */
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/* */
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/* All limitations are enforced by keeping lists of managed objects */
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/* in most-recently-used order, and flushing old nodes to make room */
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/* for new ones. */
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/* */
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typedef struct FTC_ManagerRec_* FTC_Manager;
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/*************************************************************************/
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/* */
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/* <Type> */
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/* FTC_Node */
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/* */
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/* <Description> */
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/* An opaque handle to a cache node object. Each cache node is */
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/* reference-counted. A node with a count of~0 might be flushed */
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/* out of a full cache whenever a lookup request is performed. */
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/* */
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/* If you look up nodes, you have the ability to `acquire' them, */
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/* i.e., to increment their reference count. This will prevent the */
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/* node from being flushed out of the cache until you explicitly */
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/* `release' it (see @FTC_Node_Unref). */
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/* */
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/* See also @FTC_SBitCache_Lookup and @FTC_ImageCache_Lookup. */
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/* */
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typedef struct FTC_NodeRec_* FTC_Node;
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FTC_Manager_New */
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/* */
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/* <Description> */
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/* Create a new cache manager. */
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/* */
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/* <Input> */
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/* library :: The parent FreeType library handle to use. */
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/* */
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/* max_faces :: Maximum number of opened @FT_Face objects managed by */
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/* this cache instance. Use~0 for defaults. */
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/* */
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/* max_sizes :: Maximum number of opened @FT_Size objects managed by */
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/* this cache instance. Use~0 for defaults. */
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/* */
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/* max_bytes :: Maximum number of bytes to use for cached data nodes. */
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/* Use~0 for defaults. Note that this value does not */
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/* account for managed @FT_Face and @FT_Size objects. */
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/* */
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/* requester :: An application-provided callback used to translate */
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/* face IDs into real @FT_Face objects. */
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/* */
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/* req_data :: A generic pointer that is passed to the requester */
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/* each time it is called (see @FTC_Face_Requester). */
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/* */
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/* <Output> */
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/* amanager :: A handle to a new manager object. 0~in case of */
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/* failure. */
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/* */
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/* <Return> */
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/* FreeType error code. 0~means success. */
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/* */
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FT_EXPORT( FT_Error )
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FTC_Manager_New( FT_Library library,
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FT_UInt max_faces,
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FT_UInt max_sizes,
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FT_ULong max_bytes,
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FTC_Face_Requester requester,
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FT_Pointer req_data,
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FTC_Manager *amanager );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FTC_Manager_Reset */
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/* */
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/* <Description> */
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/* Empty a given cache manager. This simply gets rid of all the */
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/* currently cached @FT_Face and @FT_Size objects within the manager. */
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/* */
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/* <InOut> */
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/* manager :: A handle to the manager. */
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/* */
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FT_EXPORT( void )
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FTC_Manager_Reset( FTC_Manager manager );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FTC_Manager_Done */
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/* */
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/* <Description> */
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/* Destroy a given manager after emptying it. */
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/* */
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/* <Input> */
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/* manager :: A handle to the target cache manager object. */
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/* */
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FT_EXPORT( void )
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FTC_Manager_Done( FTC_Manager manager );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FTC_Manager_LookupFace */
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/* */
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/* <Description> */
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/* Retrieve the @FT_Face object that corresponds to a given face ID */
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/* through a cache manager. */
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/* */
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/* <Input> */
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/* manager :: A handle to the cache manager. */
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/* */
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/* face_id :: The ID of the face object. */
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/* */
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/* <Output> */
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/* aface :: A handle to the face object. */
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/* */
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/* <Return> */
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/* FreeType error code. 0~means success. */
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/* */
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/* <Note> */
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/* The returned @FT_Face object is always owned by the manager. You */
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/* should never try to discard it yourself. */
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/* */
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/* The @FT_Face object doesn't necessarily have a current size object */
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/* (i.e., face->size can be~0). If you need a specific `font size', */
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/* use @FTC_Manager_LookupSize instead. */
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/* */
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/* Never change the face's transformation matrix (i.e., never call */
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/* the @FT_Set_Transform function) on a returned face! If you need */
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/* to transform glyphs, do it yourself after glyph loading. */
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/* */
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/* When you perform a lookup, out-of-memory errors are detected */
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/* _within_ the lookup and force incremental flushes of the cache */
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/* until enough memory is released for the lookup to succeed. */
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/* */
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/* If a lookup fails with `FT_Err_Out_Of_Memory' the cache has */
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/* already been completely flushed, and still no memory was available */
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/* for the operation. */
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/* */
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FT_EXPORT( FT_Error )
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FTC_Manager_LookupFace( FTC_Manager manager,
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FTC_FaceID face_id,
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FT_Face *aface );
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* FTC_ScalerRec */
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/* */
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/* <Description> */
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/* A structure used to describe a given character size in either */
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/* pixels or points to the cache manager. See */
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/* @FTC_Manager_LookupSize. */
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/* */
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/* <Fields> */
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/* face_id :: The source face ID. */
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/* */
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/* width :: The character width. */
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/* */
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/* height :: The character height. */
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/* */
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/* pixel :: A Boolean. If 1, the `width' and `height' fields are */
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/* interpreted as integer pixel character sizes. */
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/* Otherwise, they are expressed as 1/64th of points. */
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/* */
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/* x_res :: Only used when `pixel' is value~0 to indicate the */
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/* horizontal resolution in dpi. */
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/* */
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/* y_res :: Only used when `pixel' is value~0 to indicate the */
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/* vertical resolution in dpi. */
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/* */
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/* <Note> */
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/* This type is mainly used to retrieve @FT_Size objects through the */
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/* cache manager. */
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/* */
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typedef struct FTC_ScalerRec_
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{
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FTC_FaceID face_id;
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FT_UInt width;
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FT_UInt height;
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FT_Int pixel;
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FT_UInt x_res;
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FT_UInt y_res;
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} FTC_ScalerRec;
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/*************************************************************************/
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/* */
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/* <Struct> */
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/* FTC_Scaler */
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/* */
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/* <Description> */
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/* A handle to an @FTC_ScalerRec structure. */
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/* */
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typedef struct FTC_ScalerRec_* FTC_Scaler;
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FTC_Manager_LookupSize */
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/* */
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/* <Description> */
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/* Retrieve the @FT_Size object that corresponds to a given */
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/* @FTC_ScalerRec pointer through a cache manager. */
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/* */
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/* <Input> */
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/* manager :: A handle to the cache manager. */
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/* */
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/* scaler :: A scaler handle. */
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/* */
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/* <Output> */
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/* asize :: A handle to the size object. */
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/* */
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/* <Return> */
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/* FreeType error code. 0~means success. */
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/* */
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/* <Note> */
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/* The returned @FT_Size object is always owned by the manager. You */
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/* should never try to discard it by yourself. */
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/* */
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/* You can access the parent @FT_Face object simply as `size->face' */
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/* if you need it. Note that this object is also owned by the */
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/* manager. */
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/* */
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/* <Note> */
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/* When you perform a lookup, out-of-memory errors are detected */
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/* _within_ the lookup and force incremental flushes of the cache */
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/* until enough memory is released for the lookup to succeed. */
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/* */
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/* If a lookup fails with `FT_Err_Out_Of_Memory' the cache has */
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/* already been completely flushed, and still no memory is available */
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/* for the operation. */
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/* */
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FT_EXPORT( FT_Error )
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FTC_Manager_LookupSize( FTC_Manager manager,
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FTC_Scaler scaler,
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FT_Size *asize );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FTC_Node_Unref */
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/* */
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/* <Description> */
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/* Decrement a cache node's internal reference count. When the count */
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/* reaches 0, it is not destroyed but becomes eligible for subsequent */
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/* cache flushes. */
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/* */
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/* <Input> */
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/* node :: The cache node handle. */
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/* */
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/* manager :: The cache manager handle. */
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/* */
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FT_EXPORT( void )
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FTC_Node_Unref( FTC_Node node,
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FTC_Manager manager );
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|
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/*************************************************************************
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*
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* @function:
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* FTC_Manager_RemoveFaceID
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*
|
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* @description:
|
|
* A special function used to indicate to the cache manager that
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* a given @FTC_FaceID is no longer valid, either because its
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* content changed, or because it was deallocated or uninstalled.
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*
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* @input:
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* manager ::
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* The cache manager handle.
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*
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* face_id ::
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* The @FTC_FaceID to be removed.
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*
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|
* @note:
|
|
* This function flushes all nodes from the cache corresponding to this
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* `face_id', with the exception of nodes with a non-null reference
|
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* count.
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*
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|
* Such nodes are however modified internally so as to never appear
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* in later lookups with the same `face_id' value, and to be immediately
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* destroyed when released by all their users.
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*
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*/
|
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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 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 );
|
|
|
|
|
|
/*************************************************************************/
|
|
/* */
|
|
/* <Section> */
|
|
/* cache_subsystem */
|
|
/* */
|
|
/*************************************************************************/
|
|
|
|
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/***** *****/
|
|
/***** 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 */
|