diff options
| author | Nikolas <nikolas@boutalas.com> | 2024-10-27 12:52:55 +0200 |
|---|---|---|
| committer | Nikolas <nikolas@boutalas.com> | 2024-10-27 12:52:55 +0200 |
| commit | 43394c8a8908442982e3a7e25975c31b3c952923 (patch) | |
| tree | 2facd563e29f48fe3b0653ac5c113998940b4d5e /3rdparty/include/freetype/ftcache.h | |
Diffstat (limited to '3rdparty/include/freetype/ftcache.h')
| -rw-r--r-- | 3rdparty/include/freetype/ftcache.h | 1042 |
1 files changed, 1042 insertions, 0 deletions
diff --git a/3rdparty/include/freetype/ftcache.h b/3rdparty/include/freetype/ftcache.h new file mode 100644 index 0000000..52d5f00 --- /dev/null +++ b/3rdparty/include/freetype/ftcache.h @@ -0,0 +1,1042 @@ +/***************************************************************************/ +/* */ +/* ftcache.h */ +/* */ +/* FreeType Cache subsystem (specification). */ +/* */ +/* Copyright 1996-2018 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 <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 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, 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 */ |