| 0,0 → 1,168 |
|---|
| /******************************************************************* |
| * |
| * ttextend.h 2.0 |
| * |
| * Extensions Interface. |
| * |
| * Copyright 1996-1999 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. |
| * |
| * This is an updated version of the extension component, now |
| * located in the main library's source directory. It allows |
| * the dynamic registration/use of various face object extensions |
| * through a simple API. |
| * |
| ******************************************************************/ |
| |
| #ifndef TTEXTEND_H |
| #define TTEXTEND_H |
| |
| #include "ttconfig.h" |
| #include "tttypes.h" |
| #include "ttobjs.h" |
| |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /* The extensions don't need to be integrated at compile time into */ |
| /* the engine, only at link time. */ |
| |
| |
| /* When a new face object is created, the face constructor calls */ |
| /* the extension constructor with the following arguments: */ |
| /* */ |
| /* ext : typeless pointer to the face's extension block. */ |
| /* Its size is the one given at registration time */ |
| /* in the extension class's 'size' field. */ |
| /* */ |
| /* face : the parent face object. Note that the extension */ |
| /* constructor is called when the face object is */ |
| /* built. */ |
| |
| typedef TT_Error TExt_Constructor( void* ext, PFace face ); |
| |
| |
| /* When a face object is destroyed, the face destructor calls */ |
| /* the extension destructor with the following arguments. */ |
| /* */ |
| /* ext : typeless pointer to the face's extension block. */ |
| /* Its size is the one given at registration time */ |
| /* in the extension class's 'size' field. */ |
| /* */ |
| /* face : the parent face object. Note that the extension */ |
| /* destructor is called before the actual face object */ |
| /* is destroyed. */ |
| |
| typedef TT_Error TExt_Destructor ( void* ext, PFace face ); |
| |
| typedef TExt_Constructor* PExt_Constructor; |
| typedef TExt_Destructor* PExt_Destructor; |
| |
| |
| struct TExtension_Class_ |
| { |
| Long id; /* extension id */ |
| Long size; /* size in bytes of extension record */ |
| PExt_Constructor build; /* the extension's class constructor */ |
| PExt_Destructor destroy; /* the extension's class destructor */ |
| |
| Long offset; /* offset of ext. record in face obj */ |
| /* (set by the engine) */ |
| }; |
| |
| typedef struct TExtension_Class_ TExtension_Class; |
| typedef TExtension_Class* PExtension_Class; |
| |
| |
| #define Build_Extension_ID( a, b, c, d ) \ |
| ( ((ULong)(a) << 24) | \ |
| ((ULong)(b) << 16) | \ |
| ((ULong)(c) << 8 ) | \ |
| (ULong)(d) ) |
| |
| /* A note regarding extensions and the single-object compilation */ |
| /* mode : */ |
| /* */ |
| /* When the engine is compiled as a single object file, extensions */ |
| /* must remain linkable *after* compile time. In order to do this, */ |
| /* we need to export the functions that an extension may need. */ |
| /* Fortunately, we can limit ourselves to : */ |
| /* */ |
| /* o TT_Register_Extension (previously called Extension_Register) */ |
| /* which is to be called by each extension on within */ |
| /* it TT_Init_XXXX_Extension initializer. */ |
| /* */ |
| /* o File and frame access functions. Fortunately, these already */ |
| /* have their names prefixed by "TT_", so no change was needed */ |
| /* except replacing the LOCAL_DEF keyword with EXPORT_DEF */ |
| /* */ |
| /* o Memory access functions, i.e. TT_Alloc and TT_Free. Again, */ |
| /* the change is minimal */ |
| /* */ |
| /* o the table-lookup function : TT_LookUp_Table, formerly known */ |
| /* as Load_TrueType_Table in ttload.c. */ |
| /* */ |
| /* */ |
| /* Other than that, an extension should be able to #include all */ |
| /* relevant header files to get access to internal types, but */ |
| /* should not call engine internal functions.. */ |
| /* */ |
| /* If there is a need for a specific internal function call, let */ |
| /* me known to see if we need to export it by default.. */ |
| /* - DavidT */ |
| /* */ |
| |
| /* Register a new extension. Called by extension */ |
| /* service initializers. */ |
| EXPORT_DEF |
| TT_Error TT_Register_Extension( PEngine_Instance engine, |
| Long id, |
| Long size, |
| PExt_Constructor create, |
| PExt_Destructor destroy ); |
| |
| |
| #ifdef TT_CONFIG_OPTION_EXTEND_ENGINE |
| /* Initialize the extension component */ |
| LOCAL_DEF |
| TT_Error TTExtend_Init( PEngine_Instance engine ); |
| |
| /* Finalize the extension component */ |
| LOCAL_DEF |
| TT_Error TTExtend_Done( PEngine_Instance engine ); |
| |
| /* Create an extension within a face object. Called by the */ |
| /* face object constructor. */ |
| LOCAL_DEF |
| TT_Error Extension_Create( PFace face ); |
| |
| /* Destroy all extensions within a face object. Called by the */ |
| /* face object destructor. */ |
| LOCAL_DEF |
| TT_Error Extension_Destroy( PFace face ); |
| #endif |
| |
| /* Query an extension block by extension_ID. Called by extension */ |
| /* service routines. */ |
| EXPORT_DEF |
| TT_Error TT_Extension_Get( PFace face, |
| Long extension_id, |
| void** extension_block ); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| |
| #endif /* TTEXTEND_H */ |
| |
| |
| /* END */ |