ftcache.h

奇趣公司比较新的qt/emd版本

  /*************************************************************************
   *
   * @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   *   a given @FTC_FaceID is no longer valid, either because its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 );


  /*************************************************************************/
  /*                                                                       */
  /* <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.
   *
   *   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_Int      width;
    FT_Int      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   )

#define FTC_IMAGE_TYPE_HASH( d )                          \
          (FT_UFast)( FTC_FACE_ID_HASH( (d)->face_id )  ^ \
                      ( (d)->width << 8 ) ^ (d)->height ^ \
                      ( (d)->flags << 4 )               )


  /*************************************************************************/
  /*                                                                       */
  /* <Type>                                                                */
  /*    FTC_ImageCache                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A handle to an glyph image cache object.  They are designed to     */
  /*    hold many distinct glyph images while not exceeding a certain      */
  /*    memory threshold.                                                  */
  /*                                                                       */
  typedef struct FTC_ImageCacheRec_*  FTC_ImageCache;


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_ImageCache_New                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Creates a new glyph image cache.                                   */
  /*                                                                       */
  /* <Input>                                                               */
  /*    manager :: The parent manager for the image cache.                 */
  /*                                                                       */
  /* <Output>                                                              */
  /*    acache  :: A handle to the new glyph image cache object.           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_EXPORT( FT_Error )
  FTC_ImageCache_New( FTC_Manager      manager,
                      FTC_ImageCache  *acache );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FTC_ImageCache_Lookup                                              */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Retrieves a given glyph image from a glyph image cache.            */
  /*                                                                       */
  /* <Input>                                                               */
  /*    cache  :: A handle to the source glyph image cache.                */
  /*                                                                       */
  /*    type   :: A pointer to a glyph image type descriptor.              */
  /*                                                                       */
  /*    gindex :: The glyph index to retrieve.                             */
  /*                                                                       */
  /* <Output>                                                              */
  /*    aglyph :: The corresponding @FT_Glyph object.  0 in case of        */
  /*              failure.                                                 */
  /*                                                                       */
  /*    anode  :: Used to return the address of of the corresponding cache */
  /*              node after incrementing its reference count (see note    */
  /*              below).                                                  */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */