ftcache.h

奇趣公司比较新的qt/emd版本

  /*                                                                       */
  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 lookup 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>                                                         */
  /*    Creates 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>                                                         */
  /*    Empties 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>                                                         */
  /*    Destroys 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>                                                         */
  /*    Retrieves 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 TRUE, 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 FALSE to indicate the         */
  /*               horizontal resolution in dpi.                           */
  /*                                                                       */
  /*    y_res   :: Only used when `pixel' is FALSE 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, *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 );