ftcache.h

qt-x11-opensource-src-4.1.4.tar.gz源码

  /*                                                                       */
  /*    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.                             */
  /*                                                                       */
  /* <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 );


  /*************************************************************************/
  /*                                                                       */
  /* <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>                                                         */
  /*    Creates 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>                                                         */
  /*    Looks 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 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 );


 /* */

FT_END_HEADER

#endif /* __FTCACHE_H__ */


/* END */