truetype.h

Qt/Embedded是一个多平台的C++图形用户界面应用程序框架

  /*************************************************************/
  /*                                                           */
  /* <Struct> TT_SBit_Strike                                   */
  /*                                                           */
  /* <Description>                                             */
  /*    A structure used describe a given bitmap strike in the */
  /*    "EBLC" or "bloc" tables.                               */
  /*                                                           */
  /* <Fields>                                                  */
  /*                                                           */
  /*   num_index_ranges  :: number of index ranges             */
  /*   index_ranges      :: array of glyph index ranges        */
  /*                                                           */
  /*   color_ref   :: unused. color reference ??               */
  /*   hori        :: line metrics for horizontal layouts.     */
  /*   vert        :: line metrics for vertical layouts.       */
  /*                                                           */
  /*   start_glyph :: lowest glyph index for this strike.      */
  /*   end_glyph   :: higher glyph index for this strike.      */
  /*                                                           */
  /*   x_ppem      :: horizontal pixels per EM                 */
  /*   y_ppem      :: vertical pixels per EM                   */
  /*   bit_depth   :: bit depth. valid values are 1, 2, 4 & 8  */
  /*   flags       :: vertical or horizontal ?                 */
  /*                                                           */
  typedef struct TT_SBit_Strike_
  {
    TT_Int                 num_ranges;
    TT_SBit_Range*         sbit_ranges;
    TT_ULong               ranges_offset;

    TT_ULong               color_ref;

    TT_SBit_Line_Metrics   hori;
    TT_SBit_Line_Metrics   vert;

    TT_UShort              start_glyph;
    TT_UShort              end_glyph;

    TT_Byte                x_ppem;
    TT_Byte                y_ppem;
    TT_Byte                bit_depth;
    TT_Char                flags;

  } TT_SBit_Strike;



  
  /*************************************************************/
  /*                                                           */
  /* <Struct> TT_SBit_Component                                */
  /*                                                           */
  /* <Description>                                             */
  /*    A simple structure to describe a compound sbit element */
  /*                                                           */
  /* <Fields>                                                  */
  /*    glyph_code  :: element's glyph index                   */
  /*    x_offset    :: element's left bearing                  */
  /*    y_offset    :: element's top bearing                   */
  /*                                                           */
  typedef struct TT_SBit_Component_
  {
    TT_UShort  glyph_code;
    TT_Char    x_offset;
    TT_Char    y_offset;

  } TT_SBit_Component;



  /*************************************************************/
  /*                                                           */
  /* <Struct> TT_SBit_Scale                                    */
  /*                                                           */
  /* <Description>                                             */
  /*    A structure used describe a given bitmap scaling       */
  /*    table, asdefined for the "EBSC" table.                 */
  /*                                                           */
  /* <Fields>                                                  */
  /*                                                           */
  /*    hori   :: horizontal line metrics                      */
  /*    vert   :: vertical line metrics                        */
  /*                                                           */
  /*    x_ppem :: horizontal pixels per EM                     */
  /*    y_ppem :: vertical pixels per EM                       */
  /*                                                           */
  /*    x_ppem_substitute  :: substitution x_ppem              */
  /*    y_ppem_substitute  :: substitution y_ppem              */
  /*                                                           */
  typedef struct TT_SBit_Scale_
  {
    TT_SBit_Line_Metrics  hori;
    TT_SBit_Line_Metrics  vert;
    TT_Byte               x_ppem;
    TT_Byte               y_ppem;
    TT_Byte               x_ppem_substitute;
    TT_Byte               y_ppem_substitute;

  } TT_SBit_Scale;
#endif /* _TRUETYPE_ */


  /*************************************************************/
  /*                                                           */
  /* <Struct> TT_SBit_Image                                    */
  /*                                                           */
  /* <Description>                                             */
  /*    A structure used to describe a given embedded bitmap   */
  /*    image.                                                 */
  /*                                                           */
  /* <Fields>                                                  */
  /*    map        :: bitmap descriptor                        */
  /*    bit_depth  :: pixel bit depth                          */
  /*    metrics    :: glyph metrics for the bitmap             */
  /*                                                           */
  typedef struct TT_SBit_Image_
  {
    TT_Raster_Map         map;
    int                   bit_depth;
    TT_Big_Glyph_Metrics  metrics;

  } TT_SBit_Image;



  /*************************************************************/
  /*                                                           */
  /* <Struct> TT_EBLC                                          */
  /*                                                           */
  /* <Description>                                             */
  /*    A structure used to describe the "EBLC" table from     */
  /*    a TrueTYpe font.                                       */
  /*                                                           */
  /* <Fields>                                                  */
  /*                                                           */
  /*    version     :: version number of the EBLC table        */
  /*                                                           */
  /*    num_strikes :: the number of strikes, i.e. bitmap      */
  /*                   sizes, present in this font             */
  /*                                                           */
  /*    strikes     :: array of strikes                        */
  /*                                                           */
  typedef struct TT_EBLC_
  {
    TT_ULong         version;
    TT_ULong         num_strikes;
    TT_SBit_Strike*  strikes;

  } TT_EBLC;


  /*************************************************************/
  /*                                                           */
  /* <Function>                                                */
  /*    TT_Init_SBit_Extension                                 */
  /*                                                           */
  /* <Description>                                             */
  /*    Initialise the embedded bitmaps extension for the      */
  /*    FreeType engine.                                       */
  /*                                                           */
  /* <Input>                                                   */
  /*    engine  :: handle to current FreeType library instance */
  /*                                                           */
  /* <Return>                                                  */
  /*    Error code. 0 means success.                           */
  /*                                                           */
  EXPORT_DEF
  TT_Error  TT_Init_SBit_Extension( TT_Engine  engine );


  /*************************************************************/
  /*                                                           */
  /* <Function>                                                */
  /*    TT_Get_Face_Bitmaps                                    */
  /*                                                           */
  /* <Description>                                             */
  /*    Loads the "EBLC" table from a font file, if any.       */
  /*                                                           */
  /* <Input>                                                   */
  /*    face :: handle to the source TrueType font/face        */
  /*                                                           */
  /* <Output>                                                  */
  /*    eblc_table :: a descriptor for the EBLC table          */
  /*                                                           */
  /* <Return>                                                  */
  /*    Error code. 0 means success.                           */
  /*                                                           */
  /* <Note>                                                    */
  /*    This function returns TT_Err_Table_Missing when the    */
  /*    font contains no embedded bitmaps. All fields in       */
  /*    "eblc_table" will then be set to 0.                    */
  /*                                                           */
  EXPORT_DEF
  TT_Error  TT_Get_Face_Bitmaps( TT_Face   face,
                                 TT_EBLC  *eblc_table );

  /*************************************************************/
  /*                                                           */
  /* <Function>                                                */
  /*    TT_New_SBit_Image                                      */
  /*                                                           */
  /* <Description>                                             */
  /*    Allocates a new embedded bitmap container              */
  /*                                                           */
  /* <Output>                                                  */
  /*    image :: sbit image                                    */
  /*                                                           */
  /* <Return>                                                  */
  /*    Error code. 0 means success.                           */
  /*                                                           */
  EXPORT_DEF
  TT_Error  TT_New_SBit_Image( TT_SBit_Image*  *image );


  /*************************************************************/
  /*                                                           */
  /* <Function>                                                */
  /*    TT_Done_SBit_Image                                     */
  /*                                                           */
  /* <Description>                                             */
  /*    Releases an embedded bitmap container                  */
  /*                                                           */
  /* <Input>                                                   */
  /*    image :: sbit image                                    */
  /*                                                           */
  EXPORT_DEF
  void      TT_Done_SBit_Image( TT_SBit_Image*  image );


  /*************************************************************/
  /*                                                           */
  /* <Function>                                                */
  /*    TT_Load_Glyph_Bitmap                                   */
  /*                                                           */
  /* <Description>                                             */
  /*    Loads a given glyph embedded bitmap                    */
  /*                                                           */
  /* <Input>                                                   */
  /*    face        :: handle to the source TrueType font/face */
  /*    instance    :: current size/transform instance         */
  /*    glyph_index :: index of source glyph                   */
  /*    bitmap      :: target embedded bitmap descriptor       */
  /*                                                           */
  /* <Return>                                                  */
  /*    Error code. 0 means success.                           */
  /*                                                           */
  /* <Note>                                                    */
  /*    This function returns an error if there is no          */
  /*    embedded bitmap for the glyph at the given             */
  /*    instance.                                              */
  /*                                                           */
  EXPORT_DEF
  TT_Error  TT_Load_Glyph_Bitmap( TT_Face         face,
                                  TT_Instance     instance,
                                  TT_UShort       glyph_index,
                                  TT_SBit_Image*  bitmap );


  /*******************************************************************/
  /*                                                                 */
  /*  FreeType API                                                   */
  /*                                                                 */
  /*  All these begin with a 'TT_' prefix.                           */
  /*                                                                 */
  /*  Most of them are implemented in the 'ttapi.c' source file.     */
  /*                                                                 */
  /*******************************************************************/

  /* Initialize the engine. */

  EXPORT_DEF
  TT_Error  TT_Init_FreeType( TT_Engine*  engine );


  /* Finalize the engine, and release all allocated objects. */

  EXPORT_DEF
  TT_Error  TT_Done_FreeType( TT_Engine  engine );


  /* Set the gray level palette.  This is an array of 5 bytes used */
  /* to produce the font smoothed pixmaps.  By convention:         */
  /*                                                               */
  /*  palette[0] = background (white)                              */
  /*  palette[1] = light                                           */
  /*  palette[2] = medium                                          */
  /*  palette[3] = dark                                            */
  /*  palette[4] = foreground (black)                              */
  /*                                                               */

  EXPORT_DEF
  TT_Error  TT_Set_Raster_Gray_Palette( TT_Engine       engine,
                                        const TT_Byte*  palette );
  

  /* ----------------------- face management ----------------------- */

  /* Open a new TrueType font file, and returns a handle for */
  /* it in variable '*face'.                                 */

  /* Note: The file can be either a TrueType file (*.ttf) or  */
  /*       a TrueType collection (*.ttc, in this case, only   */
  /*       the first face is opened).  The number of faces in */
  /*       the same collection can be obtained in the face's  */
  /*       properties, using TT_Get_Face_Properties() and the */
  /*       'max_Faces' field.                                 */

  EXPORT_DEF
  TT_Error  TT_Open_Face( TT_Engine       engine,
                          const TT_Text*  fontPathName,