freetype/src/type1z/t1driver.c

/*******************************************************************
 *
 *  t1driver.c
 *
 *    High-level Type1 driver interface for FreeType 2.0
 *
 *  Copyright 1996-1998 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.
 *
 ******************************************************************/

#include <t1driver.h>
#include <t1gload.h>
#include <t1load.h>
#include <t1afm.h>

#include <freetype/internal/ftdebug.h>
#include <freetype/internal/ftstream.h>
#include <freetype/internal/psnames.h>

#undef  FT_COMPONENT
#define FT_COMPONENT  trace_t1driver

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Get_Interface                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Each driver can provide one or more extensions to the base         */
  /*    FreeType API.  These can be used to access format specific         */
  /*    features (e.g., all TrueType/OpenType resources share a common     */
  /*    file structure and common tables which can be accessed through the */
  /*    `sfnt' interface), or more simply generic ones (e.g., the          */
  /*    `postscript names' interface which can be used to retrieve the     */
  /*     PostScript name of a given glyph index).                          */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    driver    :: A handle to a driver object.                          */
  /*                                                                       */
  /* <Input>                                                               */
  /*    interface :: A string designing the interface.  Examples are       */
  /*                 `sfnt', `post_names', `charmaps', etc.                */
  /*                                                                       */
  /* <Return>                                                              */
  /*    A typeless pointer to the extension's interface (normally a table  */
  /*    of function pointers).  Returns NULL if the requested extension    */
  /*    isn't available (i.e., wasn't compiled in the driver at build      */
  /*    time).                                                             */
  /*                                                                       */
  static
  FTDriver_Interface  Get_Interface( FT_Driver         driver,
                                     const FT_String*  interface )
  {
    UNUSED(driver);
    UNUSED(interface);
    
#ifndef T1_CONFIG_OPTION_NO_AFM
    if ( strcmp( (const char*)interface, "attach_file" ) == 0 )
      return (FTDriver_Interface)T1_Read_AFM;
#endif

#ifndef T1_CONFIG_OPTION_NO_MM_SUPPORT
    if ( strcmp( (const char*)interface, "get_mm" ) == 0 )
      return (FTDriver_Interface)T1_Get_Multi_Master;
      
    if ( strcmp( (const char*)interface, "set_mm_design") == 0 )
      return (FTDriver_Interface)T1_Set_MM_Design;      

    if ( strcmp( (const char*)interface, "set_mm_blend") == 0 )
      return (FTDriver_Interface)T1_Set_MM_Blend;      
#endif
    return 0;
  }


#ifndef T1_CONFIG_OPTION_NO_AFM
  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Get_Kerning                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A driver method used to return the kerning vector between two      */
  /*    glyphs of the same face.                                           */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face        :: A handle to the source face object.                 */
  /*                                                                       */
  /*    left_glyph  :: The index of the left glyph in the kern pair.       */
  /*                                                                       */
  /*    right_glyph :: The index of the right glyph in the kern pair.      */
  /*                                                                       */
  /* <Output>                                                              */
  /*    kerning     :: The kerning vector.  This is in font units for      */
  /*                   scalable formats, and in pixels for fixed-sizes     */
  /*                   formats.                                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    Only horizontal layouts (left-to-right & right-to-left) are        */
  /*    supported by this function.  Other layouts, or more sophisticated  */
  /*    kernings are out of scope of this method (the basic driver         */
  /*    interface is meant to be simple).                                  */
  /*                                                                       */
  /*    They can be implemented by format-specific interfaces.             */
  /*                                                                       */
  static
  T1_Error  Get_Kerning( T1_Face     face,
                         T1_UInt     left_glyph,
                         T1_UInt     right_glyph,
                         T1_Vector*  kerning )
  {
    T1_AFM*  afm;

    kerning->x = 0;
    kerning->y = 0;

    afm = (T1_AFM*)face->afm_data;
    if (afm)
      T1_Get_Kerning( afm, left_glyph, right_glyph, kerning );

    return T1_Err_Ok;
  }
#endif

  /******************************************************************/
  /*                                                                */
  /* <Function> Set_Char_Sizes                                      */
  /*                                                                */
  /* <Description>                                                  */
  /*    A driver method used to reset a size's character sizes      */
  /*    (horizontal and vertical) expressed in fractional points.   */
  /*                                                                */
  /* <Input>                                                        */
  /*    size        :: handle to target size object                 */
  /*    char_width  :: character width expressed in 26.6 points     */
  /*    char_height :: character height expressed in 26.6 points    */
  /*                                                                */
  /* <Return>                                                       */
  /*    FreeType error code. 0 means success                        */
  /*                                                                */
  static
  T1_Error  Set_Char_Sizes( T1_Size      size,
                            T1_F26Dot6   char_width,
                            T1_F26Dot6   char_height,
                            T1_UInt      horz_resolution,
                            T1_UInt      vert_resolution )
  {
    UNUSED(char_width);
    UNUSED(char_height);
    UNUSED(horz_resolution);
    UNUSED(vert_resolution);

    size->valid = FALSE;
    return T1_Reset_Size( size );
  }


  /******************************************************************/
  /*                                                                */
  /* <Function> Set_Pixel_Sizes                                     */
  /*                                                                */
  /* <Description>                                                  */
  /*    A driver method used to reset a size's character sizes      */
  /*    (horizontal and vertical) expressed in integer pixels.      */
  /*                                                                */
  /* <Input>                                                        */
  /*    size         :: handle to target size object                */
  /*                                                                */
  /*    pixel_width  :: character width expressed in 26.6 points    */
  /*                                                                */
  /*    pixel_height :: character height expressed in 26.6 points   */
  /*                                                                */
  /*    char_size    :: the corresponding character size in points  */
  /*                    This value is only sent to the TrueType     */
  /*                    bytecode interpreter, even though 99% of    */
  /*                    glyph programs will simply ignore it. A     */
  /*                    safe value there is the maximum of the      */
  /*                    pixel width and height (multiplied by       */
  /*                    64 to make it a 26.6 fixed float !)         */
  /* <Return>                                                       */
  /*    FreeType error code. 0 means success                        */
  /*                                                                */
  static
  T1_Error  Set_Pixel_Sizes( T1_Size     size,
                             T1_Int      pixel_width,
                             T1_Int      pixel_height )
  {
    UNUSED(pixel_width);
    UNUSED(pixel_height);

    size->valid = FALSE;
    return T1_Reset_Size(size);
  }

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Get_Char_Index                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Uses a charmap to return a given character code's glyph index.     */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charmap  :: A handle to the source charmap object.                 */
  /*    charcode :: The character code.                                    */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Glyph index.  0 means `undefined character code'.                  */
  /*                                                                       */
  static
  T1_UInt  Get_Char_Index( FT_CharMap  charmap,
                           T1_Long     charcode )
  {
    T1_Face             face;
    T1_UInt             result = 0;
    PSNames_Interface*  psnames;

    face = (T1_Face)charmap->face;
    psnames = (PSNames_Interface*)face->psnames;
    if (psnames)
      switch (charmap->encoding)
      {
       /********************************************************************/
       /*                                                                  */
       /* Unicode encoding support                                         */
       /*                                                                  */
        case ft_encoding_unicode:
          {
            /* use the "psnames" module to synthetize the Unicode charmap */
            result = psnames->lookup_unicode( &face->unicode_map,
                                              (T1_ULong)charcode );

            /* the function returns 0xFFFF when the Unicode charcode has */
            /* no corresponding glyph..                                  */
            if (result == 0xFFFF)
              result = 0;
            goto Exit;
          }

       /********************************************************************/
       /*                                                                  */
       /* Custom Type 1 encoding                                           */
       /*                                                                  */
        case ft_encoding_adobe_custom:
          {
            T1_Encoding*  encoding = &face->type1.encoding;
            if (charcode >= encoding->code_first &&
                charcode <= encoding->code_last)
            {
              result = encoding->char_index[charcode];
            }
            goto Exit;
          }

       /********************************************************************/
       /*                                                                  */
       /* Adobe Standard & Expert encoding support                         */
       /*                                                                  */
       default:
         if (charcode < 256)
         {
           FT_UInt      code;
           FT_Int       n;
           const char*  glyph_name;

           code = psnames->adobe_std_encoding[charcode];
           if (charmap->encoding == ft_encoding_adobe_expert)
             code = psnames->adobe_expert_encoding[charcode];

           glyph_name = psnames->adobe_std_strings(code);
           if (!glyph_name) break;

           for ( n = 0; n < face->type1.num_glyphs; n++ )
           {
             const char*  gname = face->type1.glyph_names[n];

             if ( gname && gname[0] == glyph_name[0] &&
                  strcmp( gname, glyph_name ) == 0 )
             {
               result = n;
               break;
             }
           }
         }
      }
  Exit:
    return result;
  }


  /******************************************************************/
  /*                                                                */
  /* <Struct> FT_DriverInterface                                    */
  /*                                                                */
  /* <Description>                                                  */
  /*    A structure used to hold a font driver's basic interface    */
  /*    used by the high-level parts of FreeType (or other apps)    */
  /*                                                                */
  /*    Most scalable drivers provide a specialized interface to    */
  /*    access format-specific features. It can be retrieved with   */
  /*    a call to the "get_format_interface", and should be defined */
  /*    in each font driver header (e.g. ttdriver.h, t1driver.h,..) */
  /*                                                                */
  /*    All fields are function pointers ..                         */
  /*                                                                */
  /*                                                                */
  /* <Fields>                                                       */
  /*                                                                */
  /*    new_engine ::                                               */
  /*        used to create and initialise a new driver object       */
  /*                                                                */
  /*    done_engine ::                                              */
  /*        used to finalise and destroy a given driver object      */
  /*                                                                */
  /*    get_format_interface ::                                     */
  /*        return a typeless pointer to the format-specific        */
  /*        driver interface.                                       */
  /*                                                                */
  /*    new_face ::                                                 */
  /*        create a new face object from a resource                */
  /*                                                                */
  /*    done_face ::                                                */
  /*        discards a face object, as well as all child objects    */
  /*        ( sizes, charmaps, glyph slots )                        */
  /*                                                                */
  /*    get_face_properties ::                                      */
  /*        return generic face properties                          */
  /*                                                                */
  /*    get_kerning ::                                              */
  /*        return the kerning vector corresponding to a pair       */
  /*        of glyphs, expressed in unscaled font units.            */
  /*                                                                */
  /*    new_size ::                                                 */
  /*        create and initialise a new scalable size object.       */
  /*                                                                */
  /*    new_fixed_size ::                                           */
  /*        create and initialise a new fixed-size object.          */
  /*                                                                */
  /*    done_size ::                                                */
  /*        finalize a given face size object.                      */
  /*                                                                */
  /*    set_size_resolutions ::                                     */
  /*        reset a scalable size object's output resolutions       */
  /*                                                                */
  /*    set_size_char_sizes ::                                      */
  /*        reset a scalable size object's character size           */
  /*                                                                */
  /*    set_pixel_sizes ::                                          */
  /*        reset a face size object's pixel dimensions. Applies    */
  /*        to both scalable and fixed faces.                       */
  /*                                                                */
  /*    new_glyph_slot ::                                           */
  /*        create and initialise a new glyph slot                  */
  /*                                                                */
  /*    done_glyph_slot ::                                          */
  /*        discard a given glyph slot                              */
  /*                                                                */
  /*    load_glyph ::                                               */
  /*        load a given glyph into a given slot                    */
  /*                                                                */
  /*    get_glyph_metrics ::                                        */
  /*        return a loaded glyph's metrics.                        */
  /*                                                                */

  const  FT_DriverInterface  t1z_driver_interface =
  {
    sizeof( FT_DriverRec ),
    sizeof( T1_FaceRec ),
    sizeof( T1_SizeRec ),
    sizeof( T1_GlyphSlotRec ),

    "type1",
    100,
    200,

    0,   /* format interface */

    (FTDriver_initDriver)           T1_Init_Driver,
    (FTDriver_doneDriver)           T1_Done_Driver,

    (FTDriver_getInterface)         Get_Interface,

    (FTDriver_initFace)             T1_Init_Face,
    (FTDriver_doneFace)             T1_Done_Face,

#ifdef T1_CONFIG_OPTION_NO_AFM
    (FTDriver_getKerning)           0,
#else
    (FTDriver_getKerning)           Get_Kerning,
#endif

    (FTDriver_initSize)             T1_Init_Size,
    (FTDriver_doneSize)             T1_Done_Size,
    (FTDriver_setCharSizes)         Set_Char_Sizes,
    (FTDriver_setPixelSizes)        Set_Pixel_Sizes,

    (FTDriver_initGlyphSlot)        T1_Init_GlyphSlot,
    (FTDriver_doneGlyphSlot)        T1_Done_GlyphSlot,
    (FTDriver_loadGlyph)            T1_Load_Glyph,

    (FTDriver_getCharIndex)         Get_Char_Index,
  };


  /******************************************************************/
  /*                                                                */
  /*  <Function> Get_FreeType_Driver_Interface                      */
  /*                                                                */
  /*  <Description>                                                 */
  /*     This function is used when compiling the TrueType driver   */
  /*     as a shared library (.DLL or .so). It will be used by the  */
  /*     high-level library of FreeType to retrieve the address of  */
  /*     the driver's generic interface.                            */
  /*                                                                */
  /*     It shouldn't be implemented in a static build, as each     */
  /*     driver must have the same function as an exported entry    */
  /*     point.                                                     */
  /*                                                                */
  /*  <Return>                                                      */
  /*     address of TrueType's driver generic interface. The        */
  /*     forma-specific interface can then be retrieved through     */
  /*     the method interface->get_format_interface..               */
  /*                                                                */

#ifdef FT_CONFIG_OPTION_DYNAMIC_DRIVERS

  EXPORT_FUNC(FT_DriverInterface*)  getDriverInterface( void )
  {
    return &t1z_driver_interface;
  }

#endif /* FT_CONFIG_OPTION_DYNAMIC_DRIVERS */