thirdparty/freetype-2.3.12/include/freetype/ftgasp.h

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ftgasp.h                                                               */
   4 /*                                                                         */
   5 /*    Access of TrueType's `gasp' table (specification).                   */
   6 /*                                                                         */
   7 /*  Copyright 2007, 2008 by                                                */
   8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
   9 /*                                                                         */
  10 /*  This file is part of the FreeType project, and may only be used,       */
  11 /*  modified, and distributed under the terms of the FreeType project      */
  12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
  13 /*  this file you indicate that you have read the license and              */
  14 /*  understand and accept it fully.                                        */
  15 /*                                                                         */
  16 /***************************************************************************/
  17
  18
  19 #ifndef _FT_GASP_H_
  20 #define _FT_GASP_H_
  21
  22 #include <ft2build.h>
  23 #include FT_FREETYPE_H
  24
  25 #ifdef FREETYPE_H
  26 #error "freetype.h of FreeType 1 has been loaded!"
  27 #error "Please fix the directory search order for header files"
  28 #error "so that freetype.h of FreeType 2 is found first."
  29 #endif
  30
  31
  32   /***************************************************************************
  33    *
  34    * @section:
  35    *   gasp_table
  36    *
  37    * @title:
  38    *   Gasp Table
  39    *
  40    * @abstract:
  41    *   Retrieving TrueType `gasp' table entries.
  42    *
  43    * @description:
  44    *   The function @FT_Get_Gasp can be used to query a TrueType or OpenType
  45    *   font for specific entries in its `gasp' table, if any.  This is
  46    *   mainly useful when implementing native TrueType hinting with the
  47    *   bytecode interpreter to duplicate the Windows text rendering results.
  48    */
  49
  50   /*************************************************************************
  51    *
  52    * @enum:
  53    *   FT_GASP_XXX
  54    *
  55    * @description:
  56    *   A list of values and/or bit-flags returned by the @FT_Get_Gasp
  57    *   function.
  58    *
  59    * @values:
  60    *   FT_GASP_NO_TABLE ::
  61    *     This special value means that there is no GASP table in this face.
  62    *     It is up to the client to decide what to do.
  63    *
  64    *   FT_GASP_DO_GRIDFIT ::
  65    *     Grid-fitting and hinting should be performed at the specified ppem.
  66    *     This *really* means TrueType bytecode interpretation.
  67    *
  68    *   FT_GASP_DO_GRAY ::
  69    *     Anti-aliased rendering should be performed at the specified ppem.
  70    *
  71    *   FT_GASP_SYMMETRIC_SMOOTHING ::
  72    *     Smoothing along multiple axes must be used with ClearType.
  73    *
  74    *   FT_GASP_SYMMETRIC_GRIDFIT ::
  75    *     Grid-fitting must be used with ClearType's symmetric smoothing.
  76    *
  77    * @note:
  78    *   `ClearType' is Microsoft's implementation of LCD rendering, partly
  79    *   protected by patents.
  80    *
  81    * @since:
  82    *   2.3.0
  83    */
  84 #define FT_GASP_NO_TABLE               -1
  85 #define FT_GASP_DO_GRIDFIT           0x01
  86 #define FT_GASP_DO_GRAY              0x02
  87 #define FT_GASP_SYMMETRIC_SMOOTHING  0x08
  88 #define FT_GASP_SYMMETRIC_GRIDFIT    0x10
  89
  90
  91   /*************************************************************************
  92    *
  93    * @func:
  94    *   FT_Get_Gasp
  95    *
  96    * @description:
  97    *   Read the `gasp' table from a TrueType or OpenType font file and
  98    *   return the entry corresponding to a given character pixel size.
  99    *
 100    * @input:
 101    *   face :: The source face handle.
 102    *   ppem :: The vertical character pixel size.
 103    *
 104    * @return:
 105    *   Bit flags (see @FT_GASP_XXX), or @FT_GASP_NO_TABLE if there is no
 106    *   `gasp' table in the face.
 107    *
 108    * @since:
 109    *   2.3.0
 110    */
 111   FT_EXPORT( FT_Int )
 112   FT_Get_Gasp( FT_Face  face,
 113                FT_UInt  ppem );
 114
 115 /* */
 116
 117 #endif /* _FT_GASP_H_ */
 118
 119
 120 /* END */