Edit File: ftgasp.h
/***************************************************************************/ /* */ /* ftgasp.h */ /* */ /* Access of TrueType's `gasp' table (specification). */ /* */ /* Copyright 2007-2018 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. */ /* */ /***************************************************************************/ #ifndef FTGASP_H_ #define FTGASP_H_ #include <ft2build.h> #include FT_FREETYPE_H #ifdef FREETYPE_H #error "freetype.h of FreeType 1 has been loaded!" #error "Please fix the directory search order for header files" #error "so that freetype.h of FreeType 2 is found first." #endif FT_BEGIN_HEADER /*************************************************************************** * * @section: * gasp_table * * @title: * Gasp Table * * @abstract: * Retrieving TrueType `gasp' table entries. * * @description: * The function @FT_Get_Gasp can be used to query a TrueType or OpenType * font for specific entries in its `gasp' table, if any. This is * mainly useful when implementing native TrueType hinting with the * bytecode interpreter to duplicate the Windows text rendering results. */ /************************************************************************* * * @enum: * FT_GASP_XXX * * @description: * A list of values and/or bit-flags returned by the @FT_Get_Gasp * function. * * @values: * FT_GASP_NO_TABLE :: * This special value means that there is no GASP table in this face. * It is up to the client to decide what to do. * * FT_GASP_DO_GRIDFIT :: * Grid-fitting and hinting should be performed at the specified ppem. * This *really* means TrueType bytecode interpretation. If this bit * is not set, no hinting gets applied. * * FT_GASP_DO_GRAY :: * Anti-aliased rendering should be performed at the specified ppem. * If not set, do monochrome rendering. * * FT_GASP_SYMMETRIC_SMOOTHING :: * If set, smoothing along multiple axes must be used with ClearType. * * FT_GASP_SYMMETRIC_GRIDFIT :: * Grid-fitting must be used with ClearType's symmetric smoothing. * * @note: * The bit-flags `FT_GASP_DO_GRIDFIT' and `FT_GASP_DO_GRAY' are to be * used for standard font rasterization only. Independently of that, * `FT_GASP_SYMMETRIC_SMOOTHING' and `FT_GASP_SYMMETRIC_GRIDFIT' are to * be used if ClearType is enabled (and `FT_GASP_DO_GRIDFIT' and * `FT_GASP_DO_GRAY' are consequently ignored). * * `ClearType' is Microsoft's implementation of LCD rendering, partly * protected by patents. * * @since: * 2.3.0 */ #define FT_GASP_NO_TABLE -1 #define FT_GASP_DO_GRIDFIT 0x01 #define FT_GASP_DO_GRAY 0x02 #define FT_GASP_SYMMETRIC_GRIDFIT 0x04 #define FT_GASP_SYMMETRIC_SMOOTHING 0x08 /************************************************************************* * * @func: * FT_Get_Gasp * * @description: * For a TrueType or OpenType font file, return the rasterizer behaviour * flags from the font's `gasp' table corresponding to a given * character pixel size. * * @input: * face :: The source face handle. * * ppem :: The vertical character pixel size. * * @return: * Bit flags (see @FT_GASP_XXX), or @FT_GASP_NO_TABLE if there is no * `gasp' table in the face. * * @note: * If you want to use the MM functionality of OpenType variation fonts * (i.e., using @FT_Set_Var_Design_Coordinates and friends), call this * function *after* setting an instance since the return values can * change. * * @since: * 2.3.0 */ FT_EXPORT( FT_Int ) FT_Get_Gasp( FT_Face face, FT_UInt ppem ); /* */ FT_END_HEADER #endif /* FTGASP_H_ */ /* END */
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