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Diffstat (limited to 'modules/freetype2/include/freetype/ftgasp.h')
| -rw-r--r-- | modules/freetype2/include/freetype/ftgasp.h | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/modules/freetype2/include/freetype/ftgasp.h b/modules/freetype2/include/freetype/ftgasp.h new file mode 100644 index 0000000000..d5f19add8f --- /dev/null +++ b/modules/freetype2/include/freetype/ftgasp.h @@ -0,0 +1,143 @@ +/**************************************************************************** + * + * ftgasp.h + * + * Access of TrueType's 'gasp' table (specification). + * + * Copyright (C) 2007-2023 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 <freetype/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 + + + /************************************************************************** + * + * @function: + * 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 */ |