| /***************************************************************************/ |
| /* */ |
| /* ftttdrv.h */ |
| /* */ |
| /* FreeType API for controlling the TrueType driver */ |
| /* (specification only). */ |
| /* */ |
| /* Copyright 2013 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 __FTTTDRV_H__ |
| #define __FTTTDRV_H__ |
| |
| #include "../ft2build.h" |
| #include "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: |
| * tt_driver |
| * |
| * @title: |
| * The TrueType driver |
| * |
| * @abstract: |
| * Controlling the TrueType driver module. |
| * |
| * @description: |
| * While FreeType's TrueType driver doesn't expose API functions by |
| * itself, it is possible to control its behaviour with @FT_Property_Set |
| * and @FT_Property_Get. The following lists the available properties |
| * together with the necessary macros and structures. |
| * |
| * The TrueType driver's module name is `truetype'. |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @property: |
| * interpreter-version |
| * |
| * @description: |
| * Currently, two versions are available which represent the bytecode |
| * interpreter with and without subpixel hinting support, |
| * respectively. The default is subpixel support if |
| * TT_CONFIG_OPTION_SUBPIXEL_HINTING is defined, and no subpixel |
| * support otherwise (since it isn't available then). |
| * |
| * If subpixel hinting is on, many TrueType bytecode instructions |
| * behave differently compared to B/W or grayscale rendering. The |
| * main idea is to render at a much increased horizontal resolution, |
| * then sampling down the created output to subpixel precision. |
| * However, many older fonts are not suited to this and must be |
| * specially taken care of by applying (hardcoded) font-specific |
| * tweaks. |
| * |
| * Details on subpixel hinting and some of the necessary tweaks can be |
| * found in Greg Hitchcock's whitepaper at |
| * `http://www.microsoft.com/typography/cleartype/truetypecleartype.aspx'. |
| * |
| * The following example code demonstrates how to activate subpixel |
| * hinting (omitting the error handling). |
| * |
| * { |
| * FT_Library library; |
| * FT_Face face; |
| * FT_UInt interpreter_version = TT_INTERPRETER_VERSION_38; |
| * |
| * |
| * FT_Init_FreeType( &library ); |
| * |
| * FT_Property_Set( library, "truetype", |
| * "interpreter-version", |
| * &interpreter_version ); |
| * } |
| * |
| * @note: |
| * This property can be used with @FT_Property_Get also. |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @enum: |
| * TT_INTERPRETER_VERSION_XXX |
| * |
| * @description: |
| * A list of constants used for the @interpreter-version property to |
| * select the hinting engine for Truetype fonts. |
| * |
| * The numeric value in the constant names represents the version |
| * number as returned by the `GETINFO' bytecode instruction. |
| * |
| * @values: |
| * TT_INTERPRETER_VERSION_35 :: |
| * Version~35 corresponds to MS rasterizer v.1.7 as used e.g. in |
| * Windows~98; only grayscale and B/W rasterizing is supported. |
| * |
| * TT_INTERPRETER_VERSION_38 :: |
| * Version~38 corresponds to MS rasterizer v.1.9; it is roughly |
| * equivalent to the hinting provided by DirectWrite ClearType (as |
| * can be found, for example, in the Internet Explorer~9 running on |
| * Windows~7). |
| * |
| * @note: |
| * This property controls the behaviour of the bytecode interpreter |
| * and thus how outlines get hinted. It does *not* control how glyph |
| * get rasterized! In particular, it does not control subpixel color |
| * filtering. |
| * |
| * If FreeType has not been compiled with configuration option |
| * FT_CONFIG_OPTION_SUBPIXEL_HINTING, selecting version~38 causes an |
| * `FT_Err_Unimplemented_Feature' error. |
| * |
| */ |
| #define TT_INTERPRETER_VERSION_35 35 |
| #define TT_INTERPRETER_VERSION_38 38 |
| |
| |
| /* */ |
| |
| FT_END_HEADER |
| |
| |
| #endif /* __FTTTDRV_H__ */ |
| |
| |
| /* END */ |