Index: include/freetype/ftttdrv.h |
diff --git a/include/freetype/ftttdrv.h b/include/freetype/ftttdrv.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..d5d3f1ccc183ab83437d4c01d5268b8404bb1e48 |
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+++ b/include/freetype/ftttdrv.h |
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+/***************************************************************************/ |
+/* */ |
+/* 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 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: |
+ * 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 */ |