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Diffstat (limited to 'include/freetype2/ftcffdrv.h')
| -rw-r--r-- | include/freetype2/ftcffdrv.h | 254 |
1 files changed, 0 insertions, 254 deletions
diff --git a/include/freetype2/ftcffdrv.h b/include/freetype2/ftcffdrv.h deleted file mode 100644 index e4d039d..0000000 --- a/include/freetype2/ftcffdrv.h +++ /dev/null @@ -1,254 +0,0 @@ -/***************************************************************************/ -/* */ -/* ftcffdrv.h */ -/* */ -/* FreeType API for controlling the CFF 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 __FTCFFDRV_H__ -#define __FTCFFDRV_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: - * cff_driver - * - * @title: - * The CFF driver - * - * @abstract: - * Controlling the CFF driver module. - * - * @description: - * While FreeType's CFF driver doesn't expose API functions by itself, - * it is possible to control its behaviour with @FT_Property_Set and - * @FT_Property_Get. The list below gives the available properties - * together with the necessary macros and structures. - * - * The CFF driver's module name is `cff'. - * - * *Hinting* *and* *antialiasing* *principles* *of* *the* *new* *engine* - * - * The rasterizer is positioning horizontal features (e.g., ascender - * height & x-height, or crossbars) on the pixel grid and minimizing the - * amount of antialiasing applied to them, while placing vertical - * features (vertical stems) on the pixel grid without hinting, thus - * representing the stem position and weight accurately. Sometimes the - * vertical stems may be only partially black. In this context, - * `antialiasing' means that stems are not positioned exactly on pixel - * borders, causing a fuzzy appearance. - * - * There are two principles behind this approach. - * - * 1) No hinting in the horizontal direction: Unlike `superhinted' - * TrueType, which changes glyph widths to accommodate regular - * inter-glyph spacing, Adobe's approach is `faithful to the design' in - * representing both the glyph width and the inter-glyph spacing - * designed for the font. This makes the screen display as close as it - * can be to the result one would get with infinite resolution, while - * preserving what is considered the key characteristics of each glyph. - * Note that the distances between unhinted and grid-fitted positions at - * small sizes are comparable to kerning values and thus would be - * noticeable (and distracting) while reading if hinting were applied. - * - * One of the reasons to not hint horizontally is antialiasing for LCD - * screens: The pixel geometry of modern displays supplies three - * vertical sub-pixels as the eye moves horizontally across each visible - * pixel. On devices where we can be certain this characteristic is - * present a rasterizer can take advantage of the sub-pixels to add - * increments of weight. In Western writing systems this turns out to - * be the more critical direction anyway; the weights and spacing of - * vertical stems (see above) are central to Armenian, Cyrillic, Greek, - * and Latin type designs. Even when the rasterizer uses greyscale - * antialiasing instead of color (a necessary compromise when one - * doesn't know the screen characteristics), the unhinted vertical - * features preserve the design's weight and spacing much better than - * aliased type would. - * - * 2) Aligment in the vertical direction: Weights and spacing along the - * y~axis are less critical; what is much more important is the visual - * alignment of related features (like cap-height and x-height). The - * sense of alignment for these is enhanced by the sharpness of grid-fit - * edges, while the cruder vertical resolution (full pixels instead of - * 1/3 pixels) is less of a problem. - * - * On the technical side, horizontal alignment zones for ascender, - * x-height, and other important height values (traditionally called - * `blue zones') as defined in the font are positioned independently, - * each being rounded to the nearest pixel edge, taking care of - * overshoot suppression at small sizes, stem darkening, and scaling. - * - * Hstems (this is, hint values defined in the font to help align - * horizontal features) that fall within a blue zone are said to be - * `captured' and are aligned to that zone. Uncaptured stems are moved - * in one of four ways, top edge up or down, bottom edge up or down. - * Unless there are conflicting hstems, the smallest movement is taken - * to minimize distortion. - */ - - - /************************************************************************** - * - * @property: - * hinting-engine - * - * @description: - * Thanks to Adobe, which contributed a new hinting (and parsing) - * engine, an application can select between `freetype' and `adobe' if - * compiled with CFF_CONFIG_OPTION_OLD_ENGINE. If this configuration - * macro isn't defined, `hinting-engine' does nothing. - * - * The default engine is `freetype' if CFF_CONFIG_OPTION_OLD_ENGINE is - * defined, and `adobe' otherwise. - * - * The following example code demonstrates how to select Adobe's hinting - * engine (omitting the error handling). - * - * { - * FT_Library library; - * FT_UInt hinting_engine = FT_CFF_HINTING_ADOBE; - * - * - * FT_Init_FreeType( &library ); - * - * FT_Property_Set( library, "cff", - * "hinting-engine", &hinting_engine ); - * } - * - * @note: - * This property can be used with @FT_Property_Get also. - * - */ - - - /************************************************************************** - * - * @enum: - * FT_CFF_HINTING_XXX - * - * @description: - * A list of constants used for the @hinting-engine property to select - * the hinting engine for CFF fonts. - * - * @values: - * FT_CFF_HINTING_FREETYPE :: - * Use the old FreeType hinting engine. - * - * FT_CFF_HINTING_ADOBE :: - * Use the hinting engine contributed by Adobe. - * - */ -#define FT_CFF_HINTING_FREETYPE 0 -#define FT_CFF_HINTING_ADOBE 1 - - - /************************************************************************** - * - * @property: - * no-stem-darkening - * - * @description: - * By default, the Adobe CFF engine darkens stems at smaller sizes, - * regardless of hinting, to enhance contrast. This feature requires - * a rendering system with proper gamma correction. Setting this - * property, stem darkening gets switched off. - * - * Note that stem darkening is never applied if @FT_LOAD_NO_SCALE is set. - * - * { - * FT_Library library; - * FT_Bool no_stem_darkening = TRUE; - * - * - * FT_Init_FreeType( &library ); - * - * FT_Property_Set( library, "cff", - * "no-stem-darkening", &no_stem_darkening ); - * } - * - * @note: - * This property can be used with @FT_Property_Get also. - * - */ - - - /************************************************************************** - * - * @property: - * darkening-parameters - * - * @description: - * By default, the Adobe CFF engine darkens stems as follows (if the - * `no-stem-darkening' property isn't set): - * - * { - * stem width <= 0.5px: darkening amount = 0.4px - * stem width = 1px: darkening amount = 0.275px - * stem width = 1.667px: darkening amount = 0.275px - * stem width >= 2.333px: darkening amount = 0px - * } - * - * and piecewise linear in-between. Using the `darkening-parameters' - * property, these four control points can be changed, as the following - * example demonstrates. - * - * { - * FT_Library library; - * FT_Int darken_params[8] = { 500, 300, // x1, y1 - * 1000, 200, // x2, y2 - * 1500, 100, // x3, y3 - * 2000, 0 }; // x4, y4 - * - * - * FT_Init_FreeType( &library ); - * - * FT_Property_Set( library, "cff", - * "darkening-parameters", darken_params ); - * } - * - * The x~values give the stem width, and the y~values the darkening - * amount. The unit is 1000th of pixels. All coordinate values must be - * positive; the x~values must be monotonically increasing; the - * y~values must be monotonically decreasing and smaller than or - * equal to 500 (corresponding to half a pixel); the slope of each - * linear piece must be shallower than -1 (e.g., -.4). - * - * @note: - * This property can be used with @FT_Property_Get also. - * - */ - - - /* */ - -FT_END_HEADER - - -#endif /* __FTCFFDRV_H__ */ - - -/* END */ |