ref: 6a7df625df1d43770255a4efc5856ce9d2ff0566
dir: /include/freetype/ftcffdrv.h/
/***************************************************************************/
/* */
/* 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 following lists the available properties
* together with the necessary macros and structures.
*
* The CFF driver's module name is `cff'.
*
*/
/**************************************************************************
*
* @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. 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, and the
* y~values smaller than or equal to 500 (corresponding to half a
* pixel).
*
* @note:
* This property can be used with @FT_Property_Get also.
*
*/
/* */
FT_END_HEADER
#endif /* __FTCFFDRV_H__ */
/* END */