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/***************************************************************************/
/* */
/* ttsubpix.h */
/* */
/* TrueType Subpixel Hinting. */
/* */
/* Copyright 2010-2012 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 __TTSUBPIX_H__
#define __TTSUBPIX_H__
#include <ft2build.h>
#include "ttobjs.h"
#include "ttinterp.h"
FT_BEGIN_HEADER
#ifdef TT_CONFIG_OPTION_SUBPIXEL_HINTING
/*************************************************************************/
/* */
/* Tweak flags that are set for each glyph by the below rules. */
/* */
/* */
#define SPH_TWEAK_ALLOW_X_DMOVE 0x0000001
#define SPH_TWEAK_ALLOW_X_DMOVEX 0x0000002
#define SPH_TWEAK_ALLOW_X_MOVE_ZP2 0x0000004
#define SPH_TWEAK_ALWAYS_DO_DELTAP 0x0000008
#define SPH_TWEAK_ALWAYS_SKIP_DELTAP 0x0000010
#define SPH_TWEAK_COURIER_NEW_2_HACK 0x0000020
#define SPH_TWEAK_DEEMBOLDEN 0x0000040
#define SPH_TWEAK_DELTAP_SKIP_EXAGGERATED_VALUES 0x0000080
#define SPH_TWEAK_DO_SHPIX 0x0000100
#define SPH_TWEAK_EMBOLDEN 0x0000200
#define SPH_TWEAK_MIAP_HACK 0x0000400
#define SPH_TWEAK_NORMAL_ROUND 0x0000800
#define SPH_TWEAK_NO_ALIGNRP_AFTER_IUP 0x0001000
#define SPH_TWEAK_NO_CALL_AFTER_IUP 0x0002000
#define SPH_TWEAK_NO_DELTAP_AFTER_IUP 0x0004000
#define SPH_TWEAK_PIXEL_HINTING 0x0008000
#define SPH_TWEAK_RASTERIZER_35 0x0010000
#define SPH_TWEAK_ROUND_NONPIXEL_Y_MOVES 0x0020000
#define SPH_TWEAK_SKIP_INLINE_DELTAS 0x0040000
#define SPH_TWEAK_SKIP_IUP 0x0080000
#define SPH_TWEAK_SKIP_NONPIXEL_Y_MOVES 0x0100000
#define SPH_TWEAK_SKIP_OFFPIXEL_Y_MOVES 0x0200000
#define SPH_TWEAK_TIMES_NEW_ROMAN_HACK 0x0400000
#define SPH_TWEAK_MIRP_CVT_ZERO 0x0800000
FT_LOCAL( FT_Bool )
sph_test_tweak( TT_Face face,
const FT_String* family,
FT_UInt ppem,
const FT_String* style,
FT_UInt glyph_index,
const SPH_TweakRule* rule,
FT_UInt num_rules );
FT_LOCAL_DEF( FT_UInt )
scale_test_tweak( TT_Face face,
const FT_String* family,
FT_UInt ppem,
const FT_String* style,
FT_UInt glyph_index,
const SPH_ScaleRule* rule,
FT_UInt num_rules );
FT_LOCAL( void )
sph_set_tweaks( TT_Loader loader,
FT_UInt glyph_index );
#define SPH_X_SCALING_RULES_SIZE 50
FT_LOCAL( const SPH_ScaleRule* const ) sph_X_SCALING_Rules;
/*************************************************************************/
/* */
/* These rules affect how the TT Interpreter does hinting, with the */
/* goal of doing subpixel hinting by (in general) ignoring x moves. */
/* Some of these rules are fixes that go above and beyond the */
/* stated techniques in the MS whitepaper on Cleartype, due to */
/* artifacts in many glyphs. So, these rules make some glyphs render */
/* better than they do in the MS rasterizer. */
/* */
/* "" string or 0 int/char indicates to apply to all glyphs. */
/* "-" used as dummy placeholders, but any non-matching string works. */
/* */
/* Some of this could arguably be implemented in fontconfig, however: */
/* */
/* - Fontconfig can't set things on a glyph-by-glyph basis. */
/* - The tweaks that happen here are very low-level, from an average */
/* user's point of view and are best implemented in the hinter. */
/* */
/* The goal is to make the subpixel hinting techniques as generalized */
/* as possible across all fonts to prevent the need for extra rules such */
/* as these. */
/* */
/* The rule structure is designed so that entirely new rules can easily */
/* be added when a new compatibility feature is discovered. */
/* */
/* The rule structures could also use some enhancement to handle ranges. */
/* */
/* ****************** WORK IN PROGRESS ******************* */
/* */
/* These macros are defined absent a method for setting them */
#define SPH_OPTION_BITMAP_WIDTHS FALSE
#define SPH_OPTION_SET_SUBPIXEL TRUE
#define SPH_OPTION_SET_GRAYSCALE FALSE
#define SPH_OPTION_SET_COMPATIBLE_WIDTHS FALSE
#define SPH_OPTION_SET_RASTERIZER_VERSION 38
#endif /* TT_CONFIG_OPTION_SUBPIXEL_HINTING */
FT_END_HEADER
#endif /* __TTSUBPIX_H__ */
/* END */
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