0,0 → 1,231 |
/***************************************************************************/ |
/* */ |
/* autohint.h */ |
/* */ |
/* High-level `autohint' module-specific interface (specification). */ |
/* */ |
/* Copyright 1996-2001, 2002, 2007 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. */ |
/* */ |
/***************************************************************************/ |
|
|
/*************************************************************************/ |
/* */ |
/* The auto-hinter is used to load and automatically hint glyphs if a */ |
/* format-specific hinter isn't available. */ |
/* */ |
/*************************************************************************/ |
|
|
#ifndef __AUTOHINT_H__ |
#define __AUTOHINT_H__ |
|
|
/*************************************************************************/ |
/* */ |
/* A small technical note regarding automatic hinting in order to */ |
/* clarify this module interface. */ |
/* */ |
/* An automatic hinter might compute two kinds of data for a given face: */ |
/* */ |
/* - global hints: Usually some metrics that describe global properties */ |
/* of the face. It is computed by scanning more or less */ |
/* aggressively the glyphs in the face, and thus can be */ |
/* very slow to compute (even if the size of global */ |
/* hints is really small). */ |
/* */ |
/* - glyph hints: These describe some important features of the glyph */ |
/* outline, as well as how to align them. They are */ |
/* generally much faster to compute than global hints. */ |
/* */ |
/* The current FreeType auto-hinter does a pretty good job while */ |
/* performing fast computations for both global and glyph hints. */ |
/* However, we might be interested in introducing more complex and */ |
/* powerful algorithms in the future, like the one described in the John */ |
/* D. Hobby paper, which unfortunately requires a lot more horsepower. */ |
/* */ |
/* Because a sufficiently sophisticated font management system would */ |
/* typically implement an LRU cache of opened face objects to reduce */ |
/* memory usage, it is a good idea to be able to avoid recomputing */ |
/* global hints every time the same face is re-opened. */ |
/* */ |
/* We thus provide the ability to cache global hints outside of the face */ |
/* object, in order to speed up font re-opening time. Of course, this */ |
/* feature is purely optional, so most client programs won't even notice */ |
/* it. */ |
/* */ |
/* I initially thought that it would be a good idea to cache the glyph */ |
/* hints too. However, my general idea now is that if you really need */ |
/* to cache these too, you are simply in need of a new font format, */ |
/* where all this information could be stored within the font file and */ |
/* decoded on the fly. */ |
/* */ |
/*************************************************************************/ |
|
|
#include <ft2build.h> |
#include FT_FREETYPE_H |
|
|
FT_BEGIN_HEADER |
|
|
typedef struct FT_AutoHinterRec_ *FT_AutoHinter; |
|
|
/*************************************************************************/ |
/* */ |
/* <FuncType> */ |
/* FT_AutoHinter_GlobalGetFunc */ |
/* */ |
/* <Description> */ |
/* Retrieves the global hints computed for a given face object the */ |
/* resulting data is dissociated from the face and will survive a */ |
/* call to FT_Done_Face(). It must be discarded through the API */ |
/* FT_AutoHinter_GlobalDoneFunc(). */ |
/* */ |
/* <Input> */ |
/* hinter :: A handle to the source auto-hinter. */ |
/* */ |
/* face :: A handle to the source face object. */ |
/* */ |
/* <Output> */ |
/* global_hints :: A typeless pointer to the global hints. */ |
/* */ |
/* global_len :: The size in bytes of the global hints. */ |
/* */ |
typedef void |
(*FT_AutoHinter_GlobalGetFunc)( FT_AutoHinter hinter, |
FT_Face face, |
void** global_hints, |
long* global_len ); |
|
|
/*************************************************************************/ |
/* */ |
/* <FuncType> */ |
/* FT_AutoHinter_GlobalDoneFunc */ |
/* */ |
/* <Description> */ |
/* Discards the global hints retrieved through */ |
/* FT_AutoHinter_GlobalGetFunc(). This is the only way these hints */ |
/* are freed from memory. */ |
/* */ |
/* <Input> */ |
/* hinter :: A handle to the auto-hinter module. */ |
/* */ |
/* global :: A pointer to retrieved global hints to discard. */ |
/* */ |
typedef void |
(*FT_AutoHinter_GlobalDoneFunc)( FT_AutoHinter hinter, |
void* global ); |
|
|
/*************************************************************************/ |
/* */ |
/* <FuncType> */ |
/* FT_AutoHinter_GlobalResetFunc */ |
/* */ |
/* <Description> */ |
/* This function is used to recompute the global metrics in a given */ |
/* font. This is useful when global font data changes (e.g. Multiple */ |
/* Masters fonts where blend coordinates change). */ |
/* */ |
/* <Input> */ |
/* hinter :: A handle to the source auto-hinter. */ |
/* */ |
/* face :: A handle to the face. */ |
/* */ |
typedef void |
(*FT_AutoHinter_GlobalResetFunc)( FT_AutoHinter hinter, |
FT_Face face ); |
|
|
/*************************************************************************/ |
/* */ |
/* <FuncType> */ |
/* FT_AutoHinter_GlyphLoadFunc */ |
/* */ |
/* <Description> */ |
/* This function is used to load, scale, and automatically hint a */ |
/* glyph from a given face. */ |
/* */ |
/* <Input> */ |
/* face :: A handle to the face. */ |
/* */ |
/* glyph_index :: The glyph index. */ |
/* */ |
/* load_flags :: The load flags. */ |
/* */ |
/* <Note> */ |
/* This function is capable of loading composite glyphs by hinting */ |
/* each sub-glyph independently (which improves quality). */ |
/* */ |
/* It will call the font driver with FT_Load_Glyph(), with */ |
/* FT_LOAD_NO_SCALE set. */ |
/* */ |
typedef FT_Error |
(*FT_AutoHinter_GlyphLoadFunc)( FT_AutoHinter hinter, |
FT_GlyphSlot slot, |
FT_Size size, |
FT_UInt glyph_index, |
FT_Int32 load_flags ); |
|
|
/*************************************************************************/ |
/* */ |
/* <Struct> */ |
/* FT_AutoHinter_ServiceRec */ |
/* */ |
/* <Description> */ |
/* The auto-hinter module's interface. */ |
/* */ |
typedef struct FT_AutoHinter_ServiceRec_ |
{ |
FT_AutoHinter_GlobalResetFunc reset_face; |
FT_AutoHinter_GlobalGetFunc get_global_hints; |
FT_AutoHinter_GlobalDoneFunc done_global_hints; |
FT_AutoHinter_GlyphLoadFunc load_glyph; |
|
} FT_AutoHinter_ServiceRec, *FT_AutoHinter_Service; |
|
#ifndef FT_CONFIG_OPTION_PIC |
|
#define FT_DEFINE_AUTOHINTER_SERVICE(class_, reset_face_, get_global_hints_, \ |
done_global_hints_, load_glyph_) \ |
FT_CALLBACK_TABLE_DEF \ |
const FT_AutoHinter_ServiceRec class_ = \ |
{ \ |
reset_face_, get_global_hints_, done_global_hints_, load_glyph_ \ |
}; |
|
#else /* FT_CONFIG_OPTION_PIC */ |
|
#define FT_DEFINE_AUTOHINTER_SERVICE(class_, reset_face_, get_global_hints_, \ |
done_global_hints_, load_glyph_) \ |
void \ |
FT_Init_Class_##class_( FT_Library library, \ |
FT_AutoHinter_ServiceRec* clazz) \ |
{ \ |
FT_UNUSED(library); \ |
clazz->reset_face = reset_face_; \ |
clazz->get_global_hints = get_global_hints_; \ |
clazz->done_global_hints = done_global_hints_; \ |
clazz->load_glyph = load_glyph_; \ |
} |
|
#endif /* FT_CONFIG_OPTION_PIC */ |
|
FT_END_HEADER |
|
#endif /* __AUTOHINT_H__ */ |
|
|
/* END */ |