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Diffstat (limited to 'include/freetype/internal/autohint.h')
| -rw-r--r-- | include/freetype/internal/autohint.h | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/include/freetype/internal/autohint.h b/include/freetype/internal/autohint.h new file mode 100644 index 0000000..ee00402 --- /dev/null +++ b/include/freetype/internal/autohint.h @@ -0,0 +1,205 @@ +/***************************************************************************/ +/* */ +/* 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; + + +FT_END_HEADER + +#endif /* __AUTOHINT_H__ */ + + +/* END */ |