| /***************************************************************************/ |
| /* */ |
| /* autohint.h */ |
| /* */ |
| /* High-level `autohint" driver interface (specification) */ |
| /* */ |
| /* Copyright 1996-2000 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 */ |
| /* when 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 |
| * agressively 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 require a lot more horsepower. |
| * |
| * Because a sufficiently sophisticated font management system would |
| * typically implement a 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 :o) |
| * |
| * I initially though that it'd be a good idea to cache the glyph hints too, |
| * however, if my general idea now is that if you really need to cache these |
| * too, you're 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 <freetype/freetype.h> |
| |
| typedef struct FT_AutoHinterRec_ *FT_AutoHinter; |
| |
| /*********************************************************************** |
| * |
| * <FuncType> |
| * FT_AutoHinter_Get_Global_Func |
| * |
| * <Description> |
| * Retrieve 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_Done_Global_Func. |
| * |
| * <Input> |
| * hinter :: handle to source auto-hinter |
| * face :: handle to source face object |
| * |
| * <Output> |
| * global_hints :: typeless pointer to the global hints |
| * global_len :: size in bytes of global hints |
| * |
| */ |
| typedef void (*FT_AutoHinter_Get_Global_Func)( FT_AutoHinter hinter, |
| FT_Face face, |
| void* *global_hints, |
| long *global_len ); |
| |
| /*********************************************************************** |
| * |
| * <FuncType> |
| * FT_AutoHinter_Done_Global_Func |
| * |
| * <Description> |
| * Discards the global hints retrieved through |
| * FT_AutoHinter_Get_Global_Func. This is the only way these hints |
| * are freed from memory. |
| * |
| * <Input> |
| * hinter :: handle to auto-hinter module |
| * global :: pointer to retrieved global hints to discard |
| */ |
| typedef void (*FT_AutoHinter_Done_Global_Func)( FT_AutoHinter hinter, |
| void* global ); |
| |
| /*********************************************************************** |
| * |
| * <FuncType> |
| * FT_AutoHinter_Init_Func |
| * |
| * <Description> |
| * Compute or set the global hints for a given face object. |
| * |
| * <Input> |
| * hinter :: handle to source auto-hinter module |
| * face :: handle to target face object. |
| * global_hints :: typeless pointer to global hints. If 0, the |
| * hints are computed for the face |
| * |
| * <Note> |
| * it is up to client applications to ensure that the global hints |
| * were retrieved for the same face object. Strange results may occur |
| * otherwise.. |
| * |
| */ |
| typedef FT_Error (*FT_AutoHinter_Init_Func)( FT_AutoHinter hinter, |
| FT_Face face, |
| void* global_hints ); |
| |
| /*********************************************************************** |
| * |
| * <FuncType> |
| * FT_AutoHinter_Done_Func |
| * |
| * <Description> |
| * Discards the global hints for a given face.. |
| * |
| * <Input> |
| * hinter :: handle to source auto-hinter module |
| * face :: handle to target face object. |
| * |
| */ |
| typedef FT_Error (*FT_AutoHinter_Done_Func)( FT_AutoHinter hinter, |
| FT_Face face ); |
| |
| |
| |
| /*********************************************************************** |
| * |
| * <FuncType> |
| * FT_AutoHinter_Load_Func |
| * |
| * <Description> |
| * This function is used to load, scale and automatically hint a glyph |
| * from a given face. |
| * |
| * <Input> |
| * face :: handle to the face. |
| * glyph_index :: glyph index |
| * load_flags :: 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_Load_Func)( FT_Face face, |
| FT_UInt glyph_index, |
| FT_ULong load_flags ); |
| |
| /*********************************************************************** |
| * |
| * <Struct> |
| * FT_AutoHinter_Interface |
| * |
| * <Description> |
| * The auto-hinter module's interface. |
| * |
| */ |
| typedef struct FT_AutoHinter_Interface |
| { |
| FT_AutoHinter_Init_Func init_autohinter; |
| FT_AutoHinter_Done_Func done_autohinter; |
| FT_AutoHinter_Load_Func load_glyph; |
| |
| FT_AutoHinter_Get_Global_Func get_global_hints; |
| FT_AutoHinter_Done_Global_Func done_global_hints; |
| |
| } FT_AutoHinter_Interface; |
| |
| #endif /* AUTOHINT_H */ |
| |
