ref: 69473e4efc4162cc837450e86b2621594e12af6e
dir: /src/type1/t1hinter.h/
/*******************************************************************
*
* t1hinter.h 1.2
*
* Type1 hinter.
*
* Copyright 1996-1999 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 Hinter is in charge of fitting th scaled outline to the
* pixel grid in order to considerably improve the quality of
* the Type 1 font driver's output..
*
******************************************************************/
#ifndef T1HINTER_H
#define T1HINTER_H
#include <t1objs.h>
#include <t1gload.h>
#ifdef __cplusplus
extern "C" {
#endif
/************************************************************************
*
* <Struct>
* T1_Snap_Zone
*
* <Description>
* A "snap zone" is used to model either a blue zone or a stem width
* at a given character size. It is made of a minimum and maximum
* edge, defined in 26.6 pixels, as well as one "original" and
* "scaled" position.
*
* the position corresponds to the stem width (for stem snap zones)
* or to the blue position (for blue zones)
*
* <Fields>
* orus :: original position in font units
* pix :: current position in sub-pixel units
* min :: minimum boundary in sub-pixel units
* max :: maximim boundary in sub-pixel units
*
************************************************************************/
typedef struct T1_Snap_Zone_
{
T1_Pos orus;
T1_Pos pix;
T1_Pos min;
T1_Pos max;
} T1_Snap_Zone;
/************************************************************************
*
* <Struct>
* T1_Edge
*
* <Description>
* A very simply structure used to model an stem edge
*
* <Fields>
* orus :: original edge position in font units
* pix :: scaled edge position in sub-pixel units
*
************************************************************************/
typedef struct T1_Edge_
{
T1_Pos orus;
T1_Pos pix;
} T1_Edge;
/************************************************************************
*
* <Struct>
* T1_Stem_Hint
*
* <Description>
* A simple structure used to model a stem hint
*
* <Fields>
* min_edge :: the hint's minimum edge
* max_edge :: the hint's maximum edge
* hint_flags :: some flags describing the stem properties
*
* <Note>
* the min and max edges of a ghost stem have the same position,
* even if they're coded in a weird way in the charstrings
*
************************************************************************/
typedef struct T1_Stem_Hint_
{
T1_Edge min_edge;
T1_Edge max_edge;
T1_Int hint_flags;
} T1_Stem_Hint;
#define T1_HINT_FLAG_ACTIVE 1 /* indicates an active stem */
#define T1_HINT_FLAG_MIN_BORDER 2 /* unused for now.. */
#define T1_HINT_FLAG_MAX_BORDER 4 /* unused for now.. */
/* hinter's configuration constants */
#define T1_HINTER_MAX_BLUES 24 /* maximum number of blue zones */
#define T1_HINTER_MAX_SNAPS 16 /* maximum number of stem snap zones */
#define T1_HINTER_MAX_EDGES 64 /* maximum number of stem hints */
/************************************************************************
*
* <Struct>
* T1_Size_Hints
*
* <Description>
* A structure used to model the hinting information related to
* a size object
*
* <Fields>
* supress_overshoots :: a boolean flag to tell when overshoot
* supression should occur.
*
* num_blue_zones :: the total number of blue zones (top+bottom)
* num_bottom_zones :: the number of bottom zones
*
* blue_zones :: the blue zones table. bottom zones are
* stored first in the table, followed by
* all top zones
*
* num_stem_snapH :: number of horizontal stem snap zones
* stem_snapH :: horizontal stem snap zones
*
* num_stem_snapV :: number of vertical stem snap zones
* stem_snapV :: vertical stem snap zones
*
************************************************************************/
struct T1_Size_Hints_
{
T1_Bool supress_overshoots;
T1_Int num_blue_zones;
T1_Int num_bottom_zones;
T1_Snap_Zone blue_zones[ T1_HINTER_MAX_BLUES ];
T1_Int num_snap_widths;
T1_Snap_Zone snap_widths[ T1_HINTER_MAX_SNAPS ];
T1_Int num_snap_heights;
T1_Snap_Zone snap_heights[ T1_HINTER_MAX_SNAPS ];
};
/************************************************************************
*
* <Struct>
* T1_Stem_Table
*
* <Description>
* A simple structure used to model a set of stem hints in a
* single direction during the loading of a given glyph outline.
* Not all stem hints are active at a time. Moreover, stems must
* be sorted regularly
*
* <Fields>
* num_stems :: total number of stems in table
* num_active :: number of active stems in table
*
* stems :: the table of all stems
* sort :: a table of indices into the stems table, used
* to keep a sorted list of the active stems
*
************************************************************************/
typedef struct T1_Stem_Table_
{
T1_Int num_stems;
T1_Int num_active;
T1_Stem_Hint stems[ T1_HINTER_MAX_EDGES ];
T1_Int sort [ T1_HINTER_MAX_EDGES ];
} T1_Stem_Table;
/************************************************************************
*
* <Struct>
* T1_Glyph_Hints
*
* <Description>
* A structure used to model the stem hints of a given glyph outline
* during glyph loading.
*
* <Fields>
* hori_stems :: horizontal stem hints table
* vert_stems :: vertical stem hints table
*
************************************************************************/
struct T1_Glyph_Hints_
{
T1_Stem_Table hori_stems;
T1_Stem_Table vert_stems;
};
/************************************************************************
*
* <Data>
* t1_hinter_funcs
*
* <Description>
* A table containing the address of various functions used during
* the loading of an hinted scaled outline
*
************************************************************************/
LOCAL_DEF
const T1_Hinter_Funcs t1_hinter_funcs;
/************************************************************************
*
* <Function>
* T1_New_Size_Hinter
*
* <Description>
* Allocates a new hinter structure for a given size object
*
* <Input>
* size :: handle to target size object
*
* <Return>
* Error code. 0 means success
*
************************************************************************/
LOCAL_DEF
T1_Error T1_New_Size_Hinter( T1_Size size );
/************************************************************************
*
* <Function>
* T1_Done_Size_Hinter
*
* <Description>
* Releases a given size object's hinter structure
*
* <Input>
* size :: handle to target size object
*
************************************************************************/
LOCAL_DEF
void T1_Done_Size_Hinter( T1_Size size );
/************************************************************************
*
* <Function>
* T1_Reset_Size_Hinter
*
* <Description>
* Recomputes hinting information when a given size object has
* changed its resolutions/char sizes/pixel sizes
*
* <Input>
* size :: handle to size object
*
* <Return>
* Error code. 0 means success
*
************************************************************************/
LOCAL_DEF
T1_Error T1_Reset_Size_Hinter( T1_Size size );
/************************************************************************
*
* <Function>
* T1_New_Glyph_Hinter
*
* <Description>
* Allocates a new hinter structure for a given glyph slot
*
* <Input>
* glyph :: handle to target glyph slot
*
* <Return>
* Error code. 0 means success
*
************************************************************************/
LOCAL_DEF
T1_Error T1_New_Glyph_Hinter( T1_GlyphSlot glyph );
/************************************************************************
*
* <Function>
* T1_Done_Glyph_Hinter
*
* <Description>
* Releases a given glyph slot's hinter structure
*
* <Input>
* glyph :: handle to glyph slot
*
************************************************************************/
LOCAL_DEF
void T1_Done_Glyph_Hinter( T1_GlyphSlot glyph );
/************************************************************************
*
* <Function>
* T1_Hint_Points
*
* <Description>
* this function grid-fits several points in a given Type 1 builder
* at once.
*
* <Input>
* builder :: handle to target Type 1 builder
*
************************************************************************/
LOCAL_DEF
void T1_Hint_Points( T1_Builder* builder );
/************************************************************************
*
* <Function>
* T1_Hint_Stems
*
* <Description>
* This function is used to compute the location of each stem hint
* between the first and second passes of the glyph loader on the
* charstring.
*
* <Input>
* builder :: handle to target builder
*
************************************************************************/
LOCAL_DEF
void T1_Hint_Stems( T1_Builder* builder );
#ifdef __cplusplus
}
#endif
#endif /* T1HINTER_H */