afhints.h

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/***************************************************************************/
/*                                                                         */
/*  afhints.h                                                              */
/*                                                                         */
/*    Auto-fitter hinting routines (specification).                        */
/*                                                                         */
/*  Copyright 2003, 2004, 2005, 2006, 2007, 2008 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 __AFHINTS_H__
#define __AFHINTS_H__

#include "aftypes.h"

#define xxAF_SORT_SEGMENTS

FT_BEGIN_HEADER

 /*
  *  The definition of outline glyph hints.  These are shared by all
  *  script analysis routines (until now).
  */

  typedef enum  AF_Dimension_
  {
    AF_DIMENSION_HORZ = 0,  /* x coordinates,                    */
                            /* i.e., vertical segments & edges   */
    AF_DIMENSION_VERT = 1,  /* y coordinates,                    */
                            /* i.e., horizontal segments & edges */

    AF_DIMENSION_MAX  /* do not remove */

  } AF_Dimension;


  /* hint directions -- the values are computed so that two vectors are */
  /* in opposite directions iff `dir1 + dir2 == 0'                      */
  typedef enum  AF_Direction_
  {
    AF_DIR_NONE  =  4,
    AF_DIR_RIGHT =  1,
    AF_DIR_LEFT  = -1,
    AF_DIR_UP    =  2,
    AF_DIR_DOWN  = -2

  } AF_Direction;


  /* point hint flags */
  typedef enum  AF_Flags_
  {
    AF_FLAG_NONE = 0,

    /* point type flags */
    AF_FLAG_CONIC   = 1 << 0,
    AF_FLAG_CUBIC   = 1 << 1,
    AF_FLAG_CONTROL = AF_FLAG_CONIC | AF_FLAG_CUBIC,

    /* point extremum flags */
    AF_FLAG_EXTREMA_X = 1 << 2,
    AF_FLAG_EXTREMA_Y = 1 << 3,

    /* point roundness flags */
    AF_FLAG_ROUND_X = 1 << 4,
    AF_FLAG_ROUND_Y = 1 << 5,

    /* point touch flags */
    AF_FLAG_TOUCH_X = 1 << 6,
    AF_FLAG_TOUCH_Y = 1 << 7,

    /* candidates for weak interpolation have this flag set */
    AF_FLAG_WEAK_INTERPOLATION = 1 << 8,

    /* all inflection points in the outline have this flag set */
    AF_FLAG_INFLECTION = 1 << 9

  } AF_Flags;


  /* edge hint flags */
  typedef enum  AF_Edge_Flags_
  {
    AF_EDGE_NORMAL = 0,
    AF_EDGE_ROUND  = 1 << 0,
    AF_EDGE_SERIF  = 1 << 1,
    AF_EDGE_DONE   = 1 << 2

  } AF_Edge_Flags;


  typedef struct AF_PointRec_*    AF_Point;
  typedef struct AF_SegmentRec_*  AF_Segment;
  typedef struct AF_EdgeRec_*     AF_Edge;


  typedef struct  AF_PointRec_
  {
    FT_UShort  flags;    /* point flags used by hinter   */
    FT_Char    in_dir;   /* direction of inwards vector  */
    FT_Char    out_dir;  /* direction of outwards vector */

    FT_Pos     ox, oy;   /* original, scaled position                   */
    FT_Short   fx, fy;   /* original, unscaled position (font units)    */
    FT_Pos     x, y;     /* current position                            */
    FT_Pos     u, v;     /* current (x,y) or (y,x) depending on context */

    AF_Point   next;     /* next point in contour     */
    AF_Point   prev;     /* previous point in contour */

  } AF_PointRec;


  typedef struct  AF_SegmentRec_
  {
    FT_Byte     flags;       /* edge/segment flags for this segment */
    FT_Char     dir;         /* segment direction                   */
    FT_Short    pos;         /* position of segment                 */
    FT_Short    min_coord;   /* minimum coordinate of segment       */
    FT_Short    max_coord;   /* maximum coordinate of segment       */
    FT_Short    height;      /* the hinted segment height           */

    AF_Edge     edge;        /* the segment's parent edge           */
    AF_Segment  edge_next;   /* link to next segment in parent edge */

    AF_Segment  link;        /* (stem) link segment        */
    AF_Segment  serif;       /* primary segment for serifs */
    FT_Pos      num_linked;  /* number of linked segments  */
    FT_Pos      score;       /* used during stem matching  */
    FT_Pos      len;         /* used during stem matching  */

    AF_Point    first;       /* first point in edge segment             */
    AF_Point    last;        /* last point in edge segment              */
    AF_Point*   contour;     /* ptr to first point of segment's contour */

  } AF_SegmentRec;


  typedef struct  AF_EdgeRec_
  {
    FT_Short    fpos;       /* original, unscaled position (font units) */
    FT_Pos      opos;       /* original, scaled position                */
    FT_Pos      pos;        /* current position                         */

    FT_Byte     flags;      /* edge flags                                   */
    FT_Char     dir;        /* edge direction                               */
    FT_Fixed    scale;      /* used to speed up interpolation between edges */
    AF_Width    blue_edge;  /* non-NULL if this is a blue edge              */

    AF_Edge     link;
    AF_Edge     serif;
    FT_Short    num_linked;

    FT_Int      score;

    AF_Segment  first;
    AF_Segment  last;

  } AF_EdgeRec;


  typedef struct  AF_AxisHintsRec_
  {
    FT_Int        num_segments;
    FT_Int        max_segments;
    AF_Segment    segments;
#ifdef AF_SORT_SEGMENTS
    FT_Int        mid_segments;
#endif

    FT_Int        num_edges;
    FT_Int        max_edges;
    AF_Edge       edges;

    AF_Direction  major_dir;

  } AF_AxisHintsRec, *AF_AxisHints;


  typedef struct  AF_GlyphHintsRec_
  {
    FT_Memory         memory;

    FT_Fixed          x_scale;
    FT_Pos            x_delta;

    FT_Fixed          y_scale;
    FT_Pos            y_delta;

    FT_Pos            edge_distance_threshold;

    FT_Int            max_points;
    FT_Int            num_points;
    AF_Point          points;

    FT_Int            max_contours;
    FT_Int            num_contours;
    AF_Point*         contours;

    AF_AxisHintsRec   axis[AF_DIMENSION_MAX];

    FT_UInt32         scaler_flags;  /* copy of scaler flags     */
    FT_UInt32         other_flags;   /* free for script-specific */
                                     /* implementations          */
    AF_ScriptMetrics  metrics;

    FT_Pos            xmin_delta;    /* used for warping */
    FT_Pos            xmax_delta;
    
  } AF_GlyphHintsRec;


#define AF_HINTS_TEST_SCALER( h, f )  ( (h)->scaler_flags & (f) )
#define AF_HINTS_TEST_OTHER( h, f )   ( (h)->other_flags  & (f) )


#ifdef AF_DEBUG

#define AF_HINTS_DO_HORIZONTAL( h )                                     \
          ( !_af_debug_disable_horz_hints                            && \
            !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_HORIZONTAL ) )

#define AF_HINTS_DO_VERTICAL( h )                                     \
          ( !_af_debug_disable_vert_hints                          && \
            !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_VERTICAL ) )

#define AF_HINTS_DO_ADVANCE( h )                                \
          !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_ADVANCE )

#define AF_HINTS_DO_BLUES( h )  ( !_af_debug_disable_blue_hints )

#else /* !AF_DEBUG */

#define AF_HINTS_DO_HORIZONTAL( h )                                \
          !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_HORIZONTAL )

#define AF_HINTS_DO_VERTICAL( h )                                \
          !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_VERTICAL )

#define AF_HINTS_DO_ADVANCE( h )                                \
          !AF_HINTS_TEST_SCALER( h, AF_SCALER_FLAG_NO_ADVANCE )

#define AF_HINTS_DO_BLUES( h )  1

#endif /* !AF_DEBUG */


  FT_LOCAL( AF_Direction )
  af_direction_compute( FT_Pos  dx,
                        FT_Pos  dy );


  FT_LOCAL( FT_Error )
  af_axis_hints_new_segment( AF_AxisHints  axis,
                             FT_Memory     memory,
                             AF_Segment   *asegment );

  FT_LOCAL( FT_Error)
  af_axis_hints_new_edge( AF_AxisHints  axis,
                          FT_Int        fpos,
                          AF_Direction  dir,
                          FT_Memory     memory,
                          AF_Edge      *edge );

  FT_LOCAL( void )
  af_glyph_hints_init( AF_GlyphHints  hints,
                       FT_Memory      memory );



  /*
   *  recompute all AF_Point in a AF_GlyphHints from the definitions
   *  in a source outline
   */
  FT_LOCAL( void )
  af_glyph_hints_rescale( AF_GlyphHints     hints,
                          AF_ScriptMetrics  metrics );

  FT_LOCAL( FT_Error )
  af_glyph_hints_reload( AF_GlyphHints  hints,
                         FT_Outline*    outline,
                         FT_Bool        get_inflections );

  FT_LOCAL( void )
  af_glyph_hints_save( AF_GlyphHints  hints,
                       FT_Outline*    outline );

  FT_LOCAL( void )
  af_glyph_hints_align_edge_points( AF_GlyphHints  hints,
                                    AF_Dimension   dim );

  FT_LOCAL( void )
  af_glyph_hints_align_strong_points( AF_GlyphHints  hints,
                                      AF_Dimension   dim );

  FT_LOCAL( void )
  af_glyph_hints_align_weak_points( AF_GlyphHints  hints,
                                    AF_Dimension   dim );

#ifdef AF_USE_WARPER
  FT_LOCAL( void )
  af_glyph_hints_scale_dim( AF_GlyphHints  hints,
                            AF_Dimension   dim,
                            FT_Fixed       scale,
                            FT_Pos         delta );
#endif

  FT_LOCAL( void )
  af_glyph_hints_done( AF_GlyphHints  hints );

/* */

#define AF_SEGMENT_LEN( seg )          ( (seg)->max_coord - (seg)->min_coord )

#define AF_SEGMENT_DIST( seg1, seg2 )  ( ( (seg1)->pos > (seg2)->pos )   \
                                           ? (seg1)->pos - (seg2)->pos   \
                                           : (seg2)->pos - (seg1)->pos )


FT_END_HEADER

#endif /* __AFHINTS_H__ */


/* END */

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