src/autohint/ahtypes.h

/***************************************************************************/
/*                                                                         */
/*  ahtypes.h                                                              */
/*                                                                         */
/*    General types and definitions for the auto-hint module               */
/*    (specification only).                                                */
/*                                                                         */
/*  Copyright 2000 Catharon Productions Inc.                               */
/*  Author: David Turner                                                   */
/*                                                                         */
/*  This file is part of the Catharon Typography Project and shall only    */
/*  be used, modified, and distributed under the terms of the Catharon     */
/*  Open Source License that should come with this file under the name     */
/*  `CatharonLicense.txt'.  By continuing to use, modify, or distribute    */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/*  Note that this license is compatible with the FreeType license.        */
/*                                                                         */
/***************************************************************************/


#ifndef __AHTYPES_H__
#define __AHTYPES_H__


#include <ft2build.h>
#include FT_INTERNAL_OBJECTS_H
#include FT_SOURCE_FILE(autohint,ahloader.h)


#define xxAH_DEBUG


#ifdef AH_DEBUG

#include <stdio.h>
#define AH_LOG( x )  printf##x

#else

#define AH_LOG( x )  do ; while ( 0 ) /* nothing */

#endif /* AH_DEBUG */


FT_BEGIN_HEADER


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /**** COMPILE-TIME BUILD OPTIONS                                      ****/
  /****                                                                 ****/
  /**** Toggle these configuration macros to experiment with `features' ****/
  /**** of the auto-hinter.                                             ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* If this option is defined, only strong interpolation will be used to  */
  /* place the points between edges.  Otherwise, `smooth' points are       */
  /* detected and later hinted through weak interpolation to correct some  */
  /* unpleasant artefacts.                                                 */
  /*                                                                       */
#undef AH_OPTION_NO_WEAK_INTERPOLATION


  /*************************************************************************/
  /*                                                                       */
  /* If this option is defined, only weak interpolation will be used to    */
  /* place the points between edges.  Otherwise, `strong' points are       */
  /* detected and later hinted through strong interpolation to correct     */
  /* some unpleasant artefacts.                                            */
  /*                                                                       */
#undef AH_OPTION_NO_STRONG_INTERPOLATION


  /*************************************************************************/
  /*                                                                       */
  /* Undefine this macro if you don't want to hint the metrics.  There is  */
  /* no reason to do this (at least for non-CJK scripts), except for       */
  /* experimentation.                                                      */
  /*                                                                       */
#define AH_HINT_METRICS


  /*************************************************************************/
  /*                                                                       */
  /* Define this macro if you do not want to insert extra edges at a       */
  /* glyph's x and y extremum (if there isn't one already available).      */
  /* This helps to reduce a number of artefacts and allows hinting of      */
  /* metrics.                                                              */
  /*                                                                       */
#undef AH_OPTION_NO_EXTREMUM_EDGES


  /* don't touch for now */
#define AH_MAX_WIDTHS   12
#define AH_MAX_HEIGHTS  12


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****   TYPE DEFINITIONS                                              ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  /* see agangles.h */
  typedef FT_Int  AH_Angle;


  /* hint flags */
#define ah_flah_none       0

  /* bezier control points flags */
#define ah_flah_conic                 1
#define ah_flah_cubic                 2
#define ah_flah_control               ( ah_flah_conic | ah_flah_cubic )

  /* extrema flags */
#define ah_flah_extrema_x             4
#define ah_flah_extrema_y             8

  /* roundness */
#define ah_flah_round_x              16
#define ah_flah_round_y              32

  /* touched */
#define ah_flah_touch_x              64
#define ah_flah_touch_y             128

  /* weak interpolation */
#define ah_flah_weak_interpolation  256

  typedef FT_Int AH_Flags;


  /* edge hint flags */
#define ah_edge_normal  0
#define ah_edge_round   1
#define ah_edge_serif   2
#define ah_edge_done    4

  typedef FT_Int  AH_Edge_Flags;


  /* hint directions -- the values are computed so that two vectors are */
  /* in opposite directions iff `dir1+dir2 == 0'                        */
#define ah_dir_none    4
#define ah_dir_right   1
#define ah_dir_left   -1
#define ah_dir_up      2
#define ah_dir_down   -2

  typedef FT_Int  AH_Direction;


  typedef struct AH_Point    AH_Point;
  typedef struct AH_Segment  AH_Segment;
  typedef struct AH_Edge     AH_Edge;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    AH_Point                                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure used to model an outline point to the AH_Outline type. */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    flags     :: The current point hint flags.                         */
  /*                                                                       */
  /*    ox, oy    :: The current original scaled coordinates.              */
  /*                                                                       */
  /*    fx, fy    :: The current coordinates in font units.                */
  /*                                                                       */
  /*    x,  y     :: The current hinter coordinates.                       */
  /*                                                                       */
  /*    u, v      :: Point coordinates -- meaning varies with context.     */
  /*                                                                       */
  /*    in_dir    :: The direction of the inwards vector (prev->point).    */
  /*                                                                       */
  /*    out_dir   :: The direction of the outwards vector (point->next).   */
  /*                                                                       */
  /*    in_angle  :: The angle of the inwards vector.                      */
  /*                                                                       */
  /*    out_angle :: The angle of the outwards vector.                     */
  /*                                                                       */
  /*    next      :: The next point in same contour.                       */
  /*                                                                       */
  /*    prev      :: The previous point in same contour.                   */
  /*                                                                       */
  struct AH_Point
  {
    AH_Flags      flags;    /* point flags used by hinter */
    FT_Pos        ox, oy;
    FT_Pos        fx, fy;
    FT_Pos        x,  y;
    FT_Pos        u,  v;

    AH_Direction  in_dir;   /* direction of inwards vector  */
    AH_Direction  out_dir;  /* direction of outwards vector */

    AH_Angle      in_angle;
    AH_Angle      out_angle;

    AH_Point*     next;     /* next point in contour     */
    AH_Point*     prev;     /* previous point in contour */
  };


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    AH_Segment                                                         */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure used to describe an edge segment to the auto-hinter.   */
  /*    A segment is simply a sequence of successive points located on the */
  /*    same horizontal or vertical `position', in a given direction.      */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    flags      :: The segment edge flags (straight, rounded, etc.).    */
  /*                                                                       */
  /*    dir        :: The segment direction.                               */
  /*                                                                       */
  /*    first      :: The first point in the segment.                      */
  /*                                                                       */
  /*    last       :: The last point in the segment.                       */
  /*                                                                       */
  /*    contour    :: A pointer to the first point of the segment's        */
  /*                  contour.                                             */
  /*                                                                       */
  /*    pos        :: The segment position in font units.                  */
  /*                                                                       */
  /*    size       :: The segment size.                                    */
  /*                                                                       */
  /*    edge       :: The edge of the current segment.                     */
  /*                                                                       */
  /*    edge_next  :: The next segment on the same edge.                   */
  /*                                                                       */
  /*    link       :: The pairing segment for this edge.                   */
  /*                                                                       */
  /*    serif      :: The primary segment for serifs.                      */
  /*                                                                       */
  /*    num_linked :: The number of other segments that link to this one.  */
  /*                                                                       */
  /*    score      :: Used to score the segment when selecting them.       */
  /*                                                                       */
  struct AH_Segment
  {
    AH_Edge_Flags  flags;
    AH_Direction   dir;

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

    FT_Pos         pos;         /* position of segment           */
    FT_Pos         min_coord;   /* minimum coordinate of segment */
    FT_Pos         max_coord;   /* maximum coordinate of segment */

    AH_Edge*       edge;
    AH_Segment*    edge_next;

    AH_Segment*    link;        /* link segment               */
    AH_Segment*    serif;       /* primary segment for serifs */
    FT_Pos         num_linked;  /* number of linked segments  */
    FT_Int         score;
  };


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    AH_Edge                                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure used to describe an edge, which really is a horizontal */
  /*    or vertical coordinate to be hinted depending on the segments      */
  /*    located on it.                                                     */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    flags      :: The segment edge flags (straight, rounded, etc.).    */
  /*                                                                       */
  /*    dir        :: The main segment direction on this edge.             */
  /*                                                                       */
  /*    first      :: The first edge segment.                              */
  /*                                                                       */
  /*    last       :: The last edge segment.                               */
  /*                                                                       */
  /*    fpos       :: The original edge position in font units.            */
  /*                                                                       */
  /*    opos       :: The original scaled edge position.                   */
  /*                                                                       */
  /*    pos        :: The hinted edge position.                            */
  /*                                                                       */
  /*    link       :: The linked edge.                                     */
  /*                                                                       */
  /*    serif      :: The serif edge.                                      */
  /*                                                                       */
  /*    num_paired :: The number of other edges that pair to this one.     */
  /*                                                                       */
  /*    score      :: Used to score the edge when selecting them.          */
  /*                                                                       */
  /*    blue_edge  :: Indicate the blue zone edge this edge is related to. */
  /*                  Only set for some of the horizontal edges in a Latin */
  /*                  font.                                                */
  /*                                                                       */
  struct AH_Edge
  {
    AH_Edge_Flags  flags;
    AH_Direction   dir;

    AH_Segment*    first;
    AH_Segment*    last;

    FT_Pos         fpos;
    FT_Pos         opos;
    FT_Pos         pos;

    AH_Edge*       link;
    AH_Edge*       serif;
    FT_Int         num_linked;

    FT_Int         score;
    FT_Pos*        blue_edge;
  };


  /* an outline as seen by the hinter */
  typedef struct  AH_Outline_
  {
    FT_Memory     memory;

    AH_Direction  vert_major_dir;   /* vertical major direction   */
    AH_Direction  horz_major_dir;   /* horizontal major direction */

    FT_Fixed      x_scale;
    FT_Fixed      y_scale;
    FT_Pos        edge_distance_threshold;

    FT_Int        max_points;
    FT_Int        num_points;
    AH_Point*     points;

    FT_Int        max_contours;
    FT_Int        num_contours;
    AH_Point**    contours;

    FT_Int        num_hedges;
    AH_Edge*      horz_edges;

    FT_Int        num_vedges;
    AH_Edge*      vert_edges;

    FT_Int        num_hsegments;
    AH_Segment*   horz_segments;

    FT_Int        num_vsegments;
    AH_Segment*   vert_segments;

  } AH_Outline;


#define ah_blue_capital_top     0                              /* THEZOCQS */
#define ah_blue_capital_bottom  ( ah_blue_capital_top + 1 )    /* HEZLOCUS */
#define ah_blue_small_top       ( ah_blue_capital_bottom + 1 ) /* xzroesc  */
#define ah_blue_small_bottom    ( ah_blue_small_top + 1 )      /* xzroesc  */
#define ah_blue_small_minor     ( ah_blue_small_bottom + 1 )   /* pqgjy    */
#define ah_blue_max             ( ah_blue_small_minor + 1 )

  typedef FT_Int  AH_Blue;


#define ah_hinter_monochrome  1
#define ah_hinter_optimize    2

  typedef FT_Int  AH_Hinter_Flags;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    AH_Globals                                                         */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Holds the global metrics for a given font face (be it in design    */
  /*    units or scaled pixel values).                                     */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    num_widths  :: The number of widths.                               */
  /*                                                                       */
  /*    num_heights :: The number of heights.                              */
  /*                                                                       */
  /*    widths      :: Snap widths, including standard one.                */
  /*                                                                       */
  /*    heights     :: Snap height, including standard one.                */
  /*                                                                       */
  /*    blue_refs   :: The reference positions of blue zones.              */
  /*                                                                       */
  /*    blue_shoots :: The overshoot positions of blue zones.              */
  /*                                                                       */
  typedef struct AH_Globals_
  {
    FT_Int    num_widths;
    FT_Int    num_heights;

    FT_Pos    widths [AH_MAX_WIDTHS];
    FT_Pos    heights[AH_MAX_HEIGHTS];

    FT_Pos    blue_refs  [ah_blue_max];
    FT_Pos    blue_shoots[ah_blue_max];

  } AH_Globals;


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    AH_Face_Globals                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Holds the complete global metrics for a given font face (i.e., the */
  /*    design units version + a scaled version + the current scales       */
  /*    used).                                                             */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    face    :: A handle to the source face object                      */
  /*                                                                       */
  /*    design  :: The globals in font design units.                       */
  /*                                                                       */
  /*    scaled  :: Scaled globals in sub-pixel values.                     */
  /*                                                                       */
  /*    x_scale :: The current horizontal scale.                           */
  /*                                                                       */
  /*    y_scale :: The current vertical scale.                             */
  /*                                                                       */
  typedef struct  AH_Face_Globals_
  {
    FT_Face     face;
    AH_Globals  design;
    AH_Globals  scaled;
    FT_Fixed    x_scale;
    FT_Fixed    y_scale;
    FT_Bool     control_overshoot;

  } AH_Face_Globals;


  typedef struct  AH_Hinter
  {
    FT_Memory         memory;
    AH_Hinter_Flags   flags;

    FT_Int            algorithm;
    FT_Face           face;

    AH_Face_Globals*  globals;

    AH_Outline*       glyph;

    AH_Loader*        loader;
    FT_Vector         pp1;
    FT_Vector         pp2;

    FT_Bool           transformed;
    FT_Vector         trans_delta;
    FT_Matrix         trans_matrix;

  } AH_Hinter;


FT_END_HEADER

#endif /* __AHTYPES_H__ */


/* END */