ahglyph.c

qt-embedded-2.3.8.tar.gz源码

/***************************************************************************/
/*                                                                         */
/*  ahglyph.c                                                              */
/*                                                                         */
/*    Routines used to load and analyze a given glyph before hinting       */
/*    (body).                                                              */
/*                                                                         */
/*  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.        */
/*                                                                         */
/***************************************************************************/


#ifdef FT_FLAT_COMPILE

#include "ahglyph.h"
#include "ahangles.h"
#include "ahglobal.h"

#else

#include <autohint/ahglyph.h>
#include <autohint/ahangles.h>
#include <autohint/ahglobal.h>

#endif


#include <stdio.h>


#define xxxAH_DEBUG_GLYPH


  /* compute the direction value of a given vector.. */
  static
  AH_Direction  ah_compute_direction( FT_Pos  dx,
                                      FT_Pos  dy )
  {
    AH_Direction  dir;
    FT_Pos        ax = ABS( dx );
    FT_Pos        ay = ABS( dy );


    dir = ah_dir_none;

    /* test for vertical direction */
    if ( ax * 12 < ay )
    {
      dir = dy > 0 ? ah_dir_up : ah_dir_down;
    }
    /* test for horizontal direction */
    else if ( ay * 12 < ax )
    {
      dir = dx > 0 ? ah_dir_right : ah_dir_left;
    }

    return dir;
  }


  /* this function is used by ah_get_orientation (see below) to test */
  /* the fill direction of a given bbox extrema                      */
  static
  int  ah_test_extrema( FT_Outline*  outline,
                        int          n )
  {
    FT_Vector  *prev, *cur, *next;
    FT_Pos      product;
    FT_Int      first, last, c;


    /* we need to compute the `previous' and `next' point */
    /* for these extrema                                  */
    cur  = outline->points + n;
    prev = cur - 1;
    next = cur + 1;

    first = 0;
    for ( c = 0; c < outline->n_contours; c++ )
    {
      last  = outline->contours[c];

      if ( n == first )
        prev = outline->points + last;

      if ( n == last )
        next = outline->points + first;

      first = last + 1;
    }

    product = FT_MulDiv( cur->x  - prev->x,  /* in.x  */
                         next->y - cur->y,   /* out.y */
                         0x40 )
              -
              FT_MulDiv( cur->y  - prev->y,  /* in.y  */
                         next->x - cur->x,   /* out.x */
                         0x40 );

    if ( product )
      product = product > 0 ? 2 : 1;

    return product;
  }


  /* Compute the orientation of path filling.  It differs between TrueType */
  /* and Type1 formats.  We could use the `ft_outline_reverse_fill' flag,  */
  /* but it is better to re-compute it directly (it seems that this flag   */
  /* isn't correctly set for some weird composite glyphs currently).       */
  /*                                                                       */
  /* We do this by computing bounding box points, and computing their      */
  /* curvature.                                                            */
  /*                                                                       */
  /* The function returns either 1 or -1.                                  */
  /*                                                                       */
  static
  int  ah_get_orientation( FT_Outline*  outline )
  {
    FT_BBox  box;
    FT_BBox  indices;
    int      n, last;


    indices.xMin = -1;
    indices.yMin = -1;
    indices.xMax = -1;
    indices.yMax = -1;

    box.xMin = box.yMin =  32767;
    box.xMax = box.yMax = -32768;

    /* is it empty? */
    if ( outline->n_contours < 1 )
      return 1;

    last = outline->contours[outline->n_contours - 1];

    for ( n = 0; n <= last; n++ )
    {
      FT_Pos  x, y;


      x = outline->points[n].x;
      if ( x < box.xMin )
      {
        box.xMin     = x;
        indices.xMin = n;
      }
      if ( x > box.xMax )
      {
        box.xMax     = x;
        indices.xMax = n;
      }

      y = outline->points[n].y;
      if ( y < box.yMin )
      {
        box.yMin     = y;
        indices.yMin = n;
      }
      if ( y > box.yMax )
      {
        box.yMax     = y;
        indices.yMax = n;
      }
    }

    /* test orientation of the xmin */
    n = ah_test_extrema( outline, indices.xMin );
    if ( n )
      goto Exit;

    n = ah_test_extrema( outline, indices.yMin );
    if ( n )
      goto Exit;

    n = ah_test_extrema( outline, indices.xMax );
    if ( n )
      goto Exit;

    n = ah_test_extrema( outline, indices.yMax );
    if ( !n )
      n = 1;

  Exit:
    return n;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ah_outline_new                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Creates a new and empty AH_Outline object.                         */
  /*                                                                       */
  FT_LOCAL_DEF
  FT_Error  ah_outline_new( FT_Memory     memory,
                            AH_Outline**  aoutline )
  {
    FT_Error     error;
    AH_Outline*  outline;


    if ( !ALLOC( outline, sizeof ( *outline ) ) )
    {
      outline->memory = memory;
      *aoutline = outline;
    }

    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ah_outline_done                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Destroys a given AH_Outline object.                                */
  /*                                                                       */
  FT_LOCAL_DEF
  void  ah_outline_done( AH_Outline*  outline )
  {
    FT_Memory memory = outline->memory;


    FREE( outline->horz_edges );
    FREE( outline->horz_segments );
    FREE( outline->contours );
    FREE( outline->points );

    FREE( outline );
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ah_outline_save                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Saves the content of a given AH_Outline object into a face's glyph */
  /*    slot.                                                              */
  /*                                                                       */
  FT_LOCAL_DEF
  void  ah_outline_save( AH_Outline*  outline,
                         AH_Loader*   gloader )
  {
    AH_Point*   point       = outline->points;
    AH_Point*   point_limit = point + outline->num_points;
    FT_Vector*  vec         = gloader->current.outline.points;
    char*       tag         = gloader->current.outline.tags;


    /* we assume that the glyph loader has already been checked for storage */
    for ( ; point < point_limit; point++, vec++, tag++ )
    {
      vec->x = point->x;
      vec->y = point->y;

      if ( point->flags & ah_flah_conic )
        tag[0] = FT_Curve_Tag_Conic;
      else if ( point->flags & ah_flah_cubic )
        tag[0] = FT_Curve_Tag_Cubic;
      else
        tag[0] = FT_Curve_Tag_On;
    }
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    ah_outline_load                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads an unscaled outline from a glyph slot into an AH_Outline     */
  /*    object.                                                            */
  /*                                                                       */
  FT_LOCAL_DEF
  FT_Error  ah_outline_load( AH_Outline*  outline,
                             FT_Face      face )
  {
    FT_Memory   memory       = outline->memory;
    FT_Error    error        = FT_Err_Ok;
    FT_Outline* source       = &face->glyph->outline;
    FT_Int      num_points   = source->n_points;
    FT_Int      num_contours = source->n_contours;
    AH_Point*   points;


    /* check arguments */
    if ( !face                                          ||
         !face->size                                    ||
         face->glyph->format != ft_glyph_format_outline )
      return FT_Err_Invalid_Argument;

    /* first of all, reallocate the contours array if necessary */
    if ( num_contours > outline->max_contours )
    {
      FT_Int  new_contours = ( num_contours + 3 ) & -4;


      if ( REALLOC_ARRAY( outline->contours, outline->max_contours,
                          new_contours, AH_Point* ) )
        goto Exit;

      outline->max_contours = new_contours;
    }

    /* then, reallocate the points, segments & edges arrays if needed -- */
    /* note that we reserved two additional point positions, used to     */
    /* hint metrics appropriately                                        */
    /*                                                                   */
    if ( num_points + 2 > outline->max_points )
    {
      FT_Int  news = ( num_points + 2 + 7 ) & -8;
      FT_Int  max  = outline->max_points;


      if ( REALLOC_ARRAY( outline->points,
                          max, news, AH_Point )            ||
           REALLOC_ARRAY( outline->horz_edges,
                          max * 2, news * 2, AH_Edge )     ||
           REALLOC_ARRAY( outline->horz_segments,
                          max * 2, news * 2, AH_Segment ) )
        goto Exit;

      /* readjust some pointers */
      outline->vert_edges    = outline->horz_edges    + news;
      outline->vert_segments = outline->horz_segments + news;
      outline->max_points    = news;
    }

    outline->num_points   = num_points;
    outline->num_contours = num_contours;

    outline->num_hedges    = 0;
    outline->num_vedges    = 0;
    outline->num_hsegments = 0;
    outline->num_vsegments = 0;

#if 1

    /* We can't rely on the value of `FT_Outline.flags' to know the fill  */
    /* direction used for a glyph, given that some fonts are broken (e.g. */
    /* the Arphic ones). We thus recompute it each time we need to.       */
    /*                                                                    */
    outline->vert_major_dir = ah_dir_up;
    outline->horz_major_dir = ah_dir_left;

    if ( ah_get_orientation( source ) > 1 )
    {
      outline->vert_major_dir = ah_dir_down;
      outline->horz_major_dir = ah_dir_right;
    }

#else

    /* Compute the vertical and horizontal major directions; this is     */
    /* currently done by inspecting the `ft_outline_reverse_fill' flag.  */
    /* However, some fonts have improper glyphs, and it'd be a good idea */
    /* to be able to re-compute these values on the fly.                 */
    outline->vert_major_dir = ah_dir_up;
    outline->horz_major_dir = ah_dir_left;

    if ( source->flags & ft_outline_reverse_fill )
    {
      outline->vert_major_dir = ah_dir_down;
      outline->horz_major_dir = ah_dir_right;
    }

#endif /* 1 */

    outline->x_scale = face->size->metrics.x_scale;
    outline->y_scale = face->size->metrics.y_scale;

    points = outline->points;
    if ( outline->num_points == 0 )
      goto Exit;

    {
      /* do one thing at a time -- it is easier to understand, and */
      /* the code is clearer                                       */
      AH_Point*  point;
      AH_Point*  point_limit = points + outline->num_points;


      /* compute coordinates */
      {
        FT_Vector*  vec     = source->points;
        FT_Fixed    x_scale = outline->x_scale;
        FT_Fixed    y_scale = outline->y_scale;


        for ( point = points; point < point_limit; vec++, point++ )
        {
          point->fx = vec->x;
          point->fy = vec->y;
          point->ox = point->x = FT_MulFix( vec->x, x_scale );
          point->oy = point->y = FT_MulFix( vec->y, y_scale );

          point->flags = 0;
        }
      }

      /* compute Bezier flags */
      {
        char*  tag = source->tags;


        for ( point = points; point < point_limit; point++, tag++ )
        {
          switch ( FT_CURVE_TAG( *tag ) )
          {
          case FT_Curve_Tag_Conic:
            point->flags = ah_flah_conic; break;
          case FT_Curve_Tag_Cubic:
            point->flags = ah_flah_cubic; break;
          default:
            ;
          }
        }
      }

      /* compute `next' and `prev' */
      {
        FT_Int     contour_index;
        AH_Point*  prev;
        AH_Point*  first;
        AH_Point*  end;


        contour_index = 0;

        first = points;
        end   = points + source->contours[0];
        prev  = end;

        for ( point = points; point < point_limit; point++ )
        {
          point->prev = prev;
          if ( point < end )
          {
            point->next = point + 1;
            prev        = point;
          }
          else
          {
            point->next = first;
            contour_index++;
            if ( point + 1 < point_limit )
            {
              end   = points + source->contours[contour_index];
              first = point + 1;
              prev  = end;
            }
          }
        }
      }

      /* set-up the contours array */
      {
        AH_Point**  contour       = outline->contours;
        AH_Point**  contour_limit = contour + outline->num_contours;
        short*      end           = source->contours;
        short       index         = 0;


        for ( ; contour < contour_limit; contour++, end++ )
        {
          contour[0] = points + index;
          index      = end[0] + 1;