ftoutln.c

qt-embedded-2.3.8.tar.gz源码

/***************************************************************************/
/*                                                                         */
/*  ftoutln.c                                                              */
/*                                                                         */
/*    FreeType outline management (body).                                  */
/*                                                                         */
/*  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.                                        */
/*                                                                         */
/***************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* All functions are declared in freetype.h.                             */
  /*                                                                       */
  /*************************************************************************/


#include <freetype/ftoutln.h>
#include <freetype/internal/ftobjs.h>


  /*************************************************************************/
  /*                                                                       */
  /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  /* messages during execution.                                            */
  /*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_outline


  static
  const FT_Outline  null_outline = { 0, 0, 0, 0, 0, 0 };


  /* documentation is in ftoutln.h */

  FT_EXPORT_DEF( FT_Error )  FT_Outline_Decompose(
                               FT_Outline*              outline,
                               const FT_Outline_Funcs*  interface,
                               void*                    user )
  {
#undef SCALED
#define SCALED( x )  ( ( (x) << shift ) - delta )

    FT_Vector   v_last;
    FT_Vector   v_control;
    FT_Vector   v_start;

    FT_Vector*  point;
    FT_Vector*  limit;
    char*       tags;

    FT_Error    error;

    FT_Int   n;         /* index of contour in outline     */
    FT_UInt  first;     /* index of first point in contour */
    char     tag;       /* current point's state           */

    FT_Int   shift;
    FT_Pos   delta;


    if ( !outline || !interface )
      return FT_Err_Invalid_Argument;

    shift = interface->shift;
    delta = interface->delta;
    first = 0;

    for ( n = 0; n < outline->n_contours; n++ )
    {
      FT_Int  last;  /* index of last point in contour */


      last  = outline->contours[n];
      limit = outline->points + last;

      v_start = outline->points[first];
      v_last  = outline->points[last];

      v_start.x = SCALED( v_start.x ); v_start.y = SCALED( v_start.y );
      v_last.x  = SCALED( v_last.x );  v_last.y  = SCALED( v_last.y );

      v_control = v_start;

      point = outline->points + first;
      tags  = outline->tags  + first;
      tag   = FT_CURVE_TAG( tags[0] );

      /* A contour cannot start with a cubic control point! */
      if ( tag == FT_Curve_Tag_Cubic )
        goto Invalid_Outline;

      /* check first point to determine origin */
      if ( tag == FT_Curve_Tag_Conic )
      {
        /* first point is conic control.  Yes, this happens. */
        if ( FT_CURVE_TAG( outline->tags[last] ) == FT_Curve_Tag_On )
        {
          /* start at last point if it is on the curve */
          v_start = v_last;
          limit--;
        }
        else
        {
          /* if both first and last points are conic,         */
          /* start at their middle and record its position    */
          /* for closure                                      */
          v_start.x = ( v_start.x + v_last.x ) / 2;
          v_start.y = ( v_start.y + v_last.y ) / 2;

          v_last = v_start;
        }
        point--;
        tags--;
      }

      error = interface->move_to( &v_start, user );
      if ( error )
        goto Exit;

      while ( point < limit )
      {
        point++;
        tags++;

        tag = FT_CURVE_TAG( tags[0] );
        switch ( tag )
        {
        case FT_Curve_Tag_On:  /* emit a single line_to */
          {
            FT_Vector  vec;


            vec.x = SCALED( point->x );
            vec.y = SCALED( point->y );

            error = interface->line_to( &vec, user );
            if ( error )
              goto Exit;
            continue;
          }

        case FT_Curve_Tag_Conic:  /* consume conic arcs */
          v_control.x = SCALED( point->x );
          v_control.y = SCALED( point->y );

        Do_Conic:
          if ( point < limit )
          {
            FT_Vector  vec;
            FT_Vector  v_middle;


            point++;
            tags++;
            tag = FT_CURVE_TAG( tags[0] );

            vec.x = SCALED( point->x );
            vec.y = SCALED( point->y );

            if ( tag == FT_Curve_Tag_On )
            {
              error = interface->conic_to( &v_control, &vec, user );
              if ( error )
                goto Exit;
              continue;
            }

            if ( tag != FT_Curve_Tag_Conic )
              goto Invalid_Outline;

            v_middle.x = ( v_control.x + vec.x ) / 2;
            v_middle.y = ( v_control.y + vec.y ) / 2;

            error = interface->conic_to( &v_control, &v_middle, user );
            if ( error )
              goto Exit;

            v_control = vec;
            goto Do_Conic;
          }

          error = interface->conic_to( &v_control, &v_start, user );
          goto Close;

        default:  /* FT_Curve_Tag_Cubic */
          {
            FT_Vector  vec1, vec2;


            if ( point + 1 > limit                             ||
                 FT_CURVE_TAG( tags[1] ) != FT_Curve_Tag_Cubic )
              goto Invalid_Outline;

            point += 2;
            tags  += 2;

            vec1.x = SCALED( point[-2].x ); vec1.y = SCALED( point[-2].y );
            vec2.x = SCALED( point[-1].x ); vec2.y = SCALED( point[-1].y );

            if ( point <= limit )
            {
              FT_Vector  vec;


              vec.x = SCALED( point->x );
              vec.y = SCALED( point->y );

              error = interface->cubic_to( &vec1, &vec2, &vec, user );
              if ( error )
                goto Exit;
              continue;
            }

            error = interface->cubic_to( &vec1, &vec2, &v_start, user );
            goto Close;
          }
        }
      }

      /* close the contour with a line segment */
      error = interface->line_to( &v_start, user );

    Close:
      if ( error )
        goto Exit;

      first = last + 1;
    }

    return 0;

  Exit:
    return error;

  Invalid_Outline:
    return FT_Err_Invalid_Outline;
  }


  FT_EXPORT_DEF( FT_Error )  FT_Outline_New_Internal(
                               FT_Memory    memory,
                               FT_UInt      numPoints,
                               FT_Int       numContours,
                               FT_Outline  *anoutline )
  {
    FT_Error  error;


    if ( !anoutline || !memory )
      return FT_Err_Invalid_Argument;

    *anoutline = null_outline;

    if ( ALLOC_ARRAY( anoutline->points,   numPoints * 2L, FT_Pos    ) ||
         ALLOC_ARRAY( anoutline->tags,     numPoints,      FT_Byte   ) ||
         ALLOC_ARRAY( anoutline->contours, numContours,    FT_UShort ) )
      goto Fail;

    anoutline->n_points    = (FT_UShort)numPoints;
    anoutline->n_contours  = (FT_Short)numContours;
    anoutline->flags      |= ft_outline_owner;

    return FT_Err_Ok;

  Fail:
    anoutline->flags |= ft_outline_owner;
    FT_Outline_Done_Internal( memory, anoutline );

    return error;
  }


  /* documentation is in ftoutln.h */

  FT_EXPORT_DEF( FT_Error )  FT_Outline_New( FT_Library   library,
                                             FT_UInt      numPoints,
                                             FT_Int       numContours,
                                             FT_Outline  *anoutline )
  {
    if ( !library )
      return FT_Err_Invalid_Library_Handle;

    return FT_Outline_New_Internal( library->memory, numPoints,
                                    numContours, anoutline );
  }


  /* documentation is in ftoutln.h */