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lib/Algorithm/Line/Bresenham.pm  view on Meta::CPAN

Variable thickness lines are implemented as described in
http://kt8216.unixcab.org/murphy/index.html ; This allows passing of 
two subroutine references (so the left side and the right sides of the
line can have differently varying thicknesses) along with a
user originated parameter. The subroutine reference example is shown below:

   my $leftFn=sub{
      my ($arg,$p,$l)=@_;
      # C<$arg> is passed by calling routine,
      # C<$p> is point on line
      # C<$l> is length of line
	  return $p % $arg;
   };

=cut

## Variable thickness lines using Murphy's Modification of Bresenham Line Algorithm**
## Codes ported from C in http://kt8216.unixcab.org/murphy/index.html  

 #*                            X BASED LINES                            *
 

lib/Algorithm/Line/Bresenham.pm  view on Meta::CPAN

  
  my @xPoints;
  
  my $p_error= 0;
  my $error= 0;
  my $y= $y0;
  my $x= $x0;
  my $threshold = $dx - 2*$dy;
  my $E_diag= -2*$dx;
  my $E_square= 2*$dy;
  my $length = $dx+1;
  my $D= sqrt($dx*$dx+$dy*$dy);

  for(my $p=0;$p<$length;$p++)
  {
    my $w_left=  $left->($argL, $p, $length)*2*$D;
    my $w_right= $right->($argR,$p, $length)*2*$D;
    push @xPoints,x_perpendicular($x,$y, $dx, $dy, $pxstep, $pystep,
                                      $p_error,$w_left,$w_right,$error);
    if ($error>=$threshold)
    {
      $y= $y + $ystep;
      $error = $error + $E_diag;
      if ($p_error>=$threshold) 
      {
      push @xPoints,x_perpendicular($x,$y, $dx, $dy, $pxstep, $pystep,
                                    ($p_error+$E_diag+$E_square), 

lib/Algorithm/Line/Bresenham.pm  view on Meta::CPAN

    $pxstep,$pystep)=@_;
  
  my @yPoints;
  my $p_error= 0;
  my $error= 0;
  my $y= $y0;
  my $x= $x0;
  my $threshold = $dy - 2*$dx;
  my $E_diag= -2*$dy;
  my $E_square= 2*$dx;
  my $length = $dy+1;
  my $D= sqrt($dx*$dx+$dy*$dy);

  for(my $p=0;$p<$length;$p++)
  {
    my $w_left=  $left->($argL, $p, $length)*2*$D;
    my $w_right= $right->($argR,$p, $length)*2*$D;
    push @yPoints,y_perpendicular($x,$y, $dx, $dy, $pxstep, $pystep,
                                      $p_error,$w_left,$w_right,$error);
    if ($error>=$threshold)
    {
      $x= $x + $xstep;
      $error = $error + $E_diag;
      if ($p_error>=$threshold)
      {
      push @yPoints,y_perpendicular($x,$y, $dx, $dy, $pxstep, $pystep,
                                      ($p_error+$E_diag+$E_square),$w_left,$w_right,$error);