view release on metacpan or  search on metacpan

examples/burst  view on Meta::CPAN

  # Special case 360
  my $end_angle = $start_angle + $arc_angle -
    abs($arc_angle) == 360 ? abs ($arc_angle/$spokes) : 0;

  $image->undo_group_start;

  Gimp->progress_init("Burst");
  my $progress_increment = 1/$spokes;
  my $progress = 0;

  my ($dumb, $x1, $y1, $x2, $y2) = $image->selection_bounds;
  # $image->selection_none;

  my $width = $x2 - $x1;
  my $height = $y2 - $y1;

#    print "X1 = $x1, X2 = $x2, Y1 = $y1, Y2 = $y2\n";
  my $center_x = $x1 + $width/2;
  my $center_y = $y1 + $height/2;

  if ($start_angle > $end_angle)
    { # swap them
      my $angle = $end_angle;
      $end_angle = $start_angle;
      $start_angle = $angle;
    }

  if ($shape == 0)
    { #ellipse
      # do $spokes worth
      for (my $i = 0;
	   $i < $spokes;
	   #$angle <$end_angle*PI/180-0.01;
	   $i++ )
	{
	  my $angle = $i * abs($start_angle-$end_angle)*PI/($spokes-1)/180;
	  $angle += $start_angle*PI/180;

	  # use the major/minor axis description of an ellipse:
	  # x^2   y^2
	  # --- + --- = 1
	  # a^2   b^2
	  #
	  # where a is the x axis, b is the y axis, and the equation of
	  # a line passing through 0 (y=mb).  Solve for x&y, and pick the
	  # correct one for the angle.

	  my $a = $width/2 - $outside_pixels;
	  my $b = $height/2 - $outside_pixels;

	  # dimensions for an "inside ellipse"
	  my $c = ($a>$b)?$inside_pixels:$inside_pixels*$a/$b;
	  my $d = ($a>$b)?$inside_pixels*$b/$a:$inside_pixels;

	  # get the slope
	  my $m = sin($angle)/cos($angle);
	  if ($m ==0) { $m = 0.000000000001; } #avoid div by 0
	  if ($c ==0) { $c = 0.000000000001; } #avoid div by 0
	  if ($d ==0) { $d = 0.000000000001; } #avoid div by 0

	  # find the positive solution of the quadratic for the endpoints
	  my $x = sqrt(1/((1/$a/$a)+($m*$m/$b/$b)));
	  my $y = sqrt(1/((1/($m*$m*$a*$a))+(1/$b/$b)));

	  # and find the starting points in the same manner
	  my $x_start = sqrt(1/((1/$c/$c)+($m*$m/$d/$d)));
	  my $y_start = sqrt(1/((1/($m*$m*$c*$c))+(1/$d/$d)));

	  # pick the right solution of the quadratic
	  if ((find_in_2pi($angle) < PI/2) ||
	       (find_in_2pi($angle) > 3*PI/2))
	    {
	      $x = -$x;
	      $x_start = -$x_start;
	    }
	  if (find_in_2pi($angle) > PI)
	    {
	      $y = -$y;
	      $y_start = -$y_start;
	    }
	  # do translations to center stuff
	  $x = $x + $center_x;
	  $y = $y + $center_y;
	  $x_start = $x_start + $center_x;
	  $y_start = $y_start + $center_y;

	  if ($fade_dir == 1)
	    {
	      $drawable->paintbrush_default(4, [$x, $y, $x_start, $y_start]);
	    }
	  else
	    {
	      $drawable->paintbrush_default(4, [$x_start, $y_start, $x, $y]);
	    }
	  $progress += $progress_increment;
	  Gimp->progress_update($progress);
       }
    }
  else
    { #rectangle
      # The idea here is to see where the line intersects with the
      # rightmost line.  If the abs of that is higer than the height,
      # see where it intersects the top instead.

      #print "width = $width, height = $height\n";

      my ($x, $y, $x_start, $y_start);
      for (my $i = 0;
	   $i < $spokes;
	   $i++ )
	{
	  my $angle = $i * abs($start_angle-$end_angle)*PI/($spokes-1)/180;
	  $angle += $start_angle*PI/180;

	  # get the slope
	  my $m = sin($angle)/cos($angle);
	  if (abs($m*$width/2) < $height/2)
	    { # draw on the right/left borders
	      $x = $width/2-$outside_pixels;
	      $y = $m*($width/2-$outside_pixels);
	      $x_start = ($width>$height)