/// <summary>
/// Returns a DistortedOutlineShape based on the current shape and a SpiralDistortion.
/// A regular polygon with more than six corners is returned unmodified.
/// </summary>
/// <param name="r"></param>
/// <returns></returns>
private SmoothOutlineShape SpiralDistortedCopy(Random r)
{
if (this.windings == 1 && this.corners > 6)
{
return(this);
}
// d: radial distance between an edge midpoint and a corner
double d = this.sz - this.xEdge;
// dr: the same, relative to the shape size
double dr = d / this.sz;
// this would wind one corner to the following corner (over the full shape size)
double maxSpiralWinding = (double)this.windings / (double)this.corners;
// this would wind a midpoint to a corner (over their radial distance)
// this is sufficient to make the corner hang over and form a hook
maxSpiralWinding /= (2.0 * dr);
// this will produce even stronger overhanging corners
maxSpiralWinding *= (this.windings == 1 ? 1.5 : 1.2);
// Choose an actual winding ratio.
double w = (0.33 + 0.66 * r.NextDouble()) * maxSpiralWinding;
w = maxSpiralWinding;
if (r.Next(2) == 0)
{
w *= -1;
}
DistortedOutlineShape.Distortion distortion = DistortedOutlineShape.SpiralDistortion(this.xc, this.yc, this.sz, w);
return(this.DistortedCopy(distortion));
}