/// <summary>
/// Returns a DistortedOutlineShape based on the current shape and a RadialWaveDistortion.
/// The distortion is exactly aligned with the polygon shape.
/// Only the polygon edges will be bent inwards; the points will not be distorted.
/// </summary>
/// <param name="r"></param>
/// <returns></returns>
private SmoothOutlineShape RadialWaveDistortedCopy(Random r)
{
int n = this.corners;
int w = this.windings;
// Note: When slant = 0, our polygons are always oriented so that one edge is in the south.
double a;
if (n % 2 == 0)
{
// For multiples of 2, there is also an edge in the north.
// Choose a to be the negative (relative) angle of the eastern corner on that edge.
a = -(0.25 - 0.5 * w / n);
}
else
{
// Otherwise, one corner is in the north.
a = -0.25;
}
a += this.slant / (2.0 * Math.PI);
double bMin = 0.2 + (n + w - 2) * 0.03; // strongly bent edges
double bMax = 0.75 + (n - 2) * 0.01; // slightly bent edges
double b = bMin + r.NextDouble() * (bMax - bMin);
DistortedOutlineShape.Distortion distortion = DistortedOutlineShape.RadialWaveDistortion(this.xc, this.yc, n, a, b);
return(this.DistortedCopy(distortion));
}
/// <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));
}
/// <summary>
/// Returns a DistortedOutlineShape based on the current shape and a RadialWaveDistortion.
/// A regular polygon with more than six corners is returned unmodified.
/// </summary>
/// <param name="r"></param>
/// <returns></returns>
private SmoothOutlineShape RadialWaveDistortedCopy(Random r)
{
int n = 3 + r.Next(6); // number of corners
double a = r.NextDouble(); // rotation, 0..1
double bMin = 0.2 + (n - 2) * 0.03; // strongly indented sides
double bMax = 0.85 + (n - 2) * 0.0166; // almost flat sides
double b = bMin + r.NextDouble() * (bMax - bMin);
DistortedOutlineShape.Distortion distortion = DistortedOutlineShape.RadialWaveDistortion(this.xc, this.yc, n, a, b);
return(this.DistortedCopy(distortion));
}