public static NSBezierPath CreatePolygonPath(this CGRect rect, int sides, double cornerRadius = 0.0, double rotationOffset = 0.0)
{
var offsetRadians = rotationOffset * Math.PI / 180;
var path = new NSBezierPath();
var theta = 2 * Math.PI / sides;
var width = (-cornerRadius + Math.Min(rect.Size.Width, rect.Size.Height)) / 2;
var center = new CGPoint(rect.Width / 2, rect.Height / 2);
var radius = width + cornerRadius - (Math.Cos(theta) * cornerRadius) / 2;
var angle = offsetRadians;
var corner = new CGPoint(center.X + (radius - cornerRadius) * Math.Cos(angle), center.Y + (radius - cornerRadius) * Math.Sin(angle));
path.MoveTo(new CGPoint(corner.X + cornerRadius * Math.Cos(angle + theta), corner.Y + cornerRadius * Math.Sin(angle + theta)));
for (var i = 0; i < sides; i++)
{
angle += theta;
corner = new CGPoint(center.X + (radius - cornerRadius) * Math.Cos(angle), center.Y + (radius - cornerRadius) * Math.Sin(angle));
var tip = new CGPoint(center.X + radius * Math.Cos(angle), center.Y + radius * Math.Sin(angle));
var start = new CGPoint(corner.X + cornerRadius * Math.Cos(angle - theta), corner.Y + cornerRadius * Math.Sin(angle - theta));
var end = new CGPoint(corner.X + cornerRadius * Math.Cos(angle + theta), corner.Y + cornerRadius * Math.Sin(angle + theta));
path.AddLineTo(start);
path.AddQuadCurveToPoint(end, tip);
}
path.ClosePath();
return(path);
}
