for support in nonsymmetric round rectangles
static public function drawRoundRectangle(canvas:Canvas, x:Number, y:Number, width:Number, height:Number, r0:Number, r1, r2, r3):void
{
canvas.drawPolygon(Polygon.createCircle(x + r0, y + r0, r0));
canvas.drawPolygon(Polygon.createCircle(x + width - r1, y + r1, r1));
canvas.drawPolygon(Polygon.createCircle(x + r2, y + height - r2, r2));
canvas.drawPolygon(Polygon.createCircle(x + + width - r3, y + height - r3, r3));
canvas.drawPolygon(new Polygon([
x+r0, y,
x+width-r1, y,
x+width, y+r1,
x+width, y+height-r2,
x+width-r2, y+height,
x+r3, y+height,
x, y+height-r3,
x, y-r0,
]));
}