canvas 2d
transform.js
function drawRectangle(context) {
	context.save();	
	context.moveTo(leftX, topY);
	context.lineTo(leftX + width - cornerRadius, topY);
	context.arcTo(leftX + width, topY, leftX + width, topY + cornerRadius,
			cornerRadius);
	context.lineTo(leftX + width, topY + height);
	context.lineTo(leftX, topY + height);
	context.closePath();
	context.restore();
	context.strokeStyle = "black";
	context.stroke();
	context.fillStyle = "yellow";
	context.fill();
};
function drawEllipse(context, x, y, w, h) {
	var s = h / w;
	context.save();
	context.beginPath();
	context.translate(0, y - y * s);
	context.scale(1, s);
	context.arc(x + w / 2, y + w / 2, w / 2, 0, 2 * Math.PI, false);
	context.restore();
};