问从x、y、宽度、高度和旋转角度获取旋转后的矩形点

EN

function getRectFourPoints(x,y, width, height, ang, isDeg = false) {
  	
	if(isDeg) ang = ang * (Math.PI / 180)

	const points = {first: {x,y}}
	const sinAng = Math.sin(ang)	
	const cosAng = Math.cos(ang)
	
	let upDiff = sinAng * width
	let sideDiff = cosAng * width
	const sec = {x: x + sideDiff, y: y + upDiff}
	points.sec = sec
	
	upDiff = cosAng * height
	sideDiff = sinAng * height
	points.third = {x: x + sideDiff, y: y - upDiff}
	
	const fourth = {x: sec.x + sideDiff, y: sec.y - upDiff}
	points.fourth = fourth
	return points
}