我正在使用这段代码在UIImageView中绘制一个圆圈。CAShapeLayer*circleLayer=[CAShapeLayerlayer];//Givethelayerthesameboundsasyourimageview[circleLayersetBounds:CGRectMake(0.0f,0.0f,[photoViewbounds].size.width,[photoViewbounds].size.height)];//Positionthecircleanywhereyoulike,butthiswillcenterit//Intheparentlayer,whi