UIImageView 圆角设置

   

    imgLogo.layer.masksToBounds= YES;   //设置在layer之下的都盖住
    imgLogo.layer.cornerRadius = imgLogo.bounds.size.width*0.5;  //设置layer的圆角，是自身宽度的一半
    imgLogo.layer.borderWidth=3.0;  //圆角边框宽度
    imgLogo.layer.borderColor = A_RGBA(173, 173, 173, 1).CGColor;   //圆角颜色