要确保你绘制的形状是路径曲线而非形状图层（注意下图的黑箭头所示）。
Make sure you draw your shapes as paths instead of shape layers ( see arrow ) .
画一个圈背后的旋钮的形状和添加图层样式如下。
Draw a ring shape behind the knob and add following layer styles .
形状图层