在mix混合绘制下,我想给绘制的图片加一个边框,怎么利用updateOption加不上去

[gxlself]

wx.getImageInfo({
src: defaultChooseImage,
success: res=>{
let defaultPaintHeaderImage = new Shape('image', { x: 150, y: 150,w:100,h:100, file: res.path, isLineDash: true, lineWidth: 2, strokeStyle: "#ffffff"}, 'mix', true);
that.wxCanvas.add(defaultPaintHeaderImage);
defaultPaintHeaderImage.updateOption({needShadow:true,shadow:{offsetX:5,offsetY:5,blur:5,color:"#ffffff"}});
}
})