let context = wx.createCanvasContext('myCanvas',this);

context.drawImage("data:image/jpeg;base64," + wx.arrayBufferToBase64(res.data), 0, 0, 150, 100);

context.draw(true, function (rs){

wx.canvasToTempFilePath({

canvasId: 'myCanvas',

success: function (res) {

self.setData({

tempSavePath: res.tempFilePath

});

}

})

});