可以试试先画到canvas上再保存为图片
wx.canvasPutImageData({
canvasId: 'myCanvas',
x: 0,
y: 0, width: frame.width,
height: frame.height,
data: frame.data, success (res) {
wx.canvasToTempFilePath({
x: 0,
y: 0,
width: frame.width,
height: frame.height,
canvasId: 'myCanvas',
success(res) {
console.log(res.tempFilePath) }})
}})
