- 当前 Bug 的表现（可附上截图）

- 预期表现

- 复现路径

- 提供一个最简复现 Demo

// src/myOpenDataContext/index.js
开放域
let sharedCanvas = wx.getSharedCanvas()
let context 
let context = sharedCanvas.getContext('2d')
context.fillStyle = 'red'context.fillRect(0, 0, 100, 100)

//主域

let openDataContext = wx.getOpenDataContext()
let sharedCanvas 
let sharedCanvas = openDataContext.canvas

let canvas = wx.createCanvas()
let context = canvas.getContext('2d')
context.drawImage(sharedCanvas, 0, 0)