我运行示例项目的第三个demo，报错 "TypeError: Cannot set property 'width' of undefined"

[letear]

    const dp = createDrawPoster({
      selector: 'canvas',
    })
    dp.mount()
    console.log(dp.canvas) // undefined
    dp.canvas.width = 300
    dp.canvas.height = 300

    dp.draw((ctx) => {
      ctx.fillStyle = '#F4F4F4'
      ctx.fillRect(0, 0, 300, 300)
    })
    // 测试本地/网络地址
    const url = '/static/tabbar/wode.jpg' /* 网络图片 */
    // 测试案例一：绘制图片(矩形)
    dp.draw(async (ctx) => {
      await ctx.drawImage(url, 0, 150, 150, 150)
      await ctx.drawImage(url, 150, 150, 150, 150)
    })
    // 测试案例二：绘制图片(圆角)
    dp.draw(async (ctx) => {
      await ctx.drawRoundImage(url, 0, 0, 150, 150, 100)
      await ctx.drawRoundImage(url, 150, 0, 150, 150, 100)
    })
    // 创建本地地址
    this.imgUrl = await dp.create()
    console.log('创建地址:', { url: this.imgUrl })
  },
}

[letear]

插件版本3.0.2