initCanvas() {
      const query = this.createSelectorQuery()
      query.select('#canvas-handwriting').fields({
        node: true,
        size: true
      }).exec(res => {
        const {canvasWidth, canvasHeight} = this.data
        canvas = res[0].node
        console.log(res[0],this.data)
        res[0].node.width= 600 // 该步骤设置完，模拟器显示仍为300
        res[0].node.height = canvasHeight
        ctx = canvas.getContext('2d')
        ctx.fillStyle = "#07C160" //F7FBFF
        ctx.fillRect(0, 0, 500, 500)
        ctx.lineWidth = this.data._strokeWidth
        ctx.scale(2,2)
      })
    },