我是做了一个组件创建Canvas 这一直获取不到Canvas 咋回事？

wx.createSelectorQuery()

.in(this)

.select('#image-cropper')// 在 WXML 中填入的 id

.fields({ node: true, size: true })

.exec((res) => {

console.log(res,33333)

// Canvas 对象

this.canvas= res[0].node

// 渲染上下文

this.ctx = this.canvas.getContext('2d')

this.canvas.width=this.data._canvas_width * this.data.export_scale

this.canvas.height=this.data._canvas_height * this.data.export_scale

this.data.PushImg=this.canvas.createImage()

})