Page({

onReady() {

const query = wx.createSelectorQuery()

query.select('#myCanvas')

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

.exec((res) => {

//console.log(res) 打印的为null

const canvas = res[0].node

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

const dpr = wx.getSystemInfoSync().pixelRatio

canvas.width = res[0].width * dpr

canvas.height = res[0].height * dpr

ctx.scale(dpr, dpr)

ctx.fillRect(0, 0, 100, 100)

})

}

})