.select("#myCanvas") .fields({ node:true, size:true}) .exec((res)=>{ 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); _thi...