var textCanvas = res[0].node; // 重点1
var textCtx = textCanvas.getContext("2d"); // 重点\
that.setData({
printC: res[0].node,
});
// 获取设备设备像素比
const dpr = wx.getSystemInfoSync().pixelRatio;
textCanvas.width = res[0].width * dpr;
textCanvas.height = res[0].height * dpr;
textCtx.fillText(
that.data.drugData.drug_name,
220,
240
);