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                             ); [图片][图片]

在canvas中使用drawImage 方法绘制图片，有一张被覆盖掉了，各位大佬，有什么方法让两张图片都显示出来，一张覆盖在另一张上