单色位图的解析

wx.createSelectorQuery()         .select('#secondCanvas')         .fields({ node: true, size: true })         .exec(             (res) => {                 console.log('1111111111111111111')                 console.log(res)                 // Canvas 对象                 const canvas = res[0].node                 // Canvas 画布的实际绘制宽高                 const renderWidth = res[0].width                 const renderHeight = res[0].height                 // Canvas 绘制上下文                 const ctx = canvas.getContext('2d')                          // 初始化画布大小                 const dpr = wx.getSystemInfoSync().pixelRatio                 canvas.width = renderWidth * dpr                 canvas.height = renderHeight * dpr                 ctx.scale(dpr, dpr) // 若干绘制调用 // 这里绘制完成                     console.log('draw done')                 const img = canvas.createImage()                 img.onload = () => {                     ctx.drawImage(                         img,0,0)                 }                 img.src='https://open.weixin.qq.com/zh_CN/htmledition/res/assets/res-design-download/icon64_wx_logo.png'                 wx.downloadFile({                     url: 'https://open.weixin.qq.com/zh_CN/htmledition/res/assets/res-design-download/icon64_wx_logo.png',                     success: function(res) {                       // 下载成功后将文件转为临时路径                       if (res.statusCode === 200) {                         wx.setStorageSync('tempFilePath', res.tempFilePath);                       }                     }                   });                         this.setData({                             img: wx.getStorageSync('tempFilePath'),                             canvasHeight: canvas.height,                             canvasWidth:  canvas.width,                         });         const { canvasWidth, canvasHeight, deviceId, threshold } = this.data;                             const pix =res[0].node;                             const opt = {                                 deviceId,                                 ...this.character,                                 onProgress: (percentage) => {                                     console.log('percentage', percentage);                                     this.setData({                                         percentage,                                     });                                 },                                 lasterSuccess: () => {                                     console.log('laster success');                                     this.setData({                                         printing: false,                                         percentage: 0,                                     });                                     wx.showModal({                                         title: '提示',                                         content: '数据已发送完，请检查打印的内容是否正常',                                         showCancel: false,                                         confirmText: '好的',                                     });                                 },                             };                             this.setData({                                 printing: true,                             });                             console.log(threshold[0])                             console.log(pix)                             console.log(opt)                             //打印图片                             printImage(                                 opt,                                 overwriteImageData({                                     threshold: threshold[0],                                     imageData: pix,                                     width: canvasWidth,                                     height: canvasHeight,                                 }),                             );                               }

uni.canvasToTempFilePath（{ canvasId: 'myCanvas', success: function(res) { // res.tempFilePath 是图片的临时文件路径 var imagePath = res.tempFilePath; } }）， 现在界面里面有一个Canvas，这个把他转成图片，imagePath是图片的临时路径，现在怎么把他打印出来啊，在网上找了不少案例也不行，不是乱码 就是没反应，要么打印机滴滴的响