const formatTime = date => { const year = date.getFullYear() const month = date.getMonth() + 1 const day = date.getDate() const hour = date.getHours() const minute = date.getMinutes() const second = date.getSeconds() return [year, month, day].map(formatNumber).join('/') + ' ' + [hour, minute, second].map(formatNumber).join(':') } const formatNumber = n => { n = n.toString() return n[1] ? n : '0' + n } //4合1 function convert4to1(res) { let arr = []; for (let i = 0; i < res.length; i++) { if (i % 4 == 0) { let rule = 0.29900 * res[i] + 0.58700 * res[i + 1] + 0.11400 * res[i + 2]; if (rule > 200) { res[i] = 0; } else { res[i] = 1; } arr.push(res[i]); } } return arr; } //8合1 function convert8to1(arr) { let data = []; for (let k = 0; k < arr.length; k += 8) { let temp = arr[k] * 128 + arr[k + 1] * 64 + arr[k + 2] * 32 + arr[k + 3] * 16 + arr[k + 4] * 8 + arr[k + 5] * 4 + arr[k + 6] * 2 + arr[k + 7] * 1 data.push(temp); } return data; } //我的图片宽度是240,那么拼接的指令就是[29, 118, 48, 0, 30, 0, 240, 0] //我的图片宽度是160,那么拼接的指令就是[29, 118, 48, 0, 20, 0, 160, 0] //补充一点,打印非二维码的图片,宽度一定要是24的倍数,不然打印也会出现乱码 function toArrayBuffer(res) { let arr = convert4to1(res.data); let data = convert8to1(arr); let cmds = [].concat([27, 97, 1], [29, 118, 48, 0, 30, 0, 240, 0], data, [27, 74, 3], [27, 64]); return new Uint8Array(cmds).buffer; } function zip_image(res) { let arr = convert4to1(res.data); let data = convert8to1(arr); return data; } module.exports = { formatTime: formatTime, toArrayBuffer: toArrayBuffer, zip_image: zip_image, }