const formatTime = date => {
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const year = date.getFullYear()
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const month = date.getMonth() + 1
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const day = date.getDate()
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const hour = date.getHours()
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const minute = date.getMinutes()
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const second = date.getSeconds()
|
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return [year, month, day].map(formatNumber).join('/') + ' ' + [hour, minute, second].map(formatNumber).join(':')
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}
|
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const formatNumber = n => {
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n = n.toString()
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return n[1] ? n : '0' + n
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}
|
|
|
//4合1
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function convert4to1(res) {
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let arr = [];
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for (let i = 0; i < res.length; i++) {
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if (i % 4 == 0) {
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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
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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]
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//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,
|
}
|
