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68 lines
2.2 KiB
68 lines
2.2 KiB
const path = require('path')
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const sharp = require('sharp');
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const sharp1 = require('sharp');
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const getSlide = async () => {
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const width = 334
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const height = 140
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const fragmentSize = 35
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try {
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// 随机选择某个图片
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const filePath = getRandomPath()
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//随机选择空缺部分的x y 坐标
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const x = (Math.floor(Math.random() * 1000) % (width - 2 * fragmentSize)) + fragmentSize
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const y = Math.floor(Math.random() * 1000) % (height - fragmentSize)
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//获得大小图
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const { image, fragment } = await createImage(filePath, width, height, fragmentSize, x, y)
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console.log(image,fragment)
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return { success: true, data: { image, fragment, x, y } }
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} catch (err) {
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return {success: false, msg: "服务器错误:" + err, data: null }
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}
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}
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function getRandomPath() {
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const fileLength = 2
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const index = Math.floor(Math.random() * 1000) % fileLength
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return path.resolve(__dirname, `../static/images/${index + 1}.jpg`)
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}
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// 生成大图和小图,返回base64
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function createImage(filePath, w, h, s, x, y) {
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return new Promise((resolve, reject) => {
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const res = {image: "", fragment: ""}
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const bg = `C:/Users/64616/WebstormProjects/验证码/koa/static/images/bg.jpg`
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sharp(filePath)
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.resize(w, h, "!")//调整成统一尺寸
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.extract({left: x, top: y, width: s, height: s})//截取小图
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.toBuffer()
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.then(imageData => {
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let data = imageData.toString('base64');//转换成base64的形式
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res.fragment = "data:image/jpg;base64," + data
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sharp1(filePath).resize(w, h, "!")
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.composite([{input: bg, top: y, left: x, raw: {width: s, height: s, channels: 1}}])
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//把与小图部分大小相同的灰色图片覆盖在大图上，形成大图空缺的样子
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.toBuffer()
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.then(imageData => {
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let data = imageData.toString('base64');
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res.image = "data:image/jpg;base64," + data
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resolve(res)//返回结果
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})
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.catch(error => {
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throw(error)
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})
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})
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.catch(error => {
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throw(error)
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})
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})
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}
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module.exports = {
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getSlide,
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check,
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}
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