(function(window) {
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const l = 42, // 滑块边长
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r = 10, // 滑块半径
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w = 260, // canvas宽度
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h = 155, // canvas高度
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PI = Math.PI
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const L = l + r * 2 // 滑块实际边长
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function getRandomNumberByRange(start, end) {
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return Math.round(Math.random() * (end - start) + start)
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}
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function createCanvas(width, height) {
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const canvas = createElement('canvas')
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canvas.width = width
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canvas.height = height
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return canvas
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}
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function createImg(onload) {
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const img = createElement('img')
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img.crossOrigin = "Anonymous"
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img.onload = onload
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img.onerror = () => {
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img.src = getRandomImg()
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}
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img.src = getRandomImg()
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return img
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}
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function createElement(tagName) {
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return document.createElement(tagName)
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}
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function addClass(tag, className) {
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tag.classList.add(className)
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}
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function removeClass(tag, className) {
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tag.classList.remove(className)
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}
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function getRandomImg() {
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return "./img/login/"+ getRandomNumberByRange(1, 50) + ".jpg";
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//return 'https://picsum.photos/300/150/?image=' + getRandomNumberByRange(0, 100)
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}
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function draw(ctx, operation, x, y) {
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ctx.beginPath()
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ctx.moveTo(x, y)
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ctx.lineTo(x + l / 2, y)
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ctx.arc(x + l / 2, y - r + 2, r, 0, 2 * PI)
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ctx.lineTo(x + l / 2, y)
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ctx.lineTo(x + l, y)
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ctx.lineTo(x + l, y + l / 2)
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ctx.arc(x + l + r - 2, y + l / 2, r, 0, 2 * PI)
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ctx.lineTo(x + l, y + l / 2)
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ctx.lineTo(x + l, y + l)
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ctx.lineTo(x, y + l)
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ctx.lineTo(x, y)
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ctx.fillStyle = '#fff'
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ctx[operation]()
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ctx.beginPath()
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ctx.arc(x, y + l / 2, r, 1.5 * PI, 0.5 * PI)
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ctx.globalCompositeOperation = "xor"
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ctx.fill()
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}
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function sum(x, y) {
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return x + y
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}
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function square(x) {
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return x * x
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}
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class jigsaw {
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constructor(el, success, fail) {
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this.el = el
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this.success = success
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this.fail = fail
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}
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init() {
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this.initDOM()
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this.initImg()
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this.draw()
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this.bindEvents()
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}
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initDOM() {
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const canvas = createCanvas(w, h) // 画布
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const block = canvas.cloneNode(true) // 滑块
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const sliderContainer = createElement('div')
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const refreshIcon = createElement('div')
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const sliderMask = createElement('div')
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const slider = createElement('div')
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const sliderIcon = createElement('span')
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const text = createElement('span')
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block.className = 'block'
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sliderContainer.className = 'sliderContainer'
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refreshIcon.className = 'refreshIcon'
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sliderMask.className = 'sliderMask'
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slider.className = 'slider'
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sliderIcon.className = 'sliderIcon'
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text.innerHTML = '向右滑动滑块填充拼图'
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text.className = 'sliderText'
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const el = this.el
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el.appendChild(canvas)
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el.appendChild(refreshIcon)
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el.appendChild(block)
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slider.appendChild(sliderIcon)
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sliderMask.appendChild(slider)
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sliderContainer.appendChild(sliderMask)
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sliderContainer.appendChild(text)
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el.appendChild(sliderContainer)
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Object.assign(this, {
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canvas,
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block,
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sliderContainer,
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refreshIcon,
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slider,
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sliderMask,
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sliderIcon,
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text,
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canvasCtx: canvas.getContext('2d'),
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blockCtx: block.getContext('2d')
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})
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}
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initImg() {
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const img = createImg(() => {
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this.canvasCtx.drawImage(img, 0, 0, w, h)
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this.blockCtx.drawImage(img, 0, 0, w, h)
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const y = this.y - r * 2 + 2
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const ImageData = this.blockCtx.getImageData(this.x, y, L, L)
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this.block.width = L
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this.blockCtx.putImageData(this.halveAlpha(ImageData), 0, y)
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})
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this.img = img
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}
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halveAlpha(ImageData){
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var alpha = 0.5
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for (var i = 0 , len = ImageData.data.length ; i < len ; i += 4 )
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{
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// 改变每个像素的透明度
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ImageData.data[i + 1] = ImageData.data[i + 1] * alpha;
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ImageData.data[i + 2] = ImageData.data[i + 2] * alpha;
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}
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return ImageData;
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}
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draw() {
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// 随机创建滑块的位置
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this.x = getRandomNumberByRange(L + 10, w - (L + 10))
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this.y = getRandomNumberByRange(10 + r * 2, h - (L + 10))
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draw(this.canvasCtx, 'fill', this.x, this.y)
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draw(this.blockCtx, 'clip', this.x, this.y)
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}
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clean() {
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this.canvasCtx.clearRect(0, 0, w, h)
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this.blockCtx.clearRect(0, 0, w, h)
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this.block.width = w
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}
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bindEvents() {
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this.el.onselectstart = () => false
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this.refreshIcon.onclick = () => {
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this.reset()
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}
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let originX, originY, trail = [],
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isMouseDown = false
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this.block.addEventListener('mousedown', function(e) {
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originX = e.x, originY = e.y
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isMouseDown = true
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})
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this.slider.addEventListener('mousedown', function(e) {
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originX = e.x, originY = e.y
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isMouseDown = true
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})
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document.addEventListener('mousemove', (e) => {
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if(!isMouseDown) return false
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const moveX = e.x - originX
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const moveY = e.y - originY
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if(moveX < 0 || moveX + 38 >= w) return false
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this.slider.style.left = moveX + 'px'
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var blockLeft = (w - 40 - 20) / (w - 40) * moveX
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this.block.style.left = blockLeft + 'px'
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addClass(this.sliderContainer, 'sliderContainer_active')
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this.sliderMask.style.width = moveX + 'px'
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trail.push(moveY)
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})
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document.addEventListener('mouseup', (e) => {
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if(!isMouseDown) return false
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isMouseDown = false
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if(e.x == originX) return false
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removeClass(this.sliderContainer, 'sliderContainer_active')
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this.trail = trail
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const {
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spliced,
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TuringTest
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} = this.verify()
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if(spliced) {
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if(TuringTest) {
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addClass(this.sliderContainer, 'sliderContainer_success')
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this.success && this.success()
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} else {
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addClass(this.sliderContainer, 'sliderContainer_fail')
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this.text.innerHTML = '再试一次'
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this.reset()
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}
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} else {
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//alert("验证失败");
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addClass(this.sliderContainer, 'sliderContainer_fail')
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this.fail && this.fail();
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//验证失败后，1秒后重新加载图片
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setTimeout(() => {
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this.reset()
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}, 1000)
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}
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})
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}
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verify() {
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const arr = this.trail // 拖动时y轴的移动距离
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const average = arr.reduce(sum) / arr.length // 平均值
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const deviations = arr.map(x => x - average) // 偏差数组
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const stddev = Math.sqrt(deviations.map(square).reduce(sum) / arr.length) // 标准差
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const left = parseInt(this.block.style.left)
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return {
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spliced: Math.abs(left - this.x) < 10,
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TuringTest: average !== stddev, // 只是简单的验证拖动轨迹，相等时一般为0，表示可能非人为操作
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}
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}
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reset() {
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this.sliderContainer.className = 'sliderContainer'
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this.slider.style.left = 0
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this.block.style.left = 0
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this.sliderMask.style.width = 0
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this.clean()
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this.img.src = getRandomImg()
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this.draw()
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}
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}
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window.jigsaw = {
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init: function(element, success, fail) {
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new jigsaw(element, success, fail).init()
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}
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}
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}(window))
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