基于react的滑动图片验证码组件

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业务需求，需要在系统登陆的时候，使用“滑动图片验证码”，来验证操作的不是机器人。
效果图
使用方式在一般的页面组件引用即可。onReload 这个函数一般是用来请求后台图片的。
class App extends Component {
state = {
url: “”
}

componentDidMount() {
this.setState({url: getImage() })
}

onReload = () => {
this.setState({url: getImage() })
}
render() {
return (
<div>
<ImageCode
imageUrl={this.state.url}
onReload={this.onReload}
onMatch={() => {
console.log(“code is match”)
}}
/>
</div>
)
}
}
上代码
// index.js
/**
* @name ImageCode
* @desc 滑动拼图验证
* @author darcrand
* @version 2019-02-26
*
* @param {String} imageUrl 图片的路径
* @param {Number} imageWidth 展示图片的宽带
* @param {Number} imageHeight 展示图片的高带
* @param {Number} fragmentSize 滑动图片的尺寸
* @param {Function} onReload 当点击 ’ 重新验证 ’ 时执行的函数
* @param {Function} onMath 匹配成功时执行的函数
* @param {Function} onError 匹配失败时执行的函数
*/

import React from “react”

import “./styles.css”

const icoSuccess = require(“./icons/success.png”)
const icoError = require(“./icons/error.png”)
const icoReload = require(“./icons/reload.png”)
const icoSlider = require(“./icons/slider.png”)

const STATUS_LOADING = 0 // 还没有图片
const STATUS_READY = 1 // 图片渲染完成, 可以开始滑动
const STATUS_MATCH = 2 // 图片位置匹配成功
const STATUS_ERROR = 3 // 图片位置匹配失败

const arrTips = [{ico: icoSuccess, text: “ 匹配成功 ”}, {ico: icoError, text: “ 匹配失败 ”}]

// 生成裁剪路径
function createClipPath(ctx, size = 100, styleIndex = 0) {
const styles = [
[0, 0, 0, 0],
[0, 0, 0, 1],
[0, 0, 1, 0],
[0, 0, 1, 1],
[0, 1, 0, 0],
[0, 1, 0, 1],
[0, 1, 1, 0],
[0, 1, 1, 1],
[1, 0, 0, 0],
[1, 0, 0, 1],
[1, 0, 1, 0],
[1, 0, 1, 1],
[1, 1, 0, 0],
[1, 1, 0, 1],
[1, 1, 1, 0],
[1, 1, 1, 1]
]
const style = styles[styleIndex]

const r = 0.1 * size
ctx.save()
ctx.beginPath()
// left
ctx.moveTo(r, r)
ctx.lineTo(r, 0.5 * size – r)
ctx.arc(r, 0.5 * size, r, 1.5 * Math.PI, 0.5 * Math.PI, style[0])
ctx.lineTo(r, size – r)
// bottom
ctx.lineTo(0.5 * size – r, size – r)
ctx.arc(0.5 * size, size – r, r, Math.PI, 0, style[1])
ctx.lineTo(size – r, size – r)
// right
ctx.lineTo(size – r, 0.5 * size + r)
ctx.arc(size – r, 0.5 * size, r, 0.5 * Math.PI, 1.5 * Math.PI, style[2])
ctx.lineTo(size – r, r)
// top
ctx.lineTo(0.5 * size + r, r)
ctx.arc(0.5 * size, r, r, 0, Math.PI, style[3])
ctx.lineTo(r, r)

ctx.clip()
ctx.closePath()
}

class ImageCode extends React.Component {
static defaultProps = {
imageUrl: “”,
imageWidth: 500,
imageHeight: 300,
fragmentSize: 80,
onReload: () => {},
onMatch: () => {},
onError: () => {}
}

state = {
isMovable: false,
offsetX: 0, // 图片截取的 x
offsetY: 0, // 图片截取的 y
startX: 0, // 开始滑动的 x
oldX: 0,
currX: 0, // 滑块当前 x,
status: STATUS_LOADING,
showTips: false,
tipsIndex: 0
}

componentDidUpdate(prevProps) {
// 当父组件传入新的图片后，开始渲染
if (!!this.props.imageUrl && prevProps.imageUrl !== this.props.imageUrl) {
this.renderImage()
}
}

renderImage = () => {
// 初始化状态
this.setState({status: STATUS_LOADING})

// 创建一个图片对象，主要用于 canvas.context.drawImage()
const objImage = new Image()

objImage.addEventListener(“load”, () => {
const {imageWidth, imageHeight, fragmentSize} = this.props

// 先获取两个 ctx
const ctxShadow = this.refs.shadowCanvas.getContext(“2d”)
const ctxFragment = this.refs.fragmentCanvas.getContext(“2d”)

// 让两个 ctx 拥有同样的裁剪路径 (可滑动小块的轮廓)
const styleIndex = Math.floor(Math.random() * 16)
createClipPath(ctxShadow, fragmentSize, styleIndex)
createClipPath(ctxFragment, fragmentSize, styleIndex)

// 随机生成裁剪图片的开始坐标
const clipX = Math.floor(fragmentSize + (imageWidth – 2 * fragmentSize) * Math.random())
const clipY = Math.floor((imageHeight – fragmentSize) * Math.random())

// 让小块绘制出被裁剪的部分
ctxFragment.drawImage(objImage, clipX, clipY, fragmentSize, fragmentSize, 0, 0, fragmentSize, fragmentSize)

// 让阴影 canvas 带上阴影效果
ctxShadow.fillStyle = “rgba(0, 0, 0, 0.5)”
ctxShadow.fill()

// 恢复画布状态
ctxShadow.restore()
ctxFragment.restore()

// 设置裁剪小块的位置
this.setState({offsetX: clipX, offsetY: clipY})

// 修改状态
this.setState({status: STATUS_READY})
})

objImage.src = this.props.imageUrl
}

onMoveStart = e => {
if (this.state.status !== STATUS_READY) {
return
}

// 记录滑动开始时的绝对坐标 x
this.setState({isMovable: true, startX: e.clientX})
}

onMoving = e => {
if (this.state.status !== STATUS_READY || !this.state.isMovable) {
return
}
const distance = e.clientX – this.state.startX
let currX = this.state.oldX + distance

const minX = 0
const maxX = this.props.imageWidth – this.props.fragmentSize
currX = currX < minX ? 0 : currX > maxX ? maxX : currX

this.setState({currX})
}

onMoveEnd = () => {
if (this.state.status !== STATUS_READY || !this.state.isMovable) {
return
}
// 将旧的固定坐标 x 更新
this.setState(pre => ({ isMovable: false, oldX: pre.currX}))

const isMatch = Math.abs(this.state.currX – this.state.offsetX) < 5
if (isMatch) {
this.setState(pre => ({ status: STATUS_MATCH, currX: pre.offsetX}), this.onShowTips)
this.props.onMatch()
} else {
this.setState({status: STATUS_ERROR}, () => {
this.onReset()
this.onShowTips()
})
this.props.onError()
}
}

onReset = () => {
const timer = setTimeout(() => {
this.setState({oldX: 0, currX: 0, status: STATUS_READY})
clearTimeout(timer)
}, 1000)
}

onReload = () => {
if (this.state.status !== STATUS_READY && this.state.status !== STATUS_MATCH) {
return
}
const ctxShadow = this.refs.shadowCanvas.getContext(“2d”)
const ctxFragment = this.refs.fragmentCanvas.getContext(“2d”)

// 清空画布
ctxShadow.clearRect(0, 0, this.props.fragmentSize, this.props.fragmentSize)
ctxFragment.clearRect(0, 0, this.props.fragmentSize, this.props.fragmentSize)

this.setState(
{
isMovable: false,
offsetX: 0, // 图片截取的 x
offsetY: 0, // 图片截取的 y
startX: 0, // 开始滑动的 x
oldX: 0,
currX: 0, // 滑块当前 x,
status: STATUS_LOADING
},
this.props.onReload
)
}

onShowTips = () => {
if (this.state.showTips) {
return
}

const tipsIndex = this.state.status === STATUS_MATCH ? 0 : 1
this.setState({showTips: true, tipsIndex})
const timer = setTimeout(() => {
this.setState({showTips: false})
clearTimeout(timer)
}, 2000)
}

render() {
const {imageUrl, imageWidth, imageHeight, fragmentSize} = this.props
const {offsetX, offsetY, currX, showTips, tipsIndex} = this.state
const tips = arrTips[tipsIndex]

return (
<div className=”image-code” style={{width: imageWidth}}>
<div className=”image-container” style={{height: imageHeight, backgroundImage: `url(“${imageUrl}”)` }}>
<canvas
ref=”shadowCanvas”
className=”canvas”
width={fragmentSize}
height={fragmentSize}
style={{left: offsetX + “px”, top: offsetY + “px”}}
/>
<canvas
ref=”fragmentCanvas”
className=”canvas”
width={fragmentSize}
height={fragmentSize}
style={{top: offsetY + “px”, left: currX + “px”}}
/>

<div className=”slider-wrpper” onMouseMove={this.onMoving} onMouseLeave={this.onMoveEnd}>
<div className=”slider-bar”> 按住滑块，拖动完成拼图 </div>
<div
className=”slider-button”
onMouseDown={this.onMoveStart}
onMouseUp={this.onMoveEnd}
style={{left: currX + “px”, backgroundImage: `url(“${icoSlider}”)` }}
/>
</div>
</div>
)
}
}

export default ImageCode

// styles.css

.image-code {
padding: 10px;
user-select: none;
}

.image-container {
position: relative;
background-color: #ddd;
}

.canvas {
position: absolute;
top: 0;
left: 0;
}

.reload-container {
margin: 20px 0;
}

.reload-wrapper {
display: inline-flex;
align-items: center;
cursor: pointer;
}

.reload-ico {
width: 20px;
height: 20px;
margin-right: 10px;
background: center/cover no-repeat;
}

.reload-tips {
font-size: 14px;
color: #666;
}

.slider-wrpper {
position: relative;
margin: 10px 0;
}

.slider-bar {
padding: 10px;
font-size: 14px;
text-align: center;
color: #999;
background-color: #ddd;
}

.slider-button {
position: absolute;
top: 50%;
left: 0;
width: 50px;
height: 50px;
border-radius: 25px;
transform: translateY(-50%);
cursor: pointer;
background: #fff center/80% 80% no-repeat;
box-shadow: 0 2px 10px 0 #333;
}

/* 提示信息 */
.tips-container,
.tips-container–active {
position: absolute;
top: 50%;
left: 50%;
display: flex;
align-items: center;
padding: 10px;
transform: translate(-50%, -50%);
transition: all 0.25s;
background: #fff;
border-radius: 5px;

visibility: hidden;
opacity: 0;
}

.tips-container–active {
visibility: visible;
opacity: 1;
}

.tips-ico {
width: 20px;
height: 20px;
margin-right: 10px;
background: center/cover no-repeat;
}

.tips-text {
color: #666;
}

基于react的滑动图片验证码组件

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