主要思路
使用QuaggaJs这个库。调用摄像头使用的 navigator.mediaDevices.getUserMedia 这个H5的api。通过 video 和 canvas 把摄像头获取到的数据展现到页面上，同时调用监听Quagga解析。
- 获取设备摄像头权限,用于后续开启摄像头。
- 创建video元素显示摄像头画面,和canvas元素用于QuaggaJS进行图像处理和解码。
- 初始化QuaggaJS,设置解码参数和回调。
- 开启摄像头,开始扫描循环tick。
- 在tick中捕获video画面,绘制到canvas上。
- 将canvas图像数据传入QuaggaJS,进行解码识别。
- 解码成功后,在回调中处理识别结果。
- 关闭摄像头和QuaggaJS,释放资源。
- 通过组件props设置扫描相关参数,如是否高清模式、需要激活的解码器等。
功能预览
兼容说明
需要https环境才能使用，本地测试可以在 manifest.json 中点击源码展示，找到h5 ，添加："devServer" : { "https" : true},并且打开闪光灯只有在安装chrome内核中可以使用，
一、安装QuaggaJs
官网链接 https://serratus.github.io/quaggaJS/#installing
NPM安装
npm install quagga
当然也可以直接引入mainJs文件
二、获取设备摄像头权限
在mounted钩子中,使用uni.request()获取设备权限:
mounted() {
uni.request({
name: 'camera',
success: () => {
this.openScan()
}
})
}
三、创建video和canvas元素
video = document.createElement('video')
video.id = 'video'
video.width = 300
video.height = 200
canvas = document.createElement('canvas')
canvas.id = 'canvas'
canvas.width = 300
canvas.height = 200
canvas.style = 'display:none'
canvas2 = document.createElement('canvas')
canvas2.id = 'canvas2'
canvas2.width = 300
canvas2.height = 200
四、初始化Quagga并开始扫描
在openScan方法中初始化Quagga,并开始扫描循环tick:
openScan() {
this.isScanning = true
let width = 300 * this.definition
let height = 200 * this.definition
Quagga.init(this.config, (err) => {
if (err) throw err
Quagga.start()
this.tick()
})
}
五、图像处理和解码
在tick方法中,不断从video中捕获图像,绘制到canvas上,然后使用Quagga对canvas进行解码:
tick() {
if (!this.isScanning) return
if (this.video.readyState === this.video.HAVE_ENOUGH_DATA) {
this.canvas2d.drawImage(video, 0, 0, width, height)
const inputStream = {
size: width * height * 4,
canvas: this.canvas
}
Quagga.decodeSingle(inputStream, result => {
// 解码成功后的处理逻辑
})
} else {
requestAnimationFrame(this.tick)
}
}
六、关闭摄像头和Quagga
在beforeDestroy钩子中,关闭摄像头和Quagga:
beforeDestroy() {
this.isScanning = false
Quagga.stop()
if (this.video.srcObject) {
this.video.srcObject.getTracks().forEach(track => {
track.stop()
})
}
}
参数解析
readers是一维码类型，一般使用code_128_reader，可带字母。一些电子产品类别的一维码就是这个编码ean_reader ：商品常用需要更具实际需求填入。数组中可填多个，但是不推荐，因为不同类型中的一维码可能会被其他类型给解码出来，这样会导致解码不正确。具体类型规则如下图：
props: {
continue: {
type: Boolean,
default: false // ,设置自动扫描次数false 一次 true 持续扫描
},
exact: {
type: String,
default: 'environment' // environment 后摄像头 user 前摄像头
},
definition: {
type: Boolean,
default: false // fasle 正常 true 高清
},
readers: {
// 一维码类型
type: Array,
default: () => ['code_128_reader']
}
}
基于上面所诉内容，我这里有现成的组件代码，复制就可以使用！！quaggaJs的文件可以私我，我发给各位。
组件完整代码
<template>
<view class="canvasBox">
<view class="box">
<view class="line"></view>
<view class="angle"></view>
</view>
<view class="box2" v-if="isUseTorch">
<view class="track" @click="openTrack">
<svg t="1653920715959" class="icon" viewBox="0 0 1024 1024" version="1.1"
xmlns="http://www.w3.org/2000/svg" p-id="1351" width="32" height="32">
<path
d="M651.353043 550.479503H378.752795L240.862609 364.315031c-3.688944-4.897391-5.660621-10.876025-5.660621-17.045466v-60.040745c0-15.773416 12.847702-28.621118 28.621118-28.621118h502.459627c15.773416 0 28.621118 12.847702 28.621118 28.621118v59.977143c0 6.105839-1.971677 12.084472-5.660621 17.045466l-137.890187 186.228074zM378.752795 598.308571v398.024348c0 15.328199 12.402484 27.667081 27.667081 27.667081h217.266087c15.328199 0 27.667081-12.402484 27.66708-27.667081V598.308571H378.752795z m136.300124 176.942112c-14.564969 0-26.331429-11.76646-26.331428-26.331428v-81.283975c0-14.564969 11.76646-26.331429 26.331428-26.331429 14.564969 0 26.331429 11.76646 26.331429 26.331429v81.283975c0 14.564969-11.76646 26.331429-26.331429 26.331428zM512 222.608696c-17.554286 0-31.801242-14.246957-31.801242-31.801243V31.801242c0-17.554286 14.246957-31.801242 31.801242-31.801242s31.801242 14.246957 31.801242 31.801242v159.006211c0 17.554286-14.246957 31.801242-31.801242 31.801243zM280.932174 205.881242c-9.47677 0-18.889938-4.197764-25.122981-12.275279L158.242981 67.991056a31.864845 31.864845 0 0 1 5.597019-44.648944 31.864845 31.864845 0 0 1 44.648944 5.597018l97.502609 125.551305a31.864845 31.864845 0 0 1-5.597019 44.648944c-5.787826 4.579379-12.656894 6.741863-19.46236 6.741863zM723.987081 205.881242c-6.805466 0-13.674534-2.162484-19.462361-6.678261a31.794882 31.794882 0 0 1-5.597018-44.648944l97.566211-125.551304a31.794882 31.794882 0 0 1 44.648944-5.597019 31.794882 31.794882 0 0 1 5.597019 44.648944l-97.566211 125.551305c-6.360248 8.077516-15.709814 12.27528-25.186584 12.275279z"
fill="#ffffff" p-id="1352"></path>
</svg>
{{ trackStatus ? '关闭闪光灯' : '打开闪光灯' }}
</view>
</view>
<view class="mask1 mask" :style="'height:' + maskHeight + 'px;'"></view>
<view class="mask2 mask" :style="'width:' + maskWidth + 'px;top:' + maskHeight + 'px'"></view>
<view class="mask3 mask" :style="'height:' + maskHeight + 'px;'"></view>
<view class="mask4 mask" :style="'width:' + maskWidth + 'px;top:' + maskHeight + 'px'"></view>
</view>
</template>
<script>
import Quagga from './quagga.min.js'
export default {
props: {
continue: {
type: Boolean,
default: false // false 监听一次 true 持续监听
},
exact: {
type: String,
default: 'environment' // environment 后摄像头 user 前摄像头
},
definition: {
type: Boolean,
default: false // fasle 正常 true 高清
},
readers: {
// 一维码类型
type: Array,
default: () => ['code_128_reader']
}
},
data() {
return {
windowWidth: 0,
windowHeight: 0,
video: null,
canvas2d: null,
canvasDom: null,
canvasDom2: null, // 用于画框
canvas2d2: null,
canvasWidth: 300,
canvasHeight: 200,
maskWidth: 0,
maskHeight: 0,
cpu: 1,
inter: 0,
track: null,
isUseTorch: false,
trackStatus: false,
isParse: false,
data1: '',
data2: ''
}
},
mounted() {
if (origin.indexOf('https') === -1) throw '请在 https 环境中使用摄像头组件。'
this.windowWidth = document.documentElement.clientWidth || document.body.clientWidth
this.windowHeight = document.documentElement.clientHeight || document.body.clientHeight
this.isParse = true
this.$nextTick(() => {
this.video = document.createElement('video')
this.video.width = this.windowWidth
this.video.height = this.windowHeight
const canvas = document.createElement('canvas')
this.canvas = canvas
canvas.id = 'canvas'
canvas.width = this.canvasWidth
canvas.height = this.canvasHeight
canvas.style = 'display:none;'
// 设置当前宽高 满屏
const canvasBox = document.querySelector('.canvasBox')
canvasBox.append(this.video)
canvasBox.append(canvas)
canvasBox.style = `width:${this.windowWidth}px;height:${this.windowHeight}px;`
this.canvas2d = canvas.getContext('2d')
// 创建第二个canvas
const canvas2 = document.createElement('canvas')
this.canvas2 = canvas2
canvas2.id = 'canvas2'
canvas2.width = this.canvasWidth
canvas2.height = this.canvasHeight
canvas2.style =
'position: absolute;top: 50%;left: 50%;z-index: 20;transform: translate(-50%, -50%);'
this.canvas2d2 = canvas2.getContext('2d')
canvasBox.append(canvas2)
this.cpu = 1 // navigator.hardwareConcurrency || 1
// console.log(navigator.hardwareConcurrency )
this.createMsk()
setTimeout(() => {
this.openScan()
}, 500)
})
},
methods: {
openScan() {
let width = this.transtion(this.windowHeight)
let height = this.transtion(this.windowWidth)
const videoParam = {
audio: false,
video: {
facingMode: {
exact: this.exact
},
width,
height
}
}
navigator.mediaDevices
.getUserMedia(videoParam)
.then(stream => {
this.video.srcObject = stream
this.video.setAttribute('playsinline', true)
this.video.play()
this.tick()
this.track = stream.getVideoTracks()[0]
setTimeout(() => {
this.isUseTorch = this.track.getCapabilities().torch || null
}, 500)
})
.catch(err => {
console.log('设备不支持', err)
})
},
tick() {
if (!this.isParse) return
try {
if (this.video.readyState === this.video.HAVE_ENOUGH_DATA) {
this.canvas2d.drawImage(
this.video,
this.transtion(this.maskWidth),
this.transtion(this.maskHeight),
this.transtion(300),
this.transtion(200),
0,
0,
this.canvasWidth,
this.canvasHeight
)
const img = this.canvas.toDataURL('image/jpg')
Quagga.decodeSingle({
inputStream: {
size: 300 * 2
},
locator: {
patchSize: 'large',
halfSample: true
},
numOfWorkers: this.cpu,
decoder: {
readers: this.readers
},
locate: true,
src: img
},
result => {
this.canvas2d2.clearRect(0, 0, this.canvasWidth, this.canvasHeight)
requestAnimationFrame(this.tick)
if (!result || !result.codeResult) return
if (!this.data1) return (this.data1 = result.codeResult.code)
this.data2 = result.codeResult.code
console.log(this.data1, '-', this.data2)
if (this.data2 !== this.data1) return (this.data1 = '')
this.drawLine(result.box, result.line)
if (!this.continue) {
this.closeCamera()
}
this.$emit('success', result.codeResult.code)
}
)
} else {
requestAnimationFrame(this.tick)
}
} catch (e) {
console.log('出错了');
requestAnimationFrame(this.tick)
}
},
drawLine(box, line) {
if (!line[0] || !line[0]['x']) return
this.canvas2d2.beginPath()
this.canvas2d2.moveTo(line[0]['x'] / 2, line[0]['y'] / 2)
this.canvas2d2.lineTo(line[1]['x'] / 2, line[1]['y'] / 2)
this.canvas2d2.lineWidth = 2
this.canvas2d2.strokeStyle = '#FF3B58'
this.canvas2d2.stroke()
},
createMsk() {
this.maskWidth = this.windowWidth / 2 - 150
this.maskHeight = this.windowHeight / 2 - 100
},
closeCamera() {
this.isParse = false
if (this.video.srcObject) {
this.video.srcObject.getTracks().forEach(track => {
track.stop()
})
}
},
transtion(number) {
return this.definition ? number * 2.6 : number * 1.6
},
openTrack() {
this.trackStatus = !this.trackStatus
this.track.applyConstraints({
advanced: [{
torch: this.trackStatus
}]
})
}
},
beforeDestroy() {
this.closeCamera()
}
}
</script>
<style scoped>
page {
background-color: #333333;
}
.canvasBox {
width: 100vw;
position: relative;
background-image: linear-gradient(0deg,
transparent 24%,
rgba(32, 255, 77, 0.1) 25%,
rgba(32, 255, 77, 0.1) 26%,
transparent 27%,
transparent 74%,
rgba(32, 255, 77, 0.1) 75%,
rgba(32, 255, 77, 0.1) 76%,
transparent 77%,
transparent),
linear-gradient(90deg,
transparent 24%,
rgba(32, 255, 77, 0.1) 25%,
rgba(32, 255, 77, 0.1) 26%,
transparent 27%,
transparent 74%,
rgba(32, 255, 77, 0.1) 75%,
rgba(32, 255, 77, 0.1) 76%,
transparent 77%,
transparent);
background-size: 3rem 3rem;
background-position: -1rem -1rem;
z-index: 10;
background-color: #1110;
}
.box {
width: 300px;
height: 200px;
position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
overflow: hidden;
border: 0.1rem solid rgba(0, 255, 51, 0.2);
z-index: 11;
}
.line {
height: calc(100% - 2px);
width: 100%;
background: linear-gradient(180deg, rgba(0, 255, 51, 0) 43%, #00ff33 211%);
border-bottom: 3px solid #00ff33;
transform: translateY(-100%);
animation: radar-beam 2s infinite alternate;
animation-timing-function: cubic-bezier(0.53, 0, 0.43, 0.99);
animation-delay: 1.4s;
}
.box2 {
width: 300px;
height: 200px;
position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
z-index: 20;
}
.track {
position: absolute;
bottom: -100px;
left: 50%;
transform: translateX(-50%);
z-index: 20;
color: #fff;
display: flex;
flex-direction: column;
align-items: center;
}
.box:after,
.box:before,
.angle:after,
.angle:before {
content: '';
display: block;
position: absolute;
width: 3vw;
height: 3vw;
z-index: 12;
border: 0.2rem solid transparent;
}
.box:after,
.box:before {
top: 0;
border-top-color: #00ff33;
}
.angle:after,
.angle:before {
bottom: 0;
border-bottom-color: #00ff33;
}
.box:before,
.angle:before {
left: 0;
border-left-color: #00ff33;
}
.box:after,
.angle:after {
right: 0;
border-right-color: #00ff33;
}
@keyframes radar-beam {
0% {
transform: translateY(-100%);
}
100% {
transform: translateY(0);
}
}
.msg {
text-align: center;
padding: 20rpx 0;
}
.mask {
position: absolute;
z-index: 10;
background-color: rgba(0, 0, 0, 0.55);
}
.mask1 {
top: 0;
left: 0;
right: 0;
}
.mask2 {
right: 0;
height: 200px;
}
.mask3 {
right: 0;
left: 0;
bottom: 0;
}
.mask4 {
left: 0;
height: 200px;
}
</style>
总结
以上就是整个uniapp条码扫描组件的主要逻辑和步骤。如果在理解和使用上有任何疑问,欢迎随时提出。我会提供更详细的解释和指导。欢迎大家交流
