Vue實現驗證碼登入的方法範例

<template>
    <div class="s-canvas">
        <canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
    </div>
</template>
 
<script>
    export default {
        name: "SIdentify",
        props: {
            identifyCode: {
                type: String,
                default: '1234'
            },
            fontSizeMin: {
                type: Number,
                default: 25
            },
            fontSizeMax: {
                type: Number,
                default: 30
            },
            backgroundColorMin: {
                type: Number,
                default: 255
            },
            backgroundColorMax: {
                type: Number,
                default: 255
            },
            colorMin: {
                type: Number,
                default: 0
            },
            colorMax: {
                type: Number,
                default: 160
            },
            lineColorMin: {
                type: Number,
                default: 100
            },lineColorMax: {
                type: Number,
                default: 255
            },
            dotColorMin: {
                type: Number,
                default: 0
            },
            dotColorMax: {
                type: Number,
                default: 255
            },
            contentWidth: {
                type: Number,
                default: 112
            },
            contentHeight: {
                type: Number,
                default: 31
            }
        },
        methods: {
            // 生成一個亂數
            randomNum(min, max) {
                return Math.floor(Math.random() * (max - min) + min)
            },
            // 生成一個隨機的顏色
            randomColor(min, max) {
                let r = this.randomNum(min, max)
                let g = this.randomNum(min, max)
                let b = this.randomNum(min, max)
                return 'rgb(' + r + ',' + g + ',' + b + ')'
            },
            drawPic() {
                let canvas = document.getElementById('s-canvas')
                let ctx = canvas.getContext('2d')
                ctx.textBaseline = 'bottom'
                // 繪製背景
                ctx.fillStyle = this.randomColor(this.backgroundColorMin, this.backgroundColorMax)
                ctx.fillRect(0, 0, this.contentWidth, this.contentHeight)
                // 繪製文字
                for (let i = 0; i < this.identifyCode.length; i++) {
                    this.drawText(ctx, this.identifyCode[i], i)
                }
                this.drawLine(ctx)
                this.drawDot(ctx)
            },
            drawText(ctx, txt, i) {
                ctx.fillStyle = this.randomColor(this.colorMin, this.colorMax)
                ctx.font = this.randomNum(this.fontSizeMin, this.fontSizeMax) + 'px SimHei'
                let x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1))
                let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5)
                var deg = this.randomNum(-45, 45)
                // 修改座標原點和旋轉角度
                ctx.translate(x, y)
                ctx.rotate(deg * Math.PI / 180)
                ctx.fillText(txt, 0, 0)
                // 恢復座標原點和旋轉角度
                ctx.rotate(-deg * Math.PI / 180)
                ctx.translate(-x, -y)
            },
            drawLine(ctx) {
                // 繪製干擾線
                for (let i = 0; i < 5; i++) {
                    ctx.strokeStyle = this.randomColor(this.lineColorMin, this.lineColorMax)
                    ctx.beginPath()
                    ctx.moveTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight))
                    ctx.lineTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight))
                    ctx.stroke()
                }
            },
            drawDot(ctx) {
                // 繪製干擾點
                for (let i = 0; i < 80; i++) {
                    ctx.fillStyle = this.randomColor(0, 255)
                    ctx.beginPath()
                    ctx.arc(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight), 1, 0, 2 * Math.PI)
                    ctx.fill()
                }
            }
        },
        watch: {
            identifyCode() {
                this.drawPic()
            }
        },
        mounted() {
            this.drawPic()
        }
    }
</script>
 
<style scoped>
    .s-canvas {
        height: 38px;
 
    }
    .s-canvas canvas{
        margin-top: 1px;
        margin-left: 8px;
    }
</style>

<template>
  <div>
    <SIdentify:identifyCode="identifyCode" >
    </SIdentify>
  </div>
</template>
// 引入登入驗證元件
import SIdentify from "@/components/SIdentify";
<script>
    export default {
        name: "SIdentify",
        components: { SIdentify },
        data(){
            return {
                identifyCode: "", //密碼登入圖形驗證碼
                identifyCodes: "1234567890abcdefghizklmnopqrstuvwxyz", //生成圖形驗證碼的依據
            }
        },
        methods:{
            // 重新整理驗證碼
            refreshIdentifyCode() {
                this.identifyCode = "";
                this.makeIdentifyCode(4);
            },
            // 生成4位元數的隨機驗證碼
            makeIdentifyCode(l) {
                for (let i = 0; i < l; i++) {
                    this.identifyCode +=
                    this.identifyCodes[this.randomNum(0, this.identifyCodes.length)];
                }
            },
            // 生成單個驗證碼
            randomNum(min, max) {
                return Math.floor(Math.random() * (max - min) + min);
            },
        },
        mounted() {
            // 初始化驗證碼
            this.identifyCode = "";
            this.makeIdentifyCode(4);
        },
    }
</script>