本篇内容主要讲解“基于Vue如何实现手势签名”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“基于Vue如何实现手势签名”吧!
代码如下
1. template
<template> <main class="hand-sign-page"> <header class="sign-head">请在下方区域内签名</header> <div id="signContain" :></div> <footer class="sign-foot"> <button @click="clearCanvas">清除</button> <button @click="saveCanvas">保存</button> </footer> <img v-show="vaildSign" class="sign-img" :src="vaildSign" alt=" "/> </main> </template>
2. js
<script>
export default {
name: "hand-sign",
data() {
return {
domEl: null,//绘制canvas的父级div
canvas: null,//画布
cxt: null,//绘画环境
linewidth:1,//线条粗细，选填
color:"black",//线条颜色，选填
background:"aliceblue",//线条背景，选填
vaildSign: null
}
},
mounted() {
this.initCanvas();
},
methods: {
initCanvas() {
this.domEl = document.getElementById("signContain");
this.canvas = document.createElement("canvas");
this.domEl.appendChild(this.canvas);
this.cxt = this.canvas.getContext("2d");
this.canvas.width = this.domEl.clientWidth;
this.canvas.height = this.domEl.clientHeight;
this.cxt.fillStyle = this.background;
this.cxt.fillRect(0, 0, this.canvas.width, this.canvas.height);
this.cxt.strokeStyle = this.color;
this.cxt.lineWidth = this.linewidth;
//this.cxt.lineCap = "round";
this.clearCanvas();//先清理下
//开始绘制
this.canvas.addEventListener("touchstart", (e) => {
this.cxt.beginPath();
this.cxt.moveTo(e.changedTouches[0].pageX - e.target.offsetLeft, e.changedTouches[0].pageY - e.target.offsetTop);
}, false);
//绘制中
this.canvas.addEventListener("touchmove", (e)=> {
this.cxt.lineTo(e.changedTouches[0].pageX - e.target.offsetLeft, e.changedTouches[0].pageY - e.target.offsetTop);
this.cxt.stroke();
}, false);
//结束绘制
this.canvas.addEventListener("touchend", (e)=> {
this.cxt.closePath();
}, false);
},
//清除画布
clearCanvas() {
this.cxt.clearRect(0, 0, this.canvas.width, this.canvas.height);
},
//保存画布
saveCanvas() {
console.log(this.blankCanvas());//检查画布是否为空白
if(this.blankCanvas()) {
window.alert('请签名');
}else {
this.vaildSign = this.canvas.toDataURL();
}
},
//canvas非空验证
blankCanvas() {
let blank = document.createElement('canvas');//系统获取一个空canvas对象
blank.width = this.canvas.width;
blank.height = this.canvas.height;
return this.canvas.toDataURL() == blank.toDataURL();//比较值相等则为空
},
}
}
</script>3. css
<style lang="less" scoped>
.hw(@h, @w: @h) {
height: @h;
width: @w
}
.hand-sign-page{
background-color: #fff;
.sign-head {
text-align: center;
padding: 10px;
border-bottom: 1px solid #ebebeb;
color: #666;
font-size: 14px;
}
#signContain {
.hw(400px, 100%);
background-color: var(--back);
}
.sign-foot{
display: flex;
justify-content: center;
margin: 15px;
button {
margin: 0 15px;
padding: 10px 20px;
background-color: #ddd;
border-radius: 5px;
&:active {
background-color: #efefef;
}
}
}
.sign-img {
.hw(100px, 200px);
display: block;
margin: 10px auto;
}
}
</style>