vue3实现电子签名且对电子签名可进行修改画笔粗细、画笔颜色、撤销、清屏、保存等功能。

实现效果：查看源码

第一种：通过canvas

<div class="signaturePad-Box w100 h100 flex-center"><el-space class="mb10" size="large"><div><el-text>画笔粗细：</el-text><el-input-number v-model="state.signOptions.lineWidth" :min="2" :max="10" :step="1" @change="initCanvas" /></div><div><el-text>画笔颜色：</el-text><el-color-picker v-model="state.signOptions.penColor" color-format="hex" @blur="initCanvas"> </el-color-picker></div></el-space><canvas ref="canvas" @mousedown="startDrawing" @mousemove="draw" @mouseup="stopDrawing"></canvas><el-space class="mt10"><el-button  @click="clear">清除</el-button><el-button type="success" @click="view">查看</el-button><el-button type="primary" @click="save">保存</el-button></el-space><el-dialog v-model="state.dialogVisible" title="查看图片"  ><el-image :src="state.dataURL" /><template #footer><div class="dialog-footer"><el-button type="primary" @click="state.dialogVisible = false"> 确定 </el-button></div></template></el-dialog>
</div>

<script setup>import {ref,reactive,onMounted} from "vue";const canvas = ref(null);const state=reactive({dialogVisible:false,dataURL:"",signOptions: {penColor: '#000000',lineWidth: 2,},})let isDrawing = false;let lastX = 0;let lastY = 0;/* 初始化画布 */const initCanvas = () => {const ctx = canvas.value.getContext('2d');ctx.strokeStyle = state.signOptions.penColor;ctx.lineWidth = state.signOptions.lineWidth;}/* 开始绘制 */const startDrawing = (event) => {isDrawing = true;[lastX, lastY] = [event.offsetX, event.offsetY];}/* 绘制线条 */const draw = (event) => {if (!isDrawing) return;const ctx = canvas.value.getContext('2d');const currentX = event.offsetX;const currentY = event.offsetY;ctx.beginPath();ctx.moveTo(lastX, lastY);ctx.lineTo(currentX, currentY);ctx.stroke();[lastX, lastY] = [currentX, currentY];}/* 停止绘制 */const stopDrawing = () => {isDrawing = false;}/* 清除画布 */const clear = () => {const ctx = canvas.value.getContext('2d');ctx.clearRect(0, 0, canvas.value.width, canvas.value.height);}/* 保存签名 */const save = () => {state.dataURL = canvas.value.toDataURL('image/png');console.log('签名地址为:', state.dataURL);}/* 查看签名 */const view=()=>{state.dataURL = canvas.value.toDataURL('image/png');state.dialogVisible=true;}onMounted(() => initCanvas());
</script>

第二种：通过vue-signature-pad

安装依赖：

// npm
npm i vue-signature-pad// yarn
yarn add vue-signature-pad//pnpm 
pnpm i vue-signature-pad

在main.js里引用依赖：
注：在官网上写的是全局引入非单文件引入

import VueSignaturePad from 'vue-signature-pad';createApp(App).use(router).use(VueSignaturePad).mount('#app')

实现代码：

<template><div><el-space class="mb10" size="large"><div><el-text>画笔粗细：</el-text><el-input-number v-model="state.size" :min="2" :max="10" :step="1" @change="onChange" /></div><div><el-text>画笔颜色：</el-text><el-color-picker v-model="state.color" color-format="hex" @change="onChange"> </el-color-picker></div></el-space><VueSignaturePad class="line" ref="signaturePad" :options="signOptions" width="400px" height="200px" /><el-space class="mt10"><el-button @click="unDoSign">撤销</el-button><el-button @click="clearSign">清屏</el-button><el-button type="primary" @click="saveUploadSign">保存</el-button></el-space></div>
</template>

<script setup>import {ref,watch} from "vue";const signaturePad = ref();const signOptions=ref({penColor: '#000000',minWidth: 1,maxWidth:1})const state=ref({color:"#000",size:1})// 画笔颜色粗细改变时const onChange=()=>{signOptions.value={penColor:state.value.color,maxWidth:state.value.size}}// 撤销电子签名const unDoSign = () => {signaturePad.value.undoSignature();};// 清空电子签名const clearSign = () => {signaturePad.value.clearSignature();};// 保存并上传电子签名const saveUploadSign = async () => {const {isEmpty,data} = signaturePad.value.saveSignature();if (isEmpty) return;console.log("picture url：",data);};</script>