vue 移动端实现手写签名效果，功能很完美，保存时保存为base64格式。

刚好项目用到此功能，就网上找了一下，清理了无用代码，简单方便，因为项目中多个地方需要使用，所以我将它整理为组件，通过ref和传值控制，下面代码我单独整理出来，可自行封装组件(只支持移动端，不支持pc端)。

代码中，css自行修改一下宽高，背景之类即可。

代码如下

export default {

name: "signature",

data() {

return {

image: "",

mousePressed: false,

c: "",

ctx: "",

lastX: 0,

lastY: 0,

};

},

mounted() {

this.image = "";

this.mousePressed = false;

var lastX, lastY;

this.ctx = document.getElementById("myCanvas").getContext("2d");

this.c = document.getElementById("myCanvas");

var signWrap = document.getElementById("signWrap");

this.c.width = signWrap.clientWidth; // 设置宽度

this.c.height = signWrap.clientHeight; // 设置高度

// 监听touchstart事件，touchmove事件，touchend事件等事件

this.InitThis();

},

methods: {

InitThis() {

// 触摸屏

var that = this;

this.c.addEventListener(

"touchstart",

function (event) {

if (event.targetTouches.length == 1) {

event.preventDefault(); // 阻止浏览器默认事件，重要

var touch = event.targetTouches[0];

this.mousePressed = true;

that.Draw(

touch.pageX - this.offsetLeft,

touch.pageY - this.offsetTop,

false

);

}

},

false

);

this.c.addEventListener(

"touchmove",

function (event) {

if (event.targetTouches.length == 1) {

event.preventDefault(); // 阻止浏览器默认事件，重要

var touch = event.targetTouches[0];

if (this.mousePressed) {

that.Draw(

touch.pageX - this.offsetLeft,

touch.pageY - this.offsetTop,

true

);

}

}

},

false

);

this.c.addEventListener(

"touchend",

function (event) {

if (event.targetTouches.length == 1) {

event.preventDefault(); // 阻止浏览器默认事件，防止手写的时候拖动屏幕，重要

this.mousePressed = false;

}

},

false

);

// 鼠标

this.c.onmousedown = function (event) {

this.mousePressed = true;

that.Draw(

event.pageX - this.offsetLeft,

event.pageY - this.offsetTop,

false

);

};

this.c.onmousemove = function (event) {

if (this.mousePressed) {

that.Draw(

event.pageX - this.offsetLeft,

event.pageY - this.offsetTop,

true

);

}

};

this.c.onmouseup = function (event) {

this.mousePressed = false;

};

},

Draw(x, y, isDown) {

if (isDown) {

this.ctx.beginPath();

this.ctx.strokeStyle = "#000"; // 颜色

this.ctx.lineWidth = 3; // 线宽

this.ctx.lineJoin = "round";

this.ctx.lineMax = 10; // 设置画笔最大线宽

this.ctx.lineMin = 3; // 设置画笔最小线宽

this.ctx.linePressure = 1.2; // 设置画笔笔触压力

this.ctx.smoothness = 30; // 设置画笔笔触大小变化的平滑度

this.ctx.moveTo(this.lastX, this.lastY);

this.ctx.lineTo(x, y);

this.ctx.closePath();

this.ctx.stroke();

}

this.lastX = x;

this.lastY = y;

},

// 清空画板

clearArea() {

this.ctx.setTransform(1, 0, 0, 1, 0, 0);

this.ctx.clearRect(0, 0, this.ctx.canvas.width, this.ctx.canvas.height);

},

// 提交签名

saveSign() {

this.checkEmpty(); // 调用 表单非空验证

},

checkEmpty() {

var c = document.getElementById("myCanvas"); // 获取html的canvas对象，我这个id="myCanvas"

if (this.isCanvasBlank(c)) {

alert("请在签名区域签名后再次确认");

return;

} else {

var image = this.c.toDataURL("image/png"); // 得到生成后的签名base64位 url 地址

console.log(image); // 打印图片base64 url

}

},

// 验证canvas画布是否为空函数

isCanvasBlank(canvas) {

var blank = document.createElement("canvas"); // 系统获取一个空canvas对象

blank.width = canvas.width;

blank.height = canvas.height;

return canvas.toDataURL() == blank.toDataURL(); // 比较值相等则为空

},

},

};

.page {

width: 100%;

.content {

width: 100%;

height: 1.7rem;

background: url(../assets/img/photo_qmq.png) no-repeat;

background-size: 100% 100%;

background-position: center center;

.sign-wrap {

width: 100%;

height: 100%;

}

}

.con-btn {

width: 100%;

display: flex;

align-content: center;

justify-content: space-between;

opacity: 0.75;

span {

font-size: 0.14rem;

width: 100%;

height: 0.48rem;

display: flex;

align-items: center;

justify-content: center;

}

.staging-btn {

color: #4154ff;

background: #fff;

}

.submit-btn {

color: #fff;

background: #4154ff;

}

}

}