H5 VUE实现手机签名功能
功能描述:
利用canvas实现手机签名转化成图片( 包含重绘,由于手机全屏展示 所以还添加了图片翻转) 上传后台
功能展示:
这里是封装了一个小组件
废话不多说上代码:
<template>
<div class="signature" @touchmove.prevent>//防止页面滚动
<div class="boardBox" ref="boardBox">
<canvas ref="board" id="canvas" @touchstart="mStart" @touchmove="mMove" @touchend="mEnd"></canvas>
</div>
<div class="bar">
<div class="item" @click="goback">
<div class="ico">
<img src="@/assets/img/goback.svg" alt srcset />
</div>
<div class="text">退出</div>
</div>
<div class="item" @click="clearcanvas">
<div class="ico">
<img src="@/assets/img/clear.svg" alt srcset />
</div>
<div class="text">重绘</div>
</div>
<div class="item" @click="getcanvas">
<div class="ico">
<img src="@/assets/img/qm_sure.svg" alt srcset />
</div>
<div class="text">保存</div>
</div>
</div>
</div>
</template>
export default {
data() {
return {
familysignatureurl:"",
basedata: "",
ctx: null,
point: {
x: 0,
y: 0,
},
moving: false, // 是否正在绘制中且移动
};
},
mounted() {
let board = this.$refs.board; // 获取DOM
board.width = this.$refs.boardBox.offsetWidth; // 设置画布宽
board.height = this.$refs.boardBox.offsetHeight; // 设置画布高
this.ctx = board.getContext("2d"); // 二维绘图
this.ctx.strokeStyle = "#000"; // 颜色
this.ctx.lineWidth = 3; // 线条宽度
},
methods: {
// 触摸(开始)
mStart(e) {
let x = e.touches[0].clientX - e.target.offsetLeft,
y = e.touches[0].clientY - e.target.offsetTop; // 获取触摸点在画板（canvas）的坐标
this.point.x = x;
this.point.y = y;
this.ctx.beginPath();
this.moving = true;
},
// 滑动中...
mMove(e) {
if (this.moving) {
let x = e.touches[0].clientX - e.target.offsetLeft,
y = e.touches[0].clientY - e.target.offsetTop; // 获取触摸点在画板（canvas）的坐标
this.ctx.moveTo(this.point.x, this.point.y); // 把路径移动到画布中的指定点，不创建线条(起始点)
this.ctx.lineTo(x, y); // 添加一个新点，然后创建从该点到画布中最后指定点的线条，不创建线条
this.ctx.stroke(); // 绘制
(this.point.x = x), (this.point.y = y); // 重置点坐标为上一个坐标
}
},
// 滑动结束
mEnd() {
if (this.moving) {
this.ctx.closePath(); // 停止绘制
this.moving = false; // 关闭绘制开关
}
},
getcanvas() {
//绘画转图片
document.getElementById("canvas").toDataURL("image/png");
document.getElementById("canvas").toBlob(async (blobObj) => {
var file1 = new File([blobObj], "pic.png", {
type: blobObj.type,
lastModified: Date.now(),
});
this.convertImg(file1);
});
},
//旋转图片
convertImg(file) {
let _this = this;
var canvas1 = document.createElement("canvas");
var context1 = canvas1.getContext("2d");
var oReader = new FileReader();
oReader.readAsDataURL(file);
oReader.onload = function (e) {
var img = new Image();
img.src = e.target.result;
img.onload = function () {
// 图片原始尺寸
var originWidth = this.width;
var originHeight = this.height;
// 最大尺寸限制
var maxWidth = 1080,
maxHeight = 1080;
// 目标尺寸
var targetWidth = originWidth,
targetHeight = originHeight;
// 图片尺寸超过300x300的限制
if (originWidth > maxWidth || originHeight > maxHeight) {
if (originWidth / originHeight > maxWidth / maxHeight) {
targetWidth = maxWidth;
targetHeight = Math.round(
maxWidth * (originHeight / originWidth)
);
} else {
targetHeight = maxHeight;
targetWidth = Math.round(
maxHeight * (originWidth / originHeight)
);
}
}
var type = "image/jpeg";
// canvas对图片进行缩放
canvas1.width = targetHeight;
canvas1.height = targetWidth;
// 旋转90度
context1.translate(0, 0);
context1.rotate(Math.PI / 2);
// (0,-imgHeight) 从旋转原理图那里获得的起始点
// context.clearRect(0, -targetHeight, targetWidth, targetHeight);
context1.drawImage(img, 0, -targetHeight, targetWidth, targetHeight);
// 将canvas的透明背景设置成白色
var imageData = context1.getImageData(
0,
0,
canvas1.width,
canvas1.height
);
for (var i = 0; i < imageData.data.length; i += 4) {
// 当该像素是透明的，则设置成白色
if (imageData.data[i + 3] == 0) {
imageData.data[i] = 255;
imageData.data[i + 1] = 255;
imageData.data[i + 2] = 255;
imageData.data[i + 3] = 255;
}
}
context1.putImageData(imageData, 0, 0);
var dataurl = canvas1.toDataURL(type);
_this.basedata = dataurl;
console.log(dataurl);
_this.updatavue();
};
};
},
//base64转Blob
base64ToBlob(base64Data) {
let arr = base64Data.split(","),
fileType = arr[0].match(/:(.*?);/)[1],
bstr = atob(arr[1]),
l = bstr.length,
u8Arr = new Uint8Array(l);
while (l--) {
u8Arr[l] = bstr.charCodeAt(l);
}
return new Blob([u8Arr], {
type: fileType,
});
},
//上传图片
async updatavue() {
//转成file文件
let blobObj = this.base64ToBlob(this.basedata);
var file = new File([blobObj], "pic.png", {
type: blobObj.type,
lastModified: Date.now(),
});
//此处为发送请求给后台获取图片路径
let res = await upload(file);
this.familysignatureurl=res.details.data.filePath
console.log(this.familysignatureurl);//此处打印的为绘画的图片url
},
//清除画布
clearcanvas() {
var c = document.getElementById("canvas");
var cxt = c.getContext("2d");
c.height = c.height;
this.ctx.lineWidth = 3;
},
//返回上一级
goback() {
this.$emit("setshow");
},
},
};
css也奉献上吧
<style lang="less" scoped>
.loadingtext {
transform: rotate(-90deg);
color: red;
}
.item {
-webkit-transform: rotate(-90deg);
}
.text {
text-align: center;
}
.boardBox {
width: 100vw;
height: 90vh;
background: #f9f9f9;
}
.bar {
box-sizing: border-box;
padding: 0rem 1rem;
display: flex;
width: 100vw;
height: 10vh;
background-color: #ffffff;
justify-content: space-around;
align-items: center;
}
.shade {
width: 100vw;
height: 100vh;
position: fixed;
top: 0;
background-color: #333333;
z-index: 66666;
opacity: 0.9;
.minishade {
width: 100%;
height: 100%;
display: flex;
align-items: center;
justify-content: center;
}
}
</style>