uniapp实现手写签名

<template>
  <view class="container">
 
    <view class="sigh-btns">
      <button class="btn reset"
              @tap="handleReset">取消</button>
      <button class="btn confirm"
              @tap="handleConfirm">确认</button>
    </view>
    <view class="sign-box">
		<view class="signTips">请在此区域内签名</view>
		<canvas class="mycanvas"
              :style="{height:height +'px'}"
              canvas-id="mycanvas"
              @touchstart="touchstart"
              @touchmove="touchmove"
              @touchend="touchend"></canvas>
 
        <canvas canvas-id="camCacnvs"
              :style="{width:height +'px',height:width +'px'}"
               class="canvsborder"></canvas>
 
    </view>
  </view>
 
</template>
<script>
var x = 20;
var y = 20;
var tempPoint = []; //用来存放当前画纸上的轨迹点
var id = 0;
var type = '';
let that;
let canvasw;
let canvash;
import { BASE_URL } from '@/utils/request.js'
import { file } from '@/utils/file.js'
export default {
  data() {
    return {
      ctx: '', //绘图图像
      points: [], //路径点集合,
      width: 0,
      height: 0
    };
  },
  mounted() {},
 
  onLoad(option) {
    that = this;
    console.log(option);
    id = option.id;
    type = option.type;
    this.ctx = uni.createCanvasContext('mycanvas', this); //创建绘图对象
    //设置画笔样式
    this.ctx.lineWidth = 4;
    this.ctx.lineCap = 'round';
    this.ctx.lineJoin = 'round';
 
    uni.getSystemInfo({
      success: function (res) {
        console.log(res);
        that.width = res.windowWidth * 0.85;
        that.height = res.windowHeight - 40;
      }
    });
  },
 
  methods: {
	  file,
    //触摸开始，获取到起点
    touchstart: function (e) {
      let startX = e.changedTouches[0].x;
      let startY = e.changedTouches[0].y;
      let startPoint = {
        X: startX,
        Y: startY
      };
 
      /* **************************************************
				    #由于uni对canvas的实现有所不同，这里需要把起点存起来
				 * **************************************************/
      this.points.push(startPoint);
 
      //每次触摸开始，开启新的路径
      this.ctx.beginPath();
    },
 
    //触摸移动，获取到路径点
    touchmove: function (e) {
      let moveX = e.changedTouches[0].x;
      let moveY = e.changedTouches[0].y;
      let movePoint = {
        X: moveX,
        Y: moveY
      };
      this.points.push(movePoint); //存点
      let len = this.points.length;
      if (len >= 2) {
        this.draw(); //绘制路径
      }
      tempPoint.push(movePoint);
    },
 
    // 触摸结束，将未绘制的点清空防止对后续路径产生干扰
    touchend: function () {
      this.points = [];
    },
 
    /* ***********************************************	
			#   绘制笔迹
			#   1.为保证笔迹实时显示，必须在移动的同时绘制笔迹
			#   2.为保证笔迹连续，每次从路径集合中区两个点作为起点（moveTo）和终点(lineTo)
			#   3.将上一次的终点作为下一次绘制的起点（即清除第一个点）
			************************************************ */
    draw: function () {
      let point1 = this.points[0];
      let point2 = this.points[1];
      this.points.shift();
      this.ctx.moveTo(point1.X, point1.Y);
      this.ctx.lineTo(point2.X, point2.Y);
      this.ctx.stroke();
      this.ctx.draw(true);
    },
 
    handleCancel() {
      uni.navigateBack({
        delta: 1
      });
    },
 
    //清空画布
    handleReset: function () {
      console.log('handleReset');
      that.ctx.clearRect(0, 0, that.width, that.height);
      that.ctx.draw(true);
      tempPoint = [];
    },
 
    //将签名笔迹上传到服务器，并将返回来的地址存到本地
    handleConfirm: function () {
	  const that = this
      if (tempPoint.length == 0) {
        uni.showToast({
          title: '请先签名',
          icon: 'none',
          duration: 2000
        });
        return;
      }
      uni.canvasToTempFilePath({
        canvasId: 'mycanvas',
        success: function (res) {
          let tempPath = res.tempFilePath;
 
          const ctx = uni.createCanvasContext('camCacnvs', that);
          ctx.translate(0, that.width);
          ctx.rotate((-90 * Math.PI) / 180);
          ctx.drawImage(tempPath, 0, 0, that.width, that.height);
          ctx.draw();
          setTimeout(() => {
			  //保存签名图片到本地
            uni.canvasToTempFilePath(
              {
                canvasId: 'camCacnvs',
                success: function (res) {
					//这是签名图片文件的本地临时地址
                  let path = res.tempFilePath;
                 console.log(path);
				 // 图片上传
				 uni.uploadFile({
				 	url: BASE_URL + '/file/upload',
				 	filePath: path,
				 	name: 'file',
				 	header: {
				 		Authorization: uni.getStorageSync('token') ?
				 			`Bearer ${uni.getStorageSync('token')}` : '',
				 		Client: 'APP'
				 	},
				 	success: (uploadFileRes) => {
						console.log(JSON.parse(uploadFileRes.data).data);
						const param = {fileName: JSON.parse(uploadFileRes.data).data}
						that.file(param).then(res => {
							
							const imgData = {
								img: JSON.parse(uploadFileRes.data).data,
								imgShow: res
							}
							that.backData(imgData)
						})
				 	}
				 })
                },
                fail: err => {
                  console.log('fail', err);
                }
              },
              this
            );
          }, 200);
        }
      })
    },
	/**
	 * @param {Object} data 返回携带参数
	 */
	backData(data){
		// 1. 获取当前页面栈实例（此时最后一个元素为当前页）
		let pages = getCurrentPages()
		// 2. 上一页面实例
		// 注意是length长度，所以要想得到上一页面的实例需要 -2
		// 若要返回上上页面的实例就 -3，以此类推
		let prevPage = pages[pages.length - 2]
		// 3. 给上一页面实例绑定getValue()方法和参数（注意是$vm）
		prevPage.$vm.signImg(data)
		uni.navigateBack({
			delta: 1 // 返回的页面数
		})
	}
  }
};
</script>
 
<style lang="scss" scoped>
.container {
  display: flex;
  flex-direction: row;
  padding: 20rpx;
}
 
.sign-box {
  width: 82%;
  height: 100%;
  margin: auto;
  display: flex;
  flex-direction: column;
  text-align: center;
  border: 2rpx dashed #4E84F24D;
  position: relative;
}
 
.sign-view {
  height: 100%;
}
 .signTips{
	 position: fixed;
	 top: 45%;
	 right: 20%;
	transform: rotate(90deg);
	height: 44rpx;
	font-size: 38rpx;
	font-weight: 500;
	color: #CCCCCC;
	z-index: 999;
 }
.sigh-btns{
	display: flex;
	flex-direction: column;
	justify-content: flex-end;
	padding-bottom: 20rpx;
	
}
.btn{
	transform: rotate(90deg);
	margin-top: 70rpx;
	opacity: 1;
	font-weight: 500;
	color: #1B1B1B;
	display: flex;
	justify-content: center;
	align-items: center;
}
.reset{
	color: #1B1B1BFF;
	background-color: #EDF2FC;
}
.confirm{
	background-color: #4E84F2FF;
	color: #fff;
}
.mycanvas {
  margin: auto 0rpx;
  background-color: #fff;
}
 
.canvsborder {
  border: 1rpx solid #333;
  position: fixed;
  top: 0;
  left: 10000rpx;
}
</style>