微信小程序手写签名

微信小程序canvas手写签名

效果图

1. 设置屏幕横屏模式
   在app.json或当前页面xxx.json文件中添加设置屏幕横屏模式
   
   2.wxml

<view class="container">
  <canvas class="canvas" id="canvas" canvas-id="canvas" disable-scroll="true" bindtouchstart="canvasStart"
    bindtouchmove="canvasMove" bindtouchend="canvasEnd" touchcancel="canvasEnd"
    binderror="canvasIdErrorCallback">canvas>
  <view class="tips">
    请在框内签字
  view>
  <view class="addBtn">
    <button type="default" class="txt" bindtap="cleardraw">重新签名button>
    <button type="default" class="txt" bindtap="getimg">提交签字button>
  view>
view>

3. js

const fileManager = wx.getFileSystemManager();
 
// canvas 全局配置
var context = null; // 使用 wx.createContext 获取绘图上下文 context
var isButtonDown = false;
var arrx = [];
var arry = [];
var arrz = [];
var canvasw = 0;
var canvash = 0;
//获取系统信息
wx.getSystemInfo({
  success: function (res) {
    canvasw = res.windowHeight * 3.0; //设备宽度
    // canvash = res.windowWidth * 7 / 15;
    canvash = res.windowWidth * 1.2;
  }
});
//注册页面
Page({
 
  /**
 1. 页面的初始数据
   */
  data: {
    signFlag: false,
  },
 
  /**
 2. 生命周期函数--监听页面加载
   */
  onLoad: function (options) {
    context = wx.createCanvasContext("canvas");
    context.setFillStyle("#fff")
    context.fillRect(0, 0, canvasw, canvash)
    context.draw(true)
    context.beginPath()
    context.setStrokeStyle("#000000");
    context.setLineWidth(4);
    context.setLineCap("round");
    context.setLineJoin("round");
  },
  onShow() {
    arrx = [];
    arry = [];
    arrz = [];
  },
 
  isJSON(str) {
    if (typeof str == "string") {
      try {
        var obj = JSON.parse(str);
        if (typeof obj == "object" && obj) {
          return true;
        } else {
          return false;
        }
      } catch (e) {
        return false;
      }
    }
  },
 
  canvasIdErrorCallback: function (e) { },
  //开始
  canvasStart: function (event) {
    isButtonDown = true;
    arrz.push(0);
    arrx.push(event.changedTouches[0].x);
    arry.push(event.changedTouches[0].y);
    //context.moveTo(event.changedTouches[0].x, event.changedTouches[0].y);
 
  },
  //过程
  canvasMove: function (event) {
    if (isButtonDown) {
      arrz.push(1);
      arrx.push(event.changedTouches[0].x);
      arry.push(event.changedTouches[0].y);
      // context.lineTo(event.changedTouches[0].x, event.changedTouches[0].y);
      // context.stroke();
      // context.draw()
    };
 
    this.setData({
      signFlag: true,
    })
 
    for (var i = 0; i < arrx.length; i++) {
      if (arrz[i] == 0) {
        context.moveTo(arrx[i], arry[i])
      } else {
        context.lineTo(arrx[i], arry[i])
      };
 
    };
 
    context.setStrokeStyle("#000000");
    context.setLineWidth(4);
    context.setLineCap("round");
    context.setLineJoin("round");
    context.stroke();
    context.draw(true);
  },
  canvasEnd: function (event) {
    isButtonDown = false;
  },
  cleardraw: function () {
    //清除画布
    arrx = [];
    arry = [];
    arrz = [];
    context.clearRect(0, 0, canvasw, canvash);
    context.draw(true);
  },
  //导出图片
  getimg: function () {
    let that = this
    if (arrx.length == 0) {
      wx.showModal({
        title: "提示",
        content: "签名内容不能为空！",
        showCancel: false
      });
      return false;
    };
    console.log(this.data.signFlag);
    if (!this.data.signFlag) {
      wx.showModal({
        title: "提示",
        content: "签名内容不能为空！",
        showCancel: false
      });
      return false;
    }
    //生成图片
    wx.canvasToTempFilePath({
      canvasId: "canvas",
      success: function (res) {
        //将图片转换为base64 的格式
        //let base64 = "data:image/jpg;base64," + fileManager.readFileSync(res.tempFilePath,"base64"); 
        //文件图片类型上传
          wx.uploadFile({
          url: app.globalData.apiBaseUrl + app.globalData.uploadUrl,
          filePath: res.tempFilePath,//要上传文件资源的路径（本地路径）
          name:"file",
          header: {
            "X-Access-Token": app.globalData.accessToken
          },
          success: function (res){
            const jsom = JSON.parse(res.data)
             //签名图片 oss地址
            let data = {}
            data.signature = jsom.message
            data.userId = that.data.userId
             api.contractSigning(JSON.stringify(data)).then(res => {
                  if (res.success){
                    util.showErrorToast("签署成功");
                    setTimeout(()=>{
                      wx.navigateTo({
                        url: "/pages/index/index"
                      })

                    },1000)
                  }else {

                  }
             })
          },
          fail:function (err){
            
          }
        })
      }
    })
 
  },
 
})

3. wxss

page{
  background: #fff;
}
.container {
  width: 95%;
  position: absolute;
  height: 95%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  box-sizing: border-box;
  background: #fff;
  border-radius: 5px;
}
.canvas {
  width: 100%;
  height: 70%;
  border: 1px solid #aaa;
  box-sizing: border-box;
}
.tips{
  height: 10%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: #aaa;
}
  
.addBtn {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 18%;
  position: fixed;
  bottom: 0;
  width: 100%;
  background: #fff;
  z-index: 100;