微信小程序实现手势图案锁屏功能

<view class="container">
  <view class="reset" bindtap="resetpwd">重置密码</view>
  <view class="title">{{title}}</view>
  <canvas canvas-id="canvas" class="canvas" bindtouchend="ontouchend"
   bindtouchstart="ontouchstart" bindtouchmove="ontouchmove"></canvas>
</view>

var locker = class {
 constructor(page,opt){
  var obj = opt || {};

  this.page = page;
  this.width = obj.width || 300;
  this.height = obj.height || 300;
  this.canvasid = obj.id || 'canvas';
  this.clecolor = obj.clecolor || '#cfe6ff';
  this.clecentercolor = obj.clecentercolor || '#cfe6ff';

  var choosetype = obj.choosetype || 3;
  // 判断是否缓存有choosetype，有就用缓存，没有就用传入的值
  this.choosetype = number(wx.getstoragesync('choosetype')) || choosetype;

  this.init();
 }
 init(){
  this.pswobj = wx.getstoragesync('passwordxx') ? {
   step: 2,
   spassword: json.parse(wx.getstoragesync('passwordxx'))
  } : {};

  this.makestate();
  // 创建 canvas 绘图上下文（指定 canvasid）
  this.ctx = wx.createcanvascontext(this.canvasid,this);
  this.touchflag = false;
  this.lastpoint = [];

  // 绘制圆
  this.createcircle();
  // canvas绑定事件
  this.bindevent();
 }
 makestate() {
  if (this.pswobj.step == 2) {
   this.page.setdata({ title:'请解锁'});
  } else if (this.pswobj.step == 1) {
   // pass
  } else {
   // pass
  }
 }
 // 画圆方法
 drawcle(x,y){
  // 设置边框颜色。
  this.ctx.setstrokestyle(this.clecolor); // 注意用set
  // 设置线条的宽度。
  this.ctx.setlinewidth(2); // 注意用set
  // 开始创建一个路径，需要调用fill或者stroke才会使用路径进行填充或描边。
  this.ctx.beginpath();
  // 画一条弧线。
  this.ctx.arc(x, y, this.r, 0, math.pi * 2, true);
  // 关闭一个路径
  this.ctx.closepath();
  // 画出当前路径的边框。默认颜色色为黑色。
  this.ctx.stroke();
  // 将之前在绘图上下文中的描述（路径、变形、样式）画到 canvas 中。
  this.ctx.draw(true);
 }

 // 计算两点之间的距离的方法
 getdis(a, b) {
  return math.sqrt(math.pow(a.x - b.x, 2) + math.pow(a.y - b.y, 2));
 }

 // 创建解锁点的坐标，根据canvas的大小（默认300px）来平均分配半径
 createcircle() {
  var n = this.choosetype;
  var count = 0;
  // 计算圆半径
  this.r = this.width / (2 + 4 * n);
  this.arr = [];
  this.restpoint = [];
  var r = this.r;
  // 获取圆心坐标，以及当前圆所代表的数
  for (var i = 0; i < n; i++) {
   for (var j = 0; j < n; j++) {
    count++;
    var obj = {
     x: j * 4 * r + 3 * r,
     y: i * 4 * r + 3 * r,
     index: count
    };
    this.arr.push(obj);
    this.restpoint.push(obj);
   }
  }
  // 清空画布
  this.ctx.clearrect(0, 0, this.width, this.height);

  // 绘制所有的圆
  this.arr.foreach(current => {this.drawcle(current.x, current.y);});
 }



 // 设置密码绘制
 getposition(e) { // 获取touch点相对于canvas的坐标
  var po = {
   x: e.touches[0].x,
   y: e.touches[0].y
  };
  return po;
 }
 preciseposition(po){
  var arr = this.restpoint.filter(current => math.abs(po.x - current.x) < this.r && math.abs(po.y - current.y) < this.r);
  return arr[0];
 }
 drawpoint(obj) { // 初始化圆心

  for (var i = 0; i < this.lastpoint.length; i++) {
   this.ctx.setfillstyle(this.clecentercolor); // 注意用set方法
   this.ctx.beginpath();
   this.ctx.arc(this.lastpoint[i].x, this.lastpoint[i].y, this.r / 2, 0, math.pi * 2, true);
   this.ctx.closepath();
   this.ctx.fill();
   this.ctx.draw(true);
  }
 }
 drawline(po) {// 解锁轨迹
  this.ctx.beginpath();
  this.ctx.linewidth = 3;
  this.ctx.moveto(this.lastpoint[0].x,this.lastpoint[0].y);

  for (var i = 1; i < this.lastpoint.length; i++) {
   this.ctx.lineto(this.lastpoint[i].x, this.lastpoint[i].y);
  }
  this.ctx.lineto(po.x, po.y);
  this.ctx.stroke();
  this.ctx.closepath();
  this.ctx.draw(true);
 }
 pickpoints(frompt, topt) {
  var linelength = this.getdis(frompt, topt);
  var dir = topt.index > frompt.index ? 1 : -1;

  var len = this.restpoint.length;
  var i = dir === 1 ? 0 : (len - 1);
  var limit = dir === 1 ? len : -1;

  while (i !== limit) {
   var pt = this.restpoint[i];

   if (this.getdis(pt, frompt) + this.getdis(pt, topt) === linelength) {
    this.drawpoint(pt.x, pt.y);
    this.lastpoint.push(pt);
    this.restpoint.splice(i, 1);
    if (limit > 0) {
     i--;
     limit--;
    }
   }

   i += dir;
  }
 }
 update(po) {// 核心变换方法在touchmove时候调用
  this.ctx.clearrect(0, 0, this.width, this.height);

  for (var i = 0; i < this.arr.length; i++) { // 每帧先把面板画出来
   this.drawcle(this.arr[i].x, this.arr[i].y);
  }

  this.drawpoint(this.lastpoint);// 每帧花轨迹
  this.drawline(po, this.lastpoint);// 每帧画圆心

  for (var i = 0; i < this.restpoint.length; i++) {
   var pt = this.restpoint[i];

   if (math.abs(po.x - pt.x) < this.r && math.abs(po.y - pt.y) < this.r) {
    this.drawpoint(pt.x, pt.y);
    this.pickpoints(this.lastpoint[this.lastpoint.length - 1], pt);
    break;
   }
  }
 }
 checkpass(psw1, psw2) {// 检测密码
  var p1 = '',
   p2 = '';
  for (var i = 0; i < psw1.length; i++) {
   p1 += psw1[i].index + psw1[i].index;
  }
  for (var i = 0; i < psw2.length; i++) {
   p2 += psw2[i].index + psw2[i].index;
  }
  return p1 === p2;
 }
 storepass(psw) {// touchend结束之后对密码和状态的处理
  if (this.pswobj.step == 1) {
   if (this.checkpass(this.pswobj.fpassword, psw)) {
    this.pswobj.step = 2;
    this.pswobj.spassword = psw;

    this.page.setdata({title:'密码保存成功'});

    this.drawstatuspoint('#2cff26');
    wx.setstoragesync('passwordxx', json.stringify(this.pswobj.spassword));
    wx.setstoragesync('choosetype', this.choosetype);
   } else {
    this.page.setdata({ title: '两次不一致，重新输入' });
    this.drawstatuspoint('red');
    delete this.pswobj.step;
   }
  } else if (this.pswobj.step == 2) {
   if (this.checkpass(this.pswobj.spassword, psw)) {
    this.page.setdata({ title: '解锁成功' });
    this.drawstatuspoint('#2cff26');
   } else {
    this.drawstatuspoint('red');
    this.page.setdata({ title: '解锁失败' });
   }
  } else {
   this.pswobj.step = 1;
   this.pswobj.fpassword = psw;
   this.page.setdata({ title: '再次输入' });
  }
 }
 drawstatuspoint(type) { // 初始化状态线条
  for (var i = 0; i < this.lastpoint.length; i++) {
   this.ctx.strokestyle = type;
   this.ctx.beginpath();
   this.ctx.arc(this.lastpoint[i].x, this.lastpoint[i].y, this.r, 0, math.pi * 2, true);
   this.ctx.closepath();
   this.ctx.stroke();
   this.ctx.draw(true);
  }
 }

 updatepassword() {
  wx.removestoragesync('passwordxx');
  wx.removestoragesync('choosetype');
  this.pswobj = {};
  this.page.setdata({ title: '绘制解锁图案' });
  this.reset();
 }
 reset() {
  this.makestate();
  this.createcircle();
 }
 bindevent(){
  var self = this;
  this.page.ontouchstart = function(e){
   var po = self.getposition(e);
   self.lastpoint = [];
   for (var i = 0; i < self.arr.length; i++) {
    if (math.abs(po.x - self.arr[i].x) < self.r && math.abs(po.y - self.arr[i].y) < self.r) {

     self.touchflag = true;
     self.drawpoint(self.arr[i].x, self.arr[i].y);
     self.lastpoint.push(self.arr[i]);
     self.restpoint.splice(i, 1);
     break;
    }
   }
  }

  this.page.ontouchmove = function(e){
   if (self.touchflag) {
    self.update(self.getposition(e));
   }
  }

  this.page.ontouchend = function(e){
   if (self.touchflag) {
    self.touchflag = false;
    self.storepass(self.lastpoint);
    settimeout(function () {
     self.reset();
    }, 300);
   }
  }
 }
}
module.exports = locker;