通过微信小程序如何实现手势图案锁屏

<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;