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  • canvas——绘制解锁图案

    <!DOCTYPE html>
    <html>
        <head>
            <meta charset="utf-8">
            <title>手机解锁</title>
            <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no" />
            <style>
                body{
                    text-align: center;
                    background: #305066;
                }
                h4{
                    color: #22c3aa;
                }
            </style>
        </head>
        <body>
            <script type="text/javascript" src="js/index.js"></script>
            <script>
                //1.生成背景
                //2.动态title生成
                //3.用js动态生成canvas标签
                //4.js动态生成h3标签和canvas标签
                new canvasLock({chooseType:3}).init();
                
            </script>
        </body>
    </html>
    (function(){
        /*
          实现画圆和划线:
          1.添加事件touchstart、touchmove、touchend
          2.touchstart判断是否点击的位置处于园内getPosition,处于则初始化lastpoint、restPoint
          3.touchmove做的就是:画圆drawPoint和划线drawLine
        */
        /*
          实现自动画圆的效果
          1.检测手势移动的位置是否处于圆内。
          2.圆内的话则画圆 drawPoint
          3.已经画过实心圆的圆,无需重复检测
        */
       /*
          实现解锁成功:
          1.检测路径是否是对的
          2.如果是对的就重置,圆圈变绿
          3.不对也重置,圆圈变红
          4.重置
       */
        window.canvasLock = function(obj){
            this.height = obj.height;
            this.width = obj.width;
            this.chooseType = obj.chooseType;
            
        };
        
        //js方式动态生成dom
        canvasLock.prototype.initDom = function(){
            var wrap = document.createElement('div');
            var str = '<h4 id="title" class="title">绘制解锁图案</h4>';
            wrap.setAttribute('style','position:absolute;top:0;left:0;right:0;bottom:0');
            
            var canvas = document.createElement('canvas');
            canvas.setAttribute('id','canvas');
            canvas.style.cssText = "background-color:#305066;display:inline-block;margin-top=15px";
            
            wrap.innerHTML = str;
            wrap.appendChild(canvas);
            
            var width = this.width || 300;
            var height = this.height || 300;
            
            document.body.appendChild(wrap);
            
            //高清屏锁放
            canvas.style.width = width +"px";
            canvas.style.height = height + "px";
            //修改默认宽高
            canvas.width = width;
            canvas.height = height;
        }
        canvasLock.prototype.drawCle = function(x,y){  //初始化解锁密码面板,即画圆
            this.ctx.strokeStyle = '#cfe6ef';
            this.ctx.lineWidth = 2;
            this.ctx.beginPath();
            this.ctx.arc(x,y,this.r,0,Math.PI*2,true);
            this.ctx.closePath();
            this.ctx.stroke();
            
        }
        
        canvasLock.prototype.createCircle = function(){  //创建点的坐标,根据c
            var n = this.chooseType;  //n是指有几行圆
            var count = 0;
            this.r = this.ctx.canvas.width / (2+4*n);
            //圆心坐标
            this.lastPoint = [];  
            this.arr = [];   //9个圆的中心点坐标
            this.restPoint = [];  //还未选中的圆的个数
            var r = this.r;
            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);
                }
            }
            this.ctx.clearRect(0,0,this.ctx.canvas.width,this.ctx.canvas.height);
            for(var i = 0;i<this.arr.length;i++){
                this.drawCle(this.arr[i].x,this.arr[i].y);
            }
        }
        
        //程序初始化
        canvasLock.prototype.init = function(){
            this.initDom();
            this.canvas = document.getElementById('canvas');
            this.ctx = this.canvas.getContext('2d');
            this.touchFlag = false;
            //1.确定半径 2.确定每一个圆的中心坐标点
            //3.一行3个圆有14个半径,一行4个圆有18个半径
            this.createCircle();
            this.bindEvent();
        }
        //绑定事件
        canvasLock.prototype.bindEvent = function(){
            var self = this;  //一个是canvas对象,一个是window.canvasLock对象
            console.log(this);  //如果直接使用this,那么this指向的就是当前时间调用的对象,也就是this.canvas,
            console.log(self);  //但是在代码中想要使用的是window.canvasLock对象,所以在事件外面提前将this赋值给self变量,确保this的指向问题。
            this.canvas.addEventListener('touchstart',function(e){
                //2.touchstart判断是否点击的位置处于园内getPosition,处于则初始化lastpoint、restPoint
                var po = self.getPosition(e);
                //判断是否在圆内的原理:多出来的这条 x/y < r 在圆内
                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.lastPoint.push(self.arr[i]);  //把点击的圆心的x轴y轴坐标放入lastPoint数组
                        console.log(self.lastPoint);
                        self.restPoint.splice(i,1);
                        break;
                    }
                }
                
            },false);
            this.canvas.addEventListener('touchmove',function(e){
                //  3.touchmove做的就是:画圆drawPoint和划线drawLine
                if(self.touchFlag){
                    self.update(self.getPosition(e));
                }
            },false);
            this.canvas.addEventListener('touchend',function(e){
                if(self.touchFlag){
                    self.storePass(self.lastPoint);
                    setTimeout(function(){
                        self.reset();
                    },300);
                }
            },false);
        }
        canvasLock.prototype.getPosition = function(e){  //获取touch点相对于canvas
            //获取canvas上下左右离屏幕的距离
            var rect = e.currentTarget.getBoundingClientRect();  // Element.getBoundingClientRect()方法返回元素的大小及其相对于视口的位置。
            //po有x和y,并且使相较于canvas边距
            var po = {
                x: (e.touches[0].clientX - rect.left),
                y: (e.touches[0].clientY - rect.top)
            };
            return po;
        }
            
        
        canvasLock.prototype.update = function(po){  
            // 核心变换方法在touchmove时调用
            //清空画布
            this.ctx.clearRect(0,0,this.ctx.canvas.width,this.ctx.canvas.height);
            //重画9个圆
            for(var i = 0;i < this.arr.length; i++){
                this.drawCle(this.arr[i].x, this.arr[i].y);
            }
            this.drawPoint();  //画圆
            this.drawLine(po);  //画线
            
            //1.检测手势移动的位置是否处于下一圆的圆内。
            //2.圆内的话则画实心圆 drawPoint
            //3.已经画过实心圆的圆,无需重复检测
            for(var i = 0;i < this.restPoint.length;i++){
                if(Math.abs(po.x - this.restPoint[i].x) < this.r && Math.abs(po.y - this.restPoint[i].y) < this.r){
                    this.drawPoint();
                    this.lastPoint.push(this.restPoint[i]);
                    this.restPoint.splice(i,1);  //画完一个圆就将该圆从restPoint数组中去掉
                    break;
                }
            }
        }  
        canvasLock.prototype.drawLine = function(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();
        }
        canvasLock.prototype.drawPoint = function(){  //初始化圆心
            for(var i = 0; i < this.lastPoint.length;i++){
                this.ctx.fillStyle = '#cfe6fe';
                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();
            }
        }
        
        canvasLock.prototype.storePass = function(){
            
            if(this.checkPass()){
                document.getElementById('title').innerHTML = '解锁成功';
                this.drawStatusPoint('#2cff26');
            }else{
                document.getElementById('title').innerHTML = '解锁失败';
                this.drawStatusPoint('red');
            }
        }
        canvasLock.prototype.checkPass = function(){
            var p1 = '123';
            p2 = '';
            for(var i = 0; i < this.lastPoint.length; i++){
                p2 += this.lastPoint[i].index;
            }
            return p1 === p2;
        }
        canvasLock.prototype.drawStatusPoint = function(type){
            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();
            }
        }
        canvasLock.prototype.reset = function(){
            this.createCircle();
        }
    })();
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  • 原文地址:https://www.cnblogs.com/rickdiculous/p/11509709.html
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