HTML5真的是很强大，前端时间看到一个canvas实现九宫格的密码解锁。今天抽出时间模仿了一个，特定分享一下！
效果截图如下：
效果看起来还不错吧！
源码如下：
<!DOCTYPE html>
<html>
<head lang="zh-CN">
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport"/>
<meta charset="UTF-8">
<title>html5实现网页解锁功能</title>
<style type="text/css">
html, body {
margin: 0;
padding: 0;
width: 100%;
height: 100%;
}
</style>
<script type="text/javascript">
/**
* 半径，画布宽度，画布高度，画布x内边距，画布y内边距
*/
var R = 26, canvasWidth = 400, canvasHeight = 320, OffsetX = 30, OffsetY = 30;
var circleArr = [];
function createCirclePoint(diffX, diffY) {
for (var row = 0; row < 3; row++) {
for (var col = 0; col < 3; col++) {
// 计算圆心坐标
var Point = {
X: (OffsetX + col * diffX + ( col * 2 + 1) * R),
Y: (OffsetY + row * diffY + (row * 2 + 1) * R)
};
circleArr.push(Point);
}
}
}
window.onload = function () {
var canvas = document.getElementById("lockCanvas");
canvasWidth = document.body.offsetWidth;//网页可见区域宽
canvas.width = canvasWidth;
canvas.height = canvasHeight;
var cxt = canvas.getContext("2d");
/**
* 每行3个圆
* OffsetX为canvas x方向内边距
* */
var X = (canvasWidth - 2 * OffsetX - R * 2 * 3) / 2;
var Y = (canvasHeight - 2 * OffsetY - R * 2 * 3) / 2;
createCirclePoint(X, Y);
bindEvent(canvas, cxt);
//CW=2*offsetX+R*2*3+2*X
Draw(cxt, circleArr, [],null);
}
function Draw(cxt, circleArr, pwdArr,touchPoint) {
if (pwdArr.length > 0) {
cxt.beginPath();
for (var i = 0; i < pwdArr.length; i++) {
var pointIndex = pwdArr[i];
cxt.lineTo(circleArr[pointIndex].X, circleArr[pointIndex].Y);
}
cxt.lineWidth = 10;
cxt.strokeStyle = "#627eed";
cxt.stroke();
cxt.closePath();
if(touchPoint!=null){
var lastPointIndex=pwdArr[pwdArr.length-1];
var lastPoint=circleArr[lastPointIndex];
cxt.beginPath();
cxt.moveTo(lastPoint.X,lastPoint.Y);
cxt.lineTo(touchPoint.X,touchPoint.Y);
cxt.stroke();
cxt.closePath();
}
}
for (var i = 0; i < circleArr.length; i++) {
var Point = circleArr[i];
cxt.fillStyle = "#627eed";
cxt.beginPath();
cxt.arc(Point.X, Point.Y, R, 0, Math.PI * 2, true);
cxt.closePath();
cxt.fill();
cxt.fillStyle = "#ffffff";
cxt.beginPath();
cxt.arc(Point.X, Point.Y, R - 3, 0, Math.PI * 2, true);
cxt.closePath();
cxt.fill();
if(pwdArr.indexOf(i)>=0){
cxt.fillStyle = "#627eed";
cxt.beginPath();
cxt.arc(Point.X, Point.Y, R -16, 0, Math.PI * 2, true);
cxt.closePath();
cxt.fill();
}
}
}
/**
* 计算选中的密码
*/
function getSelectPwd(touches,pwdArr){
for (var i = 0; i < circleArr.length; i++) {
var currentPoint = circleArr[i];
var xdiff = Math.abs(currentPoint.X - touches.pageX);
var ydiff = Math.abs(currentPoint.Y - touches.pageY);
var dir = Math.pow((xdiff * xdiff + ydiff * ydiff), 0.5);
if(dir > R || pwdArr.indexOf(i) >= 0)
continue;
pwdArr.push(i);
break;
}
}
/**
* 给画布绑定事件
*/
function bindEvent(canvas, cxt) {
var pwdArr = [];
canvas.addEventListener("touchstart", function (e) {
getSelectPwd(e.touches[0],pwdArr);
}, false);
canvas.addEventListener("touchmove", function (e) {
e.preventDefault();
var touches = e.touches[0];
getSelectPwd(touches,pwdArr);
cxt.clearRect(0,0,canvasWidth,canvasHeight);
Draw(cxt,circleArr,pwdArr,{X:touches.pageX,Y:touches.pageY});
}, false);
canvas.addEventListener("touchend", function (e) {
cxt.clearRect(0,0,canvasWidth,canvasHeight);
Draw(cxt,circleArr,pwdArr,null);
alert("密码结果是："+pwdArr.join("->"));
pwdArr=[];
}, false);
}
</script>
</head>
<body>
<canvas id="lockCanvas"></canvas>
</body>
</html>
来自：http://blog.csdn.net/xmtblog/article/details/50252127
原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/10074.html