一個(gè)不錯(cuò)的html5 canvas多層點(diǎn)擊事件監(jiān)聽(tīng)實(shí)例

字號(hào):


    最近寫(xiě)一個(gè)html5的游戲框架。今天寫(xiě)到一個(gè)多層點(diǎn)擊事件的監(jiān)聽(tīng)。覺(jué)得還是挺好玩的。于是把它從模塊中抽化出來(lái)了。以下代碼只是一些思想。具體實(shí)現(xiàn)肯定不是那么丑陋
    代碼如下:
    <!doctype html>
    <html lang=en>
    <head>
    <meta charset=utf-8>
    <title>document</title>
    <style type=text/css>
    .box > canvas {
    position: absolute;
    }
    </style>
    </head>
    <body>
    <div class=box>
    <canvas id=layer1 width=200 height=200></canvas>
    <canvas id=layer2 width=500 height=500></canvas>
    </div>
    <script type=text/javascript>
    function getrect(obj) {
    var x1 = obj.offsetleft;
    var y1 = obj.offsettop;
    var x2 = x1+obj.offsetwidth;
    var y2 = y1+obj.offsetheight;
    return {
    x1: x1,
    y1: y1,
    x2: x2,
    y2: y2
    };
    }
    function inside(x, y, rect) {
    if(x>rect.x1 && x<rect.x2 && y>rect.y1 && y<rect.y2) {
    return true;
    }
    else {
    return false;
    }
    }
    var trigger = {};
    trigger.list = [];
    trigger.listen = function() {
    var list = trigger.list;
    document.addeventlistener('click',function(evt) {
    for(var i=0; i<list.length; ++i) {
    list[i](evt);
    }
    });
    };
    trigger.listen();
    var l1 = document.getelementbyid('layer1');
    var l2 = document.getelementbyid('layer2');
    var dl1 = function(evt) {
    if(inside(evt.clientx, evt.clienty, getrect(l1))) {
    console.log('click');
    }
    }
    trigger.list.push(dl1);
    var dl2 = function(evt) {
    if(inside(evt.clientx, evt.clienty, getrect(l2))) {
    console.log('click2');
    }
    }
    trigger.list.push(dl2);
    </script>
    </body>
    </html>