<html>
<head>
<meta charset="UTF-8">
<style type="text/css">
*{margin:0;padding:0}
.demo{width: 680px;height: 480px;position:relative;background:#333;margin:20px auto;overflow:hidden;}
.small_box{position:absolute;top: 0;}
.big_box{width: 100px;height: 100px;border:1px solid #999;background:url(./images/cc.jpg) no-repeat;position:absolute;top: 0;left: 0;border-radius:50%;cursor:none;display:none;box-shadow: 0px 0px 8px #000;}
</style>
</head>
<body>
<p id="demo" class="demo">
<img id="small_box" class="small_box" src="images/cc.jpg"/>
<p id="big_box" class="big_box">
</p>
</p>
<script type="text/javascript" src="./js/jquery-1.10.1.min.js"></script>
<script type="text/javascript">
$(function(){
(function(a){function d(b){var c=b||window.event,d=[].slice.call(arguments,1),e=0,f=!0,g=0,h=0;return b=a.event.fix(c),b.type="mousewheel",c.wheelDelta&&(e=c.wheelDelta/120),c.detail&&(e=-c.detail/3),h=e,c.axis!==undefined&&c.axis===c.HORIZONTAL_AXIS&&(h=0,g=-1*e),c.wheelDeltaY!==undefined&&(h=c.wheelDeltaY/120),c.wheelDeltaX!==undefined&&(g=-1*c.wheelDeltaX/120),d.unshift(b,e,g,h),(a.event.dispatch||a.event.handle).apply(this,d)}var b=["DOMMouseScroll","mousewheel"];if(a.event.fixHooks)for(var c=b.length;c;)a.event.fixHooks[b[--c]]=a.event.mouseHooks;a.event.special.mousewheel={setup:function(){if(this.addEventListener)for(var a=b.length;a;)this.addEventListener(b[--a],d,!1);else this.onmousewheel=d},teardown:function(){if(this.removeEventListener)for(var a=b.length;a;)this.removeEventListener(b[--a],d,!1);else this.onmousewheel=null}},a.fn.extend({mousewheel:function(a){return a?this.bind("mousewheel",a):this.trigger("mousewheel")},unmousewheel:function(a){return this.unbind("mousewheel",a)}})})(jQuery)
var origin_img = new Image();
origin_img.src = $('.small_box').attr('src');
var origin_w = origin_img.width;
var origin_h = origin_img.height;
var now_h = 480;
var now_w = (origin_w/origin_h)*now_h;
$('.small_box').css({'left':(680 -now_w)/2+'px','height':now_h+'px'})
console.log($('.small_box').offset().left);
$('#demo')[0].onmousemove = function(ev){
var _event=ev||window.event;
var x = _event.pageX||_event.clientX,
y = _event.pageY||_event.clientY;
var left=x- $('#big_box').width()/2 - $('.demo').offset().left ;
var top=y - $('#big_box').width()/2 - $('.demo').offset().top ;
$('#big_box')[0].style.left = left+ 'px';
$('#big_box')[0].style.top = top + 'px';
var percentX = ($('.small_box').offset().left -x)/now_w;
var percentY = ($('.small_box').offset().top -y)/now_h;
$('.big_box').css({
'background-position-x':percentX*origin_w + $('#big_box').width()/2+'px',
'background-position-y':percentY*origin_h + $('#big_box').height()/2+'px'
})
}
$('.big_box').on('mousewheel',function(_event,delta){
var x = _event.pageX||_event.clientX,
y = _event.pageY||_event.clientY;
var left=x- $('#big_box').width()/2 - $('.demo').offset().left ;
var top=y - $('#big_box').width()/2 - $('.demo').offset().top ;
var targe_w = $(this).width();
var targe_h = $(this).height();
if (delta>0) {
targe_w += 3;
targe_h += 3;
$('#big_box')[0].style.left = left -3+ 'px';
$('#big_box')[0].style.top = top -3 + 'px';
}else{
targe_w -= 3;
targe_h -= 3;
$('#big_box')[0].style.left = left +3+ 'px';
$('#big_box')[0].style.top = top +3 + 'px';
}
$(this).width(targe_w);
$(this).height(targe_h);
})
$('.demo').on('mouseover',function(){
$('#big_box').show();
});
$('.demo').on('mouseout',function(){
$('#big_box').hide();
});
})
</script>
<br/> <br/> <br/> <br/> <br/>
</body>
</html>
