一个简单的javascript图片放大效果代码

发布于 2017-05-09 04:07:45 | 107 次阅读 | 评论: 0 | 来源: 网友投递

JavaScript客户端脚本语言

Javascript 是一种由Netscape的LiveScript发展而来的原型化继承的基于对象的动态类型的区分大小写的客户端脚本语言，主要目的是为了解决服务器端语言，比如Perl，遗留的速度问题，为客户提供更流畅的浏览效果。

javascript图片放大效果多用于小图片产品的展示。
一个简单的图片放大效果:
参数说明:
1.berviary:String,需要被放大的图片id
2.expand:object,放大区域,如果不设置此项或者此项的id未设置,则默认为光标跟随模式,会自动创建用于显示放大区域的div.
3.clip:object,裁剪区域的大小,即鼠标移动到需要放大的图片上时,突出显示需要被放的大区域
4.opacity:float,放大时图片被遮罩的区域的透明度
效果1:

调用的js代码:

 
$E({berviary:"currentPic",expand:{id:"expand",style:{}},clip:{width:"50px",height:"50px"},opacity:"0.2"});

html代码:

 
<div> 
<div class="img_warp" id="img_warp"> 
<img src="1.jpg" alt="" class="current" id="currentPic" /> 
</div> 
<div class="expand" id="expand" style="border: 1px solid #555; width:400px; height:400px;margin:-200px auto 0 auto; overflow:hidden;"></div> 
</div>

演示效果:

cover = document.createElement("div"); 
warp.appendChild(cover); 
cover.style.position = "absolute"; 
cover.style.top = "0px"; 
cover.style.left = "0px"; 
cover.style.backgroundColor = "#ccc"; 
var opac = parseFloat(opts.opacity) || 0.3; 
cover.style.opacity = opac; 
cover.style.filter = "Alpha(Opacity=" + opac * 100 + ")"; 
cover.style.width = "100%"; 
cover.style.height = "100%"; 
cover.style.zIndex = 2; 
cover.style.visibility = "hidden";

clip = document.createElement("img"); 
warp.appendChild(clip);

clipWidth = (opts.clip && opts.clip.width) || "60px"; 
clipHeight = (opts.clip && opts.clip.height) || "60px";

clip.src = beImg.src; 
clip.className = beImg.className; 
clip.style.position = "absolute"; 
clip.style.top = "0px"; 
clip.style.left = "0px"; 
clip.style.clip = "rect(0px," + clipWidth + "," + clipHeight + ",0px)"; 
clip.style.backgroundColor = "#ccc"; 
clip.style.zIndex = 3;

//ie里面会变态的自动设置宽度和高度 
clip.removeAttribute("width"); 
clip.removeAttribute("height"); 
})();

function layerPos(e){ 
if(e.layerX && e.layerY){ 
return {x:e.layerX,y:e.layerY}; 
} else { 
return {x:e.x,y:e.y}; 
} 
}

var showExpand = function(x,y,e){ 
if(!expand){ 
initExpand(); 
}

expImg.style.left = (-1 * x) * mult + "px"; 
expImg.style.top = (-1 * y ) * mult + "px";

if((!opts.expand) || (!opts.expand.id)){ 
var aPos = absolutePos(e); 
expand.style.left = aPos.x + parseFloat(clipWidth) / 2 + 20 + "px"; 
expand.style.top = aPos.y + "px"; 
}

//初始化放大的div 
function initExpand(){ 
if(opts.expand && opts.expand.id) { 
expand = _(opts.expand.id); 
} else { 
expand = document.createElement("div"); 
if(opts.expand && opts.expand.style){ 
for(var p in opts.expand.style){ 
expand.style[p] = opts.expand.style[p]; 
} 
} 
expand.style.border = "1px solid #000";

expand.style.position = "absolute"; 
expand.style.left ="0"; 
expand.style.right = "0"; 
expand.style.display = "block"; 
document.body.appendChild(expand);

if(clip.clientWidth>clip.clientHeight){ 
expand.style.width = clip.clientWidth + "px"; 
expand.style.height = clip.clientWidth * parseFloat(clipHeight) / parseFloat(clipWidth) + "px"; 
} else { 
expand.style.height = clip.clientHeight + "px"; 
expand.style.width = clip.clientHeight * parseFloat(clipWidth) / parseFloat(clipHeight) + "px"; 
} 
expand.style.zIndex = 4; 
}

expand.style.overflow = "hidden"; 
if((expand.style.position != "relative") && (expand.style.position != "absolute")){ 
//变态的ie6和ie7的img如果为relative,需要设置其父节点也为relative,否则overflow:hidden无效 
expand.style.position = "relative"; 
expand.style.left = "0"; 
expand.style.top = "0"; 
} 
expImg = document.createElement("img"); 
expImg.src = beImg.src; 
expImg.style.position = "relative"; 
expImg.style.left = "0px"; 
expImg.style.top = "0px"; 
expand.appendChild(expImg); 
expImg.removeAttribute("width"); 
expImg.removeAttribute("height");

//计算图片放大的倍数 
var ew = expand.clientWidth; 
var eh = expand.clientHeight; 
var cw = parseFloat(clipWidth); 
var ch = parseFloat(clipHeight); 
mult = (ew/cw < eh/ch) ? ew/cw : eh/ch;

//调整放大图片的大小 
expImg.style.width = beImg.clientWidth * mult + "px"; 
expImg.style.height = beImg.clientHeight * mult + "px"; 
}

}

cover.onmousemove = clip.onmousemove = function(e){ 
var e = e || event; 
var pos = layerPos(e); 
var x = pos.x; 
var y = pos.y; 
//判断x和y坐标有没有超出范围 
var w = parseFloat(clipWidth) / 2,h = parseFloat(clipHeight) / 2;

x = (x < w)?w:x; 
y = (y < h)?h:y; 
x = (x > warp.clientWidth - w) ? (warp.clientWidth - w) : x; 
y = (y > warp.clientHeight - h) ? (warp.clientHeight - h) : y; 
clip.style.clip = "rect(" + (y - h) + "px," + (x + w) + "px," + (y + h) + "px," + (x - w) + "px)"; 
showExpand(x - w,y - h,e); 
} 
warp.onmouseover = cover.onmouseover = clip.onmouseover = function(){ 
//如果清除的定时器存在,则删除. 
if(closeTimeId){ 
clearTimeout(closeTimeId); 
closeTimeId = null; 
} 
if(cover.style.visibility === "hidden"){ 
cover.style.visibility = "visible"; 
} 
if(expand && expand.style.display === "none"){ 
expand.style.display = "block"; 
} 
}

warp.onmouseout = function(){ 
//延迟一定时间后清除 
closeTimeId = setTimeout(function(){ 
cover.style.visibility = "hidden";

if((!opts.expand) || (!opts.expand.id)){ 
expand.style.display = "none"; 
} 
},130); 
}

return { 
clear:function(){ 
//在这里清除放大镜效果 
warp.removeChild(clip); 
warp.removeChild(cover); 
warp.onmouseout = null; 
if((!opts.expand) || (!opts.expand.id)){ 
expand.style.display = "none"; 
} 
} 
} 
} 
</script> 
<div><img border="0" src="http://img.phperz.com/data/img/20170322_9/1490190829_5132.jpg" width="1280" height="800" /> </div> 
<div></div> 
</div> 
<script type="text/javascript">$E({berviary:"currentPic1",expand:{id:"expand",style:{}},clip:{width:"50px",height:"50px"},opacity:"0.2"});</script>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]

效果2:

调用的js代码:

 
$E({berviary:"currentPic",clip:{width:"100px",height:"100px"},opacity:"0.4"});

html代码:

 
<div> 
<div class="img_warp" id="img_warp"> 
<img src="1.jpg" alt="" class="current" id="currentPic" /> 
</div> 
</div>