jQuery实现图片局部放大镜效果

.zoomPad{
position:relative;
float:left;
z-index:99;
cursor:crosshair;
}
.zoomPreload{
-moz-opacity:0.8;
opacity: 0.8;
filter: alpha(opacity = 80);
color: #333;
font-size: 12px;
font-family: Tahoma;
text-decoration: none;
border: 1px solid #CCC;
padding: 8px;
text-align:center;
background-image: url(../images/zoomloader.gif);
background-repeat: no-repeat;
background-position: 43px 30px;
z-index:110;
width:90px;
height:43px;
position:absolute;
top:0px;
left:0px;
* width:100px;
* height:49px;
}
.zoomPup{
overflow:hidden;
-moz-opacity:0.6;
opacity: 0.6;
filter: alpha(opacity = 60);
z-index:120;
position:absolute;
border:1px solid #CCC;
z-index:101;
cursor:crosshair;
}
.zoomOverlay{
position:absolute;
left:0px;
top:0px;
/*opacity:0.5;*/
z-index:5000;
width:100%;
height:100%;
display:none;
z-index:101;
}
.zoomWindow{
position:absolute;
left:110%;
top:40px;
z-index:6000;
height:auto;
z-index:10000;
z-index:110;
}
.zoomWrapper{
position:relative;
border:1px solid #999;
z-index:110;
}
.zoomWrapperTitle{
display:block;
background:#999;
color:#FFF;
height:18px;
line-height:18px;
width:100%;
overflow:hidden;
text-align:center;
font-size:10px;
position:absolute;
top:0px;
left:0px;
z-index:120;
-moz-opacity:0.6;
opacity: 0.6;
filter: alpha(opacity = 60);
}
.zoomWrapperImage{
display:block;
position:relative;
overflow:hidden;
z-index:110;
}
.zoomWrapperImage img{
border:0px;
display:block;
position:absolute;
z-index:101;
}
.zoomIframe{
z-index: -1;
filter:alpha(opacity=0);
-moz-opacity: 0.80;
opacity: 0.80;
position:absolute;
display:block;
}
/*********************************************************
/ When clicking on thumbs jqzoom will add the class
/ "zoomThumbActive" on the anchor selected
/*********************************************************/ 

/*!
* jQzoom Evolution Library v2.3 - Javascript Image magnifier
* http://www.mind-projects.it
*
* Copyright 2011, Engineer Marco Renzi
* Licensed under the BSD license.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the organization nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* Date: 03 May 2011 22:16:00
*/
(function ($) {
//GLOBAL VARIABLES
var isIE6 = ($.browser.msie && $.browser.version < 7);
var body = $(document.body);
var window = $(window);
var jqzoompluging_disabled = false; //disabilita globalmente il plugin
$.fn.jqzoom = function (options) {
return this.each(function () {
var node = this.nodeName.toLowerCase();
if (node == 'a') {
new jqzoom(this, options);
}
});
};
jqzoom = function (el, options) {
var api = null;
api = $(el).data("jqzoom");
if (api) return api;
var obj = this;
var settings = $.extend({}, $.jqzoom.defaults, options || {});
obj.el = el;
el.rel = $(el).attr('rel');
//ANCHOR ELEMENT
el.zoom_active = false;
el.zoom_disabled = false; //to disable single zoom instance
el.largeimageloading = false; //tell us if large image is loading
el.largeimageloaded = false; //tell us if large image is loaded
el.scale = {};
el.timer = null;
el.mousepos = {};
el.mouseDown = false;
$(el).css({
'outline-style': 'none',
'text-decoration': 'none'
});
//BASE IMAGE
var img = $("img:eq(0)", el);
el.title = $(el).attr('title');
el.imagetitle = img.attr('title');
var zoomtitle = ($.trim(el.title).length > 0) ? el.title : el.imagetitle;
var smallimage = new Smallimage(img);
var lens = new Lens();
var stage = new Stage();
var largeimage = new Largeimage();
var loader = new Loader();
//preventing default click,allowing the onclick event [exmple: lightbox]
$(el).bind('click', function (e) {
e.preventDefault();
return false;
});
//setting the default zoomType if not in settings
var zoomtypes = ['standard', 'drag', 'innerzoom', 'reverse'];
if ($.inArray($.trim(settings.zoomType), zoomtypes) < 0) {
settings.zoomType = 'standard';
}
$.extend(obj, {
create: function () { //create the main objects
//create ZoomPad
if ($(".zoomPad", el).length == 0) {
el.zoomPad = $('<div/>').addClass('zoomPad');
img.wrap(el.zoomPad);
}
if(settings.zoomType == 'innerzoom'){
settings.zoomWidth = smallimage.w;
settings.zoomHeight = smallimage.h;
}
//creating ZoomPup
if ($(".zoomPup", el).length == 0) {
lens.append();
}
//creating zoomWindow
if ($(".zoomWindow", el).length == 0) {
stage.append();
}
//creating Preload
if ($(".zoomPreload", el).length == 0) {
loader.append();
}
//preloading images
if (settings.preloadImages || settings.zoomType == 'drag' || settings.alwaysOn) {
obj.load();
}
obj.init();
},
init: function () {
//drag option
if (settings.zoomType == 'drag') {
$(".zoomPad", el).mousedown(function () {
el.mouseDown = true;
});
$(".zoomPad", el).mouseup(function () {
el.mouseDown = false;
});
document.body.ondragstart = function () {
return false;
};
$(".zoomPad", el).css({
cursor: 'default'
});
$(".zoomPup", el).css({
cursor: 'move'
});
}
if (settings.zoomType == 'innerzoom') {
$(".zoomWrapper", el).css({
cursor: 'crosshair'
});
}
$(".zoomPad", el).bind('mouseenter mouseover', function (event) {
img.attr('title', '');
$(el).attr('title', '');
el.zoom_active = true;
//if loaded then activate else load large image
smallimage.fetchdata();
if (el.largeimageloaded) {
obj.activate(event);
} else {
obj.load();
}
});
$(".zoomPad", el).bind('mouseleave', function (event) {
obj.deactivate();
});
$(".zoomPad", el).bind('mousemove', function (e) {
//prevent fast mouse mevements not to fire the mouseout event
if (e.pageX > smallimage.pos.r || e.pageX < smallimage.pos.l || e.pageY < smallimage.pos.t || e.pageY > smallimage.pos.b) {
lens.setcenter();
return false;
}
el.zoom_active = true;
if (el.largeimageloaded && !$('.zoomWindow', el).is(':visible')) {
obj.activate(e);
}
if (el.largeimageloaded && (settings.zoomType != 'drag' || (settings.zoomType == 'drag' && el.mouseDown))) {
lens.setposition(e);
}
});
var thumb_preload = new Array();
var i = 0;
//binding click event on thumbnails
var thumblist = new Array();
thumblist = $('a').filter(function () {
var regex = new RegExp("gallery[\\s]*:[\\s]*'" + $.trim(el.rel) + "'", "i");
var rel = $(this).attr('rel');
if (regex.test(rel)) {
return this;
}
});
if (thumblist.length > 0) {
//getting the first to the last
var first = thumblist.splice(0, 1);
thumblist.push(first);
}
thumblist.each(function () {
//preloading thumbs
if (settings.preloadImages) {
var thumb_options = $.extend({}, eval("(" + $.trim($(this).attr('rel')) + ")"));
thumb_preload[i] = new Image();
thumb_preload[i].src = thumb_options.largeimage;
i++;
}
$(this).click(function (e) {
if($(this).hasClass('zoomThumbActive')){
return false;
}
thumblist.each(function () {
$(this).removeClass('zoomThumbActive');
});
e.preventDefault();
obj.swapimage(this);
return false;
});
});
},
load: function () {
if (el.largeimageloaded == false && el.largeimageloading == false) {
var url = $(el).attr('href');
el.largeimageloading = true;
largeimage.loadimage(url);
}
},
activate: function (e) {
clearTimeout(el.timer);
//show lens and zoomWindow
lens.show();
stage.show();
},
deactivate: function (e) {
switch (settings.zoomType) {
case 'drag':
//nothing or lens.setcenter();
break;
default:
img.attr('title', el.imagetitle);
$(el).attr('title', el.title);
if (settings.alwaysOn) {
lens.setcenter();
} else {
stage.hide();
lens.hide();
}
break;
}
el.zoom_active = false;
},
swapimage: function (link) {
el.largeimageloading = false;
el.largeimageloaded = false;
var options = new Object();
options = $.extend({}, eval("(" + $.trim($(link).attr('rel')) + ")"));
if (options.smallimage && options.largeimage) {
var smallimage = options.smallimage;
var largeimage = options.largeimage;
$(link).addClass('zoomThumbActive');
$(el).attr('href', largeimage);
img.attr('src', smallimage);
lens.hide();
stage.hide();
obj.load();
} else {
alert('ERROR :: Missing parameter for largeimage or smallimage.');
throw 'ERROR :: Missing parameter for largeimage or smallimage.';
}
return false;
}
});
//sometimes image is already loaded and onload will not fire
if (img[0].complete) {
//fetching data from sallimage if was previously loaded
smallimage.fetchdata();
if ($(".zoomPad", el).length == 0) obj.create();
}
/*========================================================,
| Smallimage
|---------------------------------------------------------:
| Base image into the anchor element
`========================================================*/
function Smallimage(image) {
var $obj = this;
this.node = image[0];
this.findborder = function () {
var bordertop = 0;
bordertop = image.css('border-top-width');
btop = '';
var borderleft = 0;
borderleft = image.css('border-left-width');
bleft = '';
if (bordertop) {
for (i = 0; i < 3; i++) {
var x = [];
x = bordertop.substr(i, 1);
if (isNaN(x) == false) {
btop = btop + '' + bordertop.substr(i, 1);
} else {
break;
}
}
}
if (borderleft) {
for (i = 0; i < 3; i++) {
if (!isNaN(borderleft.substr(i, 1))) {
bleft = bleft + borderleft.substr(i, 1)
} else {
break;
}
}
}
$obj.btop = (btop.length > 0) ? eval(btop) : 0;
$obj.bleft = (bleft.length > 0) ? eval(bleft) : 0;
};
this.fetchdata = function () {
$obj.findborder();
$obj.w = image.width();
$obj.h = image.height();
$obj.ow = image.outerWidth();
$obj.oh = image.outerHeight();
$obj.pos = image.offset();
$obj.pos.l = image.offset().left + $obj.bleft;
$obj.pos.t = image.offset().top + $obj.btop;
$obj.pos.r = $obj.w + $obj.pos.l;
$obj.pos.b = $obj.h + $obj.pos.t;
$obj.rightlimit = image.offset().left + $obj.ow;
$obj.bottomlimit = image.offset().top + $obj.oh;
};
this.node.onerror = function () {
alert('Problems while loading image.');
throw 'Problems while loading image.';
};
this.node.onload = function () {
$obj.fetchdata();
if ($(".zoomPad", el).length == 0) obj.create();
};
return $obj;
};
/*========================================================,
| Loader
|---------------------------------------------------------:
| Show that the large image is loading
`========================================================*/
function Loader() {
var $obj = this;
this.append = function () {
this.node = $('<div/>').addClass('zoomPreload').css('visibility', 'hidden').html(settings.preloadText);
$('.zoomPad', el).append(this.node);
};
this.show = function () {
this.node.top = (smallimage.oh - this.node.height()) / 2;
this.node.left = (smallimage.ow - this.node.width()) / 2;
//setting position
this.node.css({
top: this.node.top,
left: this.node.left,
position: 'absolute',
visibility: 'visible'
});
};
this.hide = function () {
this.node.css('visibility', 'hidden');
};
return this;
}
/*========================================================,
| Lens
|---------------------------------------------------------:
| Lens over the image
`========================================================*/
function Lens() {
var $obj = this;
this.node = $('<div/>').addClass('zoomPup');
//this.nodeimgwrapper = $("<div/>").addClass('zoomPupImgWrapper');
this.append = function () {
$('.zoomPad', el).append($(this.node).hide());
if (settings.zoomType == 'reverse') {
this.image = new Image();
this.image.src = smallimage.node.src; // fires off async
$(this.node).empty().append(this.image);
}
};
this.setdimensions = function () {
this.node.w = (parseInt((settings.zoomWidth) / el.scale.x) > smallimage.w ) ? smallimage.w : (parseInt(settings.zoomWidth / el.scale.x)); 
this.node.h = (parseInt((settings.zoomHeight) / el.scale.y) > smallimage.h ) ? smallimage.h : (parseInt(settings.zoomHeight / el.scale.y)); 
this.node.top = (smallimage.oh - this.node.h - 2) / 2;
this.node.left = (smallimage.ow - this.node.w - 2) / 2;
//centering lens
this.node.css({
top: 0,
left: 0,
width: this.node.w + 'px',
height: this.node.h + 'px',
position: 'absolute',
display: 'none',
borderWidth: 1 + 'px'
});
if (settings.zoomType == 'reverse') {
this.image.src = smallimage.node.src;
$(this.node).css({
'opacity': 1
});
$(this.image).css({
position: 'absolute',
display: 'block',
left: -(this.node.left + 1 - smallimage.bleft) + 'px',
top: -(this.node.top + 1 - smallimage.btop) + 'px'
});
}
};
this.setcenter = function () {
//calculating center position
this.node.top = (smallimage.oh - this.node.h - 2) / 2;
this.node.left = (smallimage.ow - this.node.w - 2) / 2;
//centering lens
this.node.css({
top: this.node.top,
left: this.node.left
});
if (settings.zoomType == 'reverse') {
$(this.image).css({
position: 'absolute',
display: 'block',
left: -(this.node.left + 1 - smallimage.bleft) + 'px',
top: -(this.node.top + 1 - smallimage.btop) + 'px'
});
}
//centering large image
largeimage.setposition();
};
this.setposition = function (e) {
el.mousepos.x = e.pageX;
el.mousepos.y = e.pageY;
var lensleft = 0;
var lenstop = 0;
function overleft(lens) {
return el.mousepos.x - (lens.w) / 2 < smallimage.pos.l; 
}
function overright(lens) {
return el.mousepos.x + (lens.w) / 2 > smallimage.pos.r; 
}
function overtop(lens) {
return el.mousepos.y - (lens.h) / 2 < smallimage.pos.t; 
}
function overbottom(lens) {
return el.mousepos.y + (lens.h) / 2 > smallimage.pos.b; 
}
lensleft = el.mousepos.x + smallimage.bleft - smallimage.pos.l - (this.node.w + 2) / 2;
lenstop = el.mousepos.y + smallimage.btop - smallimage.pos.t - (this.node.h + 2) / 2;
if (overleft(this.node)) {
lensleft = smallimage.bleft - 1;
} else if (overright(this.node)) {
lensleft = smallimage.w + smallimage.bleft - this.node.w - 1;
}
if (overtop(this.node)) {
lenstop = smallimage.btop - 1;
} else if (overbottom(this.node)) {
lenstop = smallimage.h + smallimage.btop - this.node.h - 1;
}
this.node.left = lensleft;
this.node.top = lenstop;
this.node.css({
'left': lensleft + 'px',
'top': lenstop + 'px'
});
if (settings.zoomType == 'reverse') {
if ($.browser.msie && $.browser.version > 7) {
$(this.node).empty().append(this.image);
}
$(this.image).css({
position: 'absolute',
display: 'block',
left: -(this.node.left + 1 - smallimage.bleft) + 'px',
top: -(this.node.top + 1 - smallimage.btop) + 'px'
});
}
largeimage.setposition();
};
this.hide = function () {
img.css({
'opacity': 1
});
this.node.hide();
};
this.show = function () { 
if (settings.zoomType != 'innerzoom' && (settings.lens || settings.zoomType == 'drag')) {
this.node.show();
} 
if (settings.zoomType == 'reverse') {
img.css({
'opacity': settings.imageOpacity
});
}
};
this.getoffset = function () {
var o = {};
o.left = $obj.node.left;
o.top = $obj.node.top;
return o;
};
return this;
};
/*========================================================,
| Stage
|---------------------------------------------------------:
| Window area that contains the large image
`========================================================*/
function Stage() {
var $obj = this;
this.node = $("<div class='zoomWindow'><div class='zoomWrapper'><div class='zoomWrapperTitle'></div><div class='zoomWrapperImage'></div></div></div>");
this.ieframe = $('<iframe class="zoomIframe" src="javascript:\'\';" marginwidth="0" marginheight="0" align="bottom" scrolling="no" frameborder="0" ></iframe>');
this.setposition = function () {
this.node.leftpos = 0;
this.node.toppos = 0;
if (settings.zoomType != 'innerzoom') {
//positioning
switch (settings.position) {
case "left":
this.node.leftpos = (smallimage.pos.l - smallimage.bleft - Math.abs(settings.xOffset) - settings.zoomWidth > 0) ? (0 - settings.zoomWidth - Math.abs(settings.xOffset)) : (smallimage.ow + Math.abs(settings.xOffset));
this.node.toppos = Math.abs(settings.yOffset);
break;
case "top":
this.node.leftpos = Math.abs(settings.xOffset);
this.node.toppos = (smallimage.pos.t - smallimage.btop - Math.abs(settings.yOffset) - settings.zoomHeight > 0) ? (0 - settings.zoomHeight - Math.abs(settings.yOffset)) : (smallimage.oh + Math.abs(settings.yOffset));
break;
case "bottom":
this.node.leftpos = Math.abs(settings.xOffset);
this.node.toppos = (smallimage.pos.t - smallimage.btop + smallimage.oh + Math.abs(settings.yOffset) + settings.zoomHeight < screen.height) ? (smallimage.oh + Math.abs(settings.yOffset)) : (0 - settings.zoomHeight - Math.abs(settings.yOffset));
break;
default:
this.node.leftpos = (smallimage.rightlimit + Math.abs(settings.xOffset) + settings.zoomWidth < screen.width) ? (smallimage.ow + Math.abs(settings.xOffset)) : (0 - settings.zoomWidth - Math.abs(settings.xOffset));
this.node.toppos = Math.abs(settings.yOffset);
break;
}
}
this.node.css({
'left': this.node.leftpos + 'px',
'top': this.node.toppos + 'px'
});
return this;
};
this.append = function () {
$('.zoomPad', el).append(this.node);
this.node.css({
position: 'absolute',
display: 'none',
zIndex: 5001
});
if (settings.zoomType == 'innerzoom') {
this.node.css({
cursor: 'default'
});
var thickness = (smallimage.bleft == 0) ? 1 : smallimage.bleft;
$('.zoomWrapper', this.node).css({
borderWidth: thickness + 'px'
}); 
}
$('.zoomWrapper', this.node).css({
width: Math.round(settings.zoomWidth) + 'px' ,
borderWidth: thickness + 'px'
});
$('.zoomWrapperImage', this.node).css({
width: '100%',
height: Math.round(settings.zoomHeight) + 'px'
});
//zoom title
$('.zoomWrapperTitle', this.node).css({
width: '100%',
position: 'absolute'
}); 
$('.zoomWrapperTitle', this.node).hide();
if (settings.title && zoomtitle.length > 0) {
$('.zoomWrapperTitle', this.node).html(zoomtitle).show();
}
$obj.setposition();
};
this.hide = function () {
switch (settings.hideEffect) {
case 'fadeout':
this.node.fadeOut(settings.fadeoutSpeed, function () {});
break;
default:
this.node.hide();
break;
}
this.ieframe.hide();
};
this.show = function () {
switch (settings.showEffect) {
case 'fadein':
this.node.fadeIn();
this.node.fadeIn(settings.fadeinSpeed, function () {});
break;
default:
this.node.show();
break;
}
if (isIE6 && settings.zoomType != 'innerzoom') {
this.ieframe.width = this.node.width();
this.ieframe.height = this.node.height();
this.ieframe.left = this.node.leftpos;
this.ieframe.top = this.node.toppos;
this.ieframe.css({
display: 'block',
position: "absolute",
left: this.ieframe.left,
top: this.ieframe.top,
zIndex: 99,
width: this.ieframe.width + 'px',
height: this.ieframe.height + 'px'
});
$('.zoomPad', el).append(this.ieframe);
this.ieframe.show();
};
};
};
/*========================================================,
| LargeImage
|---------------------------------------------------------:
| The large detailed image
`========================================================*/
function Largeimage() {
var $obj = this;
this.node = new Image();
this.loadimage = function (url) {
//showing preload
loader.show();
this.url = url;
this.node.style.position = 'absolute';
this.node.style.border = '0px';
this.node.style.display = 'none';
this.node.style.left = '-5000px';
this.node.style.top = '0px';
document.body.appendChild(this.node);
this.node.src = url; // fires off async
};
this.fetchdata = function () {
var image = $(this.node);
var scale = {};
this.node.style.display = 'block';
$obj.w = image.width();
$obj.h = image.height();
$obj.pos = image.offset();
$obj.pos.l = image.offset().left;
$obj.pos.t = image.offset().top;
$obj.pos.r = $obj.w + $obj.pos.l;
$obj.pos.b = $obj.h + $obj.pos.t;
scale.x = ($obj.w / smallimage.w);
scale.y = ($obj.h / smallimage.h);
el.scale = scale;
document.body.removeChild(this.node);
$('.zoomWrapperImage', el).empty().append(this.node);
//setting lens dimensions;
lens.setdimensions();
};
this.node.onerror = function () {
alert('Problems while loading the big image.');
throw 'Problems while loading the big image.';
};
this.node.onload = function () {
//fetching data
$obj.fetchdata();
loader.hide();
el.largeimageloading = false;
el.largeimageloaded = true;
if (settings.zoomType == 'drag' || settings.alwaysOn) {
lens.show();
stage.show();
lens.setcenter();
}
};
this.setposition = function () {
var left = -el.scale.x * (lens.getoffset().left - smallimage.bleft + 1);
var top = -el.scale.y * (lens.getoffset().top - smallimage.btop + 1);
$(this.node).css({
'left': left + 'px',
'top': top + 'px'
});
};
return this;
};
$(el).data("jqzoom", obj);
};
//es. $.jqzoom.disable('#jqzoom1');
$.jqzoom = {
defaults: {
zoomType: 'standard',
//innerzoom/standard/reverse/drag
zoomWidth: 300,
//zoomWindow default width
zoomHeight: 300,
//zoomWindow default height
xOffset: 10,
//zoomWindow x offset, can be negative(more on the left) or positive(more on the right)
yOffset: 0,
//zoomWindow y offset, can be negative(more on the left) or positive(more on the right)
position: "right",
//zoomWindow default position
preloadImages: true,
//image preload
preloadText: 'Loading zoom',
title: true,
lens: true,
imageOpacity: 0.4,
alwaysOn: false,
showEffect: 'show',
//show/fadein
hideEffect: 'hide',
//hide/fadeout
fadeinSpeed: 'slow',
//fast/slow/number
fadeoutSpeed: '2000' //fast/slow/number
},
disable: function (el) {
var api = $(el).data('jqzoom');
api.disable();
return false;
},
enable: function (el) {
var api = $(el).data('jqzoom');
api.enable();
return false;
},
disableAll: function (el) {
jqzoompluging_disabled = true;
},
enableAll: function (el) {
jqzoompluging_disabled = false;
}
};
})(jQuery); 

$(function(){
$(".jqzoom").jqzoom({
zoomWidth: 300, 
zoomHeight: 300,
lens:true,
preloadImages: false,
alwaysOn:false,
title:false,
xOffset:20,
position: "right"
});
})

<a href="images/BIGIMAGE.JPG" class="jqzoom" title="MYTITLE"> 
<img src="images/SMALLIMAGE.JPG" title="IMAGE TITLE"> 
</a>