zoom.js 使用事例

简介:

<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> 
<title>给地图加个放大镜</title> 
<SCRIPT>

var shrinkfactor=5

// left and top position of the thumbnailimage 
// (distance to the left and top browser-margin, pixels) 
var thumbleft = 30 
var thumbtop = 30

// left and top position of the zoomed image 
// (distance to the left and top browser-margin, pixels) 
var largeleft = 300 
var largetop = 30

// width and height of the enlarged image's sector (visible part, pixels) 
var clipwidth = 240 
var clipheight = 160 
</SCRIPT> 
<SCRIPT>

var isNav, isIE 
var offsetX, offsetY 
var selectedObj

var largewidth = 0 
var largeheight = 0

var thumbwidth = Math.floor(largewidth/shrinkfactor) 
var thumbheight = Math.floor(largeheight/shrinkfactor)

var dragimgwidth = Math.floor(clipwidth/shrinkfactor) 
var dragimgheight = Math.floor(clipheight/shrinkfactor) 
var dragimgleft = thumbleft+3 
var dragimgtop = thumbtop+3

var difleft= largeleft-thumbleft 
var diftop= largetop-thumbtop

var clippoints

var cliptop=0 
var clipbottom=cliptop+clipheight 
var clipleft=0 
var clipright=clipleft+clipwidth

if (parseInt(navigator.appVersion) >= 4) { 
if (navigator.appName == "Netscape") { 
isNav = true 
} else { 
isIE = true 

}

function setZIndex(obj, zOrder) { 
obj.zIndex = zOrder 
}

function shiftTo(obj, x, y) { 
if (isNav) { 
if(x<=document.thumb.left) {x=document.thumb.left} 
if(x>=(document.thumb.left+thumbwidth-dragimgwidth-2)) {x=document.thumb.left+thumbwidth-dragimgwidth-2} 
if(y<=document.thumb.top) {y=document.thumb.top} 
if(y>=(document.thumb.top+thumbheight-dragimgheight-2)) {y=document.thumb.top+thumbheight-dragimgheight-2} 
obj.moveTo(x,y) 
} else { 
if(x<=document.all.thumb.style.posLeft) {x=document.all.thumb.style.posLeft} 
if(x>=(document.all.thumb.style.posLeft+thumbwidth-dragimgwidth-2)) {x=document.all.thumb.style.posLeft+thumbwidth-dragimgwidth-2} 
if(y<=document.all.thumb.style.posTop) {y=document.all.thumb.style.posTop} 
if(y>=(document.all.thumb.style.posTop+thumbheight-dragimgheight-2)) {y=document.all.thumb.style.posTop+thumbheight-dragimgheight-2} 
obj.pixelLeft = x 
obj.pixelTop = y 

cliptop = (y-thumbtop)*shrinkfactor 
clipbottom = cliptop+clipheight 
clipleft = (x-thumbleft)*shrinkfactor 
clipright = clipleft+clipwidth

if (document.all) { 
clippoints ="rect("+cliptop+" "+clipright+" "+clipbottom+" "+clipleft+")" 
document.all.large.style.posTop=largetop-cliptop 
document.all.large.style.posLeft=largeleft-clipleft 
document.all.large.style.clip=clippoints 

if (document.layers) { 
document.large.top=largetop-cliptop 
document.large.left=largeleft-clipleft 
document.large.clip.left = clipleft 
document.large.clip.right = clipright 
document.large.clip.top = cliptop 
document.large.clip.bottom = clipbottom 

}

function setSelectedElem(evt) { 
if (isNav) { 
var testObj 
var clickX = evt.pageX 
var clickY = evt.pageY 
for (var i = document.layers.length - 1; i >= 0; i--) { 
testObj = document.layers[i] 
if ((clickX > testObj.left) && 
(clickX < testObj.left + testObj.clip.width) && 
(clickY > testObj.top) && 
(clickY < testObj.top + testObj.clip.height && document.layers[i].id=="dragimg")) { 
selectedObj = testObj 
setZIndex(selectedObj, 100) 
return 


} else { 
var imgObj = window.event.srcElement 
if (imgObj.parentElement.id.indexOf("dragimg") != -1) { 
selectedObj = imgObj.parentElement.style 
setZIndex(selectedObj,100) 
return 


selectedObj = null 
return 
}

function dragIt(evt) { 
if (selectedObj) { 
if (isNav) { 
shiftTo(selectedObj, (evt.pageX - offsetX), (evt.pageY - offsetY)) 
} else { 
shiftTo(selectedObj, (window.event.clientX - offsetX), (window.event.clientY - offsetY)) 
return false 


}

function engage(evt) { 
setSelectedElem(evt) 
if (selectedObj) { 
if (isNav) { 
offsetX = evt.pageX - selectedObj.left 
offsetY = evt.pageY - selectedObj.top 
} else { 
offsetX = window.event.offsetX 
offsetY = window.event.offsetY 


return false 
}

function release(evt) { 
if (selectedObj) { 
setZIndex(selectedObj, 0) 
selectedObj = null 

}

function setNavEventCapture() { 
if (isNav) { 
document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP) 

}

function init() { 
if (document.layers) { 
var imageurl=document.large.document.largepic.src 
largewidth=document.large.document.width 
largeheight=document.large.document.height 
thumbwidth = Math.floor(largewidth/shrinkfactor) 
thumbheight = Math.floor(largeheight/shrinkfactor) 
document.thumb.document.write("<IMG NAME='thumbpic' SRC='"+imageurl+"' width="+thumbwidth+" height="+thumbheight+">") 
document.thumb.document.close() 
document.dragimg.document.write("<IMG NAME='dragimgpic' border=2 SRC='dragimg.gif' width="+dragimgwidth+" height="+dragimgheight+">") 
document.dragimg.document.close() 
document.large.left=largeleft 
document.large.top=largetop

document.thumb.left=thumbleft 
document.thumb.top=thumbtop

document.dragimg.left=dragimgleft 
document.dragimg.top=dragimgtop

document.large.clip.left=clipleft 
document.large.clip.right=clipright 
document.large.clip.top=cliptop 
document.large.clip.bottom=clipbottom 
document.large.visibility="visible"

setNavEventCapture() 

if (document.all) { 
var imageurl=document.largepic.src 
largewidth=document.all.large.offsetWidth 
largeheight=document.all.large.offsetHeight 
thumbwidth = Math.floor(largewidth/shrinkfactor) 
thumbheight = Math.floor(largeheight/shrinkfactor) 
thumb.innerHTML="<IMG NAME='thumbpic' SRC='"+imageurl+"' width="+thumbwidth+" height="+thumbheight+">" 
dragimg.innerHTML="<IMG NAME='dragimgpic' border=2 SRC='http://www.jscode.cn/Uploadfile/200651515151450.GIF' width="+dragimgwidth+" height="+dragimgheight+">"

document.all.large.style.posLeft=largeleft 
document.all.large.style.posTop=largetop

document.all.thumb.style.posLeft=thumbleft 
document.all.thumb.style.posTop=thumbtop

document.all.dragimg.style.posLeft=dragimgleft 
document.all.dragimg.style.posTop=dragimgtop 
clippoints ="rect("+cliptop+" "+clipright+" "+clipbottom+" "+clipleft+")" 
document.all.large.style.clip=clippoints 
document.all.large.style.visibility="visible" 
}

document.onmousedown = engage 
document.onmousemove = dragIt 
document.onmouseup = release 
}

window.onload=init 
</SCRIPT></head>

<body> 
<p>用鼠标移动下面的方框,效果不错吧</p> 
<center> 
<DIV style="position:absolute;visibility:hidden;" ID="large"><IMG NAME="largepic" SRC="http://www.jscode.cn/Uploadfile/2006515151036789.JPG"></DIV> 
<DIV style="position:absolute;" ID="thumb"></DIV> 
<DIV style="position:absolute;" ID="dragimg"></DIV></center> 
</body> 
</html>

本文转自博客园执着的笨蛋的博客,原文链接:zoom.js 使用事例,如需转载请自行联系原博主。

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