JS滚轮控制图片缩放大小和拖动的实例代码
时间：2021-08-25 08:01:37|栏目：JavaScript代码|点击： 次
具体代码如下所示：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.dragAble {
position: relative;
cursor: move;
}
.img-con {
position: relative;
width: 713px;
height: 455px;
overflow: hidden;
border: 1px solid red;
}
</style>
</head>
<body>
<p class="img-con"><img src="http://img03.tooopen.com/uploadfile/downs/images/20110714/sy_20110714135215645030.jpg" class="dragAble" /></p>
<script type="text/javascript" charset="utf-8">
window.onload = function() {
var oImg = document.getElementsByTagName("img")[0];
function fnWheel(obj, fncc) {
obj.onmousewheel = fn;
if (obj.addEventListener) {
obj.addEventListener('DOMMouseScroll', fn, false);
}
function fn(ev) {
var oEvent = ev || window.event;
var down = true;
if (oEvent.detail) {
down = oEvent.detail > 0
} else {
down = oEvent.wheelDelta < 0
}
if (fncc) {
fncc.call(this, down, oEvent);
}
if (oEvent.preventDefault) {
oEvent.preventDefault();
}
return false;
}
};
fnWheel(oImg, function(down, oEvent) {
var oldWidth = this.offsetWidth;
var oldHeight = this.offsetHeight;
var oldLeft = this.offsetLeft;
var oldTop = this.offsetTop;
var scaleX = (oEvent.clientX - oldLeft) / oldWidth; //比例
var scaleY = (oEvent.clientY - oldTop) / oldHeight;
if (down) {
this.style.width = this.offsetWidth * 0.9 + "px";
this.style.height = this.offsetHeight * 0.9 + "px";
} else {
this.style.width = this.offsetWidth * 1.1 + "px";
this.style.height = this.offsetHeight * 1.1 + "px";
}
var newWidth = this.offsetWidth;
var newHeight = this.offsetHeight;
this.style.left = oldLeft - scaleX * (newWidth - oldWidth) + "px";
this.style.top = oldTop - scaleY * (newHeight - oldHeight) + "px";
});
}
<!--
//拖拽
var ie = document.all;
var nn6 = document.getElementByIdx && !document.all;
var isdrag = false;
var y, x;
var oDragObj;
function moveMouse(e) {
if (isdrag) {
oDragObj.style.top = (nn6 ? nTY + e.clientY - y : nTY + event.clientY - y) + "px";
oDragObj.style.left = (nn6 ? nTX + e.clientX - x : nTX + event.clientX - x) + "px";
return false;
}
}
function initDrag(e) {
var oDragHandle = nn6 ? e.target : event.srcElement;
var topElement = "HTML";
while (oDragHandle.tagName != topElement && oDragHandle.className != "dragAble") {
oDragHandle = nn6 ? oDragHandle.parentNode : oDragHandle.parentElement;
}
if (oDragHandle.className == "dragAble") {
isdrag = true;
oDragObj = oDragHandle;
nTY = parseInt(oDragObj.style.top + 0);
y = nn6 ? e.clientY : event.clientY;
nTX = parseInt(oDragObj.style.left + 0);
x = nn6 ? e.clientX : event.clientX;
document.onmousemove = moveMouse;
return false;
}
}
document.onmousedown = initDrag;
document.onmouseup = new Function("isdrag=false");
</script>
</body>
</html>
只缩放
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<img border="0" src="http://img03.tooopen.com/uploadfile/downs/images/20110714/sy_20110714135215645030.jpg" onmousewheel="return rollImg(this)">
</body>
<script language="javascript">
function rollImg(o){
/* 获取当前页面的缩放比
若未设置zoom缩放比，则为默认100%，即1，原图大小
*/
var zoom=parseInt(o.style.zoom)||100;
/* event.wheelDelta 获取滚轮滚动值并将滚动值叠加给缩放比zoom
wheelDelta统一为±120，其中正数表示为向上滚动，负数表示向下滚动
*/
zoom+=event.wheelDelta/12;
/* 如果缩放比大于0，则将缩放比加载到页面元素 */
if (zoom>0) o.style.zoom=zoom+'%';
/* 如果缩放比不大于0，则返回false，不执行操作 */
return false;
}
</script>
</html>
总结
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