1 使用jQueryRotate.js实现
示例代码：
复制代码 代码如下:
<!DOCTYPE html>
<html>
<head>
<title></title>
<style type="text/css">
#div1 {
width: 800px;
height: 600px;
background-color: #ff0;
position: absolute;
}
.imgRotate {
width: 100px;
height: 80px;
position: absolute;
top: 50%;
left: 50%;
margin: -40px 0 0 -50px;
}
</style>
</head>
<body>
<div>
<img src="https://www.baidu.com/img/logo-yy.gif" />
<input type="button" value="btn2"></input>
</div>
</body>
<script type="text/javascript" src="https://www.jb51.net/jquery.min.js"></script>
<script type="text/javascript" src="https://www.jb51.net/jQueryRotate.js"></script>
<script type="text/javascript">
var num = 0;
$("#input2").click(function(){
num ++;
$("#img1").rotate(90*num);
});
</script>
</html>
测试结果：chrome下效果正常，旋转后img对象仍为img对象；ie8下效果正常，但旋转后img对象变为下面对象，由于对象变化，若旋转后仍按原来方法获取img对象，则会报js错误。欲获取image对象，可根据class获取。如果图像旋转后，不进行其它操作，则可用此方法。若进行其它操作，如放大、缩小图像，则此方法实现较复杂。
复制代码 代码如下:
<span ...>
<rvml:group...>
<rvml:image.../>
</rvml:group>
</span>
2 使用Microsoft提供的Matrix对象
示例代码：
复制代码 代码如下:
<!DOCTYPE html>
<html>
<head>
<title></title>
<style type="text/css">
#div1 {
width: 800px;
height: 600px;
background-color: #ff0;
position: absolute;
}
.imgRotate {
width: 100px;
height: 100px;
position: absolute;
top: 50%;
left: 50%;
margin: -50px 0 0 -50px;
}
#imgRotate {
width: 100px;
height: 100px;
position: absolute;
top: 50%;
left: 50%;
margin: -50px 0 0 -50px;
}
</style>
</head>
<body>
<div>
<img src="https://www.baidu.com/img/logo-yy.gif" />
<input type="button" value="btn1"></input>
</div>
</body>
<script type="text/javascript" src="https://www.jb51.net/jquery.min.js"></script>
<script type="text/javascript">
function rotate(id,angle,whence) {
var p = document.getElementById(id);
// we store the angle inside the image tag for persistence
if (!whence) {
p.angle = ((p.angle==undefined?0:p.angle) + angle) % 360;
} else {
p.angle = angle;
}
if (p.angle >= 0) {
var rotation = Math.PI * p.angle / 180;
} else {
var rotation = Math.PI * (360+p.angle) / 180;
}
var costheta = Math.cos(rotation);
var sintheta = Math.sin(rotation);
if (document.all && !window.opera) {
var canvas = document.createElement('img');
canvas.src = p.src;
canvas.height = p.height;
canvas.width = p.width;
canvas.style.filter = "progid:DXImageTransform.Microsoft.Matrix(M11="+costheta+",M12="+(-sintheta)+",M21="+sintheta+",M22="+costheta+",SizingMethod='auto expand')";
} else {
var canvas = document.createElement('canvas');
if (!p.oImage) {
canvas.oImage = new Image();
canvas.oImage.src = p.src;
} else {
canvas.oImage = p.oImage;
}
canvas.style.width = canvas.width = Math.abs(costheta*canvas.oImage.width) + Math.abs(sintheta*canvas.oImage.height);
canvas.style.height = canvas.height = Math.abs(costheta*canvas.oImage.height) + Math.abs(sintheta*canvas.oImage.width);
var context = canvas.getContext('2d');
context.save();
if (rotation <= Math.PI/2) {
context.translate(sintheta*canvas.oImage.height,0);
} else if (rotation <= Math.PI) {
context.translate(canvas.width,-costheta*canvas.oImage.height);
} else if (rotation <= 1.5*Math.PI) {
context.translate(-costheta*canvas.oImage.width,canvas.height);
} else {
context.translate(0,-sintheta*canvas.oImage.width);
}
context.rotate(rotation);
context.drawImage(canvas.oImage, 0, 0, canvas.oImage.width, canvas.oImage.height);
context.restore();
}
canvas.id = p.id;
canvas.angle = p.angle;
p.parentNode.replaceChild(canvas, p);
}
function rotateRight(id,angle) {
rotate(id,angle==undefined?90:angle);
}
function rotateLeft(id,angle) {
rotate(id,angle==undefined?-90:-angle);
}
$("#input1").click(function(){
$("img.imgRotate").attr("id","imgRotate");
rotateLeft("imgRotate",90);
$("#imgRotate").attr("top","50%");
$("#imgRotate").attr("left","50%");
$("#imgRotate").attr("margin","-50px 0 0 -50px");
});
</script>
</html>
测试结果：chrome下效果正常，但旋转后img对象变为canvas对象；ie8下效果正常，旋转后img对象仍为img对象。Matrix()参数较多，使用时需较多计算。
3 使用Microsoft提供的BasicImage对象
示例代码：
复制代码 代码如下: