JS实现图片旋转代码
JS实现图片旋转代码,兼容firefox、IE和Chrome:
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75 function rotate(o,p){
var img = document.getElementById(o);
if(!img || !p) return false;
var n = img.getAttribute('step');
if(n== null) n=0;
if(p=='right')
{
(n==3)? n=0:n++;
}
else if(p=='left')
{
(n==0)? n=3:n--;
}
img.setAttribute('step',n);
/MSIE
if(document.all)
{
img.style.filter = 'progid:DXImageTransform.Microsoft.BasicImage(rotation='+ n +')';
/HACK FOR MSIE 8
switch(n){
case 0:
imgimg.parentNode.style.height = img.height;
break;
case 1:
imgimg.parentNode.style.height = img.width;
break;
case 2:
imgimg.parentNode.style.height = img.height;
break;
case 3:
imgimg.parentNode.style.height = img.width;
break;
}
/DOM
}
else
{
var c = document.getElementById('canvas_'+o);
if(c== null){
img.style.visibility = 'hidden';
img.style.position = 'absolute';
c = document.createElement('canvas');
c.setAttribute("id",'canvas_'+o);
img.parentNode.appendChild(c);
}
var canvasContext = c.getContext('2d');
switch(n) {
default :
case 0 :
c.setAttribute('width', img.width);
c.setAttribute('height', img.height);
canvasContext.rotate(0 * Math.PI / 180);
canvasContext.drawImage(img, 0, 0);
break;
case 1 :
c.setAttribute('width', img.height);
c.setAttribute('height', img.width);
canvasContext.rotate(90 * Math.PI / 180);
canvasContext.drawImage(img, 0, -img.height);
break;
case 2 :
c.setAttribute('width', img.width);
c.setAttribute('height', img.height);
canvasContext.rotate(180 * Math.PI / 180);
canvasContext.drawImage(img, -img.width, -img.height);
break;
case 3 :
c.setAttribute('width', img.height);
c.setAttribute('height', img.width);
canvasContext.rotate(270 * Math.PI / 180);
canvasContext.drawImage(img, -img.width, 0);
break;
}
}
}
用法:
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11 <html>
<body>
<img src="text.jpg" id="img" />
<button value="左转" id="left" />
<button value="右转" id="right" />
<script type="text/javascript">
getElementById("left").onclick = function (){rotate("img", "left")};
getElementById("right").onclick = function (){rotate("img", "right")};
</script>
<body>
</html>
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