Javascript图片等比例缩放

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<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk" />
<title>最新javascript自动按比例显示图片,按比例压缩图片显示</title>
<script type="text/javascript">
function AutoResizeImage(maxWidth, maxHeight, objImg) {
var img = new Image();
img.src
= objImg.src;
var hRatio,wRatio,Ratio = 1,w = img.width, h = img.height;
wRatio
= maxWidth / w;
hRatio
= maxHeight / h;
if (maxWidth == 0 && maxHeight == 0) {
Ratio
= 1;
}
else if (maxWidth == 0) {
if (hRatio < 1) Ratio = hRatio;
}
else if (maxHeight == 0) {
if (wRatio < 1) Ratio = wRatio;
}
else if (wRatio < 1 || hRatio < 1) {
Ratio
= (wRatio <= hRatio ? wRatio : hRatio);
}
if (Ratio < 1) {
w
= w * Ratio;
h
= h * Ratio;
}
objImg.height
= h;
objImg.width
= w;
}
</script>
</head>

<body>
<br />原图显示(534 X 800)
<br />onload="AutoResizeImage(0,0,this)"
<br />
<img onload="AutoResizeImage(0,0,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="534 X 800"/>
<br/>
<br />1.按宽度250压缩,不限制高度 按比例压缩
<br />onload="AutoResizeImage(250,0,this)"
<br />
<img onload="AutoResizeImage(250,0,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" alt="250 X 374"/>
<br />
<br />2.按高度250压缩,不限制宽度 按比例压缩
<br />onload="AutoResizeImage(0,250,this)"
<br />
<img onload="AutoResizeImage(0,250,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" alt="166 X 250"/>
<br />
<br />3.按高度250宽度250 按比例压缩
<br />onload="AutoResizeImage(250,250,this)"
<br />
<img onload="AutoResizeImage(250,250,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="200 X 300"/>
<br />
<br />4.高宽不等比例压缩 (400 X 512),此时高度不变,会自动按高度的比例压缩。
<br />onload="AutoResizeImage(400,512,this)"
<br />
<img onload="AutoResizeImage(400,512,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="341 X 512"/>
<br />
<br />5.高宽不等比例压缩 (300 X 600),此时宽度不变,会自动按宽度的比例压缩。
<br />onload="AutoResizeImage(300,600,this)"
<br />
<img onload="AutoResizeImage(300,600,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" alt="300 X 449"/>
<br />
<br />6.如果图片本来的高度和宽度小于压缩的最大高度和宽度,则不会拉大显示图片(按原图显示)
<br />原图444 x 207,压缩为 500 x 600,将保持原图显示
<br />onload="AutoResizeImage(500,600,this)"
<br />
<img onload="AutoResizeImage(500,600,this)" src="http://p.blog.csdn.net/images/p_blog_csdn_net/feng_sundy/242776/o_20070410_b7409cd284a0f799a357uePcEFa6ty0X.jpg" border="0" width="0" height="0"/>
<br />
<br />
</body>

</html>

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