最新javascript自动按比例显示图片，按比例压缩图片显示-优快云博客

本文介绍了一种使用JavaScript自动按比例显示和压缩图片的方法。通过一个简单的函数`AutoResizeImage`，可以实现图片在不同场景下的按比例缩放，包括仅限制宽度、仅限制高度及同时限制宽高。

最新javascript自动按比例显示图片，按比例压缩图片显示

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<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;
 var wRatio;
 var Ratio = 1;
 var w = img.width;
 var 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>
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原图显示（534 X 800） 
onload="AutoResizeImage(0,0,this) 
<a href="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" target="_blank"><img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" onload="AutoResizeImage(0,0,this)" alt="534 X 800"/></a> 
1.按宽度250压缩,不限制高度按比例压缩 
onload="AutoResizeImage(250,0,this)" 
<a href="#" target="_blank"><img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" onload="AutoResizeImage(250,0,this)" alt="250 X 374"/></a> 
2.按高度250压缩,不限制宽度按比例压缩 
onload="AutoResizeImage(0,250,this)" 
<a href="#" target="_blank"><img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" onload="AutoResizeImage(0,250,this)" alt="166 X 250"/></a> 
3.按高度250宽度250 按比例压缩 
onload="AutoResizeImage(250,250,this)" 
<a href="#" target="_blank"><img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" onload="AutoResizeImage(250,250,this)" alt="200 X 300"/></a> 
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。 
onload="AutoResizeImage(400,512,this)" 
<a href="#" target="_blank"><img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" onload="AutoResizeImage(400,512,this)" alt="341 X 512"/></a> 
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。 
onload="AutoResizeImage(300,600,this)" 
<a href="#" target="_blank"><img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/421506/o_09925c7bcead8c60f683298dacf497a6.jpg" border="0" width="0" height="0" onload="AutoResizeImage(300,600,this)" alt="300 X 449"/></a> 
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） 
原图444 x 207,压缩为 500 x 600,将保持原图显示 
onload="AutoResizeImage(500,600,this)" 
<a href="#" target="_blank"><img src="https://p-blog.youkuaiyun.com/images/p_blog_youkuaiyun.com/feng_sundy/242776/o_20070410_b7409cd284a0f799a357uePcEFa6ty0X.jpg" border="0" width="0" height="0" onload="AutoResizeImage(500,600,this)" alt="444 X 207"/></a> 
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转载于:https://www.cnblogs.com/wolfocme110/p/3912759.html