S实现控制图片显示大小的方法【图片等比例缩放功能】

S实现控制图片显示大小的方法【图片等比例缩放功能】

【需求】：读取磁盘中的图片，展示在弹出框中，等比例缩放图片，使图片显示完全。

（读取磁盘中的图片展示在前台，请参照我的另一篇文章：）

【开发】：

调用说明：

直接调用js函数即可。

我测试是一个image 标签中直接调用，如下：

    "showImageimg"       src= "/sirdifoa/applycorrection/getImage.do?imgName=2017001.jpg"       title= "2017001.jpg"  onload= "AutoResizeImage(500,500,this)" >
    "showImageimg"
    src= "/sirdifoa/applycorrection/getImage.do?imgName=2017001.jpg"
    title= "2017001.jpg"  onload= "AutoResizeImage(500,500,this)" >

【效果】：

【js代码】：

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
< html  xmlns = "http://www.w3.org/1999/xhtml" >
< head >
< meta  http-equiv = "Content-Type"  content = "text/html; charset=utf-8"  />
< 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;
}

head >
< body >
< br  />
原图显示（534 X 800）< br  />
onload="AutoResizeImage(0,0,this)< br  />
< a  href = "http://files.jb51.net/file_images/article/201702/2017218121607044.jpg"  target = "_blank" >< img  src = "http://files.jb51.net/file_images/article/201702/2017218121607044.jpg"  border = "0"  width = "0"  height = "0"  onload = "AutoResizeImage(0,0,this)"  alt = "534 X 800" /> a >< 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  />
< a  href = "http://www.jb51.net/"  target = "_blank" >< img  src = "http://files.jb51.net/file_images/article/201702/2017218121607044.jpg"  border = "0"  width = "0"  height = "0"  onload = "AutoResizeImage(250,0,this)"  alt = "250 X 374" /> a >< 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  />
< a  href = "http://www.jb51.net/"  target = "_blank" >< img  src = "http://files.jb51.net/file_images/article/201702/2017218121607044.jpg"  border = "0"  width = "0"  height = "0"  onload = "AutoResizeImage(0,250,this)"  alt = "166 X 250" /> a >< br  />< br  />
3.按高度250宽度250 按比例压缩< br  />
onload="AutoResizeImage(250,250,this)"< br  />
< a  href = "http://www.jb51.net/"  target = "_blank" >< img  src = "http://files.jb51.net/file_images/article/201702/2017218121607044.jpg"  border = "0"  width = "0"  height = "0"  onload = "AutoResizeImage(250,250,this)"  alt = "200 X 300" /> a >< 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  />
< a  href = "http://www.jb51.net/"  target = "_blank" >< img  src = "http://files.jb51.net/file_images/article/201702/2017218121607044.jpg"  border = "0"  width = "0"  height = "0"  onload = "AutoResizeImage(400,512,this)"  alt = "341 X 512" /> a >< 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  />
< a  href = "http://www.jb51.net/"  target = "_blank" >< img  src = "http://files.jb51.net/file_images/article/201702/2017218121607044.jpg"  border = "0"  width = "0"  height = "0"  onload = "AutoResizeImage(300,600,this)"  alt = "300 X 449" /> a >< 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  />
< a  href = "http://www.jb51.net/"  target = "_blank" >< img  src = "http://files.jb51.net/file_images/article/201702/2017218122006996.jpg"  border = "0"  width = "0"  height = "0"  onload = "AutoResizeImage(500,600,this)"  alt = "444 X 207" /> a >< br  />< br  />
body >
html >

运行效果图如下：

      本文转自建波李 51CTO博客，原文链接：http://blog.51cto.com/jianboli/1969528，如需转载请自行联系原作者