更改图像分辨率 [英] Change Image Resolution

问题描述

我想将一个上传图片的分辨率更改为小尺寸。如何使用c＃asp.net

  if （fileUploadImage.HasFile）
 {
  int  fileSize = fileUploadImage.PostedFile。的ContentLength; 
 
  if （fileSize >  Convert.ToInt32（ConfigurationManager.AppSettings [< span class =code-string>  fileSize]））
 {
 lblUploadImage.Visible = 真; 
} 
  else  
 {
  String  fileName = fileUploadImage.FileName.ToString（）;  //   Substring（0，fileUploadImage.FileName.IndexOf（。））;  
 
  string  fileNameUrl = ConfigurationManager.AppSettings [  imagepath] + GenerateUniqueFileName（txtFname.Text，Path.GetExtension（fileName））; 
 
 Bitmap upBmp =（Bitmap）Bitmap.FromStream（fileUploadImage.PostedFile.InputStream）; 
 
 
位图newBmp = 新位图（ 50 ， 50 ，System.Drawing.Imaging.PixelFormat.Format24bppRgb）; 
 
 
 newBmp.SetResolution（ 72 ， 72 ）; 
 
 Graphics newGraphic = Graphics.FromImage（newBmp）; 
 
 
 尝试 
 {
 
 
 newGraphic.Clear（Color。白色）; 
 
 
 newGraphic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias; 
 
 
 newGraphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; 
 
 
 newGraphic.DrawImage（upBmp， 500 ， 100 ，  500 ， 100 ）; 
 
 
 newBmp.Save（MapPath（fileNameUrl））; 
 
 
  //  在图像控件中显示已上传的已调整大小的图片 
 
 
 imgProfile.Src = fileNameUrl; 
 
 
 lblUploadImage.Visible =  true ; 
} 
  catch （Exception exp）
 {
} 
  //   fileUploadImage.SaveAs（Server.MapPath（fileNameUrl））;  
  //   HiddenField1.Value = fileNameUrl;  
  //   imgProfile.Src = fileNameUrl;  
  //   lblUploadImage.Visible = false;  
} 

解决方案

您可以查看SetResolution-Method：

http://msdn.microsoft.com/de-de/library/ system.drawing.bitmap.setresolution.aspx [ ^ ]



但是，谢尔盖提到你可能想要做的是图像的下采样。<​​/ blockquote>

你好，你的代码中有一点错误，但它是如此有用。



你必须保存upBmp对象而不是newBmp对象。



非常感谢!!

i want to change the resolution of one uploaded image to small size .how to do this usng c# asp.net

if (fileUploadImage.HasFile)
 {
 int fileSize = fileUploadImage.PostedFile.ContentLength;
  
 if (fileSize > Convert.ToInt32(ConfigurationManager.AppSettings["fileSize"]))
 {
 lblUploadImage.Visible = true;
 }
 else
 {
 String fileName = fileUploadImage.FileName.ToString();//Substring (0,fileUploadImage.FileName.IndexOf("."));
  
 string fileNameUrl = ConfigurationManager.AppSettings["imagepath"] + GenerateUniqueFileName(txtFname.Text, Path.GetExtension(fileName));
  
 Bitmap upBmp = (Bitmap)Bitmap.FromStream(fileUploadImage.PostedFile.InputStream);
  
 
Bitmap newBmp = new Bitmap(50,50, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
  
 
newBmp.SetResolution(72, 72);
  
 Graphics newGraphic = Graphics.FromImage(newBmp);
  
 
try
 {
  
 
newGraphic.Clear(Color.White);
  
 
newGraphic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
  
 
newGraphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
  
 
newGraphic.DrawImage(upBmp, 500, 100, 500, 100);
  
 
newBmp.Save(MapPath(fileNameUrl));
  
 
//Show the uploaded resized picture in the image control
  
 
imgProfile.Src = fileNameUrl;
  
 
lblUploadImage.Visible = true;
 }
 catch(Exception exp)
 {
 }
 // fileUploadImage.SaveAs(Server.MapPath(fileNameUrl));
 // HiddenField1.Value = fileNameUrl;
 // imgProfile.Src = fileNameUrl;
 // lblUploadImage.Visible = false;
 }

解决方案

You can have a look at the SetResolution-Method:
http://msdn.microsoft.com/de-de/library/system.drawing.bitmap.setresolution.aspx[^]

But as Sergey mentioned what you probably want to do is a Downsampling of the image.

Hello, you have a little mistake in your code, but it's so helpfully.

you must save the upBmp object and not the newBmp object.

Thank you so much!!

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