problem with thumbnail size

[dinoboy]

Hi!

I generate thumbnails dynamically. The function has two parameters - filename and maxfilesize. And while thumbnail size in butes is bigger than the maxfilesize, it make new thumbnail again, only a smaller one. And my problem is how I can check the thumbnail size? It tried to save it to stream and then I took its length and compared it with maxfilesize and do the while loop. But when I tried to make a new bitmap with a new size, in the loop, then it told me The invalid parameter used

 

Are there any other solution or why it tells it?

[aewarnick]

Can you post the code?

[dinoboy]

public void OutputFile(string fileName, int maxThumbSize)
	{
		System.Drawing.Image g = System.Drawing.Image.FromFile(fileName);
		ImageFormat tFormat = g.RawFormat;
		
		Size tSize = this.genThumbSize((int) g.Width, (int) g.Height);
		Bitmap imgOutPut = new Bitmap(g, tSize.Width, tSize.Height);	
		
		MemoryStream imgStream = new MemoryStream();
		imgOutPut.Save(imgStream, tFormat);
		//imgOutPut.Dispose();
		
		while(imgStream.Length>maxThumbSize)
		{
			this.thumbSize = this.thumbSize-5;
			Size s = this.genThumbSize(imgOutPut.Width, imgOutPut.Height);
			imgOutPut = new Bitmap(System.Drawing.Image.FromFile(fileName), s.Width, s.Height);
			imgOutPut.Save(imgStream, tFormat);
		}
		
		//imgOutPut.Palette = 
		if(tFormat.Equals(System.Drawing.Imaging.ImageFormat.Gif))
			Response.ContentType = "image/gif";
		else if(tFormat.Equals(System.Drawing.Imaging.ImageFormat.Bmp))
			Response.ContentType = "image/bmp";
		else if(tFormat.Equals(System.Drawing.Imaging.ImageFormat.Jpeg))
			Response.ContentType = "image/jpeg";
		else if(tFormat.Equals(System.Drawing.Imaging.ImageFormat.Png))
			Response.ContentType = "image/png";
		
		imgOutPut.Save(this.Response.OutputStream, tFormat);
	}

 

This line gives me the Invalid parameter

imgOutPut = new Bitmap(System.Drawing.Image.FromFile(fileName), s.Width, s.Height);

 

Wihtout the while loop, it's all ok, working just fine...

[aewarnick]

Try putting the Image.FromFile in it's own Bitmap variable.

Bitmap b= (Bitmap)Image.FromFile(fileName);

imgOutPut = new Bitmap(b, s.Width, s.Height);

Edited October 13, 2003 by aewarnick

[dinoboy]

I did that in while loop and before the while, but no use, it told me again Inavalid parameter used. :(

 

Hmm, maybe is there some problem with parameter nulling? or something :S

Edited October 13, 2003 by dinoboy

[aewarnick]

I think it would give a null reference exception. But you can check each parameter before it is used in the method:

if(bitmap != null && imgOutPut != null)
{
 if(imgOutPut.Width > 0 && imgOutPut.Height > 0)
 {
   do code
 }
}

[dinoboy]

Hmm, it seems it don't help me. Because parameters have a values and not null. But still it is saying that.. :S

There are some problem with while loop but I don't know which :confused:

[aewarnick]

What kind of error is this? A runtime error or a compile error?

[dinoboy]

Thanks for the replys. But I already found a solution. I saved the temporary stream to a temp fail and then read it again and got the length and then deleted the file. And it's working :)