Working on Images in Custom Controls with C#

[Amnu]

Hi there,

I've been told to write a custom control using C#.NET ( 2.0 ).
This control should be able to display images and give access to zoom functionality. I've visited numerous How-To pages and the main stream approach appears to be a panel/groupBox containing a pictureBox, resizing that pictureBox and using the PictureBoxSizeMode.StretchImage property.
I don't want that. What I want is some "real" zoom effect. So I continued my search for good tutorials until I found this. After reading this small article I began working with the 'graphics' class which appeared to have everything I need. Now I can draw all kinds of manipulated images, which almost perfectly suites my needs. Only almost because I can only DRAW them where I would also need to SAVE them ... And this basically is my question. How do I manipulate images ( for example but not restricting to Bitmaps ), draw them AND save them afterwards ?
Actually saving these images is not my actual issue. My real problem is that I would like to use the PictureBox.SizeMode.AutoSize property inside my custom control so refitting the internal pictureBox is not such a huge pain. But since I am only drawing the modified image ( e.g. using Graphics.TranslateTransform before drawing ) and cannot actually save it, I have no chance to resize the picture box to the new image's size - the image's size always stays the sime ...

Amnu

[Amnu]

Of Course ... Now that I've posted a question I've found a solution ...
Well, I've found this
and this:

public static Image ScaleImage(Image img, int outputWidth, int outputHeight)
{
Btmap outputImage = new Bitmap(outputWidth, outputHeight, img.PixelFormat);
outputImage.SetResolution(img.HorizontalResolution , img.VerticalResolution);
Graphics graphics = Graphics.FromImage(outputImage);
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.DrawImage(img, new Rectangle(0, 0, outputWidth, outputHeight),
new Rectangle(0, 0, img.Width, img.Height), GraphicsUnit.Pixel);
graphics.Dispose();
return outputImage;
}

solved my problem. It's about what I was looking for. The one thing bugging me now is a perfomance issue and some flickering.
If I apply the above code in my custom control and trigger the ScaleImage method, I do get the scaled image and I can display it in the picture box. But if I scroll through the scaled image flickering at the borders of the pictore box occurs. Why ? How do I solve this ?
Also, performance dropps super linear while increasing scaling factor. I suppose this is related to the increasing image's size but I don't know how to compensate for it. My only guess is changing the interpolation quality according to the image's size but that's not really an option...

Amnu