Resizing image before saving to server

Question

User-1246604461 posted
I use a fileupload control.
To save an image to the server I use:

MyFileUpload.SaveAs(Server.MapPath("Data\Customers") & "\" &Session("Code").ToString & "\" & FileName)
That does work, wasnt it for the fact that I still need to perform the following operations:
But the image the customers uploads can be 1024x768. However, I want to resize it for him to the max dimensions allowed (600x500).
For that I have first called my method which resizes it proportionally. Then I call the routine:

img.GetThumbnailImage(ThumbWidth, ThumbHeight, dummyCallBack, IntPtr.Zero)
So the 1024*768 file is already saved to the server, but I havent been able to resize it to the max dimensions allowed...
How can I perform those resize operations BEFORE I save the file to the server?

Answer 1

User672738083 posted
something like:

            System.Drawing.Image source = System.Drawing.Image.FromStream(fileUpload.PostedFile.InputStream);
            Bitmap bm = new Bitmap(100, 100, source.PixelFormat);
            Graphics g = Graphics.FromImage(bm);
            g.DrawImage(source, new Rectangle(0, 0, 100, 100), new Rectangle(0, 0 , source.Width, source.Height), GraphicsUnit.Pixel);
            source.Dispose();
            bm.Save(fileName, GraphicsFormat.Jpeg);
            g.Dispose();
            bm.Dispose();

       

Answer 2

User-1246604461 posted
alrite thanks, but could you please briefly explain what each line exactly does? ( Im a rookie ;) )

Answer 3

User672738083 posted

something like:

            System.Drawing.Image source = System.Drawing.Image.FromStream(fileUpload.PostedFile.InputStream);
            // Opens the image from the stream
            Bitmap bm = new Bitmap(100, 100, source.PixelFormat);
            // Creates a new image in memory that is 100x100, using the same pixel format as the uploaded
            Graphics g = Graphics.FromImage(bm);
            // gets the graphics object from the image to redraw/resize on
            g.DrawImage(source, new Rectangle(0, 0, 100, 100), new Rectangle(0, 0 , source.Width, source.Height), GraphicsUnit.Pixel);
            // redraw the source image to the destination in memory one resized to 100x100
            source.Dispose();
            // clean up memory
            bm.Save(fileName, GraphicsFormat.Jpeg);
            // save the file to your filename, use whatever graphics format is appropriate
            g.Dispose();
            // clean up memory
            bm.Dispose();
            // clean up memory

       

there are other ways, i am not sure how good this is at keeping image quality, i have a much more complicated method in other apps, this was something i am playing with at the moment. it works though