Convert System.Windows.Media.Imaging.BitmapSource to System.Drawing.Image

Question

I'm tying together two libraries. One only gives output of type System.Windows.Media.Imaging.BitmapSource, the other only accepts input of type System.Drawing.Image.

How can this conversion be performed?

score 52 · Accepted Answer · answered Sep 20 '10 at 13:08

52

private System.Drawing.Bitmap BitmapFromSource(BitmapSource bitmapsource)
{
  System.Drawing.Bitmap bitmap;
  using (MemoryStream outStream = new MemoryStream())
  {
    BitmapEncoder enc = new BmpBitmapEncoder();
    enc.Frames.Add(BitmapFrame.Create(bitmapsource));
    enc.Save(outStream);
    bitmap = new System.Drawing.Bitmap(outStream);
  }
  return bitmap;
}

answered Sep 20 '10 at 13:08

John Gietzen

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There is one issue: you will lose the transparency (for a bitmap with alpha channel). – sibvic Dec 09 '15 at 09:40

score 14 · Answer 2 · answered May 21 '15 at 17:46

14

This is an alternate technique that does the same thing. The accepted answer works, but I ran into problems with images that had alpha channels (even after switching to PngBitmapEncoder). This technique may also be faster since it just does a raw copy of pixels after converting to compatible pixel format.

public Bitmap BitmapFromSource(System.Windows.Media.Imaging.BitmapSource bitmapsource)
{
        //convert image format
        var src = new System.Windows.Media.Imaging.FormatConvertedBitmap();
        src.BeginInit();
        src.Source = bitmapsource;
        src.DestinationFormat = System.Windows.Media.PixelFormats.Bgra32;
        src.EndInit();

        //copy to bitmap
        Bitmap bitmap = new Bitmap(src.PixelWidth, src.PixelHeight, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
        var data = bitmap.LockBits(new Rectangle(Point.Empty, bitmap.Size), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
        src.CopyPixels(System.Windows.Int32Rect.Empty, data.Scan0, data.Height * data.Stride, data.Stride);
        bitmap.UnlockBits(data);

        return bitmap;
}

answered May 21 '15 at 17:46

Rngbus

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Be sure to dispose the `bitmap` object! `using(Bitmap bitmap = new Bitmap(...)) { ... }` – aholmes Mar 11 '16 at 00:20
@aholmes why people should worry about the `bitmap` object to be disposed? it is the responsibility of the caller, not the implementer – Earth Engine Apr 20 '16 at 05:12
I forgot why I wrote that comment. I think I intended to write `using(Bitmap bitmap = BitmapFromSource(...)) {...}` – aholmes Apr 20 '16 at 20:04
very good! can you say when it is required to convert the image format (first part of code)? – S.Serpooshan Dec 02 '17 at 12:03
Of all the answers on SO, this is by far the fastest – smirkingman Jun 13 '18 at 13:26

Convert System.Windows.Media.Imaging.BitmapSource to System.Drawing.Image

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