Question

I’m trying to capture the user’s entire desktop as an image. I do this in the following way:

        public Bitmap CaptureScreen()
    {
        // Set up a bitmap of the correct size
        Bitmap CapturedImage = new Bitmap((int)SystemInformation.VirtualScreen.Width,
            (int)SystemInformation.VirtualScreen.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

        // Create a graphics object from it
        System.Drawing.Size size = new System.Drawing.Size((int)SystemInformation.VirtualScreen.Width, (int)SystemInformation.VirtualScreen.Height);

        using (Graphics g = Graphics.FromImage(CapturedImage))
        {
            // copy the entire screen to the bitmap
            g.CopyFromScreen(0, 0, 0, 0,
                size, CopyPixelOperation.SourceCopy);
        }
        return CapturedImage;
    }

However, if I try to change the PixelFormat from Format32bppArgb to Format16bppArgb1555, it produces an OutOfMemoryException, which I don’t really understand, considering I’ve lowered the quality.

Any ideas? Or how can I reduce the quality of this image (as it will be being sent over the network at quite frequent intervals)

Answer 1

From the docs: (also related)

This [FromImage()] method also throws an exception if the image has
any of the following pixel formats.

• Undefined
• DontCare
• Format16bppArgb1555
• Format16bppGrayScale

In the “related” link, msdn goes on to say that:

The only issue here is that OutOfMessageException is not very accurate exception type in this situation. We’ll consider fixing it in the release after VS2010.