AsBitmap Leaks Memory

[SkyeHoefling]

Description

When using AsBitmap() it leaks memory and causes application failures that depend on the Bitmap object. This is due to the custom pointer we create and manually setting the stride.

Reproduction Steps

Load a large raw image using the following algorithm

Bitmap GetMyImage()
{
    using (var image = new RawImage("/path/to/raw/file"))
    using (var raw = image.UnpackRaw())
    {
        raw.Process(new DcrawProcessor());
        using (var processed = raw.AsProcessedImage())
            return processed.AsBitmap();
    }
}

The above code will still leak even if you manually managed the IDisposable and implement this inside of a wrapper. Once you start zooming in on the bitmap in the UI application it will quickly run out of memory

Workaround

The best workaround I could find was converting the image to a Bitmap saving it to disk and then loading the .bmp file into memory and returning it.

Bitmap GetMyImage()
{
    using (var image = new RawImage("/path/to/raw/file"))
    using (var raw = image.UnpackRaw())
    {
        raw.Process(new DcrawProcessor());
        using (var processed = raw.AsProcessedImage())
        using (var bitmap = processed.AsBitmap())
            bitmap.Save("temp.bmp", ImageFormat.Bmp);

        return new Bitmap("temp.bmp");
    }
}