'Gray out' a page of a tiff.

In an app I've been working on I display a tiff in a rasterimagelist. When an image is 'used' I draw a semi-transparent gray rectangle over the top of it (code below). Does anyone know of a better way to do this without going using CreateGdiPlusGraphics?

private static RasterImage GetRasterImageInternal(byte[] imageBytes, int bitDepth, bool touched)
{
RasterImage retval;

using (var stream = new MemoryStream(imageBytes))
using (var codecs = new RasterCodecs())
{
retval = codecs.Load(stream, bitDepth, CodecsLoadByteOrder.BgrOrGray, 1, 1);

if (touched)
{
var g = retval.CreateGdiPlusGraphics().Graphics;
var rectangle = new RectangleF(0, 0, retval.Width, retval.Height);
var solidBrush = new SolidBrush(Color.FromArgb(40, 0, 0, 0));

g.FillRectangle(solidBrush, rectangle);
}

retval.ResizeToDefault();
}

return retval;
}

You can use FillCommand Property, to fill a region you set on the RasterImage. Please see this help topic:
http://www.leadtools.com/help/leadtools/v16/dh/l/Leadtools~Leadtools.ImageProcessing.FillCommand.html

Nope, that doesn't do it. With the code I presented you can still see image underneath the gray. Using a FillCommand I end up with a totally black image (when using the color I provided in the code).

I tested your code and knew what you exactly need to do. You can do that as follows:
1. Create a new RasterImage with the desired width and height.
2. Fill the image using FillCommand. You can use this code to give Alpha to the black color:
Leadtools.RasterColor clr2 = new Leadtools.RasterColor(40, 0, 0, 0);
3. Combine these two images using CombineCommand Class.