Custom Editor draw a texture with custom material?

So I wish to extend Unity's toolbox by adding a Texture view window. The catch is I wish to use a custom shader to do some postprocessing (like masking channels, swizzle or biasing) on it so that debugging can be much more smoother.

But I didn't see any suitable functions for this task.
I tried Handles.DrawCamera, GUI.DrawTexture, EditorGUI.drawPreviewTexture etc, all of them dont allow for material customization.

Is there a way to achieve this simple task?

 

You already found the correct function: EditorGUI.DrawPreviewTexture

 

my bad. Thanks for pointing out.