So in my case I can not hide the form, I need to make it visible to the client all the time
Could you please explain what EXACTLY you are trying to achieve? There might be an easy way to work around that problem. The magnification
API is a hack .. I remember reading the article you linked in your original post. The author stated that it is not possible to obtain a bitmap from the maginification window and thats why he used the (deprecated) callback to manually save the bitmap.
I guess the magnification
API uses
DirectX to paint the screenshot, so you might be able to intercept that process by hooking some
DirectX interfaces, but thats hacky as well.