Can flash detect a screenshot (or GDI bitcopy) being taken?

Can pixels be read covertly from a browser window containing flash + HTML? (Is it possible for flash or the browser to detect a screenshot being taken?)

What about for other methods of capturing pixels? (Like the one described here: How to read the screen pixels?)

EDIT: (background info)

A C++ application is going to read pixels from a browser window (which happens to contain Flash and some regular HTML and JavaScript). The browser window would like, if possible, to detect the fact that it's pixels have been read. The method of getting the pixels could be any (short of taking a photo of the screen itself).

For sure, you cannot detect someone using a framegrabber card to get a screenshot. There is no way you can be aware of this happening, as it happens behind the graphics card output. So for this way, no, no way you can detect it.

Otherwise, it's also pretty simple: Some application can hook your browser and prevent any event from arriving, so the user can press PrintScreen as much as he wants and your browser (let alone your Flash runtime) never gets notified. Your browser app is limited to the browser, while a desktop app has lots of means to hook and do things without notifying the browser.

(Think also about stuff like Linux/X-Windows, which will send the pixels over the wire, or RDP.)