What is the best way to take screenshots of a Window with C++ in Windows?

Question

What is the best (easiest) way to take a screenshot of an running application with C++ under Windows?

Answer 1

You have to get the device context of the window (GetWindowDC()) and copy image (BitBlt()) from it. Depending on what else you know about the application you will use different methods to find which window's handle to pass into GetWindowDC().

Answer 2

On the keybd_event function documentation it states that you can use it to take a screenshot and save it to the clipboard. For example:

keybd_event(VK_SNAPSHOT, 0, KEYEVENTF_SILENT, 0);

In my version (Visual Studio 2005 help installed on my computer) it states that you can take a screenshot of the whole desktop by setting the second parameter to 0, or a screen shot of just the current application by setting it to 1.

Taking it out of the clipboard buffer is left as an exercise for the reader.

However I'd think carefully before doing this as it will turf whatever image data was already present in the clipboard.

Answer 3

Here is an example code
You can do CaptureAnImage(GetDesktopWindow()); to make a screen capture.