title: Capture a scrolling window contents screenshot
body: <p>I need to capture a screenshot of the scrolling window's client area, using .NET. My first priority is capturing web page screenshots. But this can be not the only one use case. For example it can be also a text area in the Notepad.</p>
  
  <p>Some applications (FastStone Capture, PicPick) can emulate user behavior to reach hidden part of a scrollable area and capture it. I'm looking for something like this or recommendations for alternative way to get the same result.</p>
  
  <p><img src="https://i.stack.imgur.com/OwH6z.png" alt="alt text"></p>