I'm trying to capture a screenshot of whole browser screen (e.g. with any toolbars, panels and so on) not only an entire page, so I'm got this code:
using (FirefoxDriver driver = new FirefoxDriver())
{
driver.Navigate().GoToUrl(url);
ScreenCapture sc = new ScreenCapture();
// How can I find natural IntPtr handle of window here, using GUID-like identifier returning by driver.currentWindowHandle?
Image img = sc.CaptureWindow(...);
MemoryStream ms = new MemoryStream();
img.Save(ms, ImageFormat.Jpeg);
return new FileStreamResult(ms, "image/jpeg");
}