I recently needed to take screenshots of a Flash application running at a higher resolution than my screen's native resolution. Taking screenshots of a window larger than the screen isn't easy in Windows; here's a list of things that do NOT work:
- Alt-PrtScrn (screenshot of the current window; areas outside the screen are cut off)
- GIMP's screenshot tool (areas outside the screen are black)
- Windows' "Snipping Tool"
- Screengrab for Firefox (won't capture Flash content)
- Various third-party applications
The only way I've found that works is taking individual shots of the various parts of the window, and stitching them together manually, e.g. in GIMP.
This is complicated by the fact you cannot usually move a window up; in order to move it, you have to grab its title bar and drag it, but you cannot drag it outside the screen. But there's a way around this, so here's a complete recipe:
- Take screenshots of the top parts of the browser window (use GIMP's screenshot tool, since you'll be combining the shots in GIMP anyway).
- Set the screenshot tool to capture the entire screen after a couple of seconds' delay (say 10).
- Bring the browser window to the front, open its window menu (use Alt-Spacebar if it isn't visible), select Move.
- Move the window with the cursor keys; don't touch the mouse, as moving that will snap the window back so its title bar is visible again.
- Once the right part of the window is visible, wait for the screenshot to be taken.
- Repeat these steps until you got screenshots of all parts of the window.
- Stitch them together and save the result, et voilà.
This is a complicated, time-consuming method, but it's the only one I've found so far that works, and it can be adapted for arbitrarily large windows (though it'll take proportionally more time then). It should also work for most applications, save perhaps those that bypass the usual rendering layers (certain video players come to mind).
If you want to capture a browser window of arbitrary size and do NOT need to capture plugin (e.g. Flash) content, I highly recommend the Screengrab extension instead.