For reasons like academic requirements, I need a long screenshot of an entire scrollable view in a window in a singe image. On Windows, there are tools like ShareX that can do the same. How can I do that on Ubuntu?

Note that there may be cases that this wouldn't work, like when window size doesn't affect the size of a particular component inside a GUI program.

Unfortunately, I am not aware of a direct alternative to Ubuntu of the scrolling screenshot from ShareX. But, if the application you need a screenshot off (and the contents in question) fits the above description, you may try this alternative:

Steps

1. Figure out how to take a screenshot of the active window in your distro (my Ubuntu-variant distro's method is [ Alt + PrtScrn ] ).
2. Make sure that the target window to be screenshotted doesn't cover the available space.
   • If the target window is like IMAGE 1 below, then it should be good.
   • If its like IMAGE 2, then resize it so that it doesn't cover the entire desktop.
3. Drag the target window down so that parts of it is beyond the monitor, like IMAGE 3.
4. Make sure that there's a clear view to the target window, so that you can click on it on a later step.
5. Using a terminal, type the following command: wmctrl -r :SELECT: -e 0,0,0,1368,5670
   • Change 1368 with the preferred width.
   • Change 5670 with the preferred height, probably multitudes beyond your monitor size.
6. Your cursor should now resemble a crosshair. Click on the target window.
7. Make the target window the active window (by clicking on it).
8. Take a screenshot of the active window (using info from Step 1, if you didn't know beforehand).

Image References

IMAGE 1 A window partially covering the desktop

IMAGE 2 A window fully covering the desktop

IMAGE 3 A window going beyond the monitor. Notice the missing sections below, behind the dock panel.