I'm using Spectacle to take screenshots on Kubuntu 19.10.
If I take a screenshot with Capture Mode set to Active Window, then it takes a screenshot of the active window as expected, but the image has a lot of extra space around the edges, as in the example below. This looks very ugly on a blog because of the amount of wasted space.
Is there any way to remove this extra space and just get the window in the image?
Assuming you're using Breeze for your window decorations,
Open System Settings > Application Style > Window Decorations
Hover over your selected Window Decorations theme. Click on the Settings icon that appears in the lower right corner.
In the window that opens, click the Shadow tab, and set Size to None.
(Note: this may not be available in other non-Breeze themes.)
There's an open issue here: Option to omit shadow and transparent border from windows in Active Window and Window Under Cursor modes.