gnome-shell-extension-area-screenshot is a simple extension for creating screenshots of a specific area on your screen.
To install the extension, clone this repository and symlink the directory "firstname.lastname@example.org" into "~/.local/share/gnome-shell/extensions/". Then restart gnome-shell (<Alt> + F2 and enter "r"), open gnome-tweak-tool and enable the extension.
By default, this extension is configured to work with the keybinding <Super> + Print. You can change this binding via gsettings, although a configuration tool will be added soon. When you are not installing the extension via via https://extensions.gnome.org, you have to compile the gschema file manually.
When you hit <Super> + Print now, you can select an area on your screen with your mouse. After releasing your mouse, a new screenshot will be saved in your local "Pictures" directory with the current timestamp. You can also take a screenshot of a single window by simply clicking on it.
When taking an area screenshot, you can set a timer to be able to open context menus and such, which can't usually be captured. To set the timer, simply press the numbers 1 to 9 on your keyboard to define the countdown. The timer will appear in the bottom left of your screen. After making your selection, it will count down to zero. Pressing 0 on your keyboard will deactivate the timer.
This extension allows you to process screenshots automatically after taking them. For this purpose, it checks for an executable in the directory "~/bin/area-screenshot-post". If this file exists, it will be executed with the absolute filename of the generated screenshot as argument.
An example for automatically uploading taken screenshots can be found in the examples directory.