QuickWall was initialy launched as a wallpaper app that would set wallpapers directly from the commandline. Later due to a lot of requests from users , a theme option was added which uses pywal to generate themes from the wallpapers. It currently supports a wide range of wallpaper setters like nitrogen and DE's like KDE.
Since the app is written in Python and it has a lot of Python dependencies, it is adviced to install it from PyPi.
It is available in PyPi in the name QuickWall. Use the following command to install it.
pip install QuickWall
NOTE: If you are using a WM like i3-gaps, make sure you have one of the supported wallpaper setters installed.
Clone the repo using git.
git clone https://github.com/deepjyoti30/QuickWall
Move to the directory and install it.
cd QuickWall && python setup.py install
It should be installed now, have fun using it.