HPGL thumbnails are created by calling hp2xx which needs to be installed.
This package will also install a better HPGL file detection based on a few common HPGL commands, because consistent file extensions apparently weren't a thing in the 90s (at least not within the HP test & measurements divisions).
Based on https://github.com/z3ntu/kde-thumbnailer-apk.
Install aur package kde-thumbnailer-hpgl-git
- Install the dependencies: hp2xx, kio, cmake, extra-cmake-modules
- These lines will install it correctly for Arch Linux, be careful with other distros!
mkdir build && cd build
cmake -DCMAKE_INSTALL_PREFIX='/usr' -DCMAKE_INSTALL_LIBDIR=lib ..
make
sudo make install