fish function to automatically source a catkin source when cding into it, set up rosfish and workarounds for issues with ROS melodic and Kubuntu 18.04

catkin.autosource.fish

# inspired from https://yodahuang.github.io/articles/How-to-let-ROS-play-happily-with-fish/
# added detection of catkin workspaces generated with catkin-tools
# added workaround for numeric issues with ROS melodic when the locale is not English https://github.com/ros-visualization/rviz/issues/1249#issuecomment-403351217
# added workaround for Rviz displaying in only a portion of the screen https://github.com/ros-visualization/rviz/issues/1203#issuecomment-438213723


function catkinSource --on-variable PWD
    status --is-command-substitution; and return
    if test -e ".catkin_workspace" -o -d ".catkin_tools"
        bass source devel/setup.bash
        echo "Configured the folder as a workspace"
        
        source /opt/ros/melodic/share/rosbash/rosfish
        echo "Configured rosfish"
        
        export LC_NUMERIC=C
        echo "Fixed numeric locale"
        
        export QT_AUTO_SCREEN_SCALE_FACTOR=
        export QT_SCREEN_SCALE_FACTORS=
        echo "Applied fixes for ROS Melodic and HiDPI"
        
    end
end