rqt* takes too long to launch

[LucidOne]

Working on .desktop files to be able to launch rqt tools via the GUI.

From a user experience point of view all of the rqt tools take way to long to launch.
Ex: rqt_reconfigure and rqt_bag take about 4.5 seconds to launch.

It looks like rqt needs a splash screen like rviz
https://qt-project.org/doc/qt-4.7/qsplashscreen.html

At the very least .show() the window earlier so users don't keep launching because it looks like nothing happened.

[DorianScholz]

You can try using the --cache-plugins option to speed it up (maybe this should be default anyway for normal users).
But you're right, it should start/show faster.
At least when you start in standalone mode...

[LucidOne]

--cache brings it down to about 3 seconds, which helps but isn't ideal.

[ablasdel]

These three seconds are the time it takes to scan the system for all available plugins correct?

I thought there was an enhancement ticket on rqt proper that requested not scanning for available plugins when in stand alone mode. Can't find it anymore though. Perhaps we should create that?

[DorianScholz]

if its in cache mode, it should not scan the file system for plugins and only read in the cached info...
but in stand alone mode it should also not scan for other plugins, so if thats not the case, there should be a ticket!
in any case, i think we need to check which part is actually taking how long and then decide which parts are actually necessary for which startup configuration.

[dirk-thomas]

Addressed by ros-visualization/qt_gui_core#28, ros-visualization/rqt#88, #189, #190 and ros-visualization/rqt_robot_plugins@fa5958c.