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ratt-ru / meqtrees-timba

software system for implementing and solving arbitrary Measurement Equations
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What happened to QWhatsThis? #31

Closed twillis449 closed 8 years ago

twillis449 commented 8 years ago

At one time we had access to the QWhatsThis feature and I used this to provide instructions on how to control aspects of the plotting widgets. Unfortunately displaying this option seems to have disappeared although Qt still seems to provide a QWhatsThis widget. I just wasted a couple of days trying to figure out how my N-Dimensional controller works and finally I had to resort to reading the instructions in the python code!

o-smirnov commented 8 years ago

Github's wonderful code search tools tell me it got commented out here: https://github.com/ska-sa/meqtrees-timba/commit/341ce9172c69d970085e4e426ee7690cb4ee7eaf

Don't remember the exact motivation anymore, but I suppose I did that to unclutter the toolbar. It's still there in the Help menu (and accessible as Shift+F1).

twillis449 commented 8 years ago

Thanks for pointing out that shift+f1 works in the help drop-down menu. I'm re-opening the issue because when one does a shift+f1 the WhatsThis panel does appear but there's no text! I think this is my bad somewhere because when I run one of my plugins in stand-alone test mode, the same behaviour appears. So I'm investigating further. This stuff used to work in the distant past (PyQt3 ?). The setWhatsThis function is apparently so simple to use that there are almost no examples out in Internet land

twillis449 commented 8 years ago

It looks like this may be a PyQt or PyQwt bug. A lot of the PyQwt examples have WhatsThis function calls and just like my stuff a WhatThis window pops up, but without text. I'll try to strip out PyQwt calls in one of the demos and see what happens with a pure PyQt script

twillis449 commented 8 years ago

It would appear that this issue may have some OS dependencies. On 'standard' ubuntu 14.04 and 16.04 with PyQt4 v 4.10 and 4.11 respectively the WhatsThis screen pops up but no text appears. However , on Xubuntu 14.04 which also has PyQt4 v 4.10, it works.

I'm attaching the most basic script possible to test this issue. Just start it up with your python and hit shift + f1. It things are working, text will appear in a popup window. Otherwise you get the popup window, but sadly, no text. Since github does not seem to allow uploading of scripts ending with .py I've changed the ending to .txt.

WhatsThis_test.txt

twillis449 commented 8 years ago

It looks like this problem is associated with some combination of the terminals / desktop environment that comes with the ubuntu 'gnome-session-fallback' or 'gnome-session-flashback' packages.

Yep - further investigation shows that the script works properly with both the KDE and Xfce desktop systems. Some somehow the gnome desktop environment has trouble with this particular Qt widget function.

I'm gonna switch to the Xfce environment in any case. Its a much lighter system than the gnome one.