LH calibration - Invisible text (dark theme)

[matejkarasek]

The newly introduced dark/black theme is very nice!
Unfortunately, in the Lighthouse calibration wizard we now get white text on white background in the text field, where calibration result messages are plotted.

Observed in Win 11 with dark windows theme, cfcleint 2023.11 and the "default" cfclient theme

[knmcguire]

Hi! Oh yes this is absolutely a bug. Thanks for spotting!

For reference, this is with the light theme it is supposed to look like this:

and in dark theme/hacker theme, it looks like this.

This is because we use .png with transparent background for the images... either we have to make a white variant of that, (which it switches if a black theme is selected) or add a colored background to it. The latter is probably better.

[matejkarasek]

@knmcguire In fact, this is a different bug than what I reported...

What I observe might be related to Qt6 which seems to respond to the "light/dark" settings of the Windows 11 theme (Personalization --> Colors --> Choose your mode: "Light/Dark")

I use the "Dark" theme in Windows and now the cfclient with the "Default" theme looks like this (I like this very much):

However, if I want to do Lighthouse calibration then I get this:

Strangely, if I switch to a different cfclient theme (e.g. "Navy blue") and then switch back to "Default", this gets fixed (well the window title is still not visible...):

[knmcguire]

Ahhh so that's a different issue! hmm... the first seems to be an actual bug in either windows or QT so that might be difficult to solve.

[matejkarasek]

Not sure.... More info here, it seems that this autoswitching to dark mode is ("fusion" style of QT6) might be enabled in cfclient, and that there might be a conflict with some of the styles defined in cfclient?

[knmcguire]

hmmm yeah, we have it enabled here:

crazyflie-clients-python/src/cfclient/gui.py

Line 170 in 1e88847

app.setStyle("Fusion")

If I uncomment it, it won't switch to the dark theme so the problem is not there anymore. It is too bad but that would be the quickest solution.

Weirdly, the same thing doesn't happen for the other dialogs it seems like the initial geometry dialog where you have to start this wizard from.

I also noticed, if the theme is changed on windows while cfclient is started, it doesn't work great either

[knmcguire]

This seems to be bugging more and more people so I propose just to remove that line. I need to wait until there are more people at the office to review the PRs, but at least I'll mark it for triage