No underline or strikeout option for fonts in layouts - proposal to add qt5ct to QGIS depencies

[jgrocha]

Describe the bug

When preparing layout, on some Linux computers, the font dialogue is quite simple. The user can choose only the family, style and size. The user has no option for underline or strikeout, for example.

On other Linux flavours, the font dialogue was different, with more options.

Creating and running the same QT program (with just a call to QFont font = QFontDialog::getFont(&ok, QFont("Helvetica", 10), this); shows that difference: the QT program is the same, but the rendered dialogue is different.

How to solve

After some investigation, the problem was solved by installing the qt5ct package. Installing and running qt5ct fixes the problem (and the user can use it to define other customizations).

Packaging request

Does it make sense to add this qt5ct package to the QGIS dependencies?

I've wrote the report to make it searchable, if someone else has the same problem and if we decided to not include qt5ct in QGIS dependencies.

How to Reproduce

1. Install QGIS in a fresh Ubuntu 18.04 computer.
2. Create a project
3. Create layout
4. Add a label
5. Change label font: no option for underline or strikeout.

QGIS and OS versions

QGIS 3.4 and up (not checked in previous versions).

Additional context

This problem was reported in a QGIS Talks meeting (organized by QGIS PT), by Hugo Santos (@ulmi).

[jgrocha]

I'll close the issue for now. If qt5ct package is necessary for any other customization, I'll request to include it in QGIS package dependencies.