replace explicit use of Arial with default font

[wjwwood]

Description

This pull request replaces uses of "Arial" with the default application font from Qt with QGuiApplication::font().

Checklist

• Required: Code is auto formatted using clang-format
• Extended the tutorials / documentation, if necessary reference
• Include a screenshot if changing a GUI
• Optional: Created tests, which fail without this PR reference
• Optional: Decide if this should be cherry-picked to other current ROS branches (Indigo, Jade, Kinetic)
  • I think this should be cherry-picked to indigo as well, but that's up to the maintainers.

[wjwwood]

Thanks @rhaschke for the fixup. 👍

[rhaschke]

@wjwwood Thanks for your search-and-replace work in first place ;-)

[rhaschke]

@v4hn Should we cherry-pick this into Indigo too?

[v4hn]

I don't believe this is desirable, unless users asks for it.

Thanks for taking care of this both of you!

[gavanderhoorn]

Does Indigo RViz not have the same problem? From the comment by @wjwwood I get the impression it does?

[v4hn]

Does Indigo RViz not have the same problem?

O.o I wasn't aware they changed the font in indigo too, until I just verified it.
That is a harsh change for a three year old release... Talking about "stable" releases.

In that case it makes sense to backport, yes. I'll add a request.

[gavanderhoorn]

@v4hn wrote:

That is a harsh change for a three year old release... Talking about "stable" releases.

it was a licensing issue. I guess it makes sense to address those, even in stable/old releases.

[wjwwood]

Does Indigo RViz not have the same problem? From the comment by @wjwwood I get the impression it does?

This pr is just "good to do", it wasn't fixing any problem. So it doesn't have to be backported to fix a problem unless you notice one in indigo. I think all the problems people were running into were due to mixing versions of rviz in strange ways in their workspaces.

That is a harsh change for a three year old release... Talking about "stable" releases.

it was a licensing issue. I guess it makes sense to address those, even in stable/old releases.

Exactly. Since you guys are only referring to it here and not distributing it then you do not have to backport to indigo like rviz did.

[gavanderhoorn]

@wjwwood wrote:

edited the previous comment to add an important "do not".. :)

yes, I was getting confused ;)

[v4hn]

Exactly. Since you guys are only referring to it here and not distributing it then you do not have to backport to indigo like rviz did.

Well,

1. I didn't dig deep enough but can we dismiss the possibility that the Arial font used on some system was - at least in some usages - the one provided by rviz?
2. If you removed arial usage throughout RViz in indigo, MoveIt might as well follow up for consistancy.

[wjwwood]

Yeah, I'm not sure how referring to Arial as the font family on Ubuntu does not break, since removing it from rviz, but it seems to work. I guessed that Ubuntu or Qt is silently providing a fallback font in those cases for compatibility reasons. Or maybe Arial is redistributed by Ubuntu with a correct license to do so and everything. I'm not sure.

[v4hn]

I'm not sure.

So we might as well follow your change in indigo and not use an explicit font choice in MSA.