slick-greeter: Add blur effect and fix bugs

[Hilyxx]

#264

• Add blur effect to the panel(menubar) and dashboard (dashbox)
• Fix a bug that prevented the user list from automatically repositioning in the grid when the session list was closed
• Fix toggleBox misalignment
• Fix the offset and clipping issues affecting the 'Select desktop environment' label, caused by the avatar implementation in the grid
• Remove SMALL_AVATAR_OPACITY to avoid visibility issues
• Convert some icons to SVG format to improve rendering quality on HiDPI displays

[clefebvre]

Thanks @Hilyxx! This looks great, and it falls just in time to be included in the Mint BETA.

[clefebvre]

One small detail. I don't like two things about the avatars:

• Because we fallback to the cinnamon generic avatar, we get different behaviors depending on the DE installed. i.e. in a MATE/Xfce edition where Cinnamon isn't installed, we get no avatar, in a Cinnamon ISO, we do.
• The default generic avatar for Cinnamon could look better. It's not mono, it uses gradients.. it looks a bit outdated.

I'd suggest to ship a generic avatar in slick-greeter directly, or libxapp, so that all DEs can benefit from it, and use something that look more like a symbolic/mono icon.

[Hilyxx]

@clefebvre

I’ll take care of it.
Just one thing: with a mono symbolic-style avatar, if there are multiple users, the unselected users will have their avatars either above or below the dashbox. As a result, the avatars will be displayed directly over the background, and if that background is white or light, they’ll be unreadable.
I was suggesting instead to use a regular (non-symbolic) icon to avoid this issue, something more modern than user-generic.png but still just as noticeable.

[Hilyxx]

This is just a sample icon using Linux Mint’s color. It can of course be made more neutral. I believe something in this style could be more readable. I’d be happy to hear any suggestions you might have

[clefebvre]

Ah, you're right, that's a fair point!

[clefebvre]

It would need to be neutral color wise (grey/white/black).

Ideally it could be shipped by xapp-common so that DE configuration tools can use it as well.

Another idea would simply be to show no avatar in slick-greeter when none are set. It doesn't look bad and it gives the ability to people who don't like avatars to not set any.

[clefebvre]

I'll remove the Cinnamon fallback for now in any case to tag slick-greeter.

[Hilyxx]

The second solution could be interesting, but if a user decides to set an avatar just to try it out, or later decides they don’t want one anymore, there’s no built-in option to fully remove it in something like cs_user. And an avatar will always show up by default no matter what.

There could be a third solution that might work for everyone. An avatar icon could be defined both in xapp-common for Cinnamon, MATE, and XFCE, and also stored in slick-greeter. That way, there would be one icon managed by Linux Mint desktop environments, and a separate for other distributions using slick-greeter without needing to install xapp-common, because it’s not required by slick-greeter.

An option could also be added to lightdm-settings to hide the avatar for users who prefer that… though that option would only be available in Linux Mint.

[clefebvre]

There's no need to differentiate between mint and other distros. Slick is an XApp, it's OK for it to depend on xapp-common, which itself is distro-agnostic.

In Cinnamon, I'm planning a rewrite of cs_user and cinnamon-settings-users.