LateNight :: repair [Channel2] xFader button, use button templates

[ronso0]

https://bugs.launchpad.net/mixxx/+bug/1801363
This is just started as a quick fix for the scenario when a user switches to 2 decks and the xFader orientation of deck 1 or 2 differs from default, like 1=Right and 2=Center. In that case the xFader buttons would stay visible in 2-decks mode until decks 1/2 are assigned default xFader side again.

Just added attribute to PushButton. This is necessary since scalemode="STRETCH_ASPECT" was added to most buttons in #1858 but buttons wouldn't show up without Size attribute.

Edit I continued #1858 and replaced inline PushButtons with templates wherever it makes sense (almost everywhere, except some special cases, and except in sampler templates as that's fixed in #1840 already).

Edit2 This also fixes blurred beatgrid icons next to the waveforms.

[rryan]

On macOS I don't see any issue with the xfader orientation buttons (even at its minimum size)

[rryan]

Hm, just noticed the star rating widgets don't render or work (they don't seem to receive any mouse input).

[rryan]

Hm, just noticed the star rating widgets don't render or work (they don't seem to receive any mouse input).

Nevermind, they do work (you need a track loaded). The mouse input is weirdly offset though.. clicking on star N causes a rating of N+1 to be set. And the rendering is cut off.

[ronso0]

This is just a quick fix for the scenario when a user switches to 2 decks and the xFader orientation of deck 1 or 2 differs from default, like 1=Right and 2=Center

The issue doesn't exist with 4 decks (no scalemode="STRETCH_ASPECT" there), but with 4 decks those buttons should look blurry when the skin is auto-sclaed to 4K. Will update those buttons, as well.

[ronso0]

Nevermind, they do work (you need a track loaded). The mouse input is weirdly offset though.. clicking on star N causes a rating of N+1 to be set. And the rendering is cut off.

I didn't touch that, does it happen without this PR, too?

[ronso0]

I carried on with those HiDPI fixes started in #1858 and moved from inline PushButtons to button templates.

Just in case we're in a hurry for 2.2, and no one finds the time to thoroughly review this, the essential quick fix for the orientation button(s) 142f829 and ac55845 can be cherry-picked

[ronso0]

(rebased, cleaned up commit messages)

[rryan]

Sorry for not being clear -- I wasn't saying your PR caused the star rating widget issue :) it happens without this PR.

[rryan]

Ok, sorry for being dense. It works! LGTM