Large icons for developer builds with Qt 4.8.5 and retina display

[RJ Skerry-Ryan]

It looks like we are affected by these QTBUGs in 4.8.5. Our high-DPI images are rendered incorrectly.
https://bugreports.qt-project.org/browse/QTBUG-23870
https://bugreports.qt-project.org/browse/QTBUG-31477

See attached screenshot.

[jus (jus)]

I understand from reading http://blog.qt.digia.com/blog/2013/04/25/retina-display-support-for-mac-os-ios-and-x11/ and the linked bug reports from above that we need to add:

In the info.Plist off the application bundle
<key>NSPrincipalClass</key>
<string>NSApplication</string>
<key>NSHighResolutionCapable</key>
<string>True</string>

In the Mixxx.app (dunno if backported to QT4.8.5)
#if QT_VERSION >= 0x050100
     setAttribute(Qt::AA_UseHighDpiPixmaps);
 #endif

And @2x double sized assets for the png`s.

[RJ Skerry-Ryan (rryan)]

They aren't giant when we bundle, just when developing. Still kind of annoying.

[Daniel Schürmann (daschuer)]

Related: #1297242 Add HiDPI support

[Daniel Schürmann (daschuer)]

Bug #1249539 (now with link)

[Daniel Schürmann (daschuer)]

Bug #1297242 (now with correct link)

[Daniel Schürmann (daschuer)]

This one is not relevant anymore, because we are on Qt 5.
Please file a new bug if there is still a scaling issue.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/7198