D17928: [RFC] [Effects KCM] Port to QQC2

ngraham created this revision.
ngraham added reviewers: KWin, Plasma.
Herald added a project: KWin.
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ngraham requested review of this revision.

REVISION SUMMARY
  This patch ports the Effects KCM to QQC2, which yields the following benefits:
  
  1. General performance enhancements of only using QQC2 rather than a mix of 1 And 2
  2. Improves the appearance of the checkable menu items in the dropdown menu, fixing https://bugs.kde.org/show_bug.cgi?id=402701
  3. Improves the appearance when using a fractional scale factor, fixing https://bugs.kde.org/show_bug.cgi?id=396725
  
  Along the way, two visual changes are intrpoduced as a by-product of porting:
  
  1. The scrollbar is inline, so it overlaps some of the buttons in the content. Adopting a Kirigami scrollview would fix this.
  2. The button that displays a dropdown menu no longer has a downward-pointing arrow to indicate as such. This is not my reference, but there's a benefit to being consistent, since that way we can change this in one place eventually.
  
  NOTE: This patch is RFC because there is one outstanding visual regression I need help fixing: the QQC2 scrollview does not want to draw a frame. It appears that the QQC2 style is supposed to take care of it, but I could not figure out how to make this happen. Help is appreciated.
  
  BUG: 396725
  BUG: 402701
  FIXED-IN: 5.15.0

TEST PLAN
  All functionality still works
  
  In System Settings, showing improved checkable menu item appearance:
  
  In `kcmshell` at 1x scale:
  
  In `kcmshell` at 1.3x scale:

REPOSITORY
  R108 KWin

BRANCH
  port-effects-KCM-to-qqc2 (branched from master)

REVISION DETAIL
  https://phabricator.kde.org/D17928

AFFECTED FILES
  kcmkwin/kwincompositing/qml/EffectView.qml

To: ngraham, #kwin, #plasma
Cc: kwin, GB_2, mkulinski, ragreen, jackyalcine, Pitel, iodelay, bwowk, ZrenBot, ngraham, lesliezhai, ali-mohamed, hardening, jensreuterberg, abetts, sebas, apol, mart