D13284: [decorations] Let KDecoration plugins recommend a border size per default

ngraham added a subscriber: anemeth.
ngraham added a comment.


  I'd like to re-visit this because it makes a lot of sense: Some window decoration themes (like Plastik) are designed to have a visible border that stands out from the content, while others (like Breeze) are not. So Because themes have different needs and design goals regarding whether or not to show a border, it makes sense to allow themes to make their preferences clear.
  
  Breeze's border tries its best to disappear as though it were borderless (but fails with many windows), so it appears that the only reason why Breeze even has a border at all is to work around the lack of this feature, and to provide rounded bottom corners without clipping window content.
  
  The former issue is solved by this patch, and the latter issue can be solved with an optional KWin effect like @anemeth's https://github.com/alex47/KDE-Rounded-Corners, or just accepted as the price to pay for having no borders. Either way, I would like to move forward with this. @romangg, any chance you'd like to rebase the patch on current master and proceed with review?
  
  BTW the KCM itself is now done in QML so UI changes are fun and easy. :)

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D13284

To: romangg, #kwin, #plasma, #vdg
Cc: anemeth, davidedmundson, abetts, graesslin, ngraham, zzag, kwin, jraleigh, GB_2, mkulinski, ragreen, jackyalcine, Pitel, iodelay, bwowk, ZrenBot, alexeymin, lesliezhai, ali-mohamed, hardening, jensreuterberg, sebas, apol, mart