D18000: Modernize easing function of slidingpopups effect.

sefaeyeoglu added a comment.


  I personally feel, that timing functions for things appearing should not accelerate, but rather only decelerate. 
  I am often designing things with influences from different design guidelines, but when it comes to animation I often look at the Material Design Guidelines, as I think that Material Design animations feel natural. They have a section about things appearing and disappearing here <https://material.io/design/motion/speed.html#easing>. Therefore I chose decelerating/accelerating timing functions.
  
  I probably was too fast with removing slideLength, as I didn't notice, it could be specified. My main point was, that slideLength should not be the same for all windows, as larger windows should also travel longer distances in my opinion.
  
  I will add it back for the option to specify it, but will leave it at 100% of the window height/width by default.

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D18000

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