D20437: Make selection scrolling go at 60 fps

[David Hurka]

davidhurka added a comment.


  Sorry for testing it so late, now that I’m working on PageView.
  
  I don’t like this much, see inline comment. Do you mind if I change it to error accumulation at some time?

INLINE COMMENTS

> pageview.cpp:3760
> +
> +    if (pos.x() < horizontalScrollBar()->value()) d->dragScrollVector.setX((pos.x() - horizontalScrollBar()->value())/damping);
> +    else if (horizontalScrollBar()->value() + viewport()->width() < pos.x()) d->dragScrollVector.setX((pos.x() - horizontalScrollBar()->value() - viewport()->width())/damping);

This is only integer arithmetic, so `damping = 6` makes the edge scrolling feel a bit coarse. Crossing the edge only 5 pixels does nothing, but dragging only one pixel further gives “full speed”.

I would place `damping` in slotDragScroll(), which can do smoothing by error accumulation. (Bresenham and so on.... ;) )

REPOSITORY
  R223 Okular

REVISION DETAIL
  https://phabricator.kde.org/D20437

To: kezik, #okular, aacid, sander, ngraham
Cc: davidhurka, sander, ngraham, aacid, ahmedbilal, okular-devel, kezik, joaonetto, tfella, darcyshen
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