DolphinView: Conform to global scroll speed

One scroll with the mouse wheel is supposed to scroll the view by
QApplication::wheelScrollLines, however previous to this commit Dolphin
scrolled the view by QApplication::wheelScrollLines^2 instead, which
was wrong and way too much.

This commit fixes this by defining one line height as the height of the
current default font. This value is multiplied by
QApplication::wheelScrollLines to determine the scroll amount per mouse
wheel scroll.

In details view mode however, where there really are rows to go by,
this commit makes sure to always scroll by full rows. The number of
rows to scroll is determined by rounding up from the scroll amount used
in the other view modes.

Co-authored-by: Felix Ernst

1 files changed, 5 insertions, 0 deletions

diff --git a/src/kitemviews/kitemlistview.h b/src/kitemviews/kitemlistview.h
index 7fb3344b4..1a4ff0df1 100644
--- a/src/kitemviews/kitemlistview.h
+++ b/src/kitemviews/kitemlistview.h
@@ -176,6 +176,11 @@ public:
     qreal verticalPageStep() const;
 
     /**
+     * @return The line step which should be used for the scroll by mouse wheel.
+     */
+    virtual qreal scrollSingleStep() const;
+
+    /**
      * @return Index of the item that is below the point \a pos.
      *         The position is relative to the upper right of
      *         the visible area. Only (at least partly) visible