Add Zoom scroll wheel option
Summary:
Adding a Zoom option for scrolling in the configuration
BUG: 254511
FIXED-IN: 18.12.0
Test Plan: Test scrolling in image and folder view for each configuration selection.
Reviewers: Gwenview, ngraham
Reviewed By: ngraham
Subscribers: sourabhboss, muhlenpfordt, ngraham
Tags: Gwenview
Differential Revision: https://phabricator.kde.org/D15809