Fix preview widget appearing to scale twice
Summary:
It worked when I wrote it against integer scaling, it got broken when
fractional support was added, resulting in it rendering at the wrong
size when the host scaling is non integer.
BUG: 388218
Test Plan:
Ran with QT_SCALE_FACTOR=1.5 to simulate the host being at that scale
Opened preview and moved slider
At 1.0 buttons were smaller than the main KCM
At 1.5 buttons looked the same
At 2.0 looked bigger
Reviewers: broulik
Reviewed By: broulik
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D14338