Cleanlooks style: Fix floating point exception

In QCleanlooksStyle::drawControl, if indeterminate == true and
rect.width() == 4, we will end up with slideWidth of zero, and
take a mod by zero when calculating the value of step.

This causes a crash in Quassel 0.10; see
https://bugs.gentoo.org/show_bug.cgi?id=507124

Instead, calculate slideWidth based on max(width, minWidth) where
minWidth was already set as 4, ensuring that slideWidth >= 2.

Change-Id: I6678789105e359fa26c99409f449cad0ba3bd0ae
(cherry picked from qtstyleplugins/8ff2ac6035fb1d01f5c0054ba14afb949410e3a7)
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gui/styles/qcleanlooksstyle.cpp b/src/gui/styles/qcleanlooksstyle.cpp
index 504734a..3f665ca 100644
--- a/src/gui/styles/qcleanlooksstyle.cpp
+++ b/src/gui/styles/qcleanlooksstyle.cpp
@@ -1773,7 +1773,7 @@ void QCleanlooksStyle::drawControl(ControlElement element, const QStyleOption *o
                 }
             } else {
                 Q_D(const QCleanlooksStyle);
-                int slideWidth = ((rect.width() - 4) * 2) / 3;
+                int slideWidth = (qMax(rect.width() - 4, minWidth) * 2) / 3;
                 int step = ((d->animateStep * slideWidth) / d->animationFps) % slideWidth;
                 if ((((d->animateStep * slideWidth) / d->animationFps) % (2 * slideWidth)) >= slideWidth)
                     step = slideWidth - step;