mac style (quick): sync slider setup with qmacstyle

By essentially porting Volker's change (4bee9cdc0ac)
from qmacstyle_mac.

Fixes: QTBUG-106604
Change-Id: I3d17b96cb919299eb8e33afb9bfed7778423c88a
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
(cherry picked from commit 34a42dad18681911985a3648f7d8b19e3d174b63)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/src/quicknativestyle/qstyle/mac/qquickmacstyle_mac.mm b/src/quicknativestyle/qstyle/mac/qquickmacstyle_mac.mm
index d0a1333d6b..15df436d3c 100644
--- a/src/quicknativestyle/qstyle/mac/qquickmacstyle_mac.mm
+++ b/src/quicknativestyle/qstyle/mac/qquickmacstyle_mac.mm
@@ -397,7 +397,11 @@ static bool setupSlider(NSSlider *slider, const QStyleOptionSlider *sl)
     if (sl->minimum >= sl->maximum)
         return false;
 
-    slider.frame = sl->rect.toCGRect();
+    // NSSlider seems to cache values based on tracking and the last layout of the
+    // NSView, resulting in incorrect knob rects that break the interaction with
+    // multiple sliders. So completely reinitialize the slider.
+    [slider initWithFrame:sl->rect.toCGRect()];
+
     slider.minValue = sl->minimum;
     slider.maxValue = sl->maximum;
     slider.intValue = sl->sliderPosition;
@@ -427,6 +431,14 @@ static bool setupSlider(NSSlider *slider, const QStyleOptionSlider *sl)
     // the cell for its metrics and to draw itself.
     [slider layoutSubtreeIfNeeded];
 
+    if (sl->state & QStyle::State_Sunken) {
+        const CGRect knobRect = [slider.cell knobRectFlipped:slider.isFlipped];
+        CGPoint pressPoint;
+        pressPoint.x = CGRectGetMidX(knobRect);
+        pressPoint.y = CGRectGetMidY(knobRect);
+        [slider.cell startTrackingAt:pressPoint inView:slider];
+    }
+
     return true;
 }