QMacStyle - fix tab rendering

In BigSur NSPopupButton, it would appear, is slightly different. But different
enough so that a fragment of a disclose 'arrow' button became visible within
the clipping region, making it appear as some blue strange thing in between
inactive (non-selected) tabs.

Task-number: QTBUG-86513
Change-Id: Ib03af48069056b5ecbb8b4afebd851005583293a
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
(cherry picked from commit 40fb97e97f550b8afd13ecc3a038d9d0c2d82bbb)
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 17 insertions, 1 deletions

diff --git a/src/plugins/styles/mac/qmacstyle_mac.mm b/src/plugins/styles/mac/qmacstyle_mac.mm
index d1febd81d4..6b74205fda 100644
--- a/src/plugins/styles/mac/qmacstyle_mac.mm
+++ b/src/plugins/styles/mac/qmacstyle_mac.mm
@@ -3870,6 +3870,7 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
             const auto cs = d->effectiveAquaSizeConstrain(opt, w);
             // Extra hacks to get the proper pressed appreance when not selected or selected and inactive
             const bool needsInactiveHack = (!isActive && isSelected);
+            const bool isBigSurOrAbove = QOperatingSystemVersion::current() >= QOperatingSystemVersion::MacOSBigSur;
             const auto ct = !needsInactiveHack && (isSelected || tp == QStyleOptionTab::OnlyOneTab) ?
                     QMacStylePrivate::Button_PushButton :
                     QMacStylePrivate::Button_PopupButton;
@@ -3878,6 +3879,12 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
             auto *pb = static_cast<NSButton *>(d->cocoaControl(cw));
 
             auto vOffset = isPopupButton ? 1 : 2;
+            if (isBigSurOrAbove) {
+                // Make it 1, otherwise, offset is very visible compared
+                // to selected tab (which is not a popup button).
+                vOffset = 1;
+            }
+
             if (tabDirection == QMacStylePrivate::East)
                 vOffset -= 1;
             const auto outerAdjust = isPopupButton ? 1 : 4;
@@ -3951,7 +3958,10 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
                 NSPopUpArrowPosition oldPosition = NSPopUpArrowAtCenter;
                 NSPopUpButtonCell *pbCell = nil;
                 auto rAdjusted = r;
-                if (isPopupButton && tp == QStyleOptionTab::OnlyOneTab) {
+                if (isPopupButton && (tp == QStyleOptionTab::OnlyOneTab || isBigSurOrAbove)) {
+                    // Note: starting from macOS BigSur NSPopupButton has this
+                    // arrow 'button' in a different place and it became
+                    // quite visible 'in between' inactive tabs.
                     pbCell = static_cast<NSPopUpButtonCell *>(pb.cell);
                     oldPosition = pbCell.arrowPosition;
                     pbCell.arrowPosition = NSPopUpNoArrow;
@@ -3959,6 +3969,12 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
                         // NSPopUpButton in this state is smaller.
                         rAdjusted.origin.x -= 3;
                         rAdjusted.size.width += 6;
+                        if (isBigSurOrAbove) {
+                            rAdjusted.origin.y -= 1;
+                            rAdjusted.size.height += 1;
+                            if (tp == QStyleOptionTab::End)
+                                rAdjusted.origin.x -= 2;
+                        }
                     }
                 }