macOS: fix drawing of pushbuttons of non-standard size

Cocoa renders the bevel of a push button always in the default height of
32 pixels. We handled the case that the button is larger than that by
switching to "squared" mode, but buttons that are smaller than that got
rendered incorrectly, with the bevel being clipped.

Fix this by always rendering buttons in "squared" mode when the height
of the widget is not the same as the standard. Adjust the default height
for "mini" push buttons based on visual testing. Make the equivalent
adjustment to the focus frame logic and general positioning so that
buttons and frames are centered compared to other controls.

As a drive-by, get rid of expensive QObject::inherits calls, and replace
with qobject_cast. The headers for all the relevant widget types are
already included.

Fixes: QTBUG-85972
Pick-to: 6.2
Change-Id: I4ad66fac2313fbee385c1eadcc243f69c9cace70
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 36 insertions, 25 deletions

diff --git a/src/plugins/styles/mac/qmacstyle_mac.mm b/src/plugins/styles/mac/qmacstyle_mac.mm
index bb75391ab6..4f141327e2 100644
--- a/src/plugins/styles/mac/qmacstyle_mac.mm
+++ b/src/plugins/styles/mac/qmacstyle_mac.mm
@@ -388,16 +388,15 @@ static const QMarginsF pushButtonShadowMargins[3] = {
     { 1.5, 0.5, 1.5, 2.5 }
 };
 
-// These are frame heights as reported by Xcode 9's Interface Builder.
-// Alignemnet rectangle's heights match for push and popup buttons
-// with respective values 21, 18 and 15.
+// These are frame heights as reported by Xcode 9's Interface Builder
+// and determined experimentally.
 
 static const qreal comboBoxDefaultHeight[3] = {
     26, 22, 19
 };
 
 static const qreal pushButtonDefaultHeight[3] = {
-    32, 28, 16
+    32, 28, 24
 };
 
 static const qreal popupButtonDefaultHeight[3] = {
@@ -1207,8 +1206,9 @@ void QMacStylePrivate::drawFocusRing(QPainter *p, const QRectF &targetRect, int
         focusRect = QRectF::fromCGRect([pb alignmentRectForFrame:pb.frame]);
         if (cw.type == QMacStylePrivate::Button_PushButton) {
             focusRect -= pushButtonShadowMargins[cw.size];
-        }
-        else if (cw.type == QMacStylePrivate::Button_PullDown) {
+            if (cw.size == QStyleHelper::SizeMini)
+                focusRect.adjust(0, 3, 0, -3);
+        } else if (cw.type == QMacStylePrivate::Button_PullDown) {
             focusRect -= pullDownButtonShadowMargins[cw.size];
             //fix focus ring drawn slightly off for pull downs
             if (cw.size == QStyleHelper::SizeLarge)
@@ -1598,9 +1598,9 @@ QRectF QMacStylePrivate::CocoaControl::adjustedControlFrame(const QRectF &rect)
         frameRect = QRectF(rect.topLeft(),
                            QSizeF(rect.width(), frameSize.height()));
         if (size == QStyleHelper::SizeSmall)
-            frameRect = frameRect.translated(0, 1.5);
+            frameRect.translate(0, 0.5);
         else if (size == QStyleHelper::SizeMini)
-            frameRect = frameRect.adjusted(0, 0, -8, 0).translated(4, 4);
+            frameRect = frameRect.adjusted(0, 0, -8, 0).translated(4, -0.5);
         frameRect = frameRect.adjusted(-pushButtonBevelRectOffsets[size], 0,
                                         pushButtonBevelRectOffsets[size], 0);
     } else {
@@ -1686,13 +1686,15 @@ QMacStylePrivate::CocoaControlType cocoaControlType(const QStyleOption *opt, con
 {
     if (const auto *btn = qstyleoption_cast<const QStyleOptionButton *>(opt)) {
         const bool hasMenu = btn->features & QStyleOptionButton::HasMenu;
-        // When the contents won't fit in a large sized button,
-        // and WA_MacNormalSize is not set, make the button square.
+        // Buttons that don't fit (or don't get filled by) the default bevel
+        // will be made of square type, unless WA_MacNormalSize is not set.
         // Threshold used to be at 34, not 32.
-        const auto maxNonSquareHeight = pushButtonDefaultHeight[QStyleHelper::SizeLarge];
+        // Needs to be in sync with similar logic in CE_FocusFrame handling
+        QStyleHelper::WidgetSizePolicy sizePolicy = QStyleHelper::widgetSizePolicy(w, opt);
+        if (sizePolicy == QStyleHelper::SizeDefault)
+            sizePolicy = QStyleHelper::SizeLarge;
         const bool isSquare = (btn->features & QStyleOptionButton::Flat)
-                || (btn->rect.height() > maxNonSquareHeight
-                    && !(w && w->testAttribute(Qt::WA_MacNormalSize)));
+                || (btn->rect.height() != pushButtonDefaultHeight[sizePolicy]);
         return (isSquare? QMacStylePrivate::Button_SquareButton :
                 hasMenu ? QMacStylePrivate::Button_PullDown :
                 QMacStylePrivate::Button_PushButton);
@@ -3155,7 +3157,7 @@ void QMacStyle::drawPrimitive(PrimitiveElement pe, const QStyleOption *opt, QPai
         break;
     case PE_FrameWindow:
         if (const QStyleOptionFrame *frame = qstyleoption_cast<const QStyleOptionFrame *>(opt)) {
-            if (w && w->inherits("QMdiSubWindow")) {
+            if (qobject_cast<const QMdiSubWindow*>(w)) {
                 p->save();
                 p->setPen(QPen(frame->palette.dark().color(), frame->lineWidth));
                 p->setBrush(frame->palette.window());
@@ -3767,7 +3769,13 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
             const bool isActive = btn.state & State_Active;
             const bool isPressed = btn.state & State_Sunken;
 
+            // cocoaControlType evaluates the type based on the control's geometry, not on the
+            // label's geometry
+            const QRect oldRect = btn.rect;
+            if (w)
+                btn.rect = w->rect();
             const auto ct = cocoaControlType(&btn, w);
+            btn.rect = oldRect;
 
             if (!hasMenu && ct != QMacStylePrivate::Button_SquareButton) {
                 if (isPressed
@@ -4173,17 +4181,21 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
         const auto *ffw = ff ? ff->widget() : nullptr;
         const auto ct = [=] {
             if (ffw) {
-                if (ffw->inherits("QCheckBox"))
+                if (qobject_cast<const QCheckBox*>(ffw))
                     return QMacStylePrivate::Button_CheckBox;
-                if (ffw->inherits("QRadioButton"))
+                if (qobject_cast<const QRadioButton*>(ffw))
                     return QMacStylePrivate::Button_RadioButton;
-                if (ffw->inherits("QLineEdit") || ffw->inherits("QTextEdit"))
+                if (qobject_cast<const QLineEdit*>(ffw) || qobject_cast<const QTextEdit*>(ffw))
                     return QMacStylePrivate::TextField;
                 if (const auto *pb = qobject_cast<const QPushButton *>(ffw)) {
-                    if (pb->isFlat() || (pb->rect().height()
-                        > pushButtonDefaultHeight[QStyleHelper::SizeLarge]
-                        && !(pb->testAttribute(Qt::WA_MacNormalSize))))
-                            return QMacStylePrivate::Button_SquareButton;
+                    // keep in sync with cocoaControlType
+                    auto sizePolicy = QStyleHelper::widgetSizePolicy(ffw, opt);
+                    if (sizePolicy == QStyleHelper::SizeDefault)
+                        sizePolicy = QStyleHelper::SizeLarge;
+                    if (pb->isFlat()
+                        || (pb->rect().height() != pushButtonDefaultHeight[sizePolicy])) {
+                        return QMacStylePrivate::Button_SquareButton;
+                    }
                     if (pb->menu() != nullptr)
                         return QMacStylePrivate::Button_PullDown;
                     return QMacStylePrivate::Button_PushButton;
@@ -4192,10 +4204,9 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
 
             return QMacStylePrivate::Box; // Not really, just make it the default
         } ();
-        const auto cs = ffw ? (ffw->testAttribute(Qt::WA_MacMiniSize) ? QStyleHelper::SizeMini :
-                               ffw->testAttribute(Qt::WA_MacSmallSize) ? QStyleHelper::SizeSmall :
-                               QStyleHelper::SizeLarge) :
-                        QStyleHelper::SizeLarge;
+        auto cs = QStyleHelper::widgetSizePolicy(ffw, opt);
+        if (cs == QStyleHelper::SizeDefault)
+            cs = QStyleHelper::SizeLarge;
         const int hMargin = proxy()->pixelMetric(QStyle::PM_FocusFrameHMargin, opt, w);
         const int vMargin = proxy()->pixelMetric(QStyle::PM_FocusFrameVMargin, opt, w);
         d->drawFocusRing(p, opt->rect, hMargin, vMargin, QMacStylePrivate::CocoaControl(ct, cs));