3 files changed, 71 insertions, 36 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoawindow.h b/src/plugins/platforms/cocoa/qcocoawindow.h
index e097a69c4d..a36f85d620 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.h
+++ b/src/plugins/platforms/cocoa/qcocoawindow.h
@@ -174,7 +174,8 @@ public:
 
     NSInteger windowLevel(Qt::WindowFlags flags);
     NSUInteger windowStyleMask(Qt::WindowFlags flags);
-    void setWindowZoomButton(Qt::WindowFlags flags);
+    void updateTitleBarButtons(Qt::WindowFlags flags);
+    bool isFixedSize() const;
 
     bool setWindowModified(bool modified) override;
 
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index f5f7ae6bff..16e33ee014 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -511,29 +511,14 @@ NSUInteger QCocoaWindow::windowStyleMask(Qt::WindowFlags flags)
         }
     }();
 
-    // FIXME: Control visibility of buttons directly, instead of affecting styleMask
-    if (styleMask == NSWindowStyleMaskBorderless) {
-        // Frameless windows do not display the traffic lights buttons for
-        // e.g. minimize, however StyleMaskMiniaturizable is required to allow
-        // programmatic minimize.
-        styleMask |= NSWindowStyleMaskMiniaturizable;
-    } else if (flags & Qt::CustomizeWindowHint) {
-        if (flags & Qt::WindowCloseButtonHint)
-            styleMask |= NSWindowStyleMaskClosable;
-        if (flags & Qt::WindowMinimizeButtonHint)
-            styleMask |= NSWindowStyleMaskMiniaturizable;
-        if (flags & Qt::WindowMaximizeButtonHint)
-            styleMask |= NSWindowStyleMaskResizable;
-
-        // Force tool windows to be resizable
-        if (type == Qt::Tool)
-            styleMask |= NSWindowStyleMaskResizable;
-    } else {
-        styleMask |= NSWindowStyleMaskClosable | NSWindowStyleMaskResizable;
-
-        if (type != Qt::Dialog)
-            styleMask |= NSWindowStyleMaskMiniaturizable;
-    }
+    // We determine which buttons to show in updateTitleBarButtons,
+    // so we can enable all the relevant style masks here to ensure
+    // that behaviors that don't involve the title bar buttons are
+    // working (for example minimizing frameless windows, or resizing
+    // windows that don't have zoom or fullscreen titlebar buttons).
+    styleMask |= NSWindowStyleMaskClosable
+               | NSWindowStyleMaskResizable
+               | NSWindowStyleMaskMiniaturizable;
 
     if (type == Qt::Tool)
         styleMask |= NSWindowStyleMaskUtilityWindow;
@@ -551,20 +536,41 @@ NSUInteger QCocoaWindow::windowStyleMask(Qt::WindowFlags flags)
     return styleMask;
 }
 
-void QCocoaWindow::setWindowZoomButton(Qt::WindowFlags flags)
+bool QCocoaWindow::isFixedSize() const
+{
+    return windowMinimumSize().isValid() && windowMaximumSize().isValid()
+        && windowMinimumSize() == windowMaximumSize();
+}
+
+void QCocoaWindow::updateTitleBarButtons(Qt::WindowFlags windowFlags)
 {
     if (!isContentView())
         return;
 
-    // Disable the zoom (maximize) button for fixed-sized windows and customized
-    // no-WindowMaximizeButtonHint windows. From a Qt perspective it migth be expected
-    // that the button would be removed in the latter case, but disabling it is more
-    // in line with the platform style guidelines.
-    bool fixedSizeNoZoom = (windowMinimumSize().isValid() && windowMaximumSize().isValid()
-                            && windowMinimumSize() == windowMaximumSize());
-    bool customizeNoZoom = ((flags & Qt::CustomizeWindowHint)
-        && !(flags & (Qt::WindowMaximizeButtonHint | Qt::WindowFullscreenButtonHint)));
-    [[m_view.window standardWindowButton:NSWindowZoomButton] setEnabled:!(fixedSizeNoZoom || customizeNoZoom)];
+    NSWindow *window = m_view.window;
+
+    static constexpr std::pair<NSWindowButton, Qt::WindowFlags> buttons[] = {
+        { NSWindowCloseButton, Qt::WindowCloseButtonHint },
+        { NSWindowMiniaturizeButton, Qt::WindowMinimizeButtonHint},
+        { NSWindowZoomButton, Qt::WindowMaximizeButtonHint | Qt::WindowFullscreenButtonHint }
+    };
+
+    bool hideButtons = true;
+    for (const auto &[button, buttonHint] : buttons) {
+        bool enabled = true;
+        if (windowFlags & Qt::CustomizeWindowHint)
+            enabled = windowFlags & buttonHint;
+
+        if (button == NSWindowZoomButton && isFixedSize())
+            enabled = false;
+
+        [window standardWindowButton:button].enabled = enabled;
+        hideButtons &= !enabled;
+    }
+
+    // Hide buttons in case we disabled all of them
+    for (const auto &[button, buttonHint] : buttons)
+        [window standardWindowButton:button].hidden = hideButtons;
 }
 
 void QCocoaWindow::setWindowFlags(Qt::WindowFlags flags)
@@ -609,7 +615,7 @@ void QCocoaWindow::setWindowFlags(Qt::WindowFlags flags)
     if (!(flags & Qt::FramelessWindowHint))
         setWindowTitle(window()->title());
 
-    setWindowZoomButton(flags);
+    updateTitleBarButtons(flags);
 
     // Make window ignore mouse events if WindowTransparentForInput is set.
     // Note that ignoresMouseEvents has a special initial state where events
@@ -1016,7 +1022,7 @@ void QCocoaWindow::propagateSizeHints()
     window.contentMaxSize = NSSizeFromCGSize(windowMaximumSize().toCGSize());
 
     // The window may end up with a fixed size; in this case the zoom button should be disabled.
-    setWindowZoomButton(this->window()->flags());
+    updateTitleBarButtons(this->window()->flags());
 
     // sizeIncrement is observed to take values of (-1, -1) and (0, 0) for windows that should be
     // resizable and that have no specific size increment set. Cocoa expects (1.0, 1.0) in this case.
diff --git a/src/plugins/platforms/cocoa/qnswindow.mm b/src/plugins/platforms/cocoa/qnswindow.mm
index bdd2c07f02..7c9e0dce2d 100644
--- a/src/plugins/platforms/cocoa/qnswindow.mm
+++ b/src/plugins/platforms/cocoa/qnswindow.mm
@@ -249,6 +249,7 @@ OSStatus CGSClearWindowTags(const CGSConnectionID, const CGSWindowID, int *, int
 {
     // Member variables
     QPointer<QCocoaWindow> m_platformWindow;
+    bool m_isMinimizing;
 }
 
 - (instancetype)initWithContentRect:(NSRect)contentRect styleMask:(NSWindowStyleMask)style
@@ -260,6 +261,8 @@ OSStatus CGSClearWindowTags(const CGSConnectionID, const CGSWindowID, int *, int
     // we can properly reflect the window's state during initialization.
     m_platformWindow = window;
 
+    m_isMinimizing = false;
+
     return [super initWithContentRect:contentRect styleMask:style backing:backingStoreType defer:defer screen:screen];
 }
 
@@ -395,6 +398,31 @@ OSStatus CGSClearWindowTags(const CGSConnectionID, const CGSWindowID, int *, int
         [qnsview_cast(m_platformWindow->view()) handleFrameStrutMouseEvent:theEvent];
 }
 
+- (void)miniaturize:(id)sender
+{
+    QBoolBlocker miniaturizeTracker(m_isMinimizing, true);
+    [super miniaturize:sender];
+}
+
+- (NSButton *)standardWindowButton:(NSWindowButton)buttonType
+{
+    NSButton *button = [super standardWindowButton:buttonType];
+
+    // When an NSWindow is asked to minimize it will check the
+    // NSWindowMiniaturizeButton for enablement before continuing,
+    // even if the style mask includes NSWindowStyleMaskMiniaturizable.
+    // To ensure that a window can be minimized, even when the
+    // minimize button has been disabled in response to the user
+    // setting CustomizeWindowHint, we temporarily return a default
+    // minimize-button that we haven't modified in updateTitleBarButtons.
+    // This ensures the window can be minimized, without visually
+    // toggling the actual minimize-button on and off.
+    if (buttonType == NSWindowMiniaturizeButton && m_isMinimizing && !button.enabled)
+        return [NSWindow standardWindowButton:buttonType forStyleMask:self.styleMask];
+
+    return button;
+}
+
 - (void)closeAndRelease
 {
     qCDebug(lcQpaWindow) << "Closing and releasing" << self;