1 files changed, 56 insertions, 19 deletions

diff --git a/src/plugins/platforms/cocoa/qnswindowdelegate.mm b/src/plugins/platforms/cocoa/qnswindowdelegate.mm
index 057a4c2943..14f1ca0114 100644
--- a/src/plugins/platforms/cocoa/qnswindowdelegate.mm
+++ b/src/plugins/platforms/cocoa/qnswindowdelegate.mm
@@ -39,30 +39,27 @@
 
 #include "qnswindowdelegate.h"
 #include "qcocoahelpers.h"
+#include "qcocoawindow.h"
 #include "qcocoascreen.h"
 
 #include <QDebug>
+#include <QtCore/private/qcore_mac_p.h>
 #include <qpa/qplatformscreen.h>
 #include <qpa/qwindowsysteminterface.h>
 
 static QRegExp whitespaceRegex = QRegExp(QStringLiteral("\\s*"));
 
-@implementation QNSWindowDelegate
-
-- (id)initWithQCocoaWindow:(QCocoaWindow *)cocoaWindow
+static QCocoaWindow *toPlatformWindow(NSWindow *window)
 {
-    if (self = [super init])
-        m_cocoaWindow = cocoaWindow;
-
-    return self;
+    return qnsview_cast(window.contentView).platformWindow;
 }
 
-- (BOOL)windowShouldClose:(NSNotification *)notification
+@implementation QNSWindowDelegate
+
+- (BOOL)windowShouldClose:(NSWindow *)window
 {
-    Q_UNUSED(notification);
-    if (m_cocoaWindow) {
-        return m_cocoaWindow->windowShouldClose();
-    }
+    if (QCocoaWindow *platformWindow = toPlatformWindow(window))
+        return platformWindow->windowShouldClose();
 
     return YES;
 }
@@ -76,14 +73,16 @@ static QRegExp whitespaceRegex = QRegExp(QStringLiteral("\\s*"));
 - (NSRect)windowWillUseStandardFrame:(NSWindow *)window defaultFrame:(NSRect)proposedFrame
 {
     Q_UNUSED(proposedFrame);
-    Q_ASSERT(window == m_cocoaWindow->nativeWindow());
-    const QWindow *w = m_cocoaWindow->window();
+
+    QCocoaWindow *platformWindow = toPlatformWindow(window);
+    Q_ASSERT(platformWindow);
+    const QWindow *w = platformWindow->window();
 
     // maximumSize() refers to the client size, but AppKit expects the full frame size
     QSizeF maximumSize = w->maximumSize() + QSize(0, w->frameMargins().top());
 
     // The window should never be larger than the current screen geometry
-    const QRectF screenGeometry = m_cocoaWindow->screen()->geometry();
+    const QRectF screenGeometry = platformWindow->screen()->geometry();
     maximumSize = maximumSize.boundedTo(screenGeometry.size());
 
     // Use the current frame position for the initial maximized frame,
@@ -103,25 +102,63 @@ static QRegExp whitespaceRegex = QRegExp(QStringLiteral("\\s*"));
     return QCocoaScreen::mapToNative(maximizedFrame);
 }
 
+#pragma clang diagnostic push
+// NSDisableScreenUpdates and NSEnableScreenUpdates are deprecated, but the
+// NSAnimationContext API that replaces them doesn't handle the use-case of
+// cross-thread screen update synchronization.
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+- (NSSize)windowWillResize:(NSWindow *)window toSize:(NSSize)frameSize
+{
+    Q_ASSERT(toPlatformWindow(window));
+
+    qCDebug(lcQpaWindow) << window << "will resize to" << QSizeF::fromCGSize(frameSize)
+        << "- disabling screen updates temporarily";
+
+    // There may be separate threads rendering to CA layers in this window,
+    // and if any of them do a swap while the resize is still in progress,
+    // the visual bounds of that layer will be updated before the visual
+    // bounds of the window frame, resulting in flickering while resizing.
+
+    // To prevent this we disable screen updates for the whole process until
+    // the resize is complete, which makes the whole thing visually atomic.
+    NSDisableScreenUpdates();
+
+    return frameSize;
+}
+
+- (void)windowDidResize:(NSNotification *)notification
+{
+    NSWindow *window = notification.object;
+    Q_ASSERT(toPlatformWindow(window));
+
+    qCDebug(lcQpaWindow) << window << "was resized - re-enabling screen updates";
+    NSEnableScreenUpdates();
+}
+#pragma clang diagnostic pop
+
 - (BOOL)window:(NSWindow *)window shouldPopUpDocumentPathMenu:(NSMenu *)menu
 {
-    Q_UNUSED(window);
     Q_UNUSED(menu);
 
+    QCocoaWindow *platformWindow = toPlatformWindow(window);
+    Q_ASSERT(platformWindow);
+
     // Only pop up document path if the filename is non-empty. We allow whitespace, to
     // allow faking a window icon by setting the file path to a single space character.
-    return !whitespaceRegex.exactMatch(m_cocoaWindow->window()->filePath());
+    return !whitespaceRegex.exactMatch(platformWindow->window()->filePath());
 }
 
 - (BOOL)window:(NSWindow *)window shouldDragDocumentWithEvent:(NSEvent *)event from:(NSPoint)dragImageLocation withPasteboard:(NSPasteboard *)pasteboard
 {
-    Q_UNUSED(window);
     Q_UNUSED(event);
     Q_UNUSED(dragImageLocation);
     Q_UNUSED(pasteboard);
 
+    QCocoaWindow *platformWindow = toPlatformWindow(window);
+    Q_ASSERT(platformWindow);
+
     // Only allow drag if the filename is non-empty. We allow whitespace, to
     // allow faking a window icon by setting the file path to a single space.
-    return !whitespaceRegex.exactMatch(m_cocoaWindow->window()->filePath());
+    return !whitespaceRegex.exactMatch(platformWindow->window()->filePath());
 }
 @end