OSX: hide mouse cursor harder, so it stays hidden on notifications

OSX notifications, like triggered with

    osascript -e 'display notification "hi"'

made the mouse cursor visible again. This happens behind Qt's back. Qt
most likely sets a transparent or 0-sized image, instead of actually
hiding the cursor. Work this around by using Cocoa API to hide the
cursor.

We could also just set a new blank cursor image in regular intervals,
but I think this would be a worse solution.

Sometimes the cursor fails to hide. This appears to be another Cocoa
issue, as we call [NSCursor hide] correctly. Also, the cursor is hidden
after another hide/unhide sequence, so it's not an issue with the PMP
logic, but probably a Cocoa bug.

src/player/PlayerComponent.cpp

@@ -439,16 +439,6 @@ void PlayerComponent::handleMpvEvent(mpv_event *event)
     }
     case MPV_EVENT_PLAYBACK_RESTART:
     {
-#if defined(Q_OS_MAC)
-      // On OSX, initializing VideoTooolbox (hardware decoder API) will mysteriously
-      // show the hidden mouse pointer again. The VTDecompressionSessionCreate API
-      // function does this, and we have no influence over its behavior. To make sure
-      // the cursor is gone again when starting playback, listen to the player's
-      // playbackStarting signal, at which point decoder initialization is guaranteed
-      // to be completed. Then we just have to set the cursor again on the Cocoa level.
-      if (!m_playbackStartSent && QGuiApplication::overrideCursor())
-        QGuiApplication::setOverrideCursor(QCursor(Qt::BlankCursor));
-#endif
       m_playbackStartSent = true;
       break;
     }

src/system/SystemComponent.cpp

@@ -15,6 +15,7 @@
 #include "settings/SettingsSection.h"
 #include "Paths.h"
 #include "Names.h"
+#include "utils/Utils.h"
 
 #define MOUSE_TIMEOUT 5 * 1000
 
@@ -40,7 +41,7 @@ QMap<SystemComponent::PlatformArch, QString> g_platformArchNames = {
 
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
-SystemComponent::SystemComponent(QObject* parent) : ComponentBase(parent), m_platformType(platformTypeUnknown), m_platformArch(platformArchUnknown), m_doLogMessages(false)
+SystemComponent::SystemComponent(QObject* parent) : ComponentBase(parent), m_platformType(platformTypeUnknown), m_platformArch(platformArchUnknown), m_doLogMessages(false), m_cursorVisible(false)
 {
   m_mouseOutTimer = new QTimer(this);
   m_mouseOutTimer->setSingleShot(true);
@@ -186,23 +187,26 @@ void SystemComponent::setCursorVisibility(bool visible)
   if (SettingsComponent::Get().value(SETTINGS_SECTION_MAIN, "webMode") == "desktop")
     visible = true;
 
+  if (visible == m_cursorVisible)
+    return;
+
+  m_cursorVisible = visible;
+
   if (visible)
-  {
     m_mouseOutTimer->start(MOUSE_TIMEOUT);
-
-    while (qApp->overrideCursor())
-      qApp->restoreOverrideCursor();
-  }
   else
-  {
-    if (!qApp->overrideCursor())
-    {
-      if (m_mouseOutTimer->isActive())
-        m_mouseOutTimer->stop();
+    m_mouseOutTimer->stop();
 
-      qApp->setOverrideCursor(QCursor(Qt::BlankCursor));
-    }
-  }
+#ifdef Q_OS_MAC
+  // OSX notifications will reset the cursor image (without Qt's knowledge). The
+  // only thing we can do override this is using Cocoa's native cursor hiding.
+  OSXUtils::SetCursorVisible(visible);
+#else
+  if (visible)
+    qApp->restoreOverrideCursor();
+  else
+    qApp->setOverrideCursor(QCursor(Qt::BlankCursor));
+#endif
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////

src/system/SystemComponent.h

@@ -104,6 +104,7 @@ private:
   bool m_doLogMessages;
   QString m_authenticationToken;
   QString m_webClientVersion;
+  bool m_cursorVisible;
 
 };
 

src/utils/osx/OSXUtils.h

@@ -12,6 +12,7 @@ namespace OSXUtils
   void SetPresentationOptions(unsigned long flags);
   unsigned long GetPresentationOptions();
   unsigned long GetPresentationOptionsForFullscreen(bool hideMenuAndDock);
+  void SetCursorVisible(bool visible);
 };
 
 #endif /* OSXUTILS_H */

src/utils/osx/OSXUtils.mm

@@ -72,3 +72,12 @@ OSStatus OSXUtils::SendAppleEventToSystemProcess(AEEventID eventToSendID)
 
   return status;
 }
+
+/////////////////////////////////////////////////////////////////////////////////////////
+void OSXUtils::SetCursorVisible(bool visible)
+{
+  if (visible)
+    [NSCursor unhide];
+  else
+    [NSCursor hide];
+}