Add power state to QPlatformScreen

Allows platform plugins to set the power state for each screen.

Change-Id: I4164ca63cbae9fa2ab186dc84c8f704c33fd7c69
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

src/gui/kernel/qplatformscreen.cpp

@@ -420,4 +420,22 @@ QPlatformScreen::SubpixelAntialiasingType QPlatformScreen::subpixelAntialiasingT
     return static_cast<QPlatformScreen::SubpixelAntialiasingType>(type);
 }
 
+/*!
+  Returns the current power state.
+
+  The default implementation always returns PowerStateOn.
+*/
+QPlatformScreen::PowerState QPlatformScreen::powerState() const
+{
+    return PowerStateOn;
+}
+
+/*!
+  Sets the power state for this screen.
+*/
+void QPlatformScreen::setPowerState(PowerState state)
+{
+    Q_UNUSED(state);
+}
+
 QT_END_NAMESPACE

src/gui/kernel/qplatformscreen.h

@@ -82,6 +82,13 @@ public:
         Subpixel_VBGR
     };
 
+    enum PowerState {
+        PowerStateOn,
+        PowerStateStandby,
+        PowerStateSuspend,
+        PowerStateOff
+    };
+
     QPlatformScreen();
     virtual ~QPlatformScreen();
 
@@ -117,6 +124,9 @@ public:
     virtual QPlatformCursor *cursor() const;
     virtual SubpixelAntialiasingType subpixelAntialiasingTypeHint() const;
 
+    virtual PowerState powerState() const;
+    virtual void setPowerState(PowerState state);
+
     static int angleBetween(Qt::ScreenOrientation a, Qt::ScreenOrientation b);
     static QTransform transformBetween(Qt::ScreenOrientation a, Qt::ScreenOrientation b, const QRect &target);
     static QRect mapBetween(Qt::ScreenOrientation a, Qt::ScreenOrientation b, const QRect &rect);