effects: Allow exposing an EffectScreen::transform

This way an effect can know the transformation that is applied on a
display.

src/abstract_output.h

@@ -207,6 +207,19 @@ public:
      */
     static std::chrono::milliseconds dimAnimationTime();
 
+    enum class Transform {
+        Normal,
+        Rotated90,
+        Rotated180,
+        Rotated270,
+        Flipped,
+        Flipped90,
+        Flipped180,
+        Flipped270
+    };
+    Q_ENUM(Transform)
+    virtual Transform transform() const { return Transform::Normal; }
+
 Q_SIGNALS:
     /**
      * This signal is emitted when the geometry of this output has changed.

src/abstract_wayland_output.h

@@ -32,18 +32,6 @@ class KWIN_EXPORT AbstractWaylandOutput : public AbstractOutput
 {
     Q_OBJECT
 public:
-    enum class Transform {
-        Normal,
-        Rotated90,
-        Rotated180,
-        Rotated270,
-        Flipped,
-        Flipped90,
-        Flipped180,
-        Flipped270
-    };
-    Q_ENUM(Transform)
-
     enum class ModeFlag : uint {
         Current = 0x1,
         Preferred = 0x2,
@@ -106,7 +94,7 @@ public:
      * - Rotated 270° and flipped along the horizontal axis is inv. portrait + inv. landscape +
      *   portrait
      */
-    Transform transform() const;
+    Transform transform() const override;
 
     int refreshRate() const override;
 

src/effects.cpp

@@ -1754,6 +1754,11 @@ QRect EffectScreenImpl::geometry() const
     return m_platformOutput->geometry();
 }
 
+EffectScreen::Transform EffectScreenImpl::transform() const
+{
+    return EffectScreen::Transform(m_platformOutput->transform());
+}
+
 //****************************************
 // EffectWindowImpl
 //****************************************

src/effects.h

@@ -369,6 +369,7 @@ public:
     QString name() const override;
     qreal devicePixelRatio() const override;
     QRect geometry() const override;
+    Transform transform() const override;
 
 private:
     AbstractOutput *m_platformOutput;

src/libkwineffects/kwineffects.h

@@ -1853,6 +1853,20 @@ public:
      */
     virtual QRect geometry() const = 0;
 
+
+    enum class Transform {
+        Normal,
+        Rotated90,
+        Rotated180,
+        Rotated270,
+        Flipped,
+        Flipped90,
+        Flipped180,
+        Flipped270
+    };
+    Q_ENUM(Transform)
+    virtual Transform transform() const = 0;
+
 Q_SIGNALS:
     /**
      * Notifies that the display will be dimmed in @p time ms.