diff --git a/src/nodes/QskScaleRenderer.h b/src/nodes/QskScaleRenderer.h
index 313653ef..3b185d21 100644
--- a/src/nodes/QskScaleRenderer.h
+++ b/src/nodes/QskScaleRenderer.h
@@ -23,6 +23,7 @@ class QskColorFilter;
 class QSGNode;
 class QVariant;
 class QRectF;
+class QSizeF;
 
 class QSK_EXPORT QskScaleRenderer
 {