diff --git a/compositor/LayerData.h b/compositor/LayerData.h
index 8f4b7aa..a808adc 100644
--- a/compositor/LayerData.h
+++ b/compositor/LayerData.h
@@ -33,6 +33,7 @@
 
 class DrmFbIdHandle;
 
+/* Rotation is defined in the clockwise direction */
 enum LayerTransform : uint32_t {
   kIdentity = 0,
   kFlipH = 1 << 0,