diff --git a/src/lib.rs b/src/lib.rs
index fb6c493..148f6a8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -24,6 +24,8 @@ pub enum EventType {
   MousePress(Button),
   MouseRelease(Button),
   MouseMoveTo { x: f64, y: f64 },
+  MouseWheelVertical { delta: i32 },
+  MouseWheelHorizontal { delta: i32 },
 }
 
 // #[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]