Handle touchpad scroll events

native/src/input/mouse.rs

@@ -3,4 +3,4 @@ mod button;
 mod event;
 
 pub use button::Button;
-pub use event::Event;
+pub use event::{Event, ScrollDelta};

native/src/input/mouse/event.rs

@@ -34,11 +34,22 @@ pub enum Event {
     },
 
     /// The mouse wheel was scrolled.
-    WheelScrolled {
+    WheelScrolled { delta: ScrollDelta },
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum ScrollDelta {
+    Lines {
         /// The number of horizontal lines scrolled
-        delta_x: f32,
+        x: f32,
 
         /// The number of vertical lines scrolled
-        delta_y: f32,
+        y: f32,
+    },
+    Pixels {
+        /// The number of horizontal pixels scrolled
+        x: f32,
+        /// The number of vertical pixels scrolled
+        y: f32,
     },
 }

native/src/widget/scrollable.rs

@@ -64,11 +64,16 @@ where
         // TODO: Event capture. Nested scrollables should capture scroll events.
         if is_mouse_over {
             match event {
-                Event::Mouse(mouse::Event::WheelScrolled {
-                    delta_y, ..
-                }) => {
-                    // TODO: Configurable speed (?)
-                    self.state.scroll(delta_y * 15.0, bounds, content_bounds);
+                Event::Mouse(mouse::Event::WheelScrolled { delta }) => {
+                    match delta {
+                        mouse::ScrollDelta::Lines { y, .. } => {
+                            // TODO: Configurable speed (?)
+                            self.state.scroll(y * 15.0, bounds, content_bounds);
+                        }
+                        mouse::ScrollDelta::Pixels { y, .. } => {
+                            self.state.scroll(y, bounds, content_bounds);
+                        }
+                    }
                 }
                 _ => {}
             }