From eadd7b8e8193d19ae394a73dd7b84452d5311761 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Fri, 28 Nov 2025 06:29:25 +0100
Subject: [PATCH] Smooth out auto-scrolling speed scaling in `scrollable`

---
 examples/gallery/src/main.rs |  4 ++-
 widget/src/scrollable.rs     | 48 ++++++++++++++++++++++--------------
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/examples/gallery/src/main.rs b/examples/gallery/src/main.rs
index f6ed0077..198cdc27 100644
--- a/examples/gallery/src/main.rs
+++ b/examples/gallery/src/main.rs
@@ -275,7 +275,9 @@ impl Gallery {
             .height(grid::aspect_ratio(Preview::WIDTH, Preview::HEIGHT))
             .spacing(10);
 
-        let content = container(scrollable(gallery).spacing(10)).padding(10);
+        let content =
+            container(scrollable(gallery).spacing(10).auto_scroll(true))
+                .padding(10);
         let viewer = self.viewer.view(self.now);
 
         stack![content, viewer].into()
diff --git a/widget/src/scrollable.rs b/widget/src/scrollable.rs
index 62871600..2610cb45 100644
--- a/widget/src/scrollable.rs
+++ b/widget/src/scrollable.rs
@@ -579,7 +579,7 @@ where
         _viewport: &Rectangle,
     ) {
         const AUTOSCROLL_DEADZONE: f32 = 20.0;
-        const AUTOSCROLL_SPEED: f32 = 10.0;
+        const AUTOSCROLL_SMOOTHNESS: f32 = 1.5;
 
         let state = tree.state.downcast_mut::<State>();
         let bounds = layout.bounds();
@@ -764,6 +764,21 @@ where
                 }
             }
 
+            if matches!(state.interaction, Interaction::AutoScrolling { .. })
+                && matches!(
+                    event,
+                    Event::Mouse(
+                        mouse::Event::ButtonPressed(_)
+                            | mouse::Event::WheelScrolled { .. }
+                    ) | Event::Touch(_)
+                        | Event::Keyboard(_)
+                )
+            {
+                state.interaction = Interaction::None;
+                shell.capture_event();
+                return;
+            }
+
             if state.last_scrolled.is_none()
                 || !matches!(
                     event,
@@ -820,20 +835,6 @@ where
                 return;
             }
 
-            if matches!(state.interaction, Interaction::AutoScrolling { .. })
-                && matches!(
-                    event,
-                    Event::Mouse(
-                        mouse::Event::ButtonPressed(_)
-                            | mouse::Event::WheelScrolled { .. }
-                    ) | Event::Touch(_)
-                        | Event::Keyboard(_)
-                )
-            {
-                state.interaction = Interaction::None;
-                return;
-            }
-
             if shell.is_event_captured() {
                 return;
             }
@@ -1025,13 +1026,22 @@ where
                                     Duration::ZERO
                                 };
 
-                            let scroll_factor =
-                                time_delta.as_secs_f32() * AUTOSCROLL_SPEED;
+                            let scroll_factor = time_delta.as_secs_f32();
 
                             state.scroll(
                                 self.direction.align(Vector::new(
-                                    delta.x * scroll_factor,
-                                    delta.y * scroll_factor,
+                                    delta.x.signum()
+                                        * delta
+                                            .x
+                                            .abs()
+                                            .powf(AUTOSCROLL_SMOOTHNESS)
+                                        * scroll_factor,
+                                    delta.y.signum()
+                                        * delta
+                                            .y
+                                            .abs()
+                                            .powf(AUTOSCROLL_SMOOTHNESS)
+                                        * scroll_factor,
                                 )),
                                 bounds,
                                 content_bounds,