Fix ignoring of slow touchpad scrolling

Fixes #3377.

3 files changed, 17 insertions, 16 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d35dd047..a0ab066e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -60,6 +60,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Tabstops cleared on resize
 - Tabstops not breaking across lines
 - Crash when parsing DCS escape with more than 16 parameters
+- Ignoring of slow touchpad scrolling
 
 ### Removed
 
diff --git a/alacritty/src/event.rs b/alacritty/src/event.rs
index 587a5078..5888140f 100644
--- a/alacritty/src/event.rs
+++ b/alacritty/src/event.rs
@@ -272,7 +272,7 @@ pub struct Mouse {
     pub right_button_state: ElementState,
     pub last_click_timestamp: Instant,
     pub click_state: ClickState,
-    pub scroll_px: i32,
+    pub scroll_px: f64,
     pub line: Line,
     pub column: Column,
     pub cell_side: Side,
@@ -292,11 +292,11 @@ impl Default for Mouse {
             middle_button_state: ElementState::Released,
             right_button_state: ElementState::Released,
             click_state: ClickState::None,
-            scroll_px: 0,
+            scroll_px: 0.,
             line: Line(0),
             column: Column(0),
             cell_side: Side::Left,
-            lines_scrolled: 0.0,
+            lines_scrolled: 0.,
             block_url_launcher: false,
             last_button: MouseButton::Other(0),
             inside_grid: false,
diff --git a/alacritty/src/input.rs b/alacritty/src/input.rs
index bb89417e..01adedbc 100644
--- a/alacritty/src/input.rs
+++ b/alacritty/src/input.rs
@@ -469,16 +469,16 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
         match delta {
             MouseScrollDelta::LineDelta(_columns, lines) => {
                 let new_scroll_px = lines * self.ctx.size_info().cell_height;
-                self.scroll_terminal(new_scroll_px as i32);
+                self.scroll_terminal(new_scroll_px as f64);
             },
             MouseScrollDelta::PixelDelta(lpos) => {
                 match phase {
                     TouchPhase::Started => {
                         // Reset offset to zero
-                        self.ctx.mouse_mut().scroll_px = 0;
+                        self.ctx.mouse_mut().scroll_px = 0.;
                     },
                     TouchPhase::Moved => {
-                        self.scroll_terminal(lpos.y as i32);
+                        self.scroll_terminal(lpos.y);
                     },
                     _ => (),
                 }
@@ -486,14 +486,14 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
         }
     }
 
-    fn scroll_terminal(&mut self, new_scroll_px: i32) {
-        let height = self.ctx.size_info().cell_height as i32;
+    fn scroll_terminal(&mut self, new_scroll_px: f64) {
+        let height = self.ctx.size_info().cell_height as f64;
 
         if self.ctx.terminal().mode().intersects(TermMode::MOUSE_MODE) {
             self.ctx.mouse_mut().scroll_px += new_scroll_px;
 
-            let code = if new_scroll_px > 0 { 64 } else { 65 };
-            let lines = (self.ctx.mouse().scroll_px / height).abs();
+            let code = if new_scroll_px > 0. { 64 } else { 65 };
+            let lines = (self.ctx.mouse().scroll_px / height).abs() as i32;
 
             for _ in 0..lines {
                 self.mouse_report(code, ElementState::Pressed);
@@ -505,7 +505,7 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
             .contains(TermMode::ALT_SCREEN | TermMode::ALTERNATE_SCROLL)
             && !self.ctx.modifiers().shift()
         {
-            let multiplier = i32::from(
+            let multiplier = f64::from(
                 self.ctx
                     .config()
                     .scrolling
@@ -514,8 +514,8 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
             );
             self.ctx.mouse_mut().scroll_px += new_scroll_px * multiplier;
 
-            let cmd = if new_scroll_px > 0 { b'A' } else { b'B' };
-            let lines = (self.ctx.mouse().scroll_px / height).abs();
+            let cmd = if new_scroll_px > 0. { b'A' } else { b'B' };
+            let lines = (self.ctx.mouse().scroll_px / height).abs() as i32;
 
             let mut content = Vec::with_capacity(lines as usize * 3);
             for _ in 0..lines {
@@ -525,7 +525,7 @@ impl<'a, T: EventListener, A: ActionContext<T>> Processor<'a, T, A> {
             }
             self.ctx.write_to_pty(content);
         } else {
-            let multiplier = i32::from(self.ctx.config().scrolling.multiplier());
+            let multiplier = f64::from(self.ctx.config().scrolling.multiplier());
             self.ctx.mouse_mut().scroll_px += new_scroll_px * multiplier;
 
             let lines = self.ctx.mouse().scroll_px / height;
@@ -953,8 +953,8 @@ mod tests {
                     height: 51.0,
                     cell_width: 3.0,
                     cell_height: 3.0,
-                    padding_x: 0.0,
-                    padding_y: 0.0,
+                    padding_x: 0.,
+                    padding_y: 0.,
                     dpr: 1.0,
                 };