From a9ff4012bdca0dbdbc77bc6e53a430689fc899be Mon Sep 17 00:00:00 2001
From: Ogulcan Celik <ogulcancelik@gmail.com>
Date: Fri, 22 May 2026 00:12:53 +0300
Subject: feat: add configurable mouse scroll lines

refs #236
---
 src/config/model.rs | 41 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

(limited to 'src/config')

diff --git a/src/config/model.rs b/src/config/model.rs
index e099d510..f270a69c 100644
--- a/src/config/model.rs
+++ b/src/config/model.rs
@@ -1,7 +1,10 @@
+use std::num::NonZeroUsize;
+
 use serde::{Deserialize, Deserializer, Serialize};
 
 use super::{
-    BindingConfig, CommandKeybindConfig, SoundConfig, ThemeConfig, DEFAULT_SCROLLBACK_LIMIT_BYTES,
+    BindingConfig, CommandKeybindConfig, SoundConfig, ThemeConfig, DEFAULT_MOUSE_SCROLL_LINES,
+    DEFAULT_SCROLLBACK_LIMIT_BYTES,
 };
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Deserialize, Serialize, Default)]
@@ -193,6 +196,8 @@ pub struct UiConfig {
     pub sidebar_max_width: u16,
     /// Capture mouse input for Herdr's mouse UI. Default: true.
     pub mouse_capture: bool,
+    /// Lines to scroll per mouse wheel notch. Default: 3.
+    pub mouse_scroll_lines: Option<NonZeroUsize>,
     /// Ask for confirmation before closing a workspace. Default: true.
     pub confirm_close: bool,
     /// Ask for a tab name before creating a new tab. Default: true.
@@ -328,6 +333,7 @@ impl Default for UiConfig {
             sidebar_min_width: 18,
             sidebar_max_width: 36,
             mouse_capture: true,
+            mouse_scroll_lines: None,
             confirm_close: true,
             prompt_new_tab_name: true,
             show_agent_labels_on_pane_borders: false,
@@ -339,6 +345,14 @@ impl Default for UiConfig {
     }
 }
 
+impl UiConfig {
+    pub fn mouse_scroll_lines(&self) -> usize {
+        self.mouse_scroll_lines
+            .map(NonZeroUsize::get)
+            .unwrap_or(DEFAULT_MOUSE_SCROLL_LINES)
+    }
+}
+
 impl Default for ToastConfig {
     fn default() -> Self {
         Self {
@@ -516,6 +530,31 @@ mouse_capture = false
         assert!(!config.ui.mouse_capture);
     }
 
+    #[test]
+    fn mouse_scroll_lines_defaults_to_three_and_parses() {
+        let default_config = Config::default();
+        assert_eq!(
+            default_config.ui.mouse_scroll_lines(),
+            DEFAULT_MOUSE_SCROLL_LINES
+        );
+
+        let toml = r#"
+[ui]
+mouse_scroll_lines = 1
+"#;
+        let config: Config = toml::from_str(toml).unwrap();
+        assert_eq!(config.ui.mouse_scroll_lines(), 1);
+    }
+
+    #[test]
+    fn mouse_scroll_lines_rejects_zero() {
+        let toml = r#"
+[ui]
+mouse_scroll_lines = 0
+"#;
+        assert!(toml::from_str::<Config>(toml).is_err());
+    }
+
     #[test]
     fn toast_config_parses() {
         let toml = r#"
-- 
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