From e857710d73ad660d17ce39fa3201a39aa49f6932 Mon Sep 17 00:00:00 2001
From: Ogulcan Celik <ogulcancelik@gmail.com>
Date: Tue, 31 Mar 2026 23:03:11 +0300
Subject: fix: align pane scrolling with tmux and ghostty

---
 src/input/encode.rs | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/input/mod.rs    |  2 +-
 src/input/tests.rs  | 29 ++++++++++++++++++++-
 3 files changed, 101 insertions(+), 3 deletions(-)

(limited to 'src/input')

diff --git a/src/input/encode.rs b/src/input/encode.rs
index b114935a..ee466f42 100644
--- a/src/input/encode.rs
+++ b/src/input/encode.rs
@@ -1,4 +1,4 @@
-use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
+use crossterm::event::{KeyCode, KeyEvent, KeyModifiers, MouseEventKind};
 
 use super::{KeyboardProtocol, TerminalKey};
 
@@ -23,6 +23,77 @@ pub fn encode_terminal_key(key: TerminalKey, protocol: KeyboardProtocol) -> Vec<
     encode_legacy(key.as_key_event())
 }
 
+pub fn encode_cursor_key(code: KeyCode, application_cursor: bool) -> Vec<u8> {
+    match (code, application_cursor) {
+        (KeyCode::Up, true) => b"\x1bOA".to_vec(),
+        (KeyCode::Down, true) => b"\x1bOB".to_vec(),
+        (KeyCode::Right, true) => b"\x1bOC".to_vec(),
+        (KeyCode::Left, true) => b"\x1bOD".to_vec(),
+        (KeyCode::Up, false) => b"\x1b[A".to_vec(),
+        (KeyCode::Down, false) => b"\x1b[B".to_vec(),
+        (KeyCode::Right, false) => b"\x1b[C".to_vec(),
+        (KeyCode::Left, false) => b"\x1b[D".to_vec(),
+        _ => encode_legacy(KeyEvent::new(code, KeyModifiers::empty())),
+    }
+}
+
+pub fn encode_mouse_scroll(
+    kind: MouseEventKind,
+    column: u16,
+    row: u16,
+    modifiers: KeyModifiers,
+    encoding: vt100::MouseProtocolEncoding,
+) -> Option<Vec<u8>> {
+    let button = match kind {
+        MouseEventKind::ScrollUp => 64u16,
+        MouseEventKind::ScrollDown => 65u16,
+        MouseEventKind::ScrollLeft => 66u16,
+        MouseEventKind::ScrollRight => 67u16,
+        _ => return None,
+    };
+
+    let mut cb = button;
+    if modifiers.contains(KeyModifiers::SHIFT) {
+        cb += 4;
+    }
+    if modifiers.contains(KeyModifiers::ALT) {
+        cb += 8;
+    }
+    if modifiers.contains(KeyModifiers::CONTROL) {
+        cb += 16;
+    }
+
+    let column = column as u32 + 1;
+    let row = row as u32 + 1;
+
+    match encoding {
+        vt100::MouseProtocolEncoding::Sgr => {
+            Some(format!("\x1b[<{cb};{column};{row}M").into_bytes())
+        }
+        vt100::MouseProtocolEncoding::Default => {
+            let cb = u8::try_from(cb + 32).ok()?;
+            let column = u8::try_from(column + 32).ok()?;
+            let row = u8::try_from(row + 32).ok()?;
+            Some(vec![0x1b, b'[', b'M', cb, column, row])
+        }
+        vt100::MouseProtocolEncoding::Utf8 => {
+            let mut bytes = Vec::with_capacity(16);
+            bytes.extend_from_slice(b"\x1b[M");
+            push_mouse_codepoint(&mut bytes, cb as u32 + 32)?;
+            push_mouse_codepoint(&mut bytes, column + 32)?;
+            push_mouse_codepoint(&mut bytes, row + 32)?;
+            Some(bytes)
+        }
+    }
+}
+
+fn push_mouse_codepoint(bytes: &mut Vec<u8>, value: u32) -> Option<()> {
+    let ch = char::from_u32(value)?;
+    let mut buf = [0u8; 4];
+    bytes.extend_from_slice(ch.encode_utf8(&mut buf).as_bytes());
+    Some(())
+}
+
 /// CSI u encoding: \e[{codepoint};{modifiers}u
 /// Used when the child has pushed Kitty keyboard enhancement.
 /// Returns None if the key doesn't need CSI u (unmodified basic keys).
diff --git a/src/input/mod.rs b/src/input/mod.rs
index de4330a4..b5ed99b4 100644
--- a/src/input/mod.rs
+++ b/src/input/mod.rs
@@ -2,7 +2,7 @@ mod encode;
 mod model;
 mod parse;
 
-pub use encode::{encode_key, encode_terminal_key};
+pub use encode::{encode_cursor_key, encode_key, encode_mouse_scroll, encode_terminal_key};
 pub use model::{KeyboardProtocol, TerminalKey};
 pub use parse::parse_terminal_key_sequence;
 
diff --git a/src/input/tests.rs b/src/input/tests.rs
index 0d9d2c74..e6900df7 100644
--- a/src/input/tests.rs
+++ b/src/input/tests.rs
@@ -1,7 +1,8 @@
 use crossterm::event::{KeyCode, KeyEvent, KeyModifiers, ModifierKeyCode};
 
 use super::{
-    encode_key, encode_terminal_key, parse_terminal_key_sequence, KeyboardProtocol, TerminalKey,
+    encode_cursor_key, encode_key, encode_mouse_scroll, encode_terminal_key,
+    parse_terminal_key_sequence, KeyboardProtocol, TerminalKey,
 };
 
 fn assert_terminal_key_eq(
@@ -142,6 +143,32 @@ fn legacy_alt_char_still_esc_prefix() {
     assert_eq!(encode_key(key, KeyboardProtocol::Legacy), b"\x1ba");
 }
 
+#[test]
+fn application_cursor_keys_use_ss3_sequences() {
+    assert_eq!(encode_cursor_key(KeyCode::Up, true), b"\x1bOA");
+    assert_eq!(encode_cursor_key(KeyCode::Down, true), b"\x1bOB");
+}
+
+#[test]
+fn normal_cursor_keys_use_csi_sequences() {
+    assert_eq!(encode_cursor_key(KeyCode::Up, false), b"\x1b[A");
+    assert_eq!(encode_cursor_key(KeyCode::Down, false), b"\x1b[B");
+}
+
+#[test]
+fn sgr_mouse_scroll_encodes_wheel_button_and_coordinates() {
+    let encoded = encode_mouse_scroll(
+        crossterm::event::MouseEventKind::ScrollDown,
+        4,
+        6,
+        KeyModifiers::SHIFT,
+        vt100::MouseProtocolEncoding::Sgr,
+    )
+    .expect("mouse scroll should encode");
+
+    assert_eq!(encoded, b"\x1b[<69;5;7M");
+}
+
 #[test]
 fn kitty_shift_enter() {
     let key = KeyEvent::new(KeyCode::Enter, KeyModifiers::SHIFT);
-- 
cgit v1.2.3