Add support for OSC 22 escape sequence

Add support for OSC 22 escape sequence to allow changing mouse cursor shapes. While the escape sequence could help some users with the mouse UX in TUI applications using mouse mode, it could obscure common mouse mode indication which is the `Text` cursor. Thus OSC 22 is disabled by default and could be enabled with `terminal.osc22` configuration option. Fixes alacritty#7119.
kchibisov · Sep 28, 2023 · 92fa601 · 92fa601
1 parent 47d5007
commit 92fa601
Show file tree

Hide file tree

Showing 11 changed files with 58 additions and 5 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -23,6 +23,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Bindings to create and navigate tabs on macOS
 - Support startup notify protocol to raise initial window on Wayland/X11
 - Debug option `prefer_egl` to prioritize EGL over other display APIs
+- Escape sequence to change mouse cursor shape (OSC 22);
+    use `terminal.osc22` to enable it
 
 ### Changed
 

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/alacritty/src/display/mod.rs b/alacritty/src/display/mod.rs
@@ -371,6 +371,9 @@ pub struct Display {
     /// The state of the timer for frame scheduling.
     pub frame_timer: FrameTimer,
 
+    /// Mouse icon set by the user with the OSC 22 escape sequence.
+    pub osc22_cursor: Option<CursorIcon>,
+
     // Mouse point position when highlighting hints.
     hint_mouse_point: Option<Point>,
 
@@ -516,6 +519,7 @@ impl Display {
             colors: List::from(&config.colors),
             pending_update: Default::default(),
             pending_renderer_update: Default::default(),
+            osc22_cursor: None,
             debug_damage,
             damage_rects,
             raw_window_handle,
@@ -1048,11 +1052,17 @@ impl Display {
             self.window.set_mouse_cursor(CursorIcon::Pointer);
         } else if self.highlighted_hint.is_some() {
             self.hint_mouse_point = None;
-            if term.mode().intersects(TermMode::MOUSE_MODE) && !term.mode().contains(TermMode::VI) {
-                self.window.set_mouse_cursor(CursorIcon::Default);
+            let cursor = if let Some(cursor) = self.osc22_cursor {
+                cursor
+            } else if term.mode().intersects(TermMode::MOUSE_MODE)
+                && !term.mode().contains(TermMode::VI)
+            {
+                CursorIcon::Default
             } else {
-                self.window.set_mouse_cursor(CursorIcon::Text);
-            }
+                CursorIcon::Text
+            };
+
+            self.window.set_mouse_cursor(cursor);
         }
 
         dirty |= self.highlighted_hint != highlighted_hint;

diff --git a/alacritty/src/event.rs b/alacritty/src/event.rs
@@ -1244,6 +1244,10 @@ impl input::Processor<EventProxy, ActionContext<'_, Notifier, EventProxy>> {
                         let text = format(self.ctx.size_info().into());
                         self.ctx.write_to_pty(text.into_bytes());
                     },
+                    TerminalEvent::MouseCursorIcon(icon) => {
+                        self.ctx.display().osc22_cursor = icon;
+                        self.reset_mouse_cursor();
+                    },
                     TerminalEvent::PtyWrite(text) => self.ctx.write_to_pty(text.into_bytes()),
                     TerminalEvent::MouseCursorDirty => self.reset_mouse_cursor(),
                     TerminalEvent::CursorBlinkingChange => self.ctx.update_cursor_blinking(),

diff --git a/alacritty/src/input.rs b/alacritty/src/input.rs
@@ -1149,6 +1149,8 @@ impl<T: EventListener, A: ActionContext<T>> Processor<T, A> {
             mouse_state
         } else if self.ctx.display().highlighted_hint.as_ref().map_or(false, hint_highlighted) {
             CursorIcon::Pointer
+        } else if let Some(cursor) = self.ctx.display().osc22_cursor {
+            cursor
         } else if !self.ctx.modifiers().state().shift_key() && self.ctx.mouse_mode() {
             CursorIcon::Default
         } else {

diff --git a/alacritty_terminal/Cargo.toml b/alacritty_terminal/Cargo.toml
@@ -20,6 +20,7 @@ version = "0.1.2-dev"
 [dependencies]
 base64 = "0.13.0"
 bitflags = { version = "2.2.1", features = ["serde"] }
+cursor-icon = "1.0.0"
 home = "0.5.5"
 libc = "0.2"
 log = "0.4"

diff --git a/alacritty_terminal/src/config/mod.rs b/alacritty_terminal/src/config/mod.rs
@@ -40,8 +40,11 @@ pub struct Config {
 
 #[derive(ConfigDeserialize, Clone, Debug, PartialEq, Eq, Default)]
 pub struct Terminal {
-    // OSC 52 handling (clipboard handling).
+    /// OSC 52 handling (clipboard handling).
     pub osc52: Osc52,
+
+    /// Allow to set cursor shape with the OSC 22 escape.
+    pub osc22: bool,
 }
 
 #[derive(ConfigDeserialize, Clone, Debug, PartialEq, Eq, Default)]

diff --git a/alacritty_terminal/src/event.rs b/alacritty_terminal/src/event.rs
@@ -2,6 +2,8 @@ use std::borrow::Cow;
 use std::fmt::{self, Debug, Formatter};
 use std::sync::Arc;
 
+use cursor_icon::CursorIcon;
+
 use crate::term::color::Rgb;
 use crate::term::ClipboardType;
 
@@ -17,6 +19,11 @@ pub enum Event {
     /// Window title change.
     Title(String),
 
+    /// Mouse cursor icon change.
+    ///
+    /// `None` indicates that it was unset.
+    MouseCursorIcon(Option<CursorIcon>),
+
     /// Reset to the default window title.
     ResetTitle,
 
@@ -65,6 +72,7 @@ impl Debug for Event {
             Event::Title(title) => write!(f, "Title({title})"),
             Event::CursorBlinkingChange => write!(f, "CursorBlinkingChange"),
             Event::MouseCursorDirty => write!(f, "MouseCursorDirty"),
+            Event::MouseCursorIcon(icon) => write!(f, "MouseCursorIcon({icon:?})"),
             Event::ResetTitle => write!(f, "ResetTitle"),
             Event::Wakeup => write!(f, "Wakeup"),
             Event::Bell => write!(f, "Bell"),

diff --git a/alacritty_terminal/src/term/mod.rs b/alacritty_terminal/src/term/mod.rs
@@ -5,6 +5,7 @@ use std::sync::Arc;
 use std::{cmp, mem, ptr, slice, str};
 
 use bitflags::bitflags;
+use cursor_icon::CursorIcon;
 use log::{debug, trace};
 use unicode_width::UnicodeWidthChar;
 use vte::ansi::{Hyperlink as VteHyperlink, Rgb as VteRgb};
@@ -467,6 +468,10 @@ impl<T> Term<T> {
 
         self.config = config.terminal.clone();
 
+        if !self.config.osc22 {
+            self.event_proxy.send_event(Event::MouseCursorIcon(None));
+        }
+
         // Damage everything on config updates.
         self.mark_fully_damaged();
     }
@@ -1694,6 +1699,7 @@ impl<T: EventListener> Handler for Term<T> {
         self.mode.insert(TermMode::default());
 
         self.event_proxy.send_event(Event::CursorBlinkingChange);
+        self.event_proxy.send_event(Event::MouseCursorIcon(None));
         self.mark_fully_damaged();
     }
 
@@ -1926,6 +1932,14 @@ impl<T: EventListener> Handler for Term<T> {
         self.event_proxy.send_event(Event::CursorBlinkingChange);
     }
 
+    #[inline]
+    fn set_mouse_cursor_icon(&mut self, icon: CursorIcon) {
+        if self.config.osc22 {
+            trace!("Requesting to set mouse cursor icon to {:?}", icon);
+            self.event_proxy.send_event(Event::MouseCursorIcon(Some(icon)));
+        }
+    }
+
     #[inline]
     fn set_cursor_shape(&mut self, shape: CursorShape) {
         trace!("Setting cursor shape {:?}", shape);

diff --git a/docs/escape_support.md b/docs/escape_support.md
@@ -94,6 +94,7 @@ brevity.
 | `OSC 10`  | IMPLEMENTED |                                                    |
 | `OSC 11`  | IMPLEMENTED |                                                    |
 | `OSC 12`  | IMPLEMENTED |                                                    |
+| `OSC 22`  | IMPLEMENTED |                                                    |
 | `OSC 50`  | IMPLEMENTED | Only `CursorShape` is supported                    |
 | `OSC 52`  | IMPLEMENTED | Only Clipboard and primary selection supported     |
 | `OSC 104` | IMPLEMENTED |                                                    |

diff --git a/extra/man/alacritty.5.scd b/extra/man/alacritty.5.scd
@@ -568,6 +568,13 @@ This section documents the *[terminal]* table of the configuration file.
 
 	Default: _"OnlyCopy"_
 
+*osc22* <boolean>
+
+	Controls the ability to change the mouse cursor shape with the escape
+	sequences trying to improve application mouse mode user experience.
+
+	Default: _false_
+
 # Mouse
 
 This section documents the *[mouse]* table of the configuration file.