Prototype: Detect dark/light asynchronously

Cargo.toml

@@ -52,3 +52,7 @@ repository = "https://github.com/helix-editor/helix"
 homepage = "https://helix-editor.com"
 license = "MPL-2.0"
 rust-version = "1.76"
+
+[patch.crates-io]
+crossterm = { git = "https://github.com/bash/crossterm", branch = "parse-osc" }
+terminal-colorsaurus = { git = "https://github.com/bash/terminal-colorsaurus", branch = "parse-utils" }

helix-term/Cargo.toml

@@ -43,6 +43,7 @@ tokio-stream = "0.1"
 futures-util = { version = "0.3", features = ["std", "async-await"], default-features = false }
 arc-swap = { version = "1.7.1" }
 termini = "1"
+terminal-colorsaurus = { version = "0.4.7", default-features = false }
 
 # Logging
 fern = "0.7"

helix-term/src/application.rs

@@ -642,6 +642,16 @@ impl Application {
         };
         // Handle key events
         let should_redraw = match event.unwrap() {
+            CrosstermEvent::OscString(osc_string) => {
+                if let Some(color_string) = osc_string.strip_prefix(b"11;") {
+                    if let Some(color) = terminal_colorsaurus::parse::xparsecolor(color_string) {
+                        let is_light = color.perceived_lightness() >= 50;
+                        self.editor.set_status(format!("is_light = {}", is_light))
+                    }
+                }
+
+                true
+            }
             CrosstermEvent::Resize(width, height) => {
                 self.terminal
                     .resize(Rect::new(0, 0, width, height))

helix-term/src/ui/editor.rs

@@ -1332,6 +1332,7 @@ impl Component for EditorView {
         };
 
         match event {
+            Event::Noop => EventResult::Consumed(None),
             Event::Paste(contents) => {
                 self.handle_non_key_input(&mut cx);
                 cx.count = cx.editor.count;

helix-tui/src/backend/crossterm.rs

@@ -185,6 +185,7 @@ where
                 )
             )?;
         }
+        execute!(self.buffer, QueryBackgroundColor)?;
         Ok(())
     }
 
@@ -462,3 +463,25 @@ impl Command for SetUnderlineColor {
         ))
     }
 }
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct QueryBackgroundColor;
+
+impl crossterm::Command for QueryBackgroundColor {
+    fn write_ansi(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        f.write_str("\x1b]11;?\x07")
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> std::io::Result<()> {
+        Err(std::io::Error::new(
+            std::io::ErrorKind::Other,
+            "QueryBackgroundColor not supported by winapi.",
+        ))
+    }
+
+    #[cfg(windows)]
+    fn is_ansi_code_supported(&self) -> bool {
+        true
+    }
+}

helix-view/src/input.rs

@@ -15,6 +15,7 @@ pub enum Event {
     Paste(String),
     Resize(u16, u16),
     IdleTimeout,
+    Noop,
 }
 
 #[derive(Debug, PartialOrd, PartialEq, Eq, Clone, Copy, Hash)]
@@ -441,6 +442,7 @@ impl From<crossterm::event::Event> for Event {
             crossterm::event::Event::FocusGained => Self::FocusGained,
             crossterm::event::Event::FocusLost => Self::FocusLost,
             crossterm::event::Event::Paste(s) => Self::Paste(s),
+            crossterm::event::Event::OscString(_s) => Self::Noop,
         }
     }
 }