1 files changed, 45 insertions, 6 deletions

diff --git a/helix-view/src/theme.rs b/helix-view/src/theme.rs
index 757316bd..4a2ecbba 100644
--- a/helix-view/src/theme.rs
+++ b/helix-view/src/theme.rs
@@ -15,6 +15,10 @@ pub use crate::graphics::{Color, Modifier, Style};
 pub static DEFAULT_THEME: Lazy<Theme> = Lazy::new(|| {
     toml::from_slice(include_bytes!("../../theme.toml")).expect("Failed to parse default theme")
 });
+pub static BASE16_DEFAULT_THEME: Lazy<Theme> = Lazy::new(|| {
+    toml::from_slice(include_bytes!("../../base16_theme.toml"))
+        .expect("Failed to parse base 16 default theme")
+});
 
 #[derive(Clone, Debug)]
 pub struct Loader {
@@ -35,6 +39,9 @@ impl Loader {
         if name == "default" {
             return Ok(self.default());
         }
+        if name == "base16_default" {
+            return Ok(self.base16_default());
+        }
         let filename = format!("{}.toml", name);
 
         let user_path = self.user_dir.join(&filename);
@@ -74,12 +81,20 @@ impl Loader {
     pub fn default(&self) -> Theme {
         DEFAULT_THEME.clone()
     }
+
+    /// Returns the alternative 16-color default theme
+    pub fn base16_default(&self) -> Theme {
+        BASE16_DEFAULT_THEME.clone()
+    }
 }
 
 #[derive(Clone, Debug)]
 pub struct Theme {
-    scopes: Vec<String>,
+    // UI styles are stored in a HashMap
     styles: HashMap<String, Style>,
+    // tree-sitter highlight styles are stored in a Vec to optimize lookups
+    scopes: Vec<String>,
+    highlights: Vec<Style>,
 }
 
 impl<'de> Deserialize<'de> for Theme {
@@ -88,6 +103,8 @@ impl<'de> Deserialize<'de> for Theme {
         D: Deserializer<'de>,
     {
         let mut styles = HashMap::new();
+        let mut scopes = Vec::new();
+        let mut highlights = Vec::new();
 
         if let Ok(mut colors) = HashMap::<String, Value>::deserialize(deserializer) {
             // TODO: alert user of parsing failures in editor
@@ -102,24 +119,38 @@ impl<'de> Deserialize<'de> for Theme {
                 .unwrap_or_default();
 
             styles.reserve(colors.len());
+            scopes.reserve(colors.len());
+            highlights.reserve(colors.len());
+
             for (name, style_value) in colors {
                 let mut style = Style::default();
                 if let Err(err) = palette.parse_style(&mut style, style_value) {
                     warn!("{}", err);
                 }
-                styles.insert(name, style);
+
+                // these are used both as UI and as highlights
+                styles.insert(name.clone(), style);
+                scopes.push(name);
+                highlights.push(style);
             }
         }
 
-        let scopes = styles.keys().map(ToString::to_string).collect();
-        Ok(Self { scopes, styles })
+        Ok(Self {
+            scopes,
+            styles,
+            highlights,
+        })
     }
 }
 
 impl Theme {
+    #[inline]
+    pub fn highlight(&self, index: usize) -> Style {
+        self.highlights[index]
+    }
+
     pub fn get(&self, scope: &str) -> Style {
-        self.try_get(scope)
-            .unwrap_or_else(|| Style::default().fg(Color::Rgb(0, 0, 255)))
+        self.try_get(scope).unwrap_or_default()
     }
 
     pub fn try_get(&self, scope: &str) -> Option<Style> {
@@ -134,6 +165,14 @@ impl Theme {
     pub fn find_scope_index(&self, scope: &str) -> Option<usize> {
         self.scopes().iter().position(|s| s == scope)
     }
+
+    pub fn is_16_color(&self) -> bool {
+        self.styles.iter().all(|(_, style)| {
+            [style.fg, style.bg]
+                .into_iter()
+                .all(|color| !matches!(color, Some(Color::Rgb(..))))
+        })
+    }
 }
 
 struct ThemePalette {