theme-engine

theme-engine resolves highlight capture names to concrete styles (fg/bg RGB + bold/italic/underline) with normalization and fallback.

Features

• Capture key normalization:
  • @comment and comment resolve the same key.
• Hierarchical fallback:
  • comment.documentation -> comment -> normal
• UI-role resolution:
  • supports optional ui map (default_fg, default_bg, statusline, tab_active, etc.)
  • falls back to legacy styles keys for compatibility
  • exposes default_terminal_colors() for terminal default fg/bg integration
• Built-in themes:
  • tokyonight-dark
  • tokyonight-moon
  • tokyonight-light
  • tokyonight-day
  • solarized-dark
  • solarized-light
• Theme loading from JSON and TOML strings.

Quick Example

use theme_engine::load_theme;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let theme = load_theme("tokyonight-dark")?;
    let style = theme.resolve("@comment.documentation");
    println!("style found: {}", style.is_some());
    let statusline = theme.resolve_ui("statusline");
    let active_tab = theme.resolve_ui("tab_active");
    println!(
        "ui roles: statusline={}, tab_active={}",
        statusline.is_some(),
        active_tab.is_some()
    );
    let (default_fg, default_bg) = theme.default_terminal_colors();
    println!(
        "terminal defaults available: fg={}, bg={}",
        default_fg.is_some(),
        default_bg.is_some()
    );
    Ok(())
}

default_terminal_colors() is designed to pair with terminal default-color escape sequences (OSC 10/11), for hosts that want theme-level foreground/background outside syntax spans.

Custom Theme Example

use theme_engine::Theme;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let theme = Theme::from_json_str(r#"
    {
      "styles": {
        "normal": { "fg": { "r": 220, "g": 220, "b": 220 } },
        "number": { "fg": { "r": 255, "g": 180, "b": 120 } }
      }
    }
    "#)?;

    let style = theme.resolve("number");
    println!("style found: {}", style.is_some());
    Ok(())
}