add basic support for theming and conversions from formats to colors

src/lib.rs

@@ -1,12 +1,172 @@
+use std::sync::{Mutex, MutexGuard};
+
 mod color;
 mod format;
 
-pub use color::ColorSpace;
 pub use color::Color;
+pub use color::ColorSpace;
+pub use color::Coordinate;
 
-pub use format::OutOfBoundsError;
 pub use format::AnsiColor;
+pub use format::EightBitColor;
 pub use format::EmbeddedRgb;
 pub use format::GrayGradient;
-pub use format::EightBitColor;
+pub use format::OutOfBoundsError;
 pub use format::TrueColor;
+
+/// A color theme.
+///
+/// ANSI colors do not have intrinsic color values, so we provide them through
+/// the [`current_theme`]. In addition to the 16 extended ANSI colors, a theme
+/// includes two more colors for the foreground and background defaults.
+pub struct Theme {
+    #[allow(dead_code)]
+    foreground: Color,
+    #[allow(dead_code)]
+    background: Color,
+    black: Color,
+    red: Color,
+    green: Color,
+    yellow: Color,
+    blue: Color,
+    magenta: Color,
+    cyan: Color,
+    white: Color,
+    bright_black: Color,
+    bright_red: Color,
+    bright_green: Color,
+    bright_yellow: Color,
+    bright_blue: Color,
+    bright_magenta: Color,
+    bright_cyan: Color,
+    bright_white: Color,
+}
+
+impl Theme {
+    /// Access the theme's foreground color.
+    pub fn foreground(&self) -> &Color {
+        &self.foreground
+    }
+
+    /// Access the theme's background color.
+    pub fn background(&self) -> &Color {
+        &self.background
+    }
+
+    // Access the theme's ANSI colors.
+    pub fn ansi(&self, value: AnsiColor) -> &Color {
+        use AnsiColor::*;
+
+        match value {
+            Black => &self.black,
+            Red => &self.red,
+            Green => &self.green,
+            Yellow => &self.yellow,
+            Blue => &self.blue,
+            Magenta => &self.magenta,
+            Cyan => &self.cyan,
+            White => &self.white,
+            BrightBlack => &self.bright_black,
+            BrightRed => &self.bright_red,
+            BrightGreen => &self.bright_green,
+            BrightYellow => &self.bright_yellow,
+            BrightBlue => &self.bright_blue,
+            BrightMagenta => &self.bright_magenta,
+            BrightCyan => &self.bright_cyan,
+            BrightWhite => &self.bright_white,
+        }
+    }
+}
+
+/// The default theme.
+///
+/// This theme exists to provide a well-defined initial value for the current
+/// theme. It uses the colors of VGA text mode.
+const DEFAULT_THEME: Theme = Theme {
+    foreground: Color::srgb(0.0, 0.0, 0.0),
+    background: Color::srgb(1.0, 1.0, 1.0),
+    black: Color::srgb(0.0, 0.0, 0.0),
+    red: Color::srgb(0.666666666666667, 0.0, 0.0),
+    green: Color::srgb(0.0, 0.666666666666667, 0.0),
+    yellow: Color::srgb(0.666666666666667, 0.333333333333333, 0.0),
+    blue: Color::srgb(0.0, 0.0, 0.666666666666667),
+    magenta: Color::srgb(0.666666666666667, 0.0, 0.666666666666667),
+    cyan: Color::srgb(0.0, 0.666666666666667, 0.666666666666667),
+    white: Color::srgb(0.666666666666667, 0.666666666666667, 0.666666666666667),
+    bright_black: Color::srgb(0.333333333333333, 0.333333333333333, 0.333333333333333),
+    bright_red: Color::srgb(1.0, 0.333333333333333, 0.333333333333333),
+    bright_green: Color::srgb(0.333333333333333, 1.0, 0.333333333333333),
+    bright_yellow: Color::srgb(1.0, 1.0, 0.333333333333333),
+    bright_blue: Color::srgb(0.333333333333333, 0.333333333333333, 1.0),
+    bright_magenta: Color::srgb(1.0, 0.333333333333333, 1.0),
+    bright_cyan: Color::srgb(0.333333333333333, 1.0, 1.0),
+    bright_white: Color::srgb(1.0, 1.0, 1.0),
+};
+
+// https://stackoverflow.com/questions/74085531/alternative-to-static-mut-and-unsafe-while-managing-global-application-state
+
+static THEME: Mutex<Theme> = Mutex::new(DEFAULT_THEME);
+
+/// Provide thread-safe access to the current theme, which is global state.
+pub fn current_theme() -> MutexGuard<'static, Theme> {
+    THEME.lock().unwrap()
+}
+
+// --------------------------------------------------------------------------------------------------------------------
+
+impl From<TrueColor> for Color {
+    /// Convert the "true" color object into a *true* color object... 🤪
+    fn from(value: TrueColor) -> Color {
+        let [r, g, b] = *value.coordinates();
+        Color::srgb((r as f64) / 255.0, (g as f64) / 255.0, (b as f64) / 255.0)
+    }
+}
+
+impl From<AnsiColor> for Color {
+    /// Convert the ANSI color into a color object.
+    ///
+    /// Since ANSI colors do not have any standardized or intrinsic color
+    /// values, this conversion uses the corresponding color from the current
+    /// color theme.
+    fn from(value: AnsiColor) -> Color {
+        let theme = current_theme();
+        *theme.ansi(value)
+    }
+}
+
+impl From<EmbeddedRgb> for Color {
+    /// Instantiate a new color from the embedded RGB value.
+    fn from(value: EmbeddedRgb) -> Color {
+        TrueColor::from(value).into()
+    }
+}
+
+impl From<GrayGradient> for Color {
+    /// Instantiate a new color from the embedded RGB value.
+    fn from(value: GrayGradient) -> Color {
+        TrueColor::from(value).into()
+    }
+}
+
+impl From<EightBitColor> for Color {
+    /// Instantiate a new color from the 8-bit terminal color.
+    fn from(value: EightBitColor) -> Color {
+        match value {
+            EightBitColor::Ansi(color) => Color::from(color),
+            EightBitColor::Rgb(color) => Color::from(color),
+            EightBitColor::Gray(color) => Color::from(color),
+        }
+    }
+}
+
+// --------------------------------------------------------------------------------------------------------------------
+
+// struct TerminalColorConverter {
+//     candidates: [Color; 216 + 24]
+// }
+
+// impl TerminalColorConverter {
+//     pub fn new() -> Self {
+//         Self
+//     }
+// }