feat: Add from_hex_str methods to Color and RgbColor

crates/anstyle-git/src/lib.rs

@@ -111,19 +111,9 @@ fn parse_color(word: &str) -> Result<Option<anstyle::Color>, ()> {
         "white" => Some(anstyle::AnsiColor::White.into()),
         _ => {
             if let Some(hex) = word.strip_prefix('#') {
-                let l = hex.len();
-                if l != 3 && l != 6 {
-                    return Err(());
-                }
-                let l = l / 3;
-                if let (Ok(r), Ok(g), Ok(b)) = (
-                    u8::from_str_radix(&hex[0..l], 16),
-                    u8::from_str_radix(&hex[l..(2 * l)], 16),
-                    u8::from_str_radix(&hex[(2 * l)..(3 * l)], 16),
-                ) {
-                    Some(anstyle::Color::from((r, g, b)))
-                } else {
-                    return Err(());
+                match anstyle::Color::from_hex_str(hex) {
+                    None => return Err(()),
+                    c => c,
                 }
             } else if let Ok(n) = word.parse::<u8>() {
                 Some(anstyle::Color::from(n))
@@ -217,12 +207,12 @@ mod tests {
         test!("#204060" => RgbColor(0x20,0x40,0x60).on_default());
         test!("#1a2b3c" => RgbColor(0x1a,0x2b,0x3c).on_default());
         test!("#000" => RgbColor(0,0,0).on_default());
-        test!("#cba" => RgbColor(0xc,0xb,0xa).on_default());
-        test!("#cba   " => RgbColor(0xc,0xb,0xa).on_default());
-        test!("#987 #135" => RgbColor(9,8,7).on(RgbColor(1, 3, 5)));
-        test!("#987    #135   " => RgbColor(9,8,7).on(RgbColor(1, 3, 5)));
-        test!("#123 #abcdef" => RgbColor(1,2,3).on(RgbColor(0xab, 0xcd, 0xef)));
-        test!("#654321 #a9b" => RgbColor(0x65,0x43,0x21).on(RgbColor(0xa, 0x9, 0xb)));
+        test!("#cba" => RgbColor(0xcc, 0xbb, 0xaa).on_default());
+        test!("#cba   " => RgbColor(0xcc, 0xbb, 0xaa).on_default());
+        test!("#987 #135" => RgbColor(0x99, 0x88, 0x77).on(RgbColor(0x11, 0x33, 0x55)));
+        test!("#987    #135   " => RgbColor(0x99, 0x88, 0x77).on(RgbColor(0x11, 0x33, 0x55)));
+        test!("#123 #abcdef" => RgbColor(0x11, 0x22, 0x33).on(RgbColor(0xab, 0xcd, 0xef)));
+        test!("#654321 #a9b" => RgbColor(0x65, 0x43, 0x21).on(RgbColor(0xaa, 0x99, 0xbb)));
 
         test!("bold cyan white" => Cyan.on(White).bold());
         test!("bold cyan nobold white" => Cyan.on(White));
@@ -232,8 +222,8 @@ mod tests {
         test!("italic cyan white" => Cyan.on(White).italic());
         test!("strike cyan white" => Cyan.on(White).strikethrough());
         test!("blink #050505 white" => RgbColor(5,5,5).on(White).blink());
-        test!("bold #987 green" => RgbColor(9,8,7).on(Green).bold());
-        test!("strike #147 #cba" => RgbColor(1,4,7).on(RgbColor(0xc, 0xb, 0xa)).strikethrough());
+        test!("bold #987 green" => RgbColor(0x99, 0x88, 0x77).on(Green).bold());
+        test!("strike #147 #cba" => RgbColor(0x11, 0x44, 0x77).on(RgbColor(0xcc, 0xbb, 0xaa)).strikethrough());
     }
 
     #[test]

crates/anstyle/src/color.rs

@@ -17,6 +17,23 @@ pub enum Color {
 }
 
 impl Color {
+    /// Parse a `Color` from a hex string of length 3 or 6.
+    ///
+    /// Strings of length 3 (`abc`) will get interpreted as though each character were doubled
+    /// (`aabbcc`), as in HTML or Git.
+    ///
+    /// This does not handle an initial `#`; strip it before calling this function. This allows the
+    /// caller to distinguish hex colors from other possible inputs, such as named or numbered
+    /// colors.
+    ///
+    /// The result will always be a 24-bit `RgbColor`.
+    ///
+    /// Returns `None` on parse error.
+    #[inline]
+    pub fn from_hex_str(hex: &str) -> Option<Self> {
+        Some(RgbColor::from_hex_str(hex)?.into())
+    }
+
     /// Create a [`Style`][crate::Style] with this as the foreground
     #[inline]
     pub fn on(self, background: impl Into<Self>) -> crate::Style {
@@ -476,6 +493,33 @@ impl From<AnsiColor> for Ansi256Color {
 pub struct RgbColor(pub u8, pub u8, pub u8);
 
 impl RgbColor {
+    /// Parse an `RgbColor` from a hex string of length 3 or 6.
+    ///
+    /// Strings of length 3 (`abc`) will get interpreted as though each character were doubled
+    /// (`aabbcc`), as in HTML or Git.
+    ///
+    /// This does not handle an initial `#`; strip it before calling this function. This allows the
+    /// caller to distinguish hex colors from other possible inputs, such as named or numbered
+    /// colors.
+    ///
+    /// Returns `None` on parse error.
+    pub fn from_hex_str(hex: &str) -> Option<Self> {
+        let l = hex.len();
+        if l != 3 && l != 6 {
+            return None;
+        }
+        let l = l / 3;
+        let (Ok(r), Ok(g), Ok(b)) = (
+            u8::from_str_radix(&hex[0..l], 16),
+            u8::from_str_radix(&hex[l..(2 * l)], 16),
+            u8::from_str_radix(&hex[(2 * l)..(3 * l)], 16),
+        ) else {
+            return None;
+        };
+        let m = if l == 1 { 0x11 } else { 1 };
+        Some(Self(r * m, g * m, b * m))
+    }
+
     /// Create a [`Style`][crate::Style] with this as the foreground
     #[inline]
     pub fn on(self, background: impl Into<Color>) -> crate::Style {