1 files changed, 85 insertions, 0 deletions
diff --git a/src/color.rs b/src/color.rs
new file mode 100644
index 0000000..7305c24
--- /dev/null
+++ b/src/color.rs
@@ -0,0 +1,85 @@
+use pangocairo::cairo::Context;
+use serde::de;
+use std::fmt;
+use std::str::FromStr;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Color {
+    red: f64,
+    green: f64,
+    blue: f64,
+    alpha: f64,
+}
+
+impl Color {
+    pub fn apply(self, cr: &Context) {
+        if self.alpha.is_nan() {
+            cr.set_source_rgb(self.red, self.green, self.blue);
+        } else {
+            cr.set_source_rgba(self.red, self.green, self.blue, self.alpha);
+        }
+    }
+
+    pub fn from_rgba(r: u8, g: u8, b: u8, a: u8) -> Self {
+        Self {
+            red: r as f64 / 255.0,
+            green: g as f64 / 255.0,
+            blue: b as f64 / 255.0,
+            alpha: if a == 255 { f64::NAN } else { a as f64 / 255.0 },
+        }
+    }
+
+    pub fn from_rgba_hex(hex: u32) -> Self {
+        let r = (hex >> 24 & 0xFF) as u8;
+        let g = (hex >> 16 & 0xFF) as u8;
+        let b = (hex >> 8 & 0xFF) as u8;
+        let a = (hex & 0xFF) as u8;
+        Self::from_rgba(r, g, b, a)
+    }
+}
+
+impl FromStr for Color {
+    type Err = ();
+
+    fn from_str(color: &str) -> Result<Self, Self::Err> {
+        let rgb = color.get(1..7).ok_or(())?;
+        let rgb = u32::from_str_radix(rgb, 16).map_err(|_| ())?;
+        let r = (rgb >> 16 & 0xFF) as u8;
+        let g = (rgb >> 8 & 0xFF) as u8;
+        let b = (rgb & 0xFF) as u8;
+
+        let a = match color.get(7..9) {
+            Some(a) => u8::from_str_radix(a, 16).map_err(|_| ())?,
+            None => 255,
+        };
+
+        Ok(Self::from_rgba(r, g, b, a))
+    }
+}
+
+impl<'de> de::Deserialize<'de> for Color {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: de::Deserializer<'de>,
+    {
+        struct ColorVisitor;
+
+        impl<'de> de::Visitor<'de> for ColorVisitor {
+            type Value = Color;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("RBG or RGBA color (in hex)")
+            }
+
+            fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
+            where
+                E: de::Error,
+            {
+                s.parse()
+                    .map_err(|_| E::custom(format!("'{s}' is not a valid RGB/RGBA color")))
+            }
+        }
+
+        deserializer.deserialize_str(ColorVisitor)
+    }
+}