feat: support for custom & system themes + move cosmic-theme to libcosmic

cosmic-theme/src/model/selection.rs

@@ -0,0 +1,99 @@
+use palette::{named, IntoColor, Lch, Srgba};
+use std::convert::TryFrom;
+
+/// A Selection is a group of colors from which a cosmic palette can be derived
+#[derive(Copy, Clone, Debug, Default)]
+pub struct Selection<C> {
+    /// base background container color
+    pub background: C,
+    /// base primary container color
+    pub primary_container: C,
+    /// base secondary container color
+    pub secondary_container: C,
+    /// base accent color
+    pub accent: C,
+    /// custom accent color (overrides base)
+    pub accent_fg: Option<C>,
+    /// custom accent nav handle text color (overrides base)
+    pub accent_nav_handle_fg: Option<C>,
+    /// base destructive element color
+    pub destructive: C,
+    /// base destructive element color
+    pub warning: C,
+    /// base destructive element color
+    pub success: C,
+}
+
+// vector should be in order of most common
+impl<C> TryFrom<Vec<Srgba>> for Selection<C>
+where
+    C: Clone + From<Srgba>,
+{
+    type Error = anyhow::Error;
+
+    fn try_from(mut colors: Vec<Srgba>) -> Result<Self, Self::Error> {
+        if colors.len() < 8 {
+            anyhow::bail!("length of inputted vector must be at least 8.")
+        } else {
+            let lch_colors: Vec<Lch> = colors
+                .iter()
+                .map(|x| {
+                    let srgba: Srgba = x.clone().into();
+                    srgba.color.into_format().into_color()
+                })
+                .collect();
+
+            let red_lch: Lch = named::CRIMSON.into_format().into_color();
+            let mut reddest_i = 1;
+            for (i, c) in lch_colors[1..].iter().enumerate() {
+                let d_cur = (c.hue.to_degrees() - red_lch.hue.to_degrees()).abs();
+                let reddest_d = (lch_colors[reddest_i].hue.to_degrees().abs()
+                    - red_lch.hue.to_degrees().abs())
+                .abs();
+                if d_cur < reddest_d {
+                    reddest_i = i;
+                }
+            }
+
+            let yellow_lch: Lch = named::YELLOW.into_format().into_color();
+            let mut yellow_i = 1;
+            for (i, c) in lch_colors[1..].iter().enumerate() {
+                let d_cur = (c.hue.to_degrees() - yellow_lch.hue.to_degrees()).abs();
+                let reddest_d = (lch_colors[yellow_i].hue.to_degrees().abs()
+                    - yellow_lch.hue.to_degrees().abs())
+                .abs();
+                if d_cur < reddest_d {
+                    yellow_i = i;
+                }
+            }
+
+            let green_lch: Lch = named::GREEN.into_format().into_color();
+            let mut green_i = 1;
+            for (i, c) in lch_colors[1..].iter().enumerate() {
+                let d_cur = (c.hue.to_degrees() - green_lch.hue.to_degrees()).abs();
+                let reddest_d = (lch_colors[green_i].hue.to_degrees().abs()
+                    - green_lch.hue.to_degrees().abs())
+                .abs();
+                if d_cur < reddest_d {
+                    green_i = i;
+                }
+            }
+
+            let red = colors.remove(reddest_i);
+            let green = colors.remove(green_i);
+            let yellow = colors.remove(yellow_i);
+
+            Ok(Self {
+                background: colors[0].into(),
+                primary_container: colors[1].into(),
+                secondary_container: colors[3].into(),
+                accent: colors[2].into(),
+                accent_fg: Some(colors[2].into()),
+                accent_nav_handle_fg: Some(colors[2].into()),
+                destructive: red.into(),
+                warning: yellow.into(),
+                success: green.into(),
+            })
+        }
+    }
+}