1 files changed, 158 insertions, 0 deletions
diff --git a/crates/material_theme/src/utils.rs b/crates/material_theme/src/utils.rs
new file mode 100644
index 0000000..4c62ec3
--- /dev/null
+++ b/crates/material_theme/src/utils.rs
@@ -0,0 +1,158 @@
+use iced_widget::core::{Color, Shadow, Vector};
+
+const COLOR_ERROR_MARGIN: f32 = 0.0001;
+
+pub const HOVERED_LAYER_OPACITY: f32 = 0.08;
+pub const PRESSED_LAYER_OPACITY: f32 = 0.1;
+
+pub const DISABLED_TEXT_OPACITY: f32 = 0.38;
+pub const DISABLED_CONTAINER_OPACITY: f32 = 0.12;
+
+pub fn elevation(elevation_level: u8) -> f32 {
+    (match elevation_level {
+        0 => 0.0,
+        1 => 1.0,
+        2 => 3.0,
+        3 => 6.0,
+        4 => 8.0,
+        _ => 12.0,
+    } as f32)
+}
+
+pub fn shadow_from_elevation(elevation: f32, color: Color) -> Shadow {
+    Shadow {
+        color,
+        offset: Vector {
+            x: 0.0,
+            y: elevation,
+        },
+        blur_radius: (elevation) * (1.0 + 0.4_f32.powf(elevation)),
+    }
+}
+
+pub fn disabled_text(color: Color) -> Color {
+    Color {
+        a: DISABLED_TEXT_OPACITY,
+        ..color
+    }
+}
+
+pub fn disabled_container(color: Color) -> Color {
+    Color {
+        a: DISABLED_CONTAINER_OPACITY,
+        ..color
+    }
+}
+
+pub fn parse_argb(s: &str) -> Option<Color> {
+    let hex = s.strip_prefix('#').unwrap_or(s);
+
+    let parse_channel = |from: usize, to: usize| {
+        let num =
+            usize::from_str_radix(&hex[from..=to], 16).ok()? as f32 / 255.0;
+
+        // If we only got half a byte (one letter), expand it into a full byte (two letters)
+        Some(if from == to { num + num * 16.0 } else { num })
+    };
+
+    Some(match hex.len() {
+        3 => Color::from_rgb(
+            parse_channel(0, 0)?,
+            parse_channel(1, 1)?,
+            parse_channel(2, 2)?,
+        ),
+        4 => Color::from_rgba(
+            parse_channel(1, 1)?,
+            parse_channel(2, 2)?,
+            parse_channel(3, 3)?,
+            parse_channel(0, 0)?,
+        ),
+        6 => Color::from_rgb(
+            parse_channel(0, 1)?,
+            parse_channel(2, 3)?,
+            parse_channel(4, 5)?,
+        ),
+        8 => Color::from_rgba(
+            parse_channel(2, 3)?,
+            parse_channel(4, 5)?,
+            parse_channel(6, 7)?,
+            parse_channel(0, 1)?,
+        ),
+        _ => None?,
+    })
+}
+
+pub fn color_to_argb(color: Color) -> String {
+    use std::fmt::Write;
+
+    let mut hex = String::with_capacity(9);
+
+    let [r, g, b, a] = color.into_rgba8();
+
+    let _ = write!(&mut hex, "#");
+
+    if a < u8::MAX {
+        let _ = write!(&mut hex, "{a:02X}");
+    }
+
+    let _ = write!(&mut hex, "{r:02X}");
+    let _ = write!(&mut hex, "{g:02X}");
+    let _ = write!(&mut hex, "{b:02X}");
+
+    hex
+}
+
+pub const fn lightness(color: Color) -> f32 {
+    color.r * 0.299 + color.g * 0.587 + color.b * 0.114
+}
+
+pub fn mix(color1: Color, color2: Color, p2: f32) -> Color {
+    if p2 <= 0.0 {
+        return color1;
+    } else if p2 >= 1.0 {
+        return color2;
+    }
+
+    let p1 = 1.0 - p2;
+
+    if (color1.a - 1.0).abs() > COLOR_ERROR_MARGIN
+        || (color2.a - 1.0).abs() > COLOR_ERROR_MARGIN
+    {
+        let a = color1.a * p1 + color2.a * p2;
+        if a > 0.0 {
+            let c1 = color1.into_linear().map(|c| c * color1.a * p1);
+            let c2 = color2.into_linear().map(|c| c * color2.a * p2);
+
+            let [r, g, b] =
+                [c1[0] + c2[0], c1[1] + c2[1], c1[2] + c2[2]].map(|u| u / a);
+
+            return Color::from_linear_rgba(r, g, b, a);
+        }
+    }
+
+    let c1 = color1.into_linear().map(|c| c * p1);
+    let c2 = color2.into_linear().map(|c| c * p2);
+
+    Color::from_linear_rgba(
+        c1[0] + c2[0],
+        c1[1] + c2[1],
+        c1[2] + c2[2],
+        c1[3] + c2[3],
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{Color, mix};
+
+    #[test]
+    fn mixing_works() {
+        let base = Color::from_rgba(1.0, 0.0, 0.0, 0.7);
+        let overlay = Color::from_rgba(0.0, 1.0, 0.0, 0.2);
+
+        assert_eq!(
+            mix(base, overlay, 0.75).into_rgba8(),
+            Color::from_linear_rgba(0.53846, 0.46154, 0.0, 0.325).into_rgba8()
+        );
+    }
+}