1 files changed, 88 insertions, 0 deletions
diff --git a/graphics/src/gradient.rs b/graphics/src/gradient.rs
new file mode 100644
index 00000000..3e88d9de
--- /dev/null
+++ b/graphics/src/gradient.rs
@@ -0,0 +1,88 @@
+//! A gradient that can be used as a [`Fill`] for some geometry.
+//!
+//! For a gradient that you can use as a background variant for a widget, see [`Gradient`].
+//!
+//! [`Gradient`]: crate::core::Gradient;
+use crate::core::gradient::ColorStop;
+use crate::core::{Color, Point};
+use std::cmp::Ordering;
+
+#[derive(Debug, Clone, PartialEq)]
+/// A fill which linearly interpolates colors along a direction.
+///
+/// For a gradient which can be used as a fill for a background of a widget, see [`crate::core::Gradient`].
+pub enum Gradient {
+    /// A linear gradient interpolates colors along a direction from its `start` to its `end`
+    /// point.
+    Linear(Linear),
+}
+
+impl From<Linear> for Gradient {
+    fn from(gradient: Linear) -> Self {
+        Self::Linear(gradient)
+    }
+}
+
+/// A linear gradient that can be used in the style of [`Fill`] or [`Stroke`].
+///
+/// [`Fill`]: crate::geometry::Fill;
+/// [`Stroke`]: crate::geometry::Stroke;
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Linear {
+    /// The absolute starting position of the gradient.
+    pub start: Point,
+
+    /// The absolute ending position of the gradient.
+    pub end: Point,
+
+    /// [`ColorStop`]s along the linear gradient direction.
+    pub stops: [Option<ColorStop>; 8],
+}
+
+impl Linear {
+    /// Creates a new [`Builder`].
+    pub fn new(start: Point, end: Point) -> Self {
+        Self {
+            start,
+            end,
+            stops: [None; 8],
+        }
+    }
+
+    /// Adds a new [`ColorStop`], defined by an offset and a color, to the gradient.
+    ///
+    /// Any `offset` that is not within `0.0..=1.0` will be silently ignored.
+    ///
+    /// Any stop added after the 8th will be silently ignored.
+    pub fn add_stop(mut self, offset: f32, color: Color) -> Self {
+        if offset.is_finite() && (0.0..=1.0).contains(&offset) {
+            let (Ok(index) | Err(index)) =
+                self.stops.binary_search_by(|stop| match stop {
+                    None => Ordering::Greater,
+                    Some(stop) => stop.offset.partial_cmp(&offset).unwrap(),
+                });
+
+            if index < 8 {
+                self.stops[index] = Some(ColorStop { offset, color });
+            }
+        } else {
+            log::warn!("Gradient: ColorStop must be within 0.0..=1.0 range.");
+        };
+
+        self
+    }
+
+    /// Adds multiple [`ColorStop`]s to the gradient.
+    ///
+    /// Any stop added after the 8th will be silently ignored.
+    pub fn add_stops(
+        mut self,
+        stops: impl IntoIterator<Item = ColorStop>,
+    ) -> Self {
+        for stop in stops.into_iter() {
+            self = self.add_stop(stop.offset, stop.color)
+        }
+
+        self
+    }
+}