Adds linear gradient support to 2D meshes in the canvas widget.

1 files changed, 73 insertions, 0 deletions

diff --git a/graphics/src/widget/canvas/gradient/linear.rs b/graphics/src/widget/canvas/gradient/linear.rs
new file mode 100644
index 00000000..37533e19
--- /dev/null
+++ b/graphics/src/widget/canvas/gradient/linear.rs
@@ -0,0 +1,73 @@
+//! A linear color gradient.
+use iced_native::{Color, Point};
+
+use crate::gradient::ColorStop;
+
+use super::Gradient;
+
+/// A linear gradient that can be used in the style of [`super::Fill`] or [`super::Stroke`].
+#[derive(Debug, Clone, PartialEq)]
+pub struct Linear {
+    /// The point where the linear gradient begins.
+    pub start: Point,
+    /// The point where the linear gradient ends.
+    pub end: Point,
+    /// [`ColorStop`]s along the linear gradient path.
+    pub color_stops: Vec<ColorStop>,
+}
+
+/// A [`Linear`] builder.
+#[derive(Debug)]
+pub struct Builder {
+    start: Point,
+    end: Point,
+    stops: Vec<(f32, Color)>,
+    valid: bool,
+}
+
+impl Builder {
+    /// Creates a new [`Builder`].
+    pub fn new(start: Point, end: Point) -> Self {
+        Self {
+            start,
+            end,
+            stops: vec![],
+            valid: true,
+        }
+    }
+
+    /// Adds a new stop, defined by an offset and a color, to the gradient.
+    ///
+    /// `offset` must be between `0.0` and `1.0`.
+    pub fn add_stop(mut self, offset: f32, color: Color) -> Self {
+        if !(0.0..=1.0).contains(&offset) {
+            self.valid = false;
+        }
+
+        self.stops.push((offset, color));
+        self
+    }
+
+    /// Builds the linear [`Gradient`] of this [`Builder`].
+    ///
+    /// Returns `None` if no stops were added to the builder or
+    /// if stops not between 0.0 and 1.0 were added.
+    pub fn build(self) -> Option<Gradient> {
+        if self.stops.is_empty() || !self.valid {
+            return None;
+        }
+
+        Some(Gradient::Linear(Linear {
+            start: self.start,
+            end: self.end,
+            color_stops: self
+                .stops
+                .into_iter()
+                .map(|f| ColorStop {
+                    offset: f.0,
+                    color: f.1,
+                })
+                .collect(),
+        }))
+    }
+}