Merge pull request #1871 from bungoboingo/fix/bg-gradient

[Fix] Make gradient pack fn public for iced_graphics::Gradient

2 files changed, 70 insertions, 2 deletions

diff --git a/graphics/src/gradient.rs b/graphics/src/gradient.rs
index 3e88d9de..d3eabb6f 100644
--- a/graphics/src/gradient.rs
+++ b/graphics/src/gradient.rs
@@ -4,7 +4,7 @@
 //!
 //! [`Gradient`]: crate::core::Gradient;
 use crate::core::gradient::ColorStop;
-use crate::core::{Color, Point};
+use crate::core::{self, Color, Point, Rectangle};
 use std::cmp::Ordering;
 
 #[derive(Debug, Clone, PartialEq)]
@@ -23,6 +23,15 @@ impl From<Linear> for Gradient {
     }
 }
 
+impl Gradient {
+    /// Packs the [`Gradient`] for use in shader code.
+    pub fn pack(&self) -> Packed {
+        match self {
+            Gradient::Linear(linear) => linear.pack(),
+        }
+    }
+}
+
 /// A linear gradient that can be used in the style of [`Fill`] or [`Stroke`].
 ///
 /// [`Fill`]: crate::geometry::Fill;
@@ -85,4 +94,62 @@ impl Linear {
 
         self
     }
+
+    /// Packs the [`Gradient`] for use in shader code.
+    pub fn pack(&self) -> Packed {
+        let mut data: [f32; 44] = [0.0; 44];
+
+        for (index, stop) in self.stops.iter().enumerate() {
+            let [r, g, b, a] =
+                stop.map_or(Color::default(), |s| s.color).into_linear();
+
+            data[index * 4] = r;
+            data[(index * 4) + 1] = g;
+            data[(index * 4) + 2] = b;
+            data[(index * 4) + 3] = a;
+
+            data[32 + index] = stop.map_or(2.0, |s| s.offset);
+        }
+
+        data[40] = self.start.x;
+        data[41] = self.start.y;
+        data[42] = self.end.x;
+        data[43] = self.end.y;
+
+        Packed(data)
+    }
+}
+
+/// Packed [`Gradient`] data for use in shader code.
+#[derive(Debug, Copy, Clone, PartialEq)]
+#[repr(C)]
+pub struct Packed([f32; 44]);
+
+/// Creates a new [`Packed`] gradient for use in shader code.
+pub fn pack(gradient: &core::Gradient, bounds: Rectangle) -> Packed {
+    match gradient {
+        core::Gradient::Linear(linear) => {
+            let mut data: [f32; 44] = [0.0; 44];
+
+            for (index, stop) in linear.stops.iter().enumerate() {
+                let [r, g, b, a] =
+                    stop.map_or(Color::default(), |s| s.color).into_linear();
+
+                data[index * 4] = r;
+                data[(index * 4) + 1] = g;
+                data[(index * 4) + 2] = b;
+                data[(index * 4) + 3] = a;
+                data[32 + index] = stop.map_or(2.0, |s| s.offset);
+            }
+
+            let (start, end) = linear.angle.to_distance(&bounds);
+
+            data[40] = start.x;
+            data[41] = start.y;
+            data[42] = end.x;
+            data[43] = end.y;
+
+            Packed(data)
+        }
+    }
 }
diff --git a/graphics/src/primitive.rs b/graphics/src/primitive.rs
index 9728db39..2d4f5511 100644
--- a/graphics/src/primitive.rs
+++ b/graphics/src/primitive.rs
@@ -4,6 +4,7 @@ use crate::core::image;
 use crate::core::svg;
 use crate::core::text;
 use crate::core::{Background, Color, Font, Rectangle, Size, Vector};
+use crate::gradient;
 
 use bytemuck::{Pod, Zeroable};
 use std::sync::Arc;
@@ -258,7 +259,7 @@ pub struct GradientVertex2D {
     pub position: [f32; 2],
 
     /// The packed vertex data of the gradient.
-    pub gradient: [f32; 44],
+    pub gradient: gradient::Packed,
 }
 
 #[allow(unsafe_code)]