Refactor many usages of Color to natively store linear not gamma (#2457)

node-graph/gcore/src/vector/style.rs

@@ -15,9 +15,10 @@ pub enum GradientType {
 }
 
 // TODO: Someday we could switch this to a Box[T] to avoid over-allocation
+// TODO: Use linear not gamma colors
 /// A list of colors associated with positions (in the range 0 to 1) along a gradient.
 #[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize, DynAny, specta::Type)]
-pub struct GradientStops(pub Vec<(f64, Color)>);
+pub struct GradientStops(Vec<(f64, Color)>);
 
 impl std::hash::Hash for GradientStops {
 	fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
@@ -35,8 +36,54 @@ impl Default for GradientStops {
 	}
 }
 
+impl IntoIterator for GradientStops {
+	type Item = (f64, Color);
+	type IntoIter = std::vec::IntoIter<(f64, Color)>;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.0.into_iter()
+	}
+}
+
+impl<'a> IntoIterator for &'a GradientStops {
+	type Item = &'a (f64, Color);
+	type IntoIter = std::slice::Iter<'a, (f64, Color)>;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.0.iter()
+	}
+}
+
+impl std::ops::Index<usize> for GradientStops {
+	type Output = (f64, Color);
+
+	fn index(&self, index: usize) -> &Self::Output {
+		&self.0[index]
+	}
+}
+
+impl std::ops::Deref for GradientStops {
+	type Target = Vec<(f64, Color)>;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+impl std::ops::DerefMut for GradientStops {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.0
+	}
+}
+
 impl GradientStops {
-	pub fn evalute(&self, t: f64) -> Color {
+	pub fn new(stops: Vec<(f64, Color)>) -> Self {
+		let mut stops = Self(stops);
+		stops.sort();
+		stops
+	}
+
+	pub fn evaluate(&self, t: f64) -> Color {
 		if self.0.is_empty() {
 			return Color::BLACK;
 		}
@@ -60,9 +107,17 @@ impl GradientStops {
 		Color::BLACK
 	}
 
+	pub fn sort(&mut self) {
+		self.0.sort_unstable_by(|a, b| a.0.partial_cmp(&b.0).unwrap());
+	}
+
 	pub fn reversed(&self) -> Self {
 		Self(self.0.iter().rev().map(|(position, color)| (1. - position, *color)).collect())
 	}
+
+	pub fn map_colors<F: Fn(&Color) -> Color>(&self, f: F) -> Self {
+		Self(self.0.iter().map(|(position, color)| (*position, f(color))).collect())
+	}
 }
 
 /// A gradient fill.
@@ -110,7 +165,7 @@ impl Gradient {
 		Gradient {
 			start,
 			end,
-			stops: GradientStops(vec![(0., start_color), (1., end_color)]),
+			stops: GradientStops::new(vec![(0., start_color.to_gamma_srgb()), (1., end_color.to_gamma_srgb())]),
 			transform,
 			gradient_type,
 		}
@@ -131,7 +186,7 @@ impl Gradient {
 				(position, color)
 			})
 			.collect::<Vec<_>>();
-		let stops = GradientStops(stops);
+		let stops = GradientStops::new(stops);
 		let gradient_type = if time < 0.5 { self.gradient_type } else { other.gradient_type };
 
 		Self {
@@ -156,7 +211,7 @@ impl Gradient {
 			if *position != 0. {
 				let _ = write!(stop, r#" offset="{}""#, (position * 1_000_000.).round() / 1_000_000.);
 			}
-			let _ = write!(stop, r##" stop-color="#{}""##, color.rgb_hex());
+			let _ = write!(stop, r##" stop-color="#{}""##, color.to_rgb_hex_srgb_from_gamma());
 			if color.a() < 1. {
 				let _ = write!(stop, r#" stop-opacity="{}""#, (color.a() * 1000.).round() / 1000.);
 			}
@@ -242,7 +297,7 @@ impl Gradient {
 ///
 /// Can be None, a solid [Color], or a linear/radial [Gradient].
 ///
-/// In the future we'll probably also add a pattern fill.
+/// In the future we'll probably also add a pattern fill. This will probably be named "Paint" in the future.
 #[repr(C)]
 #[derive(Default, Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize, DynAny, Hash, specta::Type)]
 pub enum Fill {
@@ -305,7 +360,7 @@ impl Fill {
 		match self {
 			Self::None => r#" fill="none""#.to_string(),
 			Self::Solid(color) => {
-				let mut result = format!(r##" fill="#{}""##, color.rgb_hex());
+				let mut result = format!(r##" fill="#{}""##, color.to_rgb_hex_srgb_from_gamma());
 				if color.a() < 1. {
 					let _ = write!(result, r#" fill-opacity="{}""#, (color.a() * 1000.).round() / 1000.);
 				}
@@ -325,6 +380,14 @@ impl Fill {
 			_ => None,
 		}
 	}
+
+	/// Extract a solid color from the fill
+	pub fn as_solid(&self) -> Option<Color> {
+		match self {
+			Self::Solid(color) => Some(*color),
+			_ => None,
+		}
+	}
 }
 
 impl From<Color> for Fill {
@@ -355,18 +418,13 @@ impl From<Gradient> for Fill {
 pub enum FillChoice {
 	#[default]
 	None,
+	/// WARNING: Color is gamma, not linear!
 	Solid(Color),
+	/// WARNING: Color stops are gamma, not linear!
 	Gradient(GradientStops),
 }
 
 impl FillChoice {
-	pub fn from_optional_color(color: Option<Color>) -> Self {
-		match color {
-			Some(color) => Self::Solid(color),
-			None => Self::None,
-		}
-	}
-
 	pub fn as_solid(&self) -> Option<Color> {
 		let Self::Solid(color) = self else { return None };
 		Some(*color)
@@ -575,7 +633,7 @@ impl Stroke {
 		let line_join_miter_limit = (self.line_join_miter_limit != 4.).then_some(self.line_join_miter_limit);
 
 		// Render the needed stroke attributes
-		let mut attributes = format!(r##" stroke="#{}""##, color.rgb_hex());
+		let mut attributes = format!(r##" stroke="#{}""##, color.to_rgb_hex_srgb_from_gamma());
 		if color.a() < 1. {
 			let _ = write!(&mut attributes, r#" stroke-opacity="{}""#, (color.a() * 1000.).round() / 1000.);
 		}

node-graph/gcore/src/vector/vector_nodes.rs

@@ -78,7 +78,7 @@ where
 			},
 		};
 
-		let color = gradient.evalute(factor);
+		let color = gradient.evaluate(factor);
 
 		if fill {
 			vector_data.instance.style.set_fill(Fill::Solid(color));