Add colors in Rust (#78)

* 🎨 Add colors in Rust

* 🌿 Use an option for the properties and #[repr(C)]

* ❌ Remove WASM dependency on document.

* 😎 Wrap Fill and stroke in a style struct.

* 📦 Use crate::Color

* Merge Add transactions for temporary modifications to the document

* Run cargo fmt

* Color without a 'U'

core/document/src/layers/rect.rs

@@ -0,0 +1,30 @@
+use super::style;
+use super::LayerData;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Rect {
+	shape: kurbo::Rect,
+	style: style::PathStyle,
+}
+
+impl Rect {
+	pub fn new(p0: impl Into<kurbo::Point>, p1: impl Into<kurbo::Point>, style: style::PathStyle) -> Rect {
+		Rect {
+			shape: kurbo::Rect::from_points(p0, p1),
+			style,
+		}
+	}
+}
+
+impl LayerData for Rect {
+	fn render(&self) -> String {
+		format!(
+			r#"<rect x="{}" y="{}" width="{}" height="{}" {} />"#,
+			self.shape.min_x(),
+			self.shape.min_y(),
+			self.shape.width(),
+			self.shape.height(),
+			self.style.render(),
+		)
+	}
+}