Implement Pen Tool (#79)

core/document/src/layers/polyline.rs

@@ -0,0 +1,24 @@
+use super::style;
+use super::LayerData;
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct PolyLine {
+	points: Vec<kurbo::Point>,
+	style: style::PathStyle,
+}
+
+impl PolyLine {
+	pub fn new(points: Vec<impl Into<kurbo::Point>>, style: style::PathStyle) -> PolyLine {
+		PolyLine {
+			points: points.into_iter().map(|it| it.into()).collect(),
+			style,
+		}
+	}
+}
+
+impl LayerData for PolyLine {
+	fn render(&self) -> String {
+		let points = self.points.iter().map(|p| format!("{},{}", p.x, p.y)).collect::<Vec<_>>().join(" ");
+		format!(r#"<polyline points="{}" {}" />"#, points, self.style.render())
+	}
+}