From 8a981efd1dcc892b22068a1214cc7b6c2a4e5fee Mon Sep 17 00:00:00 2001
From: Edwin Cheng <edwin0cheng@gmail.com>
Date: Fri, 23 Apr 2021 03:34:11 +0800
Subject: [PATCH] Use fold instead of join in PolyLine rendering (#83)

* Use fold instead of join in PolyLine rendering

* Add test
---
 core/document/src/layers/polyline.rs | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/core/document/src/layers/polyline.rs b/core/document/src/layers/polyline.rs
index fc67af88..ffb01198 100644
--- a/core/document/src/layers/polyline.rs
+++ b/core/document/src/layers/polyline.rs
@@ -1,6 +1,8 @@
 use super::style;
 use super::LayerData;
 
+use std::fmt::Write;
+
 #[derive(Debug, Clone, PartialEq)]
 pub struct PolyLine {
 	points: Vec<kurbo::Point>,
@@ -18,7 +20,23 @@ impl PolyLine {
 
 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())
+		if self.points.is_empty() {
+			return String::new();
+		}
+		let points = self.points.iter().fold(String::new(), |mut acc, p| {
+			let _ = write!(&mut acc, " {:.3} {:.3}", p.x, p.y);
+			acc
+		});
+		format!(r#"<polyline points="{}" {}/>"#, &points[1..], self.style.render())
 	}
 }
+
+#[test]
+fn polyline_should_render() {
+	let polyline = PolyLine {
+		points: vec![kurbo::Point::new(3.0, 4.12354), kurbo::Point::new(1.0, 5.54)],
+		style: style::PathStyle::new(Some(style::Stroke::new(crate::color::Color::GREEN, 0.4)), None),
+	};
+
+	assert_eq!(r#"<polyline points="3.000 4.124 1.000 5.540" style="stroke: #00FF00FF;stroke-width:0.4;"/>"#, polyline.render());
+}