From 3a7f39a6da04478b4a86f757e17b00c4f490f9bc Mon Sep 17 00:00:00 2001
From: Dustin Carlino <dabreegster@gmail.com>
Date: Thu, 4 Feb 2021 11:27:57 -0800
Subject: [PATCH] Downsample points on a line-series plot for drawing.
 Otherwise, the arrivals plot on a border intersection in downtown winds up
 with more than 2^16 points.

---
 widgetry/src/widgets/line_plot.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/widgetry/src/widgets/line_plot.rs b/widgetry/src/widgets/line_plot.rs
index d5eb5b5c2c..f3a5f2be79 100644
--- a/widgetry/src/widgets/line_plot.rs
+++ b/widgetry/src/widgets/line_plot.rs
@@ -151,7 +151,9 @@ impl<T: Yvalue<T>> LinePlot<T> {
                     (1.0 - percent_y) * height,
                 ));
             }
-            pts.dedup();
+            // Downsample to avoid creating polygons with a huge number of points. 1m is untuned,
+            // and here "meters" is really pixels.
+            pts = Pt2D::approx_dedupe(pts, Distance::meters(1.0));
             if pts.len() >= 2 {
                 closest.add(s.label.clone(), &pts);
                 batch.push(s.color, thick_lineseries(pts, Distance::meters(5.0)));