From a87f0604587ca6ad9d00ee1c0fb80c5263cb1edb Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Sat, 11 May 2024 15:18:10 +0200
Subject: [PATCH] visualizer: limit history plot to 300 packets

The drawing gets slow with too many points.
---
 impl/utils/visualizer/static/index.js | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/impl/utils/visualizer/static/index.js b/impl/utils/visualizer/static/index.js
index fa76e17..b463c02 100644
--- a/impl/utils/visualizer/static/index.js
+++ b/impl/utils/visualizer/static/index.js
@@ -3,6 +3,7 @@ const traceEvent = Symbol('trace-event');
 const tracePacket = Symbol('trace-packet');
 
 const traceMaxEvents = 200;
+const historyMaxPackets = 300;
 
 
 const state = {
@@ -171,12 +172,21 @@ function addHistory(packet) {
         }
     }
 
+    // Limit to historyMaxPackets items
+    const shift = chartHistoryHz.data.labels.length == historyMaxPackets;
+    if (shift) {
+        chartHistory.data.labels.shift();
+    }
+
     let i = 0;
     for (const x of keys) {
         let data = packet[x];
         if (data == -1e38 /* "NaN" */) {
             data = undefined;
         }
+        if (shift) {
+            chartHistory.data.datasets[i].data.shift();
+        }
         chartHistory.data.datasets[i].data.push(data);
         i++;
     }