From 620c850966718ee6d8357a08068d62c4813bffe8 Mon Sep 17 00:00:00 2001
From: Eric Fredricksen <efredricksen@gmail.com>
Date: Thu, 9 Dec 2021 13:00:32 -0800
Subject: [PATCH] Use web worker for timer so progress can take place in the
 background

---
 main.html   |  2 --
 main.js     | 27 ++++++++++++++++++---------
 progros.css |  1 +
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/main.html b/main.html
index 772b17c..23d492c 100644
--- a/main.html
+++ b/main.html
@@ -186,8 +186,6 @@
 
 </div>
 
-<br>
-
 <div id="paused"><br>PAUSED</div>
 
 </body>
diff --git a/main.js b/main.js
index 7843085..e38c9e4 100644
--- a/main.js
+++ b/main.js
@@ -1,22 +1,32 @@
 // Copyright (c)2002-2010 Eric Fredricksen <e@fredricksen.net> all rights reserved
 
 var game = {};
-var lasttick, timerid;
+var clock;
 
 function timeGetTime() {
   return new Date().getTime();
 }
 
 function StartTimer() {
-  if (!timerid) {
-    lasttick = timeGetTime();
-    timerid = setTimeout(Timer1Timer, 100);
+  if (!clock) {
+    clock = new Worker('clock.js');
+    clock.addEventListener('message', e => {
+      Timer1Timer();
+      clock.lasttick = timeGetTime();
+    });
+  }
+  if (!clock.running) {
+    clock.lasttick = timeGetTime();
+    clock.running = true;
+    clock.postMessage('start');
   }
 }
 
 function StopTimer() {
-  clearTimeout(timerid);
-  timerid = null;
+  if (clock) {
+    clock.postMessage('stop');
+    clock.running = false;
+  }
 }
 
 function Q(s) {
@@ -878,7 +888,6 @@ function Pos(needle, haystack) {
 var dealing = false;
 
 function Timer1Timer() {
-  timerid = null;  // Event has fired
   if (TaskBar.done()) {
     game.tasks += 1;
     game.elapsed += TaskBar.Max().div(1000);
@@ -916,7 +925,7 @@ function Timer1Timer() {
 
     Dequeue();
   } else {
-    var elapsed = timeGetTime() - lasttick;
+    var elapsed = timeGetTime() - clock.lasttick;
     if (elapsed > 100) elapsed = 100;
     if (elapsed < 0) elapsed = 0;
     TaskBar.increment(elapsed);
@@ -1136,7 +1145,7 @@ function FormKeyDown(e) {
   }
 
   if (key === 'p') {
-    if (timerid) {
+    if (clock && clock.running) {
       $('#paused').css('display', 'block');
       StopTimer();
     } else {
diff --git a/progros.css b/progros.css
index e2f5b37..2dd44fe 100644
--- a/progros.css
+++ b/progros.css
@@ -109,6 +109,7 @@ body {
   -moz-background-size: 100% 100%;
   background-attachment: fixed;
   text-align: center;
+  margin-top: 1em;
 }
 
 div.scroll {