From d81bb3fbf3e1a764434c23d665891fb03385a2f1 Mon Sep 17 00:00:00 2001
From: Marat Fayzullin <luarvique@gmail.com>
Date: Wed, 22 Feb 2023 16:48:24 -0500
Subject: [PATCH] Now generating canvas image blob asynchonrously.

---
 htdocs/openwebrx.js | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/htdocs/openwebrx.js b/htdocs/openwebrx.js
index d9122836..15976d36 100644
--- a/htdocs/openwebrx.js
+++ b/htdocs/openwebrx.js
@@ -98,19 +98,22 @@ function saveCanvas(canvas) {
     var c = document.getElementById(canvas);
     if (c == null) return;
 
-    // Create and click a link to the canvas data URL
-    var a = document.createElement('a');
-    a.href = c.toDataURL('image/png');
-    a.style = 'display: none';
-    a.download = canvas + ".png";
-    document.body.appendChild(a);
-    a.click();
+    // Convert canvas to a data blob
+    c.toBlob(function(blob) {
+        // Create and click a link to the canvas data URL
+        var a = document.createElement('a');
+        a.href = window.URL.createObjectURL(blob);
+        a.style = 'display: none';
+        a.download = canvas + ".png";
+        document.body.appendChild(a);
+        a.click();
 
-    // Get rid of the canvas data URL
-    setTimeout(function() {
-        document.body.removeChild(a);
-        window.URL.revokeObjectURL(a.href);
-    }, 0);
+        // Get rid of the canvas data URL
+        setTimeout(function() {
+            document.body.removeChild(a);
+            window.URL.revokeObjectURL(a.href);
+        }, 0);
+    }, 'image/png');
 }
 
 function zoomInOneStep() {