From cdbe59900c779605fe608f48be91accecf141c5a Mon Sep 17 00:00:00 2001
From: Michael Telatynski <7t3chguy@gmail.com>
Date: Tue, 4 Jan 2022 08:57:35 +0000
Subject: [PATCH] Fix offscreen canvas breaking with split-brained firefox
 support (#7440)

---
 src/ContentMessages.tsx | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/ContentMessages.tsx b/src/ContentMessages.tsx
index 1405362c83..3e37f292d1 100644
--- a/src/ContentMessages.tsx
+++ b/src/ContentMessages.tsx
@@ -127,15 +127,18 @@ async function createThumbnail(
     }
 
     let canvas: HTMLCanvasElement | OffscreenCanvas;
-    if (window.OffscreenCanvas) {
+    let context: CanvasRenderingContext2D;
+    try {
         canvas = new window.OffscreenCanvas(targetWidth, targetHeight);
-    } else {
+        context = canvas.getContext("2d");
+    } catch (e) {
+        // Fallback support for other browsers (Safari and Firefox for now)
         canvas = document.createElement("canvas");
         (canvas as HTMLCanvasElement).width = targetWidth;
         (canvas as HTMLCanvasElement).height = targetHeight;
+        context = canvas.getContext("2d");
     }
 
-    const context = canvas.getContext("2d");
     context.drawImage(element, 0, 0, targetWidth, targetHeight);
 
     let thumbnailPromise: Promise<Blob>;