From c72bb8aaa9759954e35d394ee39b0f578ca56c86 Mon Sep 17 00:00:00 2001
From: 101arrowz <arjunbarrett@gmail.com>
Date: Wed, 20 Jul 2022 14:06:03 -0700
Subject: [PATCH] [js/web] add OffscreenCanvas support to WebGL backend
 (#12159)

* Add OffscreenCanvas support to WebGL backend

* fix format

* fix lint
---
 .../lib/onnxjs/backends/webgl/webgl-context-factory.ts   | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/js/web/lib/onnxjs/backends/webgl/webgl-context-factory.ts b/js/web/lib/onnxjs/backends/webgl/webgl-context-factory.ts
index 4abc9cb7c2..e2b060955b 100644
--- a/js/web/lib/onnxjs/backends/webgl/webgl-context-factory.ts
+++ b/js/web/lib/onnxjs/backends/webgl/webgl-context-factory.ts
@@ -83,7 +83,16 @@ export function createNewWebGLContext(contextId?: 'webgl'|'webgl2'): WebGLContex
   throw new Error('WebGL is not supported');
 }
 
+// eslint-disable-next-line @typescript-eslint/naming-convention
+declare let OffscreenCanvas: {new (width: number, height: number): HTMLCanvasElement};
+
 function createCanvas(): HTMLCanvasElement {
+  if (typeof document === 'undefined') {
+    if (typeof OffscreenCanvas === 'undefined') {
+      throw new TypeError('failed to create canvas: OffscreenCanvas is not supported');
+    }
+    return new OffscreenCanvas(1, 1);
+  }
   const canvas: HTMLCanvasElement = document.createElement('canvas');
   canvas.width = 1;
   canvas.height = 1;