From c69f190af975d23118ed207280729de4e2472373 Mon Sep 17 00:00:00 2001
From: ThibG <thib@sitedethib.com>
Date: Tue, 6 Aug 2019 12:08:19 +0200
Subject: [PATCH] Fix image uploads being perfectly white when canvas read
access is blocked (#11499)
Fixes #11496
---
app/javascript/mastodon/utils/resize_image.js | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/app/javascript/mastodon/utils/resize_image.js b/app/javascript/mastodon/utils/resize_image.js
index bbdbc865e9..a8ec5f3fa7 100644
--- a/app/javascript/mastodon/utils/resize_image.js
+++ b/app/javascript/mastodon/utils/resize_image.js
@@ -67,6 +67,14 @@ const processImage = (img, { width, height, orientation, type = 'image/png' }) =
context.drawImage(img, 0, 0, width, height);
+ // The Tor Browser and maybe other browsers may prevent reading from canvas
+ // and return an all-white image instead. Assume reading failed if the resized
+ // image is perfectly white.
+ const imageData = context.getImageData(0, 0, width, height);
+ if (imageData.every(value => value === 255)) {
+ throw 'Failed to read from canvas';
+ }
+
canvas.toBlob(resolve, type);
});
--
GitLab