Failed to convert 31MB file in Firefox

[nomisum]

[Exception... "Failure" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: https://paa2.gruppe-adler.de/main.65faf26e.js :: k/< :: line 2" data: no]

paa.gruppe-adler.de couldn't convert my file.

• OS: Win10
• Browser Firefox
• Version 88.0.1
  Filesize is 13312 x 13312px

File too large to attach, will be sent via Discord

[DerZade]

Works as expected in Opera, Chrome and Edge. All three browsers show the "Dimensions have to be power of two" warning.

So I guess this is Firefox specific. I'll look into it :D

[DerZade]

Seems like Firefox can't handle CanvasRenderingContext2D.getImageData() on big canvases.

I couldn't find a bug report or anything, but could validate the behavior with this simple code:

<canvas id="canvas" />

const DIMENSIONS = 30000;

const canvas = document.getElementById('canvas');

canvas.width = DIMENSIONS;
canvas.height = DIMENSIONS;

const ctx = canvas.getContext('2d');
const data = ctx.getImageData(0, 0, 1, 1);

console.log(data);

(There is also a jsfiddle)

In Firefox 88.0.1 it worked up to a canvas size of 11180x11180. Everything bigger just failed with { name: "NS_ERROR_FAILURE" [...] result: 2147500037 }.

[DerZade]

I did some more research. The only broadly related issue I found was this. Users got a similar error, when trying to take a large screenshot via Firefox DevTools.

The limitations as pointed out by one user are:

• one dimension is larger than 32767 (which is 2¹⁵ - 1 or the upper limit of a 16 Bit number as two's complement)
• more than a total of 125,000,000 pixels (or 500MB if 4 bytes per RGBA pixel)

I guess the same limitations apply to our use case.

---

Sadly there is not much we can do about those limitations (at least not without much overhead).
This sets our upper limit of applicable images for paa.gruppe-adler.de in Firefox to dimensions of 8192x8192 pixels.