Request support for Worker thread

[ngdangtu]

Due to using Canvas, we cannot render image in worker. I suggest to allow dev to pass their canvas object.

With this feature, dev can easily pass OffscreenCanvas to worker thread.

Reference:
https://stackoverflow.com/questions/35026647/is-it-possible-to-generate-an-image-blob-or-data-url-in-a-web-worker-from-a-ca

[spacehaz]

Hi, you can use my fork if needed. Unfortunately it works only with png files right now (type: cenvas). OffscreenCanvas is used

https://github.com/LinkdropHQ/qr-code-styling-bigmac