Qrious do not work when canvas read is disabled for privacy reasons

[evilaliv3]

On many browsers, reading canvas is blocked or requires asking users permissions.

Currently it seems the qrious library while writing a canvas performs as well a read and this results in a usability issue for all the users of Firefox [1] and of the Tor browser [2].

I'm analyzing this problem in relation to the GlobaLeaks project that uses Qrious in its two factor authentication based on TOTP.

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1446472
[2] https://trac.torproject.org/projects/tor/ticket/27543

[evilaliv3]

@neocotic: Do you have by any chance any clue why you used some read capability in place of a simple write? This way i can try to fix and with your availability try to get a update working package,

[evilaliv3]

@neocotic: Actually for necessities of security i evaluated to switch to angular-qrcode.

Probably the library used by it coul be taken as reference for fixing this inconvenience with your.