Multiple readback operations using getImageData

[YUDIEL CURBELO]

Warning:

Canvas2D: Multiple readback operations using getImageData are faster with the willReadFrequently attribute set to true. See: https://html.spec.whatwg.org/multipage/canvas.html#concept-canvas-will-read-frequently

It should come from this line of code.

library/src/browser/BrowserCodeReader.ts

Line 874 in 1e9ccb3

 const ctx = elem.getContext('2d'); 

and should be resolved with the following change.

 const ctx = elem.getContext('2d', {willReadFrequently: true});

Warning can be reproduced in this example https://zxing-js.github.io/library/examples/multi-camera/

[Didi3333]

Hi @odahcam and @werthdavid can you push a new version with this fix please

[David Werth]

Will do!

[David Werth]

plz try 0.19.3

[YUDIEL CURBELO]

Confirmed, working as expected on 0.19.3. Thank you @werthdavid

[David Werth]

May I ask you to test 0.20.0 as well? I merged lots of PRs there, currently testing it myself as well

[YUDIEL CURBELO]

All my tests passed on 0.20.0, and doing some manual tests is also working as intended.