[Feature Request] Improvements to file based scanning

[mebjas]

[1] Set canvas size to min(SOME_FIXED_MIN, input image size)

Priority: P1, effort estimate: Low

File based scanning doesn’t have constraints of real time scanning. Ok to prefer accuracy of scan as compared to latency.

• Implement this.

[2] Configure tryHarder param in zxing-js

Priority: P1, effort estimate: Low

tryHarder param tells the library to try fallbacks like rotating images.

• Implement this.
• (p2) Add support for inversion of the image as if try harder or other option is enabled.

[3] Add padding to internal canvas

The library expects some padding or empty space after the code ends to ensure the code is accurately decoded. If the input image has no padding between the code and image boundary this may fail.

• Double check that the zxing-js is not adding some padding of it’s own.
• Add padding in case of file based scan (greater than the quiet area definition in the library)

[mebjas]

Implementation coming in v2.3.4 but it doesn't seem to address all issues.

Some of the issues around inability to scan a few codes still observed and need fixing.

[mebjas]

Partial changes pushed to version 2.3.4

• Github release: https://github.com/mebjas/html5-qrcode/releases/tag/v2.3.4
• NPM: https://www.npmjs.com/package/html5-qrcode/v/2.3.4