search

fukuchi / libqrencode

A fast and compact QR Code encoding library
https://fukuchi.org/works/qrencode/
GNU Lesser General Public License v2.1
2.57k stars 599 forks source link

Add option for PNG without alpha channel #187

Open tormodvolden opened 3 years ago

tormodvolden commented 3 years ago

Some tools like img2pdf refuse PNG images with alpha channel. The suggested option --png-no-alpha will omit the alpha channel so that the PNG output can be used with img2pdf directly.

tormodvolden commented 3 years ago

Or should this happen automatically if --foreground and --background are both set with only RRGGBB (no AA)?

tormodvolden commented 3 years ago

Strictly it is not an alpha channel in this case but a tRNS Transparency chunk so we should maybe say "transparency" instead of "alpha channel".

lenoleno commented 2 years ago

This is also relevant when generating PDF/A-1 compliant documents. Preflight fails on PDF/A-1 documents embedding plainqrencodePNG output, since transparency is only supported since PDF/A-2.

ROBERT-MCDOWELL commented 7 months ago

this PR is 3 years old and still open, why is it not merged? it's a very important feature!

tormodvolden commented 7 months ago

The maintainer hasn't committed anything here since 2020 (Feb 2021 on the cygwin branch).

Anyway, I would be happy to modify this PR to use "transparency" instead of "alpha channel" if preferred.

ROBERT-MCDOWELL commented 7 months ago

the most important is your option is working well. I'm now following your fork. here it's dead....