Monthly Archives: March 2020

Including qrencode generated QR codes in a PDF using prawn / ruby

I’m porting an old app into docker, and trying to avoid using stuff where the end of life has been and gone so I’ve updated ruby, and the version of linux they were using. And now I find that reason prawn doesn’t render qrencode generated QR codes any more. I think it might be because qrencode adds an alpha channel to the border of the png.

Install imagemagick and inspect a qrencode png which doesn’t work:

Colorspace: sRGB
Background color: white
Border color: srgba(223,223,223,1)
Matte color: grey74
Transparent color: none

Whereas if run the same png through imagemagick with convert test.png newtest.png:

Colorspace: Gray
Background color: gray(255)
Border color: gray(223)
Matte color: gray(189)
Transparent color: gray(0)

Causes newtest.png to render in your prawn pdf.

Coronavirus hits Oslo

I’ve been meaning to post about some of the strange things in this country – one of them is how they have a hairdresser on every corner. I mean, within a 5 minute walk from my flat there are at least 4 I can think of, probably more. B and I get uneasy if we don’t see one on a street we’re walking through “Are we still in Norway??” we say to each other in mock alarm.

Anyway, so I got an email from my work (the University of Oslo) explaining it was stopping all physical lectures and lessons – ‘fine, probably sensible’ I think. Get told we are cancelling our international workshops and that all the schools in the country are closing – ‘oof, but still it’s probably necessary’, you know? But you know things are serious when they close the hairdressers, which is apparently the latest measure. Yikes!

A series of peculiar things that I’ve seen Norwegians put their children into

I’ll add to these when I spot more of them out in the wild.