Various bugfixes with non-square pixel maps.

[cyphar]

If you try to use k2flix to render pixel maps which do not have a square aspect ratio (such as 204367097), the image is the wrong aspect ratio. In addition, after fixing that, I realised that there were no safety checks for the annotations, so they can overlap.

I've fixed both in this PR (because they are both caused by non-square pixel maps).

Signed-off-by: Aleksa Sarai [email protected]

[cyphar]

Actually, I also just realised that 65c550b fixes another bug where certain FITS files will fail to be rendered as a movie because the default ffmpeg codec requires the height and width to be divisible by 2. You can double check this by trying to use the linked fits file to render an mp4.

[barentsen]

Hi @cyphar -- many thanks for looking into these issues. I fetched the pull request and tried e.g.

k2flix --start 1 --stop 5 --step 1 https://archive.stsci.edu/pub/k2/target_pixel_files/c3/200000000/04000/ktwo200004716-c03_lpd-targ.fits.gz

but unfortunately this gives me a 337x22894 animated gif, which doesn't look quite right. I'll look more into this tomorrow to understand what's happening!

[cyphar]

@barentsen If you look at it with the code on HEAD, you get a wide image with large streaks. I'm fairly sure that this is not correct. My patch fixes a flat out bug in the aspect ratio code, since any non-square pixel map gives you an image with the wrong aspect ratio. You might want to figure out a nicer way of making the image smaller, but the aspect ratio issue (and some other issues) are fixed.

[cyphar]

@barentsen Have you taken another look at it? The current code is flat-out broken for non-square pixel maps, and also the code doesn't handle very thin pixel maps (such that the text would be overlapping) properly either. I've fixed both, and the output of that image is as I would expect (look at the pixel map in fv or DS9, and you'll see a very elongated image).