Pixel aspect support?

[virtualritz]

It would be great if the crate also returned a num-rational::Ratio pixel_aspect for image formats that support this.

This would just be 1:1 for any image format that doesn't, or if absent.

[Roughsketch]

I'm not entirely opposed to potentially getting this info, but I want to try to not rely on any external creates, sans dev dependencies.

Is there a flow that would require this information? How would you anticipate it fitting into the current library? Curious about how you'd want it to work.

[virtualritz]

When you want to call an external tool to resize an image, e.g. for a preview, it is often preferable to make sure the latter has a pixel aspect of 1:1.

Particularly OpenEXRs that were converted from CinemaDNGs shot with anamorphic lenses will often have 1:1.33 or 1:2 pixel aspects and need non-linear scaling to display correctly.

[Roughsketch]

How would you want it integrated into the library? My first thought would be a pixel_size method that returns a new struct called PixelSize which seems simple enough.

Also if you happen to know which file types support different pixel sizes please let me know.

[virtualritz]

Yes, that sounds good. But it would be pixel_aspect which is short for pixel aspect ratio which is what literature and industry have settled on, as a term for this, since decades.

[virtualritz]

I also suggest to put this behind a feature flag. 😁