# Which image rotation libraries use the Paeth algorithm?

I'm teaching linear algebra, and thought I'd show my students Paeth's rotation by shearing algorithm as a nice quick example of matrix manipulations. I'd like to include the information of which graphics libraries actually implement this, and I wasn't able to find anything other than the linked 2007 webpage referencing "ImageMagick, pnmrotate, etc". Can anyone give an updated, larger list?

• I guess this question might belong on math-educators, since I'm teaching in the math dept, but I figured CS educators would be more likely to know this. Feel free to migrate. – David E Speyer Jan 25 at 18:16
• Also, is there a tag like libraries I should be using? Or would someone please create one? Thanks! – David E Speyer Jan 25 at 18:16
• This isn't in my wheelhouse, but it is certainly topical here. – Ben I. Jan 25 at 18:39
• Unfortunately a bit specialized for this audience. I wonder if StackOverflow might be a better place to find people with their heads deep in the libraries. But I also wonder why you want this. Do you intend for students to explore the code? That might be worth doing, though library code might be a bit messy with specialized bits and pieces obscuring the algorithm. – Buffy Jan 25 at 19:01
• Is there any particular reason why you need a large list of libraries? Over here, we're generally helpful with questions about lesson plans, teaching techniques and things like that, but we generally aren't good with questions like this since we aren't necessarily knowledgeable about practical CS. If you could give some context about the lesson you're trying to use this list in, we could probably be much more helpful. However, if you just need this list, it'd probably be best for you to try another site, since we don't really have the experts to answer this. – thesecretmaster Jan 25 at 20:15