I had a pair of leggings that had a hole, so i thought I will unpick them and cut a pattern so that we can all benefit. The leggins in question are size L. They come down almost to the ankle. It's a one-piece pattern, you just cut two of it (opposites obviously).
Each piece encompasses one butt side and one front side (there's no outer-side-hip-seam). The little foldover bit on the top is to hold the wide elastic you're going to sew onto it. The F and B on the pattern show you what side is what. Hope there are enough measurements to help you draw it out.
First, sew each piece together down the leg (so you have 2 tubes). Then sew the crotch. (I say do it this way because when I unpicked the leggins I noticed thats how they did it). The seams are pretty much included, but if you want a little seam allowance, just add whatever. The fabric used in these was quite a lightweight, stretchy jersey knit.
I haven't made any yet, but I will definitely post a follow up when I do. Hope they make you happy!!!