Chart/grid Software

Hello,
I like to knit mini sweaters and would like to be able to create my own charts/grids/motifs. What software is best? I have a MAC and often have trouble with downloads. Any software that you can buy and install? Thanks!

I was going to suggest this one as I’ve heard it’s good (no personal experience though other than the trial), but it’s only PC. If I find something I’ll post it.