I use a command-line tool (
k2pdfopt) to process some PDFs, and I need to properly crop these PDFs by supplying margins in inches in the format
left,top,right,bottom. I need a software with which I can quickly and easily select an area and get its margins.
I prefer a crossplatform tool, but otherwise feel free to suggest a tool for any OS but Windows. (I use both macOS and Linux.)