PMeter is described as 'very handy pixel meter. There are plenty of desktop rulers around, but it's hard to find a good one, which is free. PMeter is a simple to use desktop ruler allowing to switch between 3 user configurations easily'. There are more than 10 alternatives to PMeter for a variety of platforms, including Windows, Mac, Android, iPhone and Android Tablet. The best alternative is PicPick. It's not free, so if you're looking for a free alternative, you could try Meazure or Bluegrams Screen Ruler. Other great apps like PMeter are Pixus (Free, Open Source), On-Screen Ruler (Free), Measure Schmeasure (Free Personal) and Screen Ruler (Paid).