PolyGm

• Draw polygons freehand or point-by-point
• Move polygons and individual points
• Rotate, scale and flip polygons
• Duplicate and delete polygons
• Edit texture, colour and alpha of polygons
• Save and load in .json format
• Easy to setup and intuitive user interface

Start by looking at the wiki.

Look at the Trello board to see the roadmap, known bugs. If you would like to contribute to the project, this might be a good place to get some ideas.

Download the latest .yymps from here.