Image area selection tool (JavaScript / HTML5 / jQuery)

General information for the business: Image editing
Description of requirements/functionality: We need a javascript function / jQuery plugin for this functionality:

1. We have an arbitrary image and need up to 5 areas selected
( Buttons: Add area, Remove area)

2. The areas are not rectangular
Compare this demo: https://bl.ocks.org/mbostock/10571478

3. Each area has to be filled with a different color during editing of each corner
(doesn't have to be filled with image like in demo!)

4. Area must be draggable inside the image

5. Coordinates (x1-4, y1-4) have to be stored in a hidden input field

This must be "universal", i.e. I just have an image and can call a method with the Image-ID. The image then gets this functionality.

Nice to have:
Integrate this function into Magento (Product selection -> Image selection)
Specific technologies required: Javascript
Extra notes: Easy usage is important, as is compatibility with Safari, Firefox & Chrome.
Please compare with demo https://bl.ocks.org/mbostock/10571478