App to Analyzing a photo to calculate area of each

I have an idea for a phone app, but not sure if it can be done or has been done.

I want to take a pic of a logo with my phone, select a size, select background color to ignore, select number of colors, then calculate area for each color.

I’ve never written a phone app, but have programmed lots of php interactive websites, so understand programming logic.

Hello Alisa -

I doubt that Fiji / ImageJ would be a good fit for a phone app,
among other reasons because I am not aware of any phones
that run Fiji / ImageJ. For the case of android, see:

Status of ImageJ on Android

(Having said that, you could probably do the processing you
want using Fiji / ImageJ.)

Thanks, mm