So I currently have a transparent web page (all the elements are visible but the background is transparent - I am using a software to do this and the background is completely transparent and can be clicked through).
What I need to do is to be able to move a box to select a specific part of the web page and then for the box to detect the colour that is behind the window (as the background is transparent)?
This picture should make a little more sense of it; the red is, for example, a desktop background. This window would be opened and the box moved to be able to detect the colour.
The idea would be like this: http://lokeshdhakar.com/projects/color-thief/ but I need it to work on a transparent window and not an image which I am unsure is possible with HTML and JS?
I understand it is possible to use an image but I would need this to continuously check the colour and when there is a change, update quickly.
Thanks for any help!