Restrict MousePosition to specific Graphics object

Question

I have a problem using MousePosition. I want to restrict the value returned by MousePosition to a specific Graphics object. Consider the following example:

g1 = Graphics[{Green, Disk[]}]; 
g2 = Graphics[{Blue,Disk[]}];
{g1, g2, Dynamic[MousePosition["Graphics"]]}

I would like to have the mouse position updated only if the mouse is on the second (blue) disk and not on the first one (green). This seems to be an easy problem, but I can't figure out how it works in Mathematica.

Thanks for help!

Answer 1

Something like this?

g1 = Graphics[{Green, Disk[]}];
g2 = Graphics[{Blue, Disk[]}];
{g1, Mouseover[g2, Dynamic@(mp = MousePosition["Graphics"]; g2)], Dynamic@mp}

Answer 2

I have overlooked the example in the help for MousePosition

Graphics[Disk[Dynamic[MousePosition[{"Graphics", Graphics}, {0, 0}]]],
  PlotRange -> 10, ImageSize -> 100]

With that the value returned by MousePosition is restricted to the Graphics object it is associated with.