For a Standalone / Plug-in app made with Juce, we looking for an color EyeDropper. The built in Juce color picker does most of the job, but we really need an eyedropper as well in order to collect color information from any pixel on the screen (not just the plug-in GUI). Crossplatform and open source of course…
Here is my ‘off the top of my head’ solution:
When the ‘color picker is activated’ execute
Component::createComponentSnapshot() for the area for which you will be picking colors
Capture the mouse events (either through mouse listeners or a transparent component overlay)
Using the mouse position grab the pixel from the image created in step 1.