[Lazarus] How to mimic MWSnap's "Window Information" feature on X11

[Felipe Monteiro de Carvalho]

Lazarus supports screenshot taking, so this part is easy. If you are
using pure X11 then take a look at the gtk2 implementation for
screenshots, it uses x11.

Next you take the mouse position and give to a X11 routine to get the
window. I don't know which routine to use, but surely there is one,
and further using X11 you can get the size of the window.

Then you have a fullscreen app, draw the screenshot and then draw a
rectangle making the window look selected. You can further draw
anything else. This is how the Virtual Magnifying Glass works (I draw
a glass instead of rectangles and texts)

You can also do that with hardware overlays (so you don't need a
screenshot, and the background is still alive), but it's a real
painful thing to implement, requiring special hardware and offering
tons of headackes, so I recomend in screenshot method =)

-- 
Felipe Monteiro de Carvalho