Overlaying text and graphics (stroked rectangles) on desktop screen

  accessibility, c++, desktop, graphics

For an accessibility desktop application I must overlay the desktop screen with numbers, text and a grid of rectangles (stroked with e.g. red brush).

Ideally this should work on any window manager system (windows, linux KDE/GNOME, possibly even mac).

What is the standard approach to something like this? I was thinking of taking a screenshot of the screen and then drawing on top of it but I’m unsure on what to use to draw.

Source: Windows Questions C++