mouse desktop Highlighted area

[vitalisse]

hi,

i need to highlight my desktop specific area with mouse and get the area's cordinates...
- my goal is to create an app like snipping tool from scratch
- for now, i know how to get picture of given cordinates area.

in other words i need exactely like in picture
https://i.postimg.cc/RS8kpzD6/Untitled.jpg


can any one help me

[Duthomhas]

Simplest answer:
Get screenshot. Create a new, borderless, fullscreen, toplevel window. Draw screenshot. Draw on the window in response to mouse movement.

Less simple answer:
Google around "msdn layered windows".
Though less simple, this will produce a nicer UI result, as running applications can update their windows in the background and the user will still see the updates through your layered window.

Good luck!