client_pos
Entity: predicate

Usage:
client_size(Win, Width, Height) will return in variables (Width, Height) the difference between the right-bottom and the left-top corners of the client area of the window Win.
client_pos(Win, X, Y) will return in variables (X, Y) the left-top corner of the client area of the window Win.

Gets the size or the position of the client area of the window Win (Use _ for Win to point the current window).
 

Example:

win_func(mouse_wheel(Delta, X, Y)):-
  client_pos(_,A,B),
  draw_point(X-A, Y-B, rgb(255, 0, 0)).
 

See also:
size and position
Messages

Look at the example:
Fractals.pro (in folder Programs)