How to determine whether a Window is visible on the screen with AHK?

I am trying to run this script from here https://autohotkey.com/board/topic/25619-detect-on-screen/, but it does not work if the Window top border is not touching the screen top:

^F2::
If ( ID := WinExist("Calculator") ) 
 {
   WinGetPos , X, Y, , , ahk_id %ID%
   If  ( DllCall("WindowFromPoint", Int,X+5, Int,Y+5 ) = ID ) 
       MsgBox, Calculator is ON SCREEN
 }
Return

Solution

use det_winIsVisible := WinGetStyle("ahk_id " . hwnd) & WS_VISIBLE

WS_VISIBLE                := 0x10000000

; Is a Window Visible on Screen - AutoHotkey Community
; https://www.autohotkey.com/boards/viewtopic.php?t=107797
;
; WinGetStyle / WinGetExStyle - Syntax & Usage | AutoHotkey v2
; https://www.autohotkey.com/docs/v2/lib/WinGetStyle.htm
/**
 * 
 * @param hwnd - The window handle.
 * @returns {Boolean|""} - true if visible, false if hidden, null if non-existent.
 */
detm_winIsVisible(hwnd) {
  DetectHiddenWindows_prev := DetectHiddenWindows(true)
  try {
    det_winIsVisible := WinGetStyle("ahk_id " . hwnd) & WS_VISIBLE
    return det_winIsVisible
  } catch TargetError as e {
    return ""
  } finally {
    DetectHiddenWindows(DetectHiddenWindows_prev)
  }
}

ahk v2
not the best, maybe Dll can be better
basing on question title, may not fit op's specific case

WinGetMinMax - Syntax & Usage | AutoHotkey v2
https://www.autohotkey.com/docs/v2/lib/WinGetMinMax.htm
Returns a non-zero number if the specified window is maximized or minimized.