IsVisible 함수는 프로세스 이름(ProcessName)으로 현재 활성창인지 확인합니다.

function IsVisible(ProcessName: string): Boolean;
var
 SnapShot: THandle;
 ProcEntry: TProcessEntry32;
 ProcList: TList<DWORD>;

 function EnumWindowsProc(hWnd: THandle; List: TList<DWORD>): BOOL; stdcall;
 var
   ProcessID: DWORD;
 begin
   Result := True;

   if IsWindowVisible(hWnd) then
   begin
     GetWindowThreadProcessId(hWnd, @ProcessID);
     List.Add(ProcessID);
   end;
 end;

begin
 Result := False;

 SnapShot := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
 ProcList := TList<DWORD>.Create;
 try
   EnumWindows(@EnumWindowsProc, LParam(ProcList));

   ProcEntry.dwSize := SizeOf(TProcessEntry32);
   if Process32First(SnapShot, ProcEntry) then
   begin
     repeat
       if SameText(ProcEntry.szExeFile, ProcessName) then
      begin
         if ProcList.Contains(ProcEntry.th32ProcessID) then
         begin
           Result := True;
           Exit;
         end;
      end;
     until not Process32Next(SnapShot, ProcEntry);
   end;
 finally
   ProcList.Free;
   CloseHandle(SnapShot);
 end;
end;