Java code from example showing use of Timer and Robot to click mouse to eventually stop a running Impress Slide Show. Works on Windows 10 and Linux Mint 19.

ImpressShowRunner_TimerCode.java

	//
	// a timer task to tick down the time
	// up the tics and click the mouse
	//
	private class MyTimerTask extends TimerTask {
		@Override
		public void run()
		{
			nTimerTics++;
			tfTimerTics.setText(String.valueOf(nTimerTics));
			// try to click the mouse here
			try {
				Robot bot = new Robot();
				int mask = InputEvent.BUTTON1_DOWN_MASK;
				// don't move the mouse in case the user wants to click on Stop Show or
				// something else. It will be fine, the show will stop on the click
				// if it's at the end.
				//bot.mouseMove(100, 100);           
				bot.mousePress(mask);     
				bot.mouseRelease(mask);
				
				try {
					// hang for a bit before release
				    Thread.sleep(100);
				}
				catch(InterruptedException ex) {
				    Thread.currentThread().interrupt();
				    System.out.println("MyTimerTask interrupted");
				}
				bot.mouseRelease(mask);
			}
			catch (Exception e ) {
				System.out.println("MyTimerTask Robot exception");
			}
			
			// if the show is running, watch for it to end in a strange way
			
			if ( bShowRunning ) {
				
				try {
					// so, rather than a wait, we check for exit value
					// and if that tosses an exception, the process is
					// still running. Ooooooookkkkkaaaaaayyyyyy No Problem
					int exitValue = pShowProcess.exitValue();
					// guess we don't do this to get rid of the not referened warning
					//(void)exitValue;
					// we don't care what the exit value was
					exitValue = 0;
					// but if we get here, then the show stopped, so
					// if we stop it now, it won't need to wait, it will be fine
					// we think.
					stopShow();
				} catch (Exception ex) {
					// Process is still running. So just keep going until
					// mouse clicks or something else stops the show
				}
			}
		}
	}
	
	public void startTimer( long msecsPerTic ) {
		try {
			if ( bTimerRunning ) {
				System.out.println("startTimer already running" );
				return;
			}
			aTimer = new Timer();
			timerTask = new MyTimerTask();
			aTimer.schedule(timerTask, msecsPerTic, msecsPerTic);
			bTimerRunning = true;
			System.out.println("startTimer started for "+String.valueOf(msecsPerTic) );
		} catch (Exception ex)
		{
			// just ignore any exceptions
			System.out.println("startTimer exception" );
		}

	}
	
	public void stopTimer() {
		try {
		if ( !bTimerRunning ) {
			System.out.println("stopTimer not running" );
			return;
		}
		timerTask.cancel();
		bTimerRunning = false;
		System.out.println("stopTimer cancelled" );
		} catch (Exception ex) {
			System.out.println("stopTimer exception" );
		}
	}