Combining presenting a stimuli for a fixed number of frames and continuoulsy assessing RT

Coding
1

I came across a problem in my experiment during RT measurement. I want to present a stimulus for a fixed period, while continuously assessing RT. If no response occurred until a response deadline, the stimulus should dissappear, i.e. stimulus duration = response deadline.

In my initial version, as stimulus duration can be best controlled by presenting the stimulus for a fixed number of frames (to the best of my knowledge), I tried this routine:

def present_induct(picture):
    pic.setImage(dir_pics + picture + '.bmp') # selects the picture
    event.clearEvents()
    win.callOnFlip(rt_ind_clock.reset)
	for frameN in range(msec_to_fr(rt_deadline)): # msec_to_fr is a custom-written function to calculate a number of frames for a given msec input
		pic.draw()
		win.flip()
		trigger_in = ~port_in.readData() & 255 # I assessed RT using a parallel port
		if trigger_in in resp_keys:
			rt_ind = rt_ind_clock.getTime()
			resp_ind = [[trigger_in,rt_ind]]
		return resp_ind
	present_feedback('Too slow!')  # if no response occured until the deadline, give feedback
	resp_ind = [['deadline',0]]
	return resp_ind

However, I realized that RT was only recorded at each screen refresh using this approach, i.e. my recorded RTs had only a resolution of 16ms. (The screen refresh rate was 60ms).

I could fix this problem by not drawing the stimulus each frame:

def present_induct(picture):
    pic.setImage(dir_pics + picture + '.bmp')
    event.clearEvents() 
    win.callOnFlip(rt_ind_clock.reset)
    pic.draw()
    win.flip()
	while True:    # do not skip the loop until a response occured or the deadline is reached
		rt_ind = rt_ind_clock.getTime()
		trigger_in = ~port_in.readData() & 255
		if trigger_in in resp_keys:
			resp_ind = [[trigger_in,rt_ind]]
			return resp_ind
		if rt_ind >= rt_deadline/1000: # the deadline was given in msec
			present_feedback('Too slow!')
			resp_ind = [['deadline',0]]
			return resp_ind

This approach worked fine, assessing RT continuously. However, I was wondering if both approaches possibly could be combined, i.e. drawing the stimulus for an exact fixed number of frames and assessing RT continously during the stimulus presentation. I came across this thread (Calling win.flip() at every frame when using static stimuli: pros and cons), which I think would say no, but I was curious if there may be an updated approach allowing for that…

P.S: I will present the stimulus for 2.5 sec, so I guess presenting it for a fixed number of screen refreshes will be a bit over-the-top for my purpose. However, I was curious if it would be possible in principle.