.pos argument of BufferImageStim not working properly- buffer image position

Coding
1

Hi, if anyone has any ideas I would be very grateful.

I have seen some discussion that the function itself doesn’t work position-property-of-bufferimagestim-isnt-used-correctly, but I’m not 100% sure whether it is my code or the function.

my code is below:

def present_ss11_hor_str(starting_x, target_starting_y):
        ss11_max_time = int(((win_width / 2 - long_box_width) + abs(starting_x)) / speed)
        ss11_time = random.randint(min_time, ss11_max_time)
        
        # draw stim to buffer
        ss11_hor_str_num = 4
        ss11_hor_str_black = int(ss11_hor_str_num / 2)
        ss11_hor_str_height = ss11_box_height / ss11_hor_str_num
        ss11_hor_str_width = ss11_box_width
        ss11_white = visual.Rect(win, width=ss11_box_width, height=ss11_box_height, fillColor=ss11_rect_color, units='pix')
        
        # Create a list to hold the stripe stimuli
        stripes = []
        for i in range(ss11_hor_str_black):
            ss11_hor_str = visual.Rect(win, width=ss11_hor_str_width, height=ss11_hor_str_height, fillColor=ss11_stripe_color, units='pix')
            ss11_hor_str.pos = (0, (2 * (i * ss11_hor_str_height) - (ss11_hor_str_height * ss11_hor_str_num / 2) + (ss11_hor_str_height * 1.5)))
            stripes.append(ss11_hor_str)
        
        ss11_hor_str_stim = visual.BufferImageStim(win, stim=[ss11_white] + stripes, pos = (0.5,0.2))
        
        if starting_x < 0:
            for frameN in range(ss11_time):
                ss11_hor_str_stim.pos = (starting_x, target_starting_y)
                ss11_hor_str_stim.draw()
                starting_x += speed
                win.flip()
        elif starting_x >= 0:
            for frameN in range(ss11_time):
                ss11_hor_str_stim.pos = (starting_x, target_starting_y)
                ss11_hor_str_stim.draw()
                starting_x -= speed
                win.flip()
        
        clear_screen()

my window units are in pix, everything else in my code is in pixels. The problem is that the bufferstim is drawn at 0,0 and doesn’t move. If I leave a line in to print the position I can see it is being updated correctly. I have also tried changing the position to normalised units to no avail.

If it is the BufferImageStim function that is broken, does anyone know a way around it?

Any help massively appreciated!

2

to clarify, the pos = (0.5,0.2) argument was added to see if I could change the position outside of the loop and that didn’t work either. Tried it with normalized units and pixels but stimulus was drawn at 0,0 regardless.

3

Solved- sort of.

This seems to have been a bug for a fair while, although solution is just to convert it to a normal stimulus

BufferImageStim set pos has no effect · Issue #840 · psychopy/psychopy