Sending video frame accurate triggers using Pixel Mode

from psychopy import visual, core
from pypixxlib import _libdpx as dp


def drawPixelModeTrigger(win, pixelValue):
    #takes a pixel colour and draws it as a single pixel in the top left corner of the window
    #window must cover top left of screen to work
    #interpolate must be set to FALSE before color is set
    #call this just before flip to ensure pixel is drawn over other stimuli

    topLeftCorner = [-win.size[0]/2, win.size[1]/2]
    line = visual.Line(
            win=win,
            units = 'pix',
            start=topLeftCorner,
            end=[topLeftCorner[0]+1, topLeftCorner[1]],
            interpolate = False,
            colorSpace = 'rgb255',
            lineColor = pixelValue)
    line.draw()


def RGB2Trigger(color):
    #helper function determines expected trigger from a given RGB 255 colour value
    #return triggerVal
    return int( (color[2]<<16)+(color[1]<<8)+color[0] ) 


def Trigger2RGB(trigger):
    #helper function determines pixel mode RGB 255 colour value based on 24-bit trigger (in decimal, base 10)  
    # return [red, green, blue]
    return [ trigger%256, (trigger>>8)%256, (trigger>>16)%256] 

##
#START
#Initialize connection and set up some default parameters.
dp.DPxOpen()
dp.DPxEnableDoutPixelMode()
dp.DPxWriteRegCache()

win = visual.Window(
        screen = 0, # change here to 1 to display on second screen!
        monitor = None,
        fullscr=True, 
        pos = [0,0],
        color='black',
        units = "pix"
        )

testvals = [0, 64, 128, 191, 255]
failcount =0
print('\nStarting Pixel Mode Test\n\nTest#\tRGB225 Color\t    Expected Dout    Returned Dout')
for k in range(0,len(testvals)):
    for i in range(0,3):
        color =[0,0,0]
        color[i] = testvals[k]

        drawPixelModeTrigger(win, color)
        win.flip()

        core.wait(0.2)
        dp.DPxUpdateRegCache()

        value = dp.DPxGetDoutValue()
        expectedValue = RGB2Trigger(color)
        if value == expectedValue:
            outcome = 'PASS'
        else:
            outcome = 'FAIL'
            failcount +=1

        # print('Color is: ',  color,  'Expected value: ',  expectedValue,  ' , returned: ', value,  '   ', outcome)
        print('%d\t[% 4d,% 4d,% 4d]\t% 9d\t% 9d' % (i+3*k+1,color[0],color[1],color[2],expectedValue,value),  '   ', outcome)

print('Tests run: %d, % d failed.\nPixel Mode Test Complete\n\n' % (len(testvals)*3, failcount) )
win.close()
dp.DPxDisableDoutPixelMode()
dp.DPxWriteRegCache()
dp.DPxClose()