[open] Merging Pygaze with other experimental library.

rrr

Hello,

The questions is about how can I merge Pygaze with other experimental library (http://www.expyriment.org/).

To measure eye movements, I try to add pygaze to my script which I have been using in experiment by python.
Is it possible just by adding some triger (stimulus onsets/offsets, keypress events) to my script for data analysis?
If so, do you have any examples or suggestions (which pygaze functions I should use)?

Best,

rrr

Hello,

This is additional information.

1. libscreen

In Pygaze, the libscreen library is used to control the experiment display and stumuli.
But, like in my case, which libraries should I use to control it, Pygaze (libscreen) or other experimental library?

2. Value error

When I tried to take Pygaze 'calibrate()' in my script, 'ValueError: Projection failed!' occurred.

Best,

eduard

Hi,

I'm not sure whether I understand what you mean with "merging Pygaze with expyriment". Would you mind explaining what exactly is your idea?

Is it possible just by adding some trigger

I think something like exp.pygaze_eyetracker.log("!V TRIAL_VAR <var_name> %s" % <value>) should do the trick. Doing it in this way, will create a variable with corresponding value in the logfile of your tracker that. If you just want to send a message, this will suffice:

exp.pygaze_eyetracker.log("message")

(At least that is what I do, when I use the eyelink eyetracker. I'm not sure whether it will work for any tracker.)

Best,

Eduard

rrr

Hello,

1.
What I mean is how send triggers and keep records (time, trialID, condition name, stimulus onsets/offsets, keypress, RT...) on edf files for data analysis using the Data Viewer.
I already made python scripts for experiments, and try to add Pygaze to it.

Is it sufficient to do it by exp.pygaze_eyetracker.log functions?

2.
When I tried to use Pygaze 'calibrate()' in my script, 'ValueError: Projection failed!' occurred. Do you have any ideas for this error?

Best,

eduard

Hi,

1) Yes, exp.pygaze_eyetracker.log() should be sufficient for that, but keep in mind that it generally only sends a message. If you want to have those variables in the data viewer and interact with them, you'll have to send them as a variable (the first I described above).

2) Sorry, unfortunately, I don't know what this error is about.

Eduard

Edwin

Hi there,

So, first things first: PyGaze is essentially an experimental library, so you could use it to run your experiments with, not unlike expyriment. If you prefer sticking with expyriment (probably the most time-effective thing here, considering you already have a script), we might need to do a bit of hacking here and there.

There are two main options:

1) You write your own back-end based on expyriment, and use this to get a handle to the active expyriment window. Then the rest of your script should run fine. Note that this is the most time-consuming solution, as it requires you to create your own Display implementation (and likely also others, such as Screen and Keyboard).

2) You use the currently existing tools, and hack your way to the PyGame active Surface handle within expyriment:

import pygaze
from pygaze import EyeTracker
from expyriment import control

# EXAMPLE initialisation of expyriment
exp = control.initialize()

# get the active PyGame Surface
window = exp.screen._surface

# define a custom Display class
# the parent is the actual Display class,
# but we're going to overwrite the initialisation function
class Display(pygaze.display):

    def __init__(self, pygamewindow):

        # use the passed handle to the active surface
        pygaze.expdisplay = window
        self.dispsize = window.get_size()
        self.fgc = (0, 0, 0)
        self.bgc = (128, 128, 128)
        self.mousevis = False

# now initialise a dummy Display,
# and pass the active PyGame window
disp = Display(window)

# and initialise an EyeTracker object
tracker = EyeTracker(disp)

# REST OF YOUR SCRIPT

Now I can't promise this will work, but it should in theory. That is: as far as I understand the logic behind expyriment.

On your other question: You can simply use tracker.log("example message") to log things to the EDF.

Good luck!

rrr

Hello,

This script causes an error,

class Display(pygaze.display):
TypeError: Error when calling the metaclass bases
module.init() takes at most 2 arguments (3 given)

What should I do?

Best,

rrr

Hello,

When I added just eyetracker.log to the onset/offset for triggers (no hacking of display as Edwin above), the error occurred below.

Traceback (most recent call last):
File "/Users〜/test.py", line 56, in
eyetracker.log("start_trial %d" % trialnr)
AttributeError: 'module' object has no attribute 'log'

Should I add other modules or functions, except for tracker.start and end, logfile write and close, eyetracker.log (e.g., "trial %d" % trialnr)?

Best,