Incorrect detection of mismatch between screen distance unit and gaze data

[gjheij]

pspm_find_valid_fixations should flag scenarios where there is a mismatch between input unit for the screen distance and the passed gaze data.

It finds the units of all channels using (see this line):

channelunits_list = cellfun(@(x) data.header.units, alldata.data, 'uni', false);

However, data.header should be x.header, to iterate over all channels in alldata.data. Otherwise the first element is always appended to the channelunits_list (e.g., all 'diameter'):

channelunits_list =

  7×1 cell array

    {'diameter'}
    {'diameter'}
    {'diameter'}
    {'diameter'}
    {'diameter'}
    {'diameter'}
    {'diameter'}

whereas i clearly have pixel data:

  7×1 cell array

    {'events'  }
    {'diameter'}
    {'pixel'   }
    {'pixel'   }
    {'diameter'}
    {'pixel'   }
    {'pixel'   }

If data.header is set to x.header, 'pixel' is correctly picked up, filtered out, resulting in the desired error.

% channels with 'pixel' are filtered out
>> channels_correct_units = find(~contains(channelunits_list, 'degree') & ~contains(channelunits_list, 'pixel'));
>> channels_correct_units

channels_correct_units =

     1
     2
     5

% gaze data only contains 'marker' and 'pupil' data
gazedata = 

  struct with fields:

    infos: [1×1 struct]
     data: {3×1 cell}

% resulting in desired prompt
[sts_gaze, gaze_x, gaze_y, eye] = pspm_load_gaze(gazedata, data.header.chantype);

    if sts_gaze < 1
        warning('ID:invalid_input', ['Unable to perform gaze ', ...
            'validation. Cannot find gaze channels with distance ',...
            'unit values. Maybe you need to convert them with ', ...
            'pspm_convert_pixel2unit()']);
Warning: There are no channels of type 'gaze_x_r' in the data file 
> In pspm_select_channels (line 82)
In pspm_load_data (line 234)
In pspm_load_channel (line 77)
In pspm_load_gaze (line 39) 
Warning: There are no channels of type 'gaze_y_r' in the data file 
> In pspm_select_channels (line 82)
In pspm_load_data (line 234)
In pspm_load_channel (line 77)
In pspm_load_gaze (line 40) 
end
Warning: Unable to perform gaze validation. Cannot find gaze channels with distance unit values. Maybe you need to convert them with pspm_convert_pixel2unit() 
>> 

Sidenote: pspm_convert_pixel2unit should be pspm_convert_gaze in the prompt.