/usr/share/psychtoolbox-3/PsychGLImageProcessing/kPsychNeedHalfWidthWindow.m is in psychtoolbox-3-common 3.0.11.20131230.dfsg1-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | function rval = kPsychNeedHalfWidthWindow
% rval = kPsychNeedHalfWidthWindow
%
% Return a flag that you can pass to the 'imagingmode' parameter of
% Screen('OpenWindow') in order to request use of half-width windows. These
% onscreen windows are treated by all drawing functions (and geometry query
% functions like Screen('Rect', window); or Screen('WindowSize', window);
% as if they only have half the width in pixels. This is a trick to handle
% dual-display stereo modes or special display modes like CRS Color++ mode
% for the Bits++ box, where useable horizontal drawing area is only half
% the physical monitor resolution due to the special image processing
% inside the Bits++ box. Usually user scripts won't pass this flag, but
% only special setup routines that are part of the Psychtoolbox itself.
%
rval = 2048;
return
|