deg2pix.m

% Permission is hereby granted, free of charge, to any person obtaining a 
% copy of this software and associated documentation files (the "Software"), 
% to deal in the Software without restriction, including without limitation 
% the rights to use, copy, modify, merge, publish, distribute, sublicense, 
% and/or sell copies of the Software, and to permit persons to whom the 
% Software is furnished to do so, subject to the following conditions:
% 
% The above copyright notice and this permission notice shall be included 
% in all copies or substantial portions of the Software.
% If you use the Software for your own research, cite the paper.
% 
% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 
% OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
% FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
% DEALINGS IN THE SOFTWARE.
%
% Anne Urai and Klaus Wimmer, 2016
% anne.urai@gmail.com / kwimmer@clinic.ub.es

function pix = deg2pix(window, ang)

% Converts visual angles in degrees to pixels.
%
% Inputs:
% window.dist (distance from screen (cm))
% window.width (width of screen (cm))
% window.res (number of pixels of display in horizontal direction)
% ang (visual angle)
% Warning: assumes isotropic (square) pixels
%
% Written 11/1/07 gmb zre
% Adapted by Anne Urai, August 2013

pixSize = window.width/window.res.width;   %cm/pix
sz      = 2*window.dist*tan(pi*ang/(2*180));  %cm
pix     = (sz/pixSize);   %pix 

return