refactor fixation from retinotopy

Author: Remi-Gau

drawFixation.m

@@ -1,16 +1,35 @@
 function drawFixation(cfg)
     % Define the parameters of the fixation cross in `cfg` and `expParameters`
-
-    if strcmp(cfg.fixation.type, 'cross')
-
-        smooth = 1;
-
-        Screen('DrawLines', ...
-            cfg.screen.win, ...
-            cfg.fixation.allCoords, ...
-            cfg.fixation.lineWidthPix, ...
-            cfg.fixation.color, ...
-            [cfg.screen.center(1) cfg.screen.center(2)], smooth);
+    
+    switch cfg.fixation.type
+        case 'cross'
+            
+            smooth = 1;
+            
+            Screen('DrawLines', ...
+                cfg.screen.win, ...
+                cfg.fixation.allCoords, ...
+                cfg.fixation.lineWidthPix, ...
+                cfg.fixation.color, ...
+                [cfg.screen.center(1) cfg.screen.center(2)], smooth);
+            
+        case 'dot'
+            
+            % Draw gap around fixation of 20% the size
+            Screen('FillOval', ...
+                cfg.screen.win, ...
+                cfg.color.background, ...
+                CenterRect( ...
+                [0 0 repmat(1.2 * cfg.fixation.widthPix, 1, 2)], ...
+                cfg.screen.winRect));
+            
+            % Draw fixation
+            Screen('FillOval', ...
+                cfg.screen.win, ...
+                cfg.color.foreground, ...
+                CenterRect( ...
+                [0 0 repmat(cfg.fixation.widthPix, 1, 2)], ...
+                cfg.screen.winRect));
     end
-
+    
 end

initFixation.m

@@ -1,12 +1,12 @@
 function cfg = initFixation(cfg)
+    
+    % Convert some values from degrees to pixels
+    cfg.fixation = degToPix('width', cfg.fixation, cfg);
+    cfg.fixation = degToPix('xDisplacement', cfg.fixation, cfg);
+    cfg.fixation = degToPix('yDisplacement', cfg.fixation, cfg);
 
     if strcmp(cfg.fixation.type, 'cross')
 
-        % Convert some values from degrees to pixels
-        cfg.fixation = degToPix('width', cfg.fixation, cfg);
-        cfg.fixation = degToPix('xDisplacement', cfg.fixation, cfg);
-        cfg.fixation = degToPix('yDisplacement', cfg.fixation, cfg);
-
         % Prepare fixation cross
         cfg.fixation.xCoords = [-cfg.fixation.widthPix cfg.fixation.widthPix 0 0] / 2 + ...
             cfg.fixation.xDisplacementPix;

setDefaultsPTB.m

@@ -35,7 +35,7 @@
     fieldsToSet.fixation.xDisplacement = 0;
     fieldsToSet.fixation.yDisplacement = 0;
     fieldsToSet.fixation.color = [255 255 255];
-    fieldsToSet.fixation.width = 1;
+    fieldsToSet.fixation.width = 1; % degrees of visual angle
     fieldsToSet.fixation.lineWidthPix = 5;
 
     % define visual apperture field