GtVolView: fixed error with 2D images

Signed-off-by: Nicola Vigano <nicola.vigano@esrf.fr>

zUtil_TomoUtils/GtVolView.m

@@ -269,7 +269,8 @@ classdef GtVolView < GtBaseGuiElem
                 point = round(point);
             end
             % At the border, rounding gives a wrong pixel position
-            point = min(point, size(obj.conf.vol));
+            [vol_size(1), vol_size(2), vol_size(3)] = size(obj.conf.vol);
+            point = min(point, vol_size);
             value = obj.getVolValue(point);
         end
     end