Adaptation for R2019a in getWebElements() for uiaxes inputs

In R2019a a <img> node is returned, as opposed to earlier versions, in which <canvas> would be returned.

Author: Dev-iL

mlapptools.m

@@ -305,14 +305,19 @@ function fontWeight(hUIElement, weight)
           widgetID = arrayfun(@(x)WidgetID(mlapptools.DEF_ID_ATTRIBUTE, x), ...
                               string(tmp.id(contains(tmp.id, TAB_PREFIX))));
         case 'axes'
-          % For uiaxes we return the <canvas> object. This canvas has a context 
-          % of type "webgl".
-          % See also: https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API
-          warning(['UIAxes object detected. Returning the innermost <canvas> element. '...
+          switch subsref(ver('matlab'), substruct('.','Version'))
+            case {'9.6'} % R2019a
+              descendType = 'img';
+            otherwise  % R2016a-R2018b
+              descendType = 'canvas';
+              % This canvas has a context of type "webgl".
+              % See also: https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API
+              warning(['UIAxes object detected. Returning the innermost <canvas> element. '...
                    'Be advised that mlapptools cannot modify this element, which '...
-                   'instead requires using WebGL commands via `hWin.executeJS(...)`.']);          
+                   'instead requires using WebGL commands via `hWin.executeJS(...)`.']); 
+          end         
           widgetID = mlapptools.getDecendentOfType( ...
-            hWin, mlapptools.getDataTag(hUIElement), 'canvas');
+            hWin, mlapptools.getDataTag(hUIElement), descendType);
         otherwise % default:
           widgetID = mlapptools.getWidgetID(hWin, mlapptools.getDataTag(hUIElement));
       end