Added the "setStyle" method for setting generic styles

- Improved internal documentation of the class.
- Added check for JS SyntaxError to use in setStyle.
- Readme updated accordingly.

Author: Dev-iL

README.md

@@ -7,6 +7,7 @@ For additional information, see Iliya Romm's guest Undocumented Matlab article,
 [`textAlign`](#textAlign) - Modify text alignment  
 [`fontWeight`](#fontWeight) - Modify font weight  
 [`fontColor`](#fontColor) - Modify font folor  
+[`setStyle`](#setStyle) - Modify a specified style property
 
 <a name="textAlign"></a>
 #### *mlapptools*.**textAlign**(*uielement*, *alignment*)
@@ -82,4 +83,21 @@ mlapptools.fontColor(myGUI.TextArea, 'aqua');
 ```MATLAB
 myGUI = DOMdemoGUI;
 mlapptools.fontColor(myGUI.TextArea, 'rgb(255,165,0)');
+```
+
+<a name="setStyle"></a>
+#### *mlapptools*.**setStyle**(*uielement*, *styleAttr*, *styleValue*)
+##### Description
+Set the style attribute `styleAttr` of the specified UI element, `'uielement'`, to the value `styleValue`. `styleAttr` should be any valid CSS attribute, and `styleValue` a valid setting thereof. 
+
+This method provides a general interface to change CSS style attributes, with minimal input testing and error reporting, so it is up to the user to provide valid inputs.
+
+Valid style attributes and corresponding settings can be found [here](https://www.w3schools.com/cssref/).
+
+##### Examples
+Using the demo GUI generated by `./Demo/DOMdemoGUI.m`
+```MATLAB
+myGUI = DOMdemoGUI;
+mlapptools.setStyle(myGUI.TextArea, 'background-image',...
+ 'url(https://upload.wikimedia.org/wikipedia/commons/8/80/Wikipedia-logo-v2.svg)');
 ```

mlapptools.m

@@ -1,7 +1,13 @@
 classdef mlapptools
-    % MLAPPTOOLS is a class definition
+    % MLAPPTOOLS A collection of static methods for customizing various aspects
+    % MATLAB App Designer UIFigures.
     %
     % MLAPPTOOLS methods:
+    % textAlign  - utility method for modifying text alignment.
+    % fontWeight - utility method for modifying font weight (bold etc.).
+    % fontColor  - utility method for modifying font color.
+    % setStyle   - utility method for modifying styles that do not (yet) have a
+    %              dedicated mutator.
 
     properties (Access = private, Constant = true)
         QUERY_TIMEOUT = 5;  % Dojo query timeout period, seconds
@@ -13,9 +19,10 @@
             clear obj
         end
     end
-    
-    
+        
     methods (Static)
+            
+    methods (Access = public, Static = true)
         function textAlign(uielement, alignment)
             alignment = lower(alignment);
             mlapptools.validatealignmentstr(alignment)
@@ -45,10 +52,32 @@ function fontColor(uielement, newcolor)
             fontColorSetStr = sprintf('dojo.style(dojo.query("#%s")[0], "color", "%s")', widgetID, newcolor);
             win.executeJS(fontColorSetStr);
         end
-    end
-    
-    
-    methods (Static, Access = private)
+        
+        
+        function widgetID = setStyle(hControl, styleAttr, styleValue)
+            % This method provides a simple interface for modifying style attributes
+            % of uicontrols.
+            %
+            % WARNING: Due to the large amount of available style attributes and 
+            % corresponding settings, input checking is not performed. As this
+            % might lead to unexpected results or errors - USE AT YOUR OWN RISK!
+            [win, widgetID] = mlapptools.getWebElements(hControl);
+            
+            styleSetStr = sprintf('dojo.style(dojo.query("#%s")[0], "%s", "%s")', widgetID, styleAttr, styleValue);
+            % ^ this might result in junk if widgetId=='null'.
+            try 
+              win.executeJS(styleSetStr);
+              % ^ this might crash in case of invalid styleAttr/styleValue.
+            catch ME
+                % Test for "Invalid or unexpected token":
+                ME = mlapptools.checkJavascriptSyntaxError(ME, styleSetStr);
+                rethrow(ME);       
+            end
+        end
+
+    end % Public static methods
+        
+    methods (Static = true, Access = private)
         function [win] = getWebWindow(uifigurewindow)
             mlapptools.togglewarnings('off')
             % Test if uifigurewindow is a valid handle
@@ -194,6 +223,20 @@ function validatealignmentstr(alignment)
 
 
         function [newcolor] = validateCSScolor(newcolor)
+          % TODO
+        end
+        
+        
+        function ME = checkJavascriptSyntaxError(ME,styleSetStr)        
+            if (strcmp(ME.identifier,'cefclient:webwindow:jserror'))                    
+                c = strfind(ME.message,'Uncaught SyntaxError:');
+                if ~isempty(c)
+                  v = str2double(regexp(ME.message(c:end),'-?\d+\.?\d*|-?\d*\.?\d+','match'));
+                  msg = ['Syntax error: unexpected token in styleValue: ' styleSetStr(v(1),v(2))];
+                  causeException = MException('mlapptools:setStyle:invalidInputs',msg);
+                  ME = addCause(ME,causeException);
+                end
+            end
         end
     end
 end