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| <h1>Providing Rendering Decorators</h1> |
| <h2>Enhancing the Tool Behavior Provider</h2> |
| <p>It is possible to draw so called "rendering decorators" on top of active pictogram |
| elements. These rendering decorators are transiently determined and not persisted |
| in the diagram.</p> |
| <p>A typical use case is the rendering of error-markers on top of incorrect pictogram |
| elements.</p> |
| <p>The rendering decorators are defined in the tool behavior provider.</p> |
| <p>If you didn’t do so already you must <strong>first create a tool behavior provider |
| and add it to the diagram type provider as described </strong> |
| <a href="tool-behavior-provider.htm"><strong>here</strong></a>.</p> |
| <p>There is one method of the tool behavior provider to overwrite: </p> |
| <ul> |
| <li>The method |
| <a href="../../../javadoc/org/eclipse/graphiti/tb/IToolBehaviorProvider.html#getDecorators(org.eclipse.graphiti.mm.pictograms.PictogramElement)"> |
| getDecorators</a> has to return the rendering decorators for the given pictogram |
| element. A rendering decorator must implement the interface |
| <a href="../../../javadoc/org/eclipse/graphiti/tb/IDecorator.html">IDecorator</a> |
| and may also implement |
| <a href="../../../javadoc/org/eclipse/graphiti/datatypes/ILocation.html">ILocation</a>, |
| which provides the decorator location relative to the pictogram element.</li> |
| </ul> |
| <p>Currently only the |
| <a href="../../../javadoc/org/eclipse/graphiti/tb/ImageDecorator.html">ImageDecorator</a> |
| is supported, which renders an image at the defined location and can show a text |
| message as tooltip.</p> |
| <p>In this example we want to show an image decorator for a EClass, whenever the |
| class name does not start with an upper case letter.</p> |
| <p> </p> |
| <p><img alt="" height="100" src="visio/rendering-decorator.gif" width="321"></p> |
| <p><strong>Figure: Rendering decorator displaying a warning</strong></p> |
| <p> </p> |
| <p>You can see the complete implementation of the rendering decorators here:</p> |
| <!-- Begin code ------------------------------------------------------------------------------- --> |
| <p> </p> |
| <div class="literallayout"> |
| <div class="incode"> |
| <p class="code">@Override<br><span class="keyword">public</span> IDecorator[] |
| getDecorators(PictogramElement pe) {<br> IFeatureProvider |
| featureProvider = getFeatureProvider();<br> Object bo |
| = featureProvider.getBusinessObjectForPictogramElement(pe);<br> |
| <span class="keyword">if</span> (bo instanceof EClass) {<br> |
| EClass eClass = (EClass) bo;<br> |
| String name = eClass.getName();<br> |
| <span class="keyword">if</span> (name != <span class="keyword">null</span> |
| && name.length() > 0<br> |
| && !(name.charAt(0) >= <span class="string">'A'</span> && name.charAt(0) |
| <= <span class="string">'Z'</span>)) {<br> |
| IDecorator imageRenderingDecorator =<br> |
| <span class="keyword">new</span> ImageDecorator(<br> |
| IPlatformImageConstants.<span class="string"><em>IMG_ECLIPSE_WARNING_TSK</em></span>);<br> |
| imageRenderingDecorator<br> |
| .setMessage(<span class="string">"Name should start with upper case letter"</span>);<br> |
| <span class="keyword">return new</span> IDecorator[] { imageRenderingDecorator |
| };<br> }<br> |
| }<br> <br> <span class="keyword">return super</span>.getDecorators(pe);<br> |
| }<br></p> |
| </div> |
| </div> |
| <p> </p> |
| <!-- End code ------------------------------------------------------------------------------- --> |
| <h2>Test: Show Warning Decorator for EClass</h2> |
| <p>Now start the editor and create a new EClass named “address”. Verify that the |
| warning decorator is shown and the tooltip displays the warning message. Create |
| another EClass named "Address" and verify that no warning decorator is displayed.</p> |
| <p> </p> |
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