# Layouts

###### Identifier:

org.eclipse.rap.ui.layouts

###### Since:

RAP 1.2

###### Description:

This extension point is used to register a custom Layout. This means a grafical Layout not a Layout from the programmers point of view.
Every Layout can hold attributes called LayoutSets. A LayoutSet is a simple container for images, fonts, colors and position data. These sets are usually coupled to a `ElementBuilder`.
A Layout can override LayoutSets of other Layouts. These overriden LayoutSets are used if the user switch the Layout during runtime.
The default Layout can be defined by contributing to the `org.eclipse.rap.ui.branding` extension point. If there is no default Layout defined a fallback mechanism will be used to show the standard Layout.

###### Configuration Markup:

<!ELEMENT extension (layout+)>

<!ATTLIST extension

point CDATA #REQUIRED

id CDATA #IMPLIED

name CDATA #IMPLIED>

<!ELEMENT layoutSet EMPTY>

<!ATTLIST layoutSet

id CDATA #REQUIRED

name CDATA #IMPLIED

class CDATA #REQUIRED

overridesId IDREF #IMPLIED>

- id - The unique identifier for a LayoutSet. This id can be used to override a LayoutSet in a different Layout.
- name - This optional attribute is just to give the LayoutSet a readable name.
- class - The definition of a LayoutSet. This is a class that has to implement the ILayoutSetInitializer interface.
- overridesId - To replace a layoutSet you can define a a new one and set the overrides attribute to make clear that the new layoutSet will replace the one defined in this attribute.

<!ELEMENT layout (layoutSet+)>

<!ATTLIST layout

id CDATA #REQUIRED

name CDATA #IMPLIED>

- id - The unique identifier for a Layout.
- name - This optional attribute is just to give the Layout a readable name.

###### Examples:

The following is an example of a Layout with three LayoutSets:

    <extension
        point="org.eclipse.rap.ui.layouts">
      <layout
          id="org.eclipse.presentation.example.layout"
          name="Example Layout">
        <layoutSet
            class="org.eclipse.rap.ui.interactiondesign.example.layoutset.HeaderLayoutSet2"
            id="header.layoutset"
            name="Header2">
        </layoutSet>
        <layoutSet
            class="org.eclipse.rap.ui.interactiondesign.example.layoutset.MacBarLayoutSet2"
            id="macBar.layoutset"
            name="MacBar 2">
        </layoutSet>
        <layoutSet
            class="org.eclipse.rap.ui.interactiondesign.example.layoutset.FooterLayoutSet2"
            id="footer.layoutset"
            name="Footer">
        </layoutSet>
        <layoutSet
            class="org.eclipse.rap.ui.interactiondesign.example.layoutset.NavigationPaneLayoutSet2"
            id="navigationpane.layoutset"
            name="NavigationPane">
        </layoutSet>
      </layout>
    </extension>

###### API Information:

Each LayoutSet in a Layout has to implement the `ILayoutSetInitializer` interface. The method within is called during the plugin activation to initialize components like images or fonts for this LayoutSet. This implementation can look like this:

    public class HeaderLayoutSet implements ILayoutSetInitializer {
      public void initializeLayoutSet( LayoutSet layoutSet ) {
        layoutSet.addImagePath( HeaderBuilderData.LEFT, "icons/headerLeft.png" );
        layoutSet.addImagePath( HeaderBuilderData.CENTER, "icons/headerCenter.png" );
        layoutSet.addImagePath( HeaderBuilderData.RIGHT, "icons/headerRight.png" );
        layoutSet.addImagePath( HeaderBuilderData.LOGO, "icons/headerLogo.png" );
        addHeaderPositions( layoutSet );
      }
    }

###### Supplied Implementation:

A detailed implementation example can be found in the `org.eclipse.rap.presentation.example` project. This project defines two Layouts and a bunch of LayoutSets. They look not pretty but they do their job.

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All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html