WWW/Internet - Portal do Software Público Brasileiro

IADIS International Conference WWW/Internet 2010The WDiM application start-up procedure is the following:1. Conductor and Players respectively send HTTP requests to the URL of WrapperCommander andWrapperReceiver.2. Both Wrappers load the TileConfiguration of the WDiM.3. WrapperCommander sends Commander to Conductor and Wrapper-Receiver sends Receiver to allPlayers.4. Commander is a web application displayed on the web browser of the Conductor;Receivers is a web application displayed on the web browser of the Players.5. Finally, Commander and distributed Receivers is executed cooperatively and shows high-resolutionweb application on the tiled displays of WDiM.5.2 MessagingThe messaging between Commander and Receiver is based on Ajax over HTTP. However, as describedabove, Commander on the Coordinator can not communicate directly to Receiver on the Players becauseHTTP does not allow browser-to-browser connection. Therefore, all Players and the Conductor poll the webserver on the Coordinator. Actually, WDiM has messaging of two kinds: Command and SyncData (Figure10). SyncData is a method used to synchronize data between Commander and all Receivers. If a JSON objectthat is declared as SyncData is changed on the Commander, then the object is sent immediately to all Playersto inform Receivers. Command is a method to sending JSON object from Commander to Receivers onspecified Players. The Commander publishes Command and SyncData via methods of WDiM middlewareand the Receiver receives Command and SyncData via a handler for which the user is defined. The WDiMmiddleware manages the exchange information between Commander and Receivers.5.3 Tile ConfigurationCommander and Receiver get the TileConfiguration when starting a WDiM application. Figure 11 showsproperties for our 16-monitor WDiM tiled display wall. User only defines the width and height of LCDmonitor and its bezel and Number of LCD monitors of the Tiled Display Wall. In addition, some usefulproperties, e.g. distance from the center and bounds of the LCD monitor draw, calculated. The WDiMapplication can use the properties to draw the high-resolution contents.The WDiM middleware and applications can correspond to various sizes of tiled display walls bychanging the TileConfiguration. For example, it is possible to build a tiled display wall made of two laptopcomputers arranged side-by-side on the desk.Figure 11. Tile configuration157