Metacat

/*

License: LGPL as per: http://www.gnu.org/copyleft/lesser.html

Dependancies: Context

$Id: MovieLoop.js 3881 2008-02-27 15:41:07Z gjvoosten $

*/

// Ensure this object's dependancies are loaded.

mapbuilder.loadScript(baseDir+"/tool/ToolBase.js");

/**

 * Controller for a movie loop.  Set framesPerSec to control the frame rate 

 * and frameIncrement (+n/-n) to control the steps through the loop (n is number

 * of frames to increment.

 * @constructor

 * @base ToolBase

 * @author Adair

 * @param toolNode The tool node from the config document for this tool

 * @param model  the model object that contains this tool

 */

function MovieLoop(toolNode, model) {

  ToolBase.apply(this, new Array(toolNode, model));

  this.frameIncrement = 1;

  this.model.setParam("firstFrame", 0);

  this.timestampIndex = 0;

  window.movieLoop = this;

  this.isRunning = false;

  this.frameIsLoading = false;

  //delay in milliseconds

  this.delay = 1000/this.getProperty("mb:framesPerSecond", 10);

  //set a limit to the number of frames to be loaded

  this.maxFrames = this.getProperty("mb:maxFrames", 30);

  /**

   * Sets the frame to the specified index in the frame array

   * @param index the 0-based frame index in the frame array

   */

  this.setFrame = function(index) {

    var timestampList = this.model.timestampList;

    var ts;

    if (this.timestampIndex!=null) {

      var ts = timestampList.childNodes[this.timestampIndex];

      if (ts) {

        ts.setAttribute("current", "0");

        this.model.setParam("timestamp", this.timestampIndex);

      }

    }

    var firstFrame = this.model.getParam("firstFrame");

    var lastFrame = this.model.getParam("lastFrame");

    if (index > lastFrame) index = firstFrame;

    if (index < firstFrame) index = lastFrame;

    this.timestampIndex = index;

    ts = timestampList.childNodes[this.timestampIndex];

    ts.setAttribute("current", "1");

    this.model.setParam("timestamp", this.timestampIndex);

  }

  /**

   * Advances the frame array by the frame increment. 

   * 

   * @param step optional parameter to override default frame increment

   */

  this.nextFrame = function(step) {

    var objRef = window.movieLoop;

    var increment = objRef.frameIncrement;

    if (step) increment = step;   //arg passed in overrides default

    if (!this.frameIsLoading) {

        // play() will continue calling nextFrame, so that 

        // nextFrame() will continually be called at a regular interval, until the current frame is loaded        

        // The 'bug' is that if the user clicks the next button rapidly, subsequent requests will be ignored

        // while the initial frame is loading. This needs to be resolved.

	    objRef.setFrame(objRef.timestampIndex + increment);

	}

  }

  /**

   * Listener fucntion to set the start and end frames based on the 

   * firstFrame and maxFrames property values.

   * @param objRef pointer to this object

   */

  this.setFrameLimits = function(objRef) {

    var timestampList = objRef.model.timestampList;

    //timestampList.firstFrame = objRef.firstFrame;  //set these from a widget, or config

    var firstFrame = objRef.model.getParam("firstFrame");

    var lastFrame = firstFrame+objRef.maxFrames;

    if (lastFrame > timestampList.childNodes.length) lastFrame = timestampList.childNodes.length-1;

    objRef.model.setParam("lastFrame",lastFrame);

    timestampList.childNodes[firstFrame].setAttribute("current","1");

  }

  this.model.addFirstListener("refresh",this.setFrameLimits,this);

  this.model.addListener("firstFrame",this.setFrameLimits,this);

  /**

   * Resets the frame index to the firstFrame property

   * @param objRef pointer to this object

   */

  this.reset = function(objRef) {

    objRef.pause();

    objRef.setFrame(objRef.model.getParam("firstFrame"));

  }

  this.model.addListener("loadModel",this.reset,this);

  /**

   * initialize the movie loop. This only happens at the first bbox event,

   * which shows us that the map is loaded.

   */

  this.init = function(objRef) {

    //TBD: this is an ugly workaround because we do not have an event that

    // tells us when the OL map finished loading. 

    if (!objRef.initialized) {

      objRef.initialized = true;

      objRef.reset(objRef);

    }

  }

  this.model.addListener("bbox", this.init, this);

  /**

   * set the initialized state of the movie loop to false

   */

  this.uninit = function(objRef) {

    objRef.initialized = false;

  }

  this.model.addListener("newModel", this.uninit, this);

  /**

   * Starts the movie loop playing by using a JavaScript timer.

   */

  this.play = function() {

  	if (!this.isRunning) {

	    this.movieTimer = setInterval('window.movieLoop.nextFrame()',this.delay);

	    this.isRunning = true;

	}

  }

  /**

   * Stops the JavaScript movie loop timer.

   */

  this.pause = function() {

    this.isRunning = false;

    clearInterval(this.movieTimer);

  }

  /**

   * Stops the JavaScript movie loop timer and sets the index back to the first 

   * frame.

   */

  this.stop = function() { 

    this.pause();

    this.reset(this);

  }

  /**

   * A "stopLoop" event listener to call the stop method

   * @param objRef pointer to this object

   */

  this.stopListener = function(objRef) {

    objRef.stop();

  }

  this.model.addListener("stopLoop",this.stopListener,this);

}