bundles/org.eclipse.rap.rwt/js/org/eclipse/swt/custom/ScrolledComposite.js

/*******************************************************************************
 * Copyright (c) 2002-2006 Innoopract Informationssysteme GmbH.
 * 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
 * 
 * Contributors:
 *     Innoopract Informationssysteme GmbH - initial API and implementation
 ******************************************************************************/

qx.OO.defineClass(
  "org.eclipse.swt.custom.ScrolledComposite", 
  qx.ui.layout.CanvasLayout,
  function( style ) {
    qx.ui.layout.CanvasLayout.call( this );
    this._initialScrollLeft = null;
    this._lastScrollLeft = 0;
    this._lastScrollTop = 0;
    var req = org.eclipse.swt.Request.getInstance();
    req.addEventListener( "send", this._onRequestSend, this );
  }
);

qx.Proto.dispose = function() {
  if ( this.getDisposed() ) {
    return;
  }
  var req = org.eclipse.swt.Request.getInstance();
  req.removeEventListener( "send", this._onRequestSend, this );
  return qx.ui.layout.CanvasLayout.prototype.dispose.call( this );
}

qx.Proto.setHBarSelection = function( value ) {
  if( !this.isMaterialized() || !this.isCreated() ) {
    this._initialScrollLeft = value;
    this.addEventListener( "create", this._onAppear );
  } else {
    this.setScrollLeft( value );
    this._lastScrollLeft = value;
  }
}

qx.Proto.setVBarSelection = function( value ) {
// this._materialize();
// TODO [rst] the above line didn't seem to work:
// An error when a SC on an invisible tab was created
// --> copied code from setHBarSelection
  if( !this.isMaterialized() || !this.isCreated() ) {
    this._initialScrollTop = value;
    this.addEventListener( "create", this._onAppear );
  } else {
    this.setScrollTop( value );
    this._lastScrollTop = value;
  }
}

qx.Proto.setVBarMaximum = function( value ) {
  this.setScrollHeight( value );
}

qx.Proto.setHBarMaximum = function( value ) {
  this.setScrollWidth( value );
}

// TODO [rst] remove (see comment above)
qx.Proto._materialize = function() {
  if( !this.isMaterialized() || !this.isCreated() ) {
    qx.ui.core.Widget.flushGlobalQueues();    
  }
}

qx.Proto._onAppear = function( evt ) {
  if( this._initialScrollLeft != null ) {
    this.setScrollLeft( this._initialScrollLeft );
    this._lastScrollLeft = this._initialScrollLeft;
  }
  if( this._initialScrollTop != null ) {
    this.setScrollLeft( this._initialScrollTop );
    this._lastScrollLeft = this._initialScrollTop;
  }
  this.removeEventListener( "create", this._onAppear );
}

/**
 * Creates request parameters that denote the current scroll position just 
 * before a request is sent.
 * This is a workaround, it seems that there is no 'scroll event'.
 */
qx.Proto._onRequestSend = function( evt ) {
  if( this.isCreated() ) {
    var wm = org.eclipse.swt.WidgetManager.getInstance();
    var id = wm.findIdByWidget( this );
    var scrollX = this.getScrollLeft();
    if( scrollX != this._lastScrollLeft ) {
      evt.getTarget().addParameter( id + ".horizontalBar.selection", scrollX );
      this._lastScrollLeft = scrollX;
    }
    var scrollY = this.getScrollTop();
    if( scrollY != this._lastScrollTop ) {
      evt.getTarget().addParameter( id + ".verticalBar.selection", scrollY );
      this._lastScrollTop = scrollY;
    }
  }
}