Source code file content

granite / src / org / pushingpixels / granite / content / Stage3AnimatedScrolling.java

/*
 * Copyright (c) 2009 Granite Kirill Grouchnikov. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * 
 *  o Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer. 
 *     
 *  o Redistributions in binary form must reproduce the above copyright notice, 
 *    this list of conditions and the following disclaimer in the documentation 
 *    and/or other materials provided with the distribution. 
 *     
 *  o Neither the name of Granite Kirill Grouchnikov nor the names of 
 *    its contributors may be used to endorse or promote products derived 
 *    from this software without specific prior written permission. 
 *     
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */
package org.pushingpixels.granite.content;

import org.eclipse.swt.widgets.Composite;
import org.pushingpixels.trident.Timeline;

/**
 * Adds the following functionality to the album scroller container:
 * 
 * <ul>
 * <li>Animated scrolling of album overview components with mouse wheel and left
 * / right arrow keys</li>
 * </ul>
 * 
 * @author Kirill Grouchnikov
 */
public class Stage3AnimatedScrolling extends Stage2Components {
	/**
	 * Contains the target leading position - this is the index of the album
	 * which should appear at the left edge once the current
	 * {@link #scrollTimeline} is done. Note that the user scrolling can be done
	 * in the middle of the current scrolling animation. In this case, the field
	 * is updated with the new target index.
	 */
	float targetLeadingPosition;

	/**
	 * The scroll timeline. Note that the user scrolling can be done in the
	 * middle of the current scrolling animation. In this case, the current
	 * timeline is cancelled, and a new one is created - this allows quick
	 * scrolling with multiple mouse wheel / arrow events.
	 */
	Timeline scrollTimeline;

	/**
	 * Creates the new container that can animate the album scrolling.
	 */
	public Stage3AnimatedScrolling(Composite composite) {
		super(composite);
		this.targetLeadingPosition = 0;
	}

	@Override
	protected void scrollToNext() {
		if (this.targetLeadingPosition < (this.comps.size() - 1)) {
			this.targetLeadingPosition++;
			scrollContents();
		}
	}

	@Override
	protected void scrollToPrevious() {
		if (this.targetLeadingPosition > 0) {
			this.targetLeadingPosition--;
			scrollContents();
		}
	}

	/**
	 * Scrolls the contents of this container.
	 */
	private synchronized void scrollContents() {
		if (this.scrollTimeline != null) {
			// abort the playing scroll timeline
			this.scrollTimeline.abort();
		}

		// and dynamically create a new one to change the
		// leading position
		this.scrollTimeline = new Timeline(this);
		this.scrollTimeline
				.addPropertyToInterpolate(Timeline.<Float> property(
						"leadingPosition").fromCurrent().to(
						this.targetLeadingPosition));
		this.scrollTimeline.setDuration(250);

		this.scrollTimeline.play();
	}

	/**
	 * Sets the new value for the leading position. This is called from
	 * {@link #scrollTimeline}.
	 * 
	 * @param leadingPosition
	 *            The new value for the leading position.
	 */
	public void setLeadingPosition(float leadingPosition) {
		this.leadingPosition = leadingPosition;
		this.albumComponentsHolder.layout(true);
	}

	public float getLeadingPosition() {
		return this.leadingPosition;
	}
}