GradientBoxComposite.java

/*
 * Copyright 2010-2012 Amazon Technologies, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 * 
 *    http://aws.amazon.com/apache2.0
 *
 * This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
 * OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and
 * limitations under the License.
 */

package com.amazonaws.eclipse.core.ui.overview;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;
import org.eclipse.ui.forms.widgets.FormToolkit;
import org.eclipse.ui.forms.widgets.TableWrapData;

import com.amazonaws.eclipse.core.AwsToolkitCore;

/**
 * Composite that uses gradients for the top and bottom borders. Subclasses are
 * expected to fill in the content through the header, main and footer
 * composites in this class.
 * <p>
 * This composite manages its own images so that they can be released as soon as
 * possible when this composite is disposed, so ensure that all instances are
 * properly disposed and that subclasses correctly call super.dispose() if they
 * override the dispose method.
 */
class GradientBoxComposite extends Composite {

	/**
	 * Image registry so that any image resources are disposed of when this
	 * object is disposed. Assumes only one GradientBoxComposite will be used,
	 * so images aren't shared between multiple instances.
	 */
	private ImageRegistry imageRegistry = new ImageRegistry();
	
	/** Form toolkit for creating the UI widgets */
	private FormToolkit toolkit;
	
	/** The header composite, for subclasses to populate */ 
	protected Composite headerComposite;
	
	/** The main composite, for subclasses to populate */
	protected Composite mainComposite;
	
	/** The footer composite, for subclasses to populate */
	protected Composite footerComposite;

	/**
	 * Creates a new GradientBoxComposite widget within the specified parent and
	 * using the specified form toolkit.
	 * 
	 * @param parent
	 *            The composite to contain the new GradientBoxComposite.
	 * @param toolkit
	 *            The form toolkit to use for creating the UI.
	 */
	public GradientBoxComposite(Composite parent, FormToolkit toolkit) {
		super(parent, SWT.NONE);
		this.toolkit = toolkit;
		
        initializeImageRegistry();
        setLayout(LayoutUtils.newSlimTableWrapLayout(3));
		
		createLabel("upper-left");
		headerComposite = createHorizontalComposite("top");
		createLabel("upper-right");

		createVerticalComposite("left");
		mainComposite = createHorizontalComposite(null);
		createVerticalComposite("right");

		createLabel("lower-left");
		footerComposite = createHorizontalComposite("bottom");
		createLabel("lower-right");
	}

	/* (non-Javadoc)
	 * @see org.eclipse.swt.widgets.Widget#dispose()
	 */
	@Override
	public void dispose() {
		imageRegistry.dispose();
		super.dispose();
	}

	
	/*
	 * Private Interface
	 */

	/**
	 * Creates a new label with a specified image, and sizes the label so that
	 * it is the same size as the image.
	 * 
	 * @param imageKey
	 *            The key of the image to use in the new label.
	 * @return The new label.
	 */
	private Label createLabel(String imageKey) {
		Image image = imageRegistry.get(imageKey);
		Label label = toolkit.createLabel(this, null);
		label.setImage(image);

		TableWrapData layoutData = new TableWrapData(TableWrapData.FILL);
		layoutData.heightHint = image.getImageData().height;
		layoutData.maxHeight = image.getImageData().height;
		layoutData.maxWidth = image.getImageData().width;
		label.setLayoutData(layoutData);

		return label;
	}

	/**
	 * Creates a horizontal composite for this gradient box with the specified
	 * background image tiled repeatedly in the horizontal direction.
	 * 
	 * @param imageKey
	 *            The key of the image to use for the background.
	 * @return The new composite.
	 */
	private Composite createHorizontalComposite(String imageKey) {
		Composite composite = toolkit.createComposite(this);
		TableWrapData layoutData = new TableWrapData(TableWrapData.FILL);
		if (imageKey != null) {
			composite.setBackgroundImage(imageRegistry.get(imageKey));
			composite.setBackgroundMode(SWT.INHERIT_DEFAULT);
			layoutData.heightHint = imageRegistry.get(imageKey).getImageData().height;
			layoutData.maxWidth = imageRegistry.get(imageKey).getImageData().width;
		}
		composite.setLayoutData(layoutData);

		return composite;
	}
	
	/**
	 * Creates a vertical composite for this gradient box with the specified
	 * background image tiled repeatedly in the vertical direction.
	 * 
	 * @param imageKey
	 *            The key of the image to use for the background.
	 * @return The new composite.
	 */
	private Composite createVerticalComposite(String imageKey) {
		Composite composite = toolkit.createComposite(this);
		composite.setBackgroundImage(imageRegistry.get(imageKey));
		composite.setBackgroundMode(SWT.INHERIT_DEFAULT);
		TableWrapData layoutData = new TableWrapData(TableWrapData.FILL, TableWrapData.FILL);
		layoutData.maxWidth = imageRegistry.get(imageKey).getImageData().width;
		layoutData.grabVertical = true;
		composite.setLayoutData(layoutData);

		return composite;
	}
	
	/**
	 * Initializes the image resources used by this widget.
	 */
	private void initializeImageRegistry() {
		imageRegistry.put("upper-left", createImageDescriptor("icons/gradient-box/upper-left.png"));
        imageRegistry.put("top", createImageDescriptor("icons/gradient-box/top.png"));
        imageRegistry.put("upper-right", createImageDescriptor("icons/gradient-box/upper-right.png"));
        
        imageRegistry.put("left", createImageDescriptor("icons/gradient-box/left.png"));
        imageRegistry.put("right", createImageDescriptor("icons/gradient-box/right.png"));

        imageRegistry.put("lower-left", createImageDescriptor("icons/gradient-box/lower-left.png"));
        imageRegistry.put("bottom", createImageDescriptor("icons/gradient-box/bottom.png"));
        imageRegistry.put("lower-right", createImageDescriptor("icons/gradient-box/lower-right.png"));
	}

	/**
	 * Creates an ImageDescriptor from this plugin for the specified path.
	 * 
	 * @param imagePath
	 *            The path of the image to load.
	 * @return The new image descriptor.
	 */
	private ImageDescriptor createImageDescriptor(String imagePath) {
		return ImageDescriptor.createFromURL(AwsToolkitCore.getDefault().getBundle().getEntry(imagePath));
	}

}