/*******************************************************************************
 * Copyright (c) 2001, 2005 IBM Corporation and others.
 * 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:
 *     IBM Corporation - initial API and implementation
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.extension;


import java.net.MalformedURLException;
import java.net.URL;

import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.resource.ImageDescriptor;
import org.osgi.framework.Bundle;

public class ImageUtil {


	/**
	 * Convenience Method. Returns an ImageDescriptor whose path, relative to
	 * the plugin containing the <code>extension</code> is
	 * <code>subdirectoryAndFilename</code>. If there isn't any value
	 * associated with the name then <code>null
	 * </code> is returned.
	 * 
	 * This method is convenience and only intended for use by the workbench
	 * because it explicitly uses the workbench's registry for
	 * caching/retrieving images from other extensions -- other plugins must
	 * user their own registry. This convenience method is subject to removal.
	 * 
	 * Note: subdirectoryAndFilename must not have any leading "." or path
	 * separators / or \ ISV's should use icons/mysample.gif and not
	 * ./icons/mysample.gif
	 * 
	 * Note: This consults the plugin for extension and obtains its
	 * installation location. all requested images are assumed to be in a
	 * directory below and relative to that plugins installation directory.
	 */
	public static ImageDescriptor getImageDescriptorFromExtension(IExtension extension, String subdirectoryAndFilename) {
		String pluginId = extension.getNamespace();
		Bundle bundle = Platform.getBundle(pluginId);
		return getImageDescriptorFromBundle(bundle, subdirectoryAndFilename);
	}

	/**
	 * Convenience Method. Return an ImageDescriptor whose path relative to
	 * the plugin described by <code>bundle</code> is
	 * <code>subdirectoryAndFilename</code>. Returns <code>null</code> if
	 * no image could be found.
	 * 
	 * This method is convenience and only intended for use by the workbench
	 * because it explicitly uses the workbench's registry for
	 * caching/retrieving images from other extensions -- other plugins must
	 * user their own registry. This convenience method is subject to removal.
	 * 
	 * Note: subdirectoryAndFilename must not have any leading "." or path
	 * separators / or \ ISV's should use icons/mysample.gif and not
	 * ./icons/mysample.gif
	 * 
	 * Note: This consults the plugin for extension and obtains its
	 * installation location. all requested images are assumed to be in a
	 * directory below and relative to that plugins installation directory.
	 */
	public static ImageDescriptor getImageDescriptorFromBundle(Bundle bundle, String subdirectoryAndFilename) {

		URL path = bundle.getEntry("/"); //$NON-NLS-1$
		URL fullPathString = null;
		try {
			fullPathString = new URL(path, subdirectoryAndFilename);
			return ImageDescriptor.createFromURL(fullPathString);
		} catch (MalformedURLException e) {
		}
		return null;
	}
}