Content of file ExtendedFontRegistry.java

/**
 * Copyright (c) 2008-2010 IBM Corporation and others.
 * 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 * IBM - Initial API and implementation
 */
// REUSED CLASS
package org.eclipse.emf.edit.ui.provider;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;

import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.edit.provider.IItemFontProvider;
import org.eclipse.jface.resource.DeviceResourceException;
import org.eclipse.jface.resource.FontDescriptor;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.widgets.Display;

/**
 * A font registry for turning a font description into an actual font object.
 *
 * @see IItemFontProvider
 */
public class ExtendedFontRegistry {

	public static final ExtendedFontRegistry INSTANCE = new ExtendedFontRegistry() {
		@Override
		public Font getFont(Font baseFont, Object object) {
			return ExtendedImageRegistry.getInstance(ExtendedFontRegistry.class).getFont(baseFont, object);
		}
	};

	protected Display display;
	protected HashMap<Collection<?>, Font> table = new HashMap<Collection<?>, Font>(10);

	public ExtendedFontRegistry() {
		display = Display.getCurrent();
		hookDisplayDispose(display);
	}

	public ExtendedFontRegistry(Display display) {
		this.display = display;
		hookDisplayDispose(display);
	}

	public Font getFont(Font baseFont, Object object) {
		if (object instanceof Font) {
			return (Font) object;
		} else {
			final Collection<Object> key = new ArrayList<Object>(2);
			key.add(baseFont);
			key.add(object);

			Font result = table.get(key);
			if (result == null) {
				if (object instanceof FontDescriptor) {
					final FontDescriptor fontDescriptor = (FontDescriptor) object;
					try {
						result = fontDescriptor.createFont(display);
					} catch (final DeviceResourceException exception) {
						Activator.log(exception);
					}
				} else if (object instanceof URI) {
					final URI fontURI = (URI) object;
					if (!"font".equals(fontURI.scheme())) {
						throw new IllegalArgumentException("Only 'font' scheme is recognized" + fontURI);
					}
					String fontNameSpecification = fontURI.authority();
					if ("".equals(fontNameSpecification)) {
						fontNameSpecification = null;
					}
					final String heightSpecification = fontURI.segment(0);
					boolean delta;
					int height;
					if (heightSpecification.startsWith("+")) {
						delta = true;
						height = Integer.parseInt(heightSpecification.substring(1));
					} else if ("".equals(heightSpecification)) {
						delta = true;
						height = 0;
					} else {
						height = Integer.parseInt(heightSpecification);
						delta = height < 0;
					}

					final String styleSpecification = fontURI.segment(1);
					final int style = "bold".equals(styleSpecification) ? SWT.BOLD
						: "italic".equals(styleSpecification) ? SWT.ITALIC
							: "italic+bold".equals(styleSpecification) || "bold+italic".equals(styleSpecification)
								? SWT.ITALIC | SWT.BOLD
								: "normal".equals(styleSpecification) ? SWT.NORMAL : -1;

					final FontData[] baseFontData = baseFont.getFontData();
					final FontData[] fontData = new FontData[baseFontData.length];

					for (int i = 0; i < baseFontData.length; ++i) {
						fontData[i] = new FontData(
							fontNameSpecification == null ? baseFontData[i].getName() : fontNameSpecification,
							delta ? baseFontData[i].getHeight() + height : height,
							style == -1 ? baseFontData[i].getStyle() : style);
					}

					try {
						result = FontDescriptor.createFrom(fontData).createFont(display);
					} catch (final DeviceResourceException exception) {
						Activator.log(exception);
					}
				}

				if (result != null) {
					table.put(key, result);
				}
			}
			return result;
		}
	}

	protected void handleDisplayDispose() {
		for (final Font image : table.values()) {
			image.dispose();
		}
		table = null;
	}

	protected void hookDisplayDispose(Display display) {
		display.disposeExec(new Runnable() {
			@Override
			public void run() {
				handleDisplayDispose();
			}
		});
	}
}