考试系统 java rcp

/******************************************************************************* * Copyright (c) 2011 Google, Inc. * 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: * Google, Inc. - initial API and implementation *******************************************************************************/ package org.eclipse.wb.swt; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.Map; import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.Color; import org.eclipse.swt.graphics.Cursor; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.FontData; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.graphics.ImageData; import org.eclipse.swt.graphics.RGB; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.widgets.Display; /** * Utility class for managing OS resources associated with SWT controls such as colors, fonts, images, etc. * <p> * !!! IMPORTANT !!! Application code must explicitly invoke the <code>dispose()</code> method to release the * operating system resources managed by cached objects when those objects and OS resources are no longer * needed (e.g. on application shutdown) * <p> * This class may be freely distributed as part of any application or plugin. * <p> * @author scheglov_ke * @author Dan Rubel */ public class SWTResourceManager { //////////////////////////////////////////////////////////////////////////// // // Color // //////////////////////////////////////////////////////////////////////////// private static Map<RGB, Color> m_colorMap = new HashMap<RGB, Color>(); /** * Returns the system {@link Color} matching the specific ID. * * @param systemColorID * the ID value for the color * @return the system {@link Color} matching the specific ID */ public static Color getColor(int systemColorID) { Display display = Display.getCurrent(); return display.getSystemColor(systemColorID); } /** * Returns a {@link Color} given its red, green and blue component values. * * @param r * the red component of the color * @param g * the green component of the color * @param b * the blue component of the color * @return the {@link Color} matching the given red, green and blue component values */ public static Color getColor(int r, int g, int b) { return getColor(new RGB(r, g, b)); } /** * Returns a {@link Color} given its RGB value. * * @param rgb * the {@link RGB} value of the color * @return the {@link Color} matching the RGB value */ public static Color getColor(RGB rgb) { Color color = m_colorMap.get(rgb); if (color == null) { Display display = Display.getCurrent(); color = new Color(display, rgb); m_colorMap.put(rgb, color); } return color; } /** * Dispose of all the cached {@link Color}'s. */ public static void disposeColors() { for (Color color : m_colorMap.values()) { color.dispose(); } m_colorMap.clear(); } //////////////////////////////////////////////////////////////////////////// // // Image // //////////////////////////////////////////////////////////////////////////// /** * Maps image paths to images. */ private static Map<String, Image> m_imageMap = new HashMap<String, Image>(); /** * Returns an {@link Image} encoded by the specified {@link InputStream}. * * @param stream * the {@link InputStream} encoding the image data * @return the {@link Image} encoded by the specified input stream */ protected static Image getImage(InputStream stream) throws IOException { try { Display display = Display.getCurrent(); ImageData data = new ImageData(stream); if (data.transparentPixel > 0) { return new Image(display, data, data.getTransparencyMask()); } return new Image(display, data); } finally { stream.close(); } } /** * Returns an {@link Image} stored in the file at the specified path. * * @param path * the path to the image file * @return the {@link Image} stored in the file at the specified path */ public static Image getImage(String path) { Image image = m_imageMap.get(path); if (image == null) { try { image = getImage(new FileInputStream(path)); m_imageMap.put(path, image); } catch (Exception e) { image = getMissingImage(); m_imageMap.put(path, image); } } return image; } /** * Returns an {@link Image} stored in the file at the specified path relative to the specified class. * * @param clazz * the {@link Class} relative to which to find the image * @param path * the path to the image file, if starts with <code>'/'</code> * @return the {@link Image} stored in the file at the specified path */ public static Image getImage(Class<?> clazz, String path) { String key = clazz.getName() + '|' + path; Image image = m_imageMap.get(key); if (image == null) { try { image = getImage(clazz.getResourceAsStream(path)); m_imageMap.put(key, image); } catch (Exception e) { image = getMissingImage(); m_imageMap.put(key, image); } } return image; } private static final int MISSING_IMAGE_SIZE = 10; /** * @return the small {@link Image} that can be used as placeholder for missing image. */ private static Image getMissingImage() { Image image = new Image(Display.getCurrent(), MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE); // GC gc = new GC(image); gc.setBackground(getColor(SWT.COLOR_RED)); gc.fillRectangle(0, 0, MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE); gc.dispose(); // return image; } /** * Style constant for placing decorator image in top left corner of base image. */ public static final int TOP_LEFT = 1; /** * Style constant for placing decorator image in top right corner of base image. */ public static final int TOP_RIGHT = 2; /** * Style constant for placing decorator image in bottom left corner of base image. */ public static final int BOTTOM_LEFT = 3; /** * Style constant for placing decorator image in bottom right corner of base image. */ public static final int BOTTOM_RIGHT = 4; /** * Internal value. */ protected static final int LAST_CORNER_KEY = 5; /** * Maps images to decorated images. */ @SuppressWarnings("unchecked") private static Map<Image, Map<Image, Image>>[] m_decoratedImageMap = new Map[LAST_CORNER_KEY]; /** * Returns an {@link Image} composed of a base image decorated by another image. * * @param baseImage * the base {@link Image} that should be decorated * @param decorator * the {@link Image} to decorate the base image * @return {@link Image} The resulting decorated image */ public static Image decorateImage(Image baseImage, Image decorator) { return decorateImage(baseImage, decorator, BOTTOM_RIGHT); } /** * Returns an {@link Image} composed of a base image decorated by another image. * * @param baseImage * the base {@link Image} that should be decorated * @param decorator * the {@link Image} to decorate the base image * @param corner * the corner to place decorator image * @return the resulting decorated {@link Image} */ public static Image decorateImage(final Image baseImage, final Image decorator, final int corner) { if (corner <= 0 || corner >= LAST_CORNER_KEY) { throw new IllegalArgumentException("Wrong decorate corner"); } Map<Image, Map<Image, Image>> cornerDecoratedImageMap = m_decoratedImageMap[corner]; if (cornerDecoratedImageMap == null) { cornerDecoratedImageMap = new HashMap<Image, Map<Image, Image>>(); m_decoratedImageMap