Java tutorial
/* * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.awt; /** * Capabilities and properties of buffers. * * @see java.awt.image.BufferStrategy#getCapabilities() * @see GraphicsConfiguration#getBufferCapabilities * @author Michael Martak * @since 1.4 */ public class BufferCapabilities implements Cloneable { private ImageCapabilities frontCaps; private ImageCapabilities backCaps; private FlipContents flipContents; /** * Creates a new object for specifying buffering capabilities * @param frontCaps the capabilities of the front buffer; cannot be * {@code null} * @param backCaps the capabilities of the back and intermediate buffers; * cannot be {@code null} * @param flipContents the contents of the back buffer after page-flipping, * {@code null} if page flipping is not used (implies blitting) * @exception IllegalArgumentException if frontCaps or backCaps are * {@code null} */ public BufferCapabilities(ImageCapabilities frontCaps, ImageCapabilities backCaps, FlipContents flipContents) { if (frontCaps == null || backCaps == null) { throw new IllegalArgumentException("Image capabilities specified cannot be null"); } this.frontCaps = frontCaps; this.backCaps = backCaps; this.flipContents = flipContents; } /** * @return the image capabilities of the front (displayed) buffer */ public ImageCapabilities getFrontBufferCapabilities() { return frontCaps; } /** * @return the image capabilities of all back buffers (intermediate buffers * are considered back buffers) */ public ImageCapabilities getBackBufferCapabilities() { return backCaps; } /** * @return whether or not the buffer strategy uses page flipping; a set of * buffers that uses page flipping * can swap the contents internally between the front buffer and one or * more back buffers by switching the video pointer (or by copying memory * internally). A non-flipping set of * buffers uses blitting to copy the contents from one buffer to * another; when this is the case, {@code getFlipContents} returns * {@code null} */ public boolean isPageFlipping() { return (getFlipContents() != null); } /** * @return the resulting contents of the back buffer after page-flipping. * This value is {@code null} when the {@code isPageFlipping} * returns {@code false}, implying blitting. It can be one of * {@code FlipContents.UNDEFINED} * (the assumed default), {@code FlipContents.BACKGROUND}, * {@code FlipContents.PRIOR}, or * {@code FlipContents.COPIED}. * @see #isPageFlipping * @see FlipContents#UNDEFINED * @see FlipContents#BACKGROUND * @see FlipContents#PRIOR * @see FlipContents#COPIED */ public FlipContents getFlipContents() { return flipContents; } /** * @return whether page flipping is only available in full-screen mode. If this * is {@code true}, full-screen exclusive mode is required for * page-flipping. * @see #isPageFlipping * @see GraphicsDevice#setFullScreenWindow */ public boolean isFullScreenRequired() { return false; } /** * @return whether or not * page flipping can be performed using more than two buffers (one or more * intermediate buffers as well as the front and back buffer). * @see #isPageFlipping */ public boolean isMultiBufferAvailable() { return false; } /** * @return a copy of this BufferCapabilities object. */ public Object clone() { try { return super.clone(); } catch (CloneNotSupportedException e) { // Since we implement Cloneable, this should never happen throw new InternalError(e); } } // Inner class FlipContents /** * A type-safe enumeration of the possible back buffer contents after * page-flipping * @since 1.4 */ public static final class FlipContents extends AttributeValue { private static int I_UNDEFINED = 0; private static int I_BACKGROUND = 1; private static int I_PRIOR = 2; private static int I_COPIED = 3; private static final String[] NAMES = { "undefined", "background", "prior", "copied" }; /** * When flip contents are {@code UNDEFINED}, the * contents of the back buffer are undefined after flipping. * @see #isPageFlipping * @see #getFlipContents * @see #BACKGROUND * @see #PRIOR * @see #COPIED */ public static final FlipContents UNDEFINED = new FlipContents(I_UNDEFINED); /** * When flip contents are {@code BACKGROUND}, the * contents of the back buffer are cleared with the background color after * flipping. * @see #isPageFlipping * @see #getFlipContents * @see #UNDEFINED * @see #PRIOR * @see #COPIED */ public static final FlipContents BACKGROUND = new FlipContents(I_BACKGROUND); /** * When flip contents are {@code PRIOR}, the * contents of the back buffer are the prior contents of the front buffer * (a true page flip). * @see #isPageFlipping * @see #getFlipContents * @see #UNDEFINED * @see #BACKGROUND * @see #COPIED */ public static final FlipContents PRIOR = new FlipContents(I_PRIOR); /** * When flip contents are {@code COPIED}, the * contents of the back buffer are copied to the front buffer when * flipping. * @see #isPageFlipping * @see #getFlipContents * @see #UNDEFINED * @see #BACKGROUND * @see #PRIOR */ public static final FlipContents COPIED = new FlipContents(I_COPIED); private FlipContents(int type) { super(type, NAMES); } } // Inner class FlipContents }