| /* BufferCapabilities.java -- double-buffering capabilities descriptor |
| Copyright (C) 2002, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.awt; |
| |
| import java.awt.image.BufferStrategy; |
| |
| /** |
| * A double-buffering capability descriptor. This class exposes |
| * details about the double-buffering algorithms used by image |
| * buffers. |
| * |
| * BufferCapabilities represents algorithms that involve at least two |
| * buffers but it can also specify so-called "multi-buffer" schemes |
| * involving more than two buffers. This class describes the |
| * capabilities of the front and back buffers as well as the results |
| * of "flipping" -- that is, what happens when an image is transferred |
| * from the back buffer to the front buffer. |
| * |
| * Flipping may or may not be supported or may be supported only in |
| * fullscreen mode. If it is not supported then "blitting" is implied |
| * -- that is, the contents of the back buffer are copied using a fast |
| * block transfer operation from the back buffer to the front buffer. |
| * |
| * The front buffer is the one that is displayed. |
| * |
| * @author Eric Blake (ebb9@email.byu.edu) |
| * |
| * @see BufferStrategy#getCapabilities() |
| * @see GraphicsConfiguration#getBufferCapabilities() |
| * |
| * @since 1.4 |
| */ |
| public class BufferCapabilities implements Cloneable |
| { |
| /** |
| * A type-safe enumeration of buffer flipping results. |
| * |
| * @see AttributeValue |
| */ |
| public static final class FlipContents extends AttributeValue |
| { |
| /** |
| * The names of the different flipping results. |
| */ |
| private static final String[] NAMES |
| = { "undefined", "background", "prior", "copied" }; |
| |
| /** |
| * The contents of the back buffer are undefined after flipping. |
| */ |
| public static final FlipContents UNDEFINED = new FlipContents(0); |
| |
| /** |
| * The back buffer is cleared with the background color after |
| * flipping. |
| */ |
| public static final FlipContents BACKGROUND = new FlipContents(1); |
| |
| /** |
| * The back buffer contains the pre-flipping contents of the front |
| * buffer after flipping. In other words a true "flip" has been |
| * performed. |
| */ |
| public static final FlipContents PRIOR = new FlipContents(2); |
| |
| /** |
| * The back buffer has the same contents as the front buffer after |
| * flipping. |
| */ |
| public static final FlipContents COPIED = new FlipContents(3); |
| |
| /** |
| * Create a new flipping result descriptor. |
| * |
| * @param value the enumeration value |
| */ |
| private FlipContents(int value) |
| { |
| super(value, NAMES); |
| } |
| } |
| |
| /** |
| * Front buffer capabilities descriptor. |
| */ |
| private final ImageCapabilities front; |
| |
| /** |
| * Back buffer capabilities descriptor. |
| */ |
| private final ImageCapabilities back; |
| |
| /** |
| * Describes the results of a "flip" operation. |
| */ |
| private final FlipContents flip; |
| |
| /** |
| * Creates a buffer capabilities object. |
| * |
| * @param frontCaps front buffer capabilities descriptor |
| * @param backCaps back buffer capabilities descriptor |
| * @param flip the results of a flip operation or null if |
| * flipping is not supported |
| * |
| * @exception IllegalArgumentException if frontCaps or backCaps is |
| * null |
| */ |
| public BufferCapabilities(ImageCapabilities frontCaps, |
| ImageCapabilities backCaps, |
| FlipContents flip) |
| { |
| if (frontCaps == null || backCaps == null) |
| throw new IllegalArgumentException(); |
| this.front = frontCaps; |
| this.back = backCaps; |
| this.flip = flip; |
| } |
| |
| /** |
| * Retrieve the front buffer's image capabilities. |
| * |
| * @return the front buffer's image capabilities |
| */ |
| public ImageCapabilities getFrontBufferCapabilities() |
| { |
| return front; |
| } |
| |
| /** |
| * Retrieve the back buffer's image capabilities. |
| * |
| * @return the back buffer's image capabilities |
| */ |
| public ImageCapabilities getBackBufferCapabilities() |
| { |
| return back; |
| } |
| |
| /** |
| * Return whether or not flipping is supported. |
| * |
| * @return true if flipping is supported, false otherwise |
| */ |
| public boolean isPageFlipping() |
| { |
| return flip != null; |
| } |
| |
| /** |
| * Retrieve the result of a flipping operation. If this method |
| * returns null then flipping is not supported. This implies that |
| * "blitting", a fast block transfer, is used to copy the contents |
| * of the back buffer to the front buffer. Other possible return |
| * values are: |
| * <ul> |
| * <li><code>FlipContents.UNDEFINED</code> the contents of the |
| * back buffer are undefined after flipping.</li> |
| * <li><code>FlipContents.BACKGROUND</code> the contents of the |
| * back buffer are cleared to the background color after |
| * flipping.</li> |
| * <li><code>FlipContents.PRIOR</code> the back buffer contains |
| * the pre-flipping contents of the front * buffer after |
| * flipping.</li> |
| * <li><code>FlipContents.COPIED</code> the back buffer has the |
| * same contents as the front buffer after flipping.</li> |
| * </ul> |
| * |
| * @return the result of a flipping operation or null if flipping is |
| * not supported |
| */ |
| public FlipContents getFlipContents() |
| { |
| return flip; |
| } |
| |
| /** |
| * Returns true if flipping is only supported in fullscreen mode. |
| * |
| * @return true if flipping is only supported in fullscreen mode, |
| * false otherwise |
| */ |
| public boolean isFullScreenRequired() |
| { |
| return true; |
| } |
| |
| /** |
| * Returns true if flipping can involve more than two buffers. One |
| * or more intermediate buffers may be available in addition to the |
| * front and back buffers. |
| * |
| * @return true if there are more than two buffers available for |
| * flipping, false otherwise |
| */ |
| public boolean isMultiBufferAvailable() |
| { |
| return false; |
| } |
| |
| /** |
| * Clone this buffering capability descriptor. |
| * |
| * @return a clone of this buffer capability descriptor |
| */ |
| public Object clone() |
| { |
| try |
| { |
| return super.clone(); |
| } |
| catch (CloneNotSupportedException e) |
| { |
| throw (Error) new InternalError().initCause(e); |
| } |
| } |
| } |