1 /* 2 * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.awt; 27 28 /** 29 * Capabilities and properties of buffers. 30 * 31 * @see java.awt.image.BufferStrategy#getCapabilities() 32 * @see GraphicsConfiguration#getBufferCapabilities 33 * @author Michael Martak 34 * @since 1.4 35 */ 36 public class BufferCapabilities implements Cloneable { 37 38 private ImageCapabilities frontCaps; 39 private ImageCapabilities backCaps; 40 private FlipContents flipContents; 41 42 /** 43 * Creates a new object for specifying buffering capabilities 44 * @param frontCaps the capabilities of the front buffer; cannot be 45 * {@code null} 46 * @param backCaps the capabilities of the back and intermediate buffers; 47 * cannot be {@code null} 48 * @param flipContents the contents of the back buffer after page-flipping, 49 * {@code null} if page flipping is not used (implies blitting) 50 * @exception IllegalArgumentException if frontCaps or backCaps are 51 * {@code null} 52 */ BufferCapabilities(ImageCapabilities frontCaps, ImageCapabilities backCaps, FlipContents flipContents)53 public BufferCapabilities(ImageCapabilities frontCaps, 54 ImageCapabilities backCaps, FlipContents flipContents) { 55 if (frontCaps == null || backCaps == null) { 56 throw new IllegalArgumentException( 57 "Image capabilities specified cannot be null"); 58 } 59 this.frontCaps = frontCaps; 60 this.backCaps = backCaps; 61 this.flipContents = flipContents; 62 } 63 64 /** 65 * @return the image capabilities of the front (displayed) buffer 66 */ getFrontBufferCapabilities()67 public ImageCapabilities getFrontBufferCapabilities() { 68 return frontCaps; 69 } 70 71 /** 72 * @return the image capabilities of all back buffers (intermediate buffers 73 * are considered back buffers) 74 */ getBackBufferCapabilities()75 public ImageCapabilities getBackBufferCapabilities() { 76 return backCaps; 77 } 78 79 /** 80 * @return whether or not the buffer strategy uses page flipping; a set of 81 * buffers that uses page flipping 82 * can swap the contents internally between the front buffer and one or 83 * more back buffers by switching the video pointer (or by copying memory 84 * internally). A non-flipping set of 85 * buffers uses blitting to copy the contents from one buffer to 86 * another; when this is the case, {@code getFlipContents} returns 87 * {@code null} 88 */ isPageFlipping()89 public boolean isPageFlipping() { 90 return (getFlipContents() != null); 91 } 92 93 /** 94 * @return the resulting contents of the back buffer after page-flipping. 95 * This value is {@code null} when the {@code isPageFlipping} 96 * returns {@code false}, implying blitting. It can be one of 97 * {@code FlipContents.UNDEFINED} 98 * (the assumed default), {@code FlipContents.BACKGROUND}, 99 * {@code FlipContents.PRIOR}, or 100 * {@code FlipContents.COPIED}. 101 * @see #isPageFlipping 102 * @see FlipContents#UNDEFINED 103 * @see FlipContents#BACKGROUND 104 * @see FlipContents#PRIOR 105 * @see FlipContents#COPIED 106 */ getFlipContents()107 public FlipContents getFlipContents() { 108 return flipContents; 109 } 110 111 /** 112 * @return whether page flipping is only available in full-screen mode. If this 113 * is {@code true}, full-screen exclusive mode is required for 114 * page-flipping. 115 * @see #isPageFlipping 116 * @see GraphicsDevice#setFullScreenWindow 117 */ isFullScreenRequired()118 public boolean isFullScreenRequired() { 119 return false; 120 } 121 122 /** 123 * @return whether or not 124 * page flipping can be performed using more than two buffers (one or more 125 * intermediate buffers as well as the front and back buffer). 126 * @see #isPageFlipping 127 */ isMultiBufferAvailable()128 public boolean isMultiBufferAvailable() { 129 return false; 130 } 131 132 /** 133 * @return a copy of this BufferCapabilities object. 134 */ clone()135 public Object clone() { 136 try { 137 return super.clone(); 138 } catch (CloneNotSupportedException e) { 139 // Since we implement Cloneable, this should never happen 140 throw new InternalError(e); 141 } 142 } 143 144 // Inner class FlipContents 145 /** 146 * A type-safe enumeration of the possible back buffer contents after 147 * page-flipping 148 * @since 1.4 149 */ 150 public static final class FlipContents extends AttributeValue { 151 152 private static int I_UNDEFINED = 0; 153 private static int I_BACKGROUND = 1; 154 private static int I_PRIOR = 2; 155 private static int I_COPIED = 3; 156 157 private static final String[] NAMES = 158 { "undefined", "background", "prior", "copied" }; 159 160 /** 161 * When flip contents are {@code UNDEFINED}, the 162 * contents of the back buffer are undefined after flipping. 163 * @see #isPageFlipping 164 * @see #getFlipContents 165 * @see #BACKGROUND 166 * @see #PRIOR 167 * @see #COPIED 168 */ 169 public static final FlipContents UNDEFINED = 170 new FlipContents(I_UNDEFINED); 171 172 /** 173 * When flip contents are {@code BACKGROUND}, the 174 * contents of the back buffer are cleared with the background color after 175 * flipping. 176 * @see #isPageFlipping 177 * @see #getFlipContents 178 * @see #UNDEFINED 179 * @see #PRIOR 180 * @see #COPIED 181 */ 182 public static final FlipContents BACKGROUND = 183 new FlipContents(I_BACKGROUND); 184 185 /** 186 * When flip contents are {@code PRIOR}, the 187 * contents of the back buffer are the prior contents of the front buffer 188 * (a true page flip). 189 * @see #isPageFlipping 190 * @see #getFlipContents 191 * @see #UNDEFINED 192 * @see #BACKGROUND 193 * @see #COPIED 194 */ 195 public static final FlipContents PRIOR = 196 new FlipContents(I_PRIOR); 197 198 /** 199 * When flip contents are {@code COPIED}, the 200 * contents of the back buffer are copied to the front buffer when 201 * flipping. 202 * @see #isPageFlipping 203 * @see #getFlipContents 204 * @see #UNDEFINED 205 * @see #BACKGROUND 206 * @see #PRIOR 207 */ 208 public static final FlipContents COPIED = 209 new FlipContents(I_COPIED); 210 FlipContents(int type)211 private FlipContents(int type) { 212 super(type, NAMES); 213 } 214 215 } // Inner class FlipContents 216 217 } 218