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25 
26 package sun.java2d.pipe.hw;
27 
28 import java.awt.BufferCapabilities;
29 import java.awt.ImageCapabilities;
30 
31 /**
32  * Provides extended BufferStrategy capabilities, allowing to specify
33  * the type of vertical refresh synchronization for a buffer strategy.
34  *
35  * This BS capability is always page flipping because v-sync is only relevant
36  * to flipping buffer strategies.
37  *
38  * Note that asking for a v-synced BS doesn't necessarily guarantee that it will
39  * be v-synced since the vsync capability may be disabled in the driver, or
40  * there may be other restriction (like a number of v-synced buffer strategies
41  * allowed per vm). Because of this {@code createBufferStrategy} doesn't
42  * throw {@code AWTException} when a v-synced BS could not be created when
43  * requested.
44  *
45  * @see java.awt.Canvas#createBufferStrategy(int, BufferCapabilities)
46  * @see java.awt.Window#createBufferStrategy(int, BufferCapabilities)
47  */
48 public class ExtendedBufferCapabilities extends BufferCapabilities {
49 
50     /**
51      * Type of synchronization on vertical retrace.
52      */
53     public static enum VSyncType {
54         /**
55          * Use the default v-sync mode appropriate for given BufferStrategy
56          * and situation.
57          */
58         VSYNC_DEFAULT(0),
59 
60         /**
61          * Synchronize flip on vertical retrace.
62          */
63         VSYNC_ON(1),
64 
65         /**
66          * Do not synchronize flip on vertical retrace.
67          */
68         VSYNC_OFF(2);
69 
70         /**
71          * Used to identify the v-sync type (independent of the constants
72          * order as opposed to {@code ordinal()}).
73          */
id()74         public int id() {
75             return id;
76         }
77 
VSyncType(int id)78         private VSyncType(int id) {
79             this.id = id;
80         }
81         private int id;
82     }
83 
84     private VSyncType vsync;
85 
86     /**
87      * Creates an ExtendedBufferCapabilities object with front/back/flip caps
88      * from the passed cap, and VSYNC_DEFAULT v-sync mode.
89      */
ExtendedBufferCapabilities(BufferCapabilities caps)90     public ExtendedBufferCapabilities(BufferCapabilities caps) {
91         super(caps.getFrontBufferCapabilities(),
92               caps.getBackBufferCapabilities(),
93               caps.getFlipContents());
94 
95         this.vsync = VSyncType.VSYNC_DEFAULT;
96     }
97 
98     /**
99      * Creates an ExtendedBufferCapabilities instance with front/back/flip caps
100      * from the passed caps, and VSYNC_DEFAULT v-sync mode.
101      */
ExtendedBufferCapabilities(ImageCapabilities front, ImageCapabilities back, FlipContents flip)102     public ExtendedBufferCapabilities(ImageCapabilities front,
103                                       ImageCapabilities back, FlipContents flip)
104     {
105         super(front, back, flip);
106 
107         this.vsync = VSyncType.VSYNC_DEFAULT;
108     }
109 
110     /**
111      * Creates an ExtendedBufferCapabilities instance with front/back/flip caps
112      * from the passed image/flip caps, and the v-sync type.
113      */
ExtendedBufferCapabilities(ImageCapabilities front, ImageCapabilities back, FlipContents flip, VSyncType t)114     public ExtendedBufferCapabilities(ImageCapabilities front,
115                                       ImageCapabilities back, FlipContents flip,
116                                       VSyncType t)
117     {
118         super(front, back, flip);
119 
120         this.vsync = t;
121     }
122 
123     /**
124      * Creates an ExtendedBufferCapabilities instance with front/back/flip caps
125      * from the passed cap, and the passed v-sync mode.
126      */
ExtendedBufferCapabilities(BufferCapabilities caps, VSyncType t)127     public ExtendedBufferCapabilities(BufferCapabilities caps, VSyncType t) {
128         super(caps.getFrontBufferCapabilities(),
129               caps.getBackBufferCapabilities(),
130               caps.getFlipContents());
131 
132         this.vsync = t;
133     }
134 
135     /**
136      * Creates an ExtendedBufferCapabilities instance with front/back/flip caps
137      * from the object, and passed v-sync mode.
138      */
derive(VSyncType t)139     public ExtendedBufferCapabilities derive(VSyncType t) {
140         return new ExtendedBufferCapabilities(this, t);
141     }
142 
143     /**
144      * Returns the type of v-sync requested by this capabilities instance.
145      */
getVSync()146     public VSyncType getVSync() {
147         return vsync;
148     }
149 
150     @Override
isPageFlipping()151     public final boolean isPageFlipping() {
152         return true;
153     }
154 }
155