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25 
26 package sun.java2d;
27 
28 import java.awt.Rectangle;
29 import java.awt.image.Raster;
30 import java.awt.image.ColorModel;
31 import java.awt.GraphicsConfiguration;
32 
33 import sun.java2d.StateTrackable.State;
34 import sun.java2d.loops.SurfaceType;
35 import sun.java2d.pipe.NullPipe;
36 
37 /**
38  * This class provides an empty implementation of the SurfaceData
39  * abstract superclass.  All operations on it translate into NOP
40  * or harmless operations.
41  */
42 public class NullSurfaceData extends SurfaceData {
43     public static final SurfaceData theInstance = new NullSurfaceData();
44 
NullSurfaceData()45     private NullSurfaceData() {
46         super(State.IMMUTABLE, SurfaceType.Any, ColorModel.getRGBdefault());
47     }
48 
49     /**
50      * Sets this SurfaceData object to the invalid state.  All Graphics
51      * objects must get a new SurfaceData object via the refresh method
52      * and revalidate their pipelines before continuing.
53      */
invalidate()54     public void invalidate() {
55     }
56 
57     /**
58      * Return a new SurfaceData object that represents the current state
59      * of the destination that this SurfaceData object describes.
60      * This method is typically called when the SurfaceData is invalidated.
61      */
getReplacement()62     public SurfaceData getReplacement() {
63         return this;
64     }
65 
66     private static final NullPipe nullpipe = new NullPipe();
67 
validatePipe(SunGraphics2D sg2d)68     public void validatePipe(SunGraphics2D sg2d) {
69         sg2d.drawpipe = nullpipe;
70         sg2d.fillpipe = nullpipe;
71         sg2d.shapepipe = nullpipe;
72         sg2d.textpipe = nullpipe;
73         sg2d.imagepipe = nullpipe;
74     }
75 
getDeviceConfiguration()76     public GraphicsConfiguration getDeviceConfiguration() {
77         return null;
78     }
79 
80     /**
81      * Return a readable Raster which contains the pixels for the
82      * specified rectangular region of the destination surface.
83      * The coordinate origin of the returned Raster is the same as
84      * the device space origin of the destination surface.
85      * In some cases the returned Raster might also be writeable.
86      * In most cases, the returned Raster might contain more pixels
87      * than requested.
88      *
89      * @see #useTightBBoxes
90      */
getRaster(int x, int y, int w, int h)91     public Raster getRaster(int x, int y, int w, int h) {
92         throw new InvalidPipeException("should be NOP");
93     }
94 
95     /**
96      * Does the pixel accessibility of the destination surface
97      * suggest that rendering algorithms might want to take
98      * extra time to calculate a more accurate bounding box for
99      * the operation being performed?
100      * The typical case when this will be true is when a copy of
101      * the pixels has to be made when doing a getRaster.  The
102      * fewer pixels copied, the faster the operation will go.
103      *
104      * @see #getRaster
105      */
useTightBBoxes()106     public boolean useTightBBoxes() {
107         return false;
108     }
109 
110     /**
111      * Returns the pixel data for the specified Argb value packed
112      * into an integer for easy storage and conveyance.
113      */
pixelFor(int rgb)114     public int pixelFor(int rgb) {
115         return rgb;
116     }
117 
118     /**
119      * Returns the Argb representation for the specified integer value
120      * which is packed in the format of the associated ColorModel.
121      */
rgbFor(int pixel)122     public int rgbFor(int pixel) {
123         return pixel;
124     }
125 
126     /**
127      * Returns the bounds of the destination surface.
128      */
getBounds()129     public Rectangle getBounds() {
130         return new Rectangle();
131     }
132 
133     /**
134      * Performs Security Permissions checks to see if a Custom
135      * Composite object should be allowed access to the pixels
136      * of this surface.
137      */
checkCustomComposite()138     protected void checkCustomComposite() {
139         return;
140     }
141 
142     /**
143      * Performs a copyarea within this surface.  Returns
144      * false if there is no algorithm to perform the copyarea
145      * given the current settings of the SunGraphics2D.
146      */
copyArea(SunGraphics2D sg2d, int x, int y, int w, int h, int dx, int dy)147     public boolean copyArea(SunGraphics2D sg2d,
148                             int x, int y, int w, int h, int dx, int dy)
149     {
150         return true;
151     }
152 
153     /**
154      * Returns destination Image associated with this SurfaceData (null)
155      */
getDestination()156     public Object getDestination() {
157         return null;
158     }
159 }
160