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25 
26 
27 package sun.awt.image;
28 
29 import java.awt.image.DataBuffer;
30 import sun.java2d.SurfaceData;
31 import java.awt.Rectangle;
32 
33 /**
34  * This class extends {@code DataBuffer} and allows access to
35  * native data via the DataBuffer methods.  Note that, unlike other
36  * DataBuffer classes, the data is not stored in this class but
37  * has been created and stored elsewhere and this class is used
38  * merely to access that data.  Note also that this class subclasses
39  * from DataBuffer and not from any of the standard subclasses
40  * (e.g., DataBufferInt); those subclasses allow the user to
41  * get a pointer to the data and manipulate it directly.  That
42  * operation may not be possible or wise with native data.
43  * One important use of this DataBuffer class is in accessing the
44  * data stored in an offscreen vram surface, such as that created
45  * by the createVolatileImage() method.
46  */
47 
48 public class DataBufferNative extends DataBuffer
49 {
50     protected SurfaceData surfaceData;
51     protected int width;
52 
53     /**
54      * Constructor.  The constructor of this object requires a
55      * SurfaceData object; that surfaceData object will be used
56      * to access the actual pixel data in native code.
57      */
DataBufferNative(SurfaceData sData, int type, int width, int height)58     public DataBufferNative(SurfaceData sData, int type, int width, int height) {
59         super(type, width*height);
60         this.width = width;
61         this.surfaceData = sData;
62     }
63 
getElem(int x, int y, SurfaceData sData)64     protected native int getElem(int x, int y, SurfaceData sData);
65 
66     /**
67      * getElem returns the pixel value for a given index into the
68      * dataBuffer array.  The bank value is currently ignored (the
69      * type of data accessed through this class is not stored in
70      * separate banks).  The x and y coordinates of a pixel are calculated
71      * from the index value and the native getElem() method is
72      * called with the internal surfaceData object.
73      */
getElem(int bank, int i)74     public int getElem(int bank, int i) {
75         return getElem(i % width, i / width, surfaceData);
76     }
77 
setElem(int x, int y, int val, SurfaceData sData)78     protected native void setElem(int x, int y, int val, SurfaceData sData);
79 
80     /**
81      * setElem sets the pixel value of a given index into the
82      * dataBuffer array.  The bank value is currently ignored (the
83      * type of data accessed through this class is not stored in
84      * separate banks).  The x and y coordinates of a pixel are calculated
85      * from the index value and the native setElem() method is
86      * called with the internal surfaceData object.
87      */
setElem(int bank, int i, int val)88     public void setElem(int bank, int i, int val) {
89         setElem(i % width, i / width, val, surfaceData);
90     }
91 
92 }
93