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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
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15   * accompanied this code).
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25  
26  package java.awt.image;
27  
28  /**
29   *  This class represents image data which is stored in a pixel interleaved
30   *  fashion and for
31   *  which each sample of a pixel occupies one data element of the DataBuffer.
32   *  It subclasses ComponentSampleModel but provides a more efficient
33   *  implementation for accessing pixel interleaved image data than is provided
34   *  by ComponentSampleModel.  This class
35   *  stores sample data for all bands in a single bank of the
36   *  DataBuffer. Accessor methods are provided so that image data can be
37   *  manipulated directly. Pixel stride is the number of
38   *  data array elements between two samples for the same band on the same
39   *  scanline. Scanline stride is the number of data array elements between
40   *  a given sample and the corresponding sample in the same column of the next
41   *  scanline.  Band offsets denote the number
42   *  of data array elements from the first data array element of the bank
43   *  of the DataBuffer holding each band to the first sample of the band.
44   *  The bands are numbered from 0 to N-1.
45   *  Bank indices denote the correspondence between a bank of the data buffer
46   *  and a band of image data.
47   *  This class supports
48   *  {@link DataBuffer#TYPE_BYTE TYPE_BYTE},
49   *  {@link DataBuffer#TYPE_USHORT TYPE_USHORT},
50   *  {@link DataBuffer#TYPE_SHORT TYPE_SHORT},
51   *  {@link DataBuffer#TYPE_INT TYPE_INT},
52   *  {@link DataBuffer#TYPE_FLOAT TYPE_FLOAT} and
53   *  {@link DataBuffer#TYPE_DOUBLE TYPE_DOUBLE} datatypes.
54   */
55  
56  public class PixelInterleavedSampleModel extends ComponentSampleModel
57  {
58      /**
59       * Constructs a PixelInterleavedSampleModel with the specified parameters.
60       * The number of bands will be given by the length of the bandOffsets
61       * array.
62       * @param dataType  The data type for storing samples.
63       * @param w         The width (in pixels) of the region of
64       *                  image data described.
65       * @param h         The height (in pixels) of the region of
66       *                  image data described.
67       * @param pixelStride The pixel stride of the image data.
68       * @param scanlineStride The line stride of the image data.
69       * @param bandOffsets The offsets of all bands.
70       * @throws IllegalArgumentException if <code>w</code> or
71       *         <code>h</code> is not greater than 0
72       * @throws IllegalArgumentException if any offset between bands is
73       *         greater than the scanline stride
74       * @throws IllegalArgumentException if the product of
75       *         <code>pixelStride</code> and <code>w</code> is greater
76       *         than <code>scanlineStride</code>
77       * @throws IllegalArgumentException if <code>pixelStride</code> is
78       *         less than any offset between bands
79       * @throws IllegalArgumentException if <code>dataType</code> is not
80       *         one of the supported data types
81       */
82      public PixelInterleavedSampleModel(int dataType,
83                                         int w, int h,
84                                         int pixelStride,
85                                         int scanlineStride,
86                                         int bandOffsets[]) {
87          super(dataType, w, h, pixelStride, scanlineStride, bandOffsets);
88          int minBandOff=this.bandOffsets[0];
89          int maxBandOff=this.bandOffsets[0];
90          for (int i=1; i<this.bandOffsets.length; i++) {
91              minBandOff = Math.min(minBandOff,this.bandOffsets[i]);
92              maxBandOff = Math.max(maxBandOff,this.bandOffsets[i]);
93          }
94          maxBandOff -= minBandOff;
95          if (maxBandOff > scanlineStride) {
96              throw new IllegalArgumentException("Offsets between bands must be"+
97                                                 " less than the scanline "+
98                                                 " stride");
99          }
100         if (pixelStride*w > scanlineStride) {
101             throw new IllegalArgumentException("Pixel stride times width "+
102                                                "must be less than or "+
103                                                "equal to the scanline "+
104                                                "stride");
105         }
106         if (pixelStride < maxBandOff) {
107             throw new IllegalArgumentException("Pixel stride must be greater"+
108                                                " than or equal to the offsets"+
109                                                " between bands");
110         }
111     }
112 
113     /**
114      * Creates a new PixelInterleavedSampleModel with the specified
115      * width and height.  The new PixelInterleavedSampleModel will have the
116      * same number of bands, storage data type, and pixel stride
117      * as this PixelInterleavedSampleModel.  The band offsets may be
118      * compressed such that the minimum of all of the band offsets is zero.
119      * @param w the width of the resulting <code>SampleModel</code>
120      * @param h the height of the resulting <code>SampleModel</code>
121      * @return a new <code>SampleModel</code> with the specified width
122      *         and height.
123      * @throws IllegalArgumentException if <code>w</code> or
124      *         <code>h</code> is not greater than 0
125      */
126     public SampleModel createCompatibleSampleModel(int w, int h) {
127         int minBandoff=bandOffsets[0];
128         int numBands = bandOffsets.length;
129         for (int i=1; i < numBands; i++) {
130             if (bandOffsets[i] < minBandoff) {
131                 minBandoff = bandOffsets[i];
132             }
133         }
134         int[] bandOff;
135         if (minBandoff > 0) {
136             bandOff = new int[numBands];
137             for (int i=0; i < numBands; i++) {
138                 bandOff[i] = bandOffsets[i] - minBandoff;
139             }
140         }
141         else {
142             bandOff = bandOffsets;
143         }
144         return new PixelInterleavedSampleModel(dataType, w, h, pixelStride,
145                                                pixelStride*w, bandOff);
146     }
147 
148     /**
149      * Creates a new PixelInterleavedSampleModel with a subset of the
150      * bands of this PixelInterleavedSampleModel.  The new
151      * PixelInterleavedSampleModel can be used with any DataBuffer that the
152      * existing PixelInterleavedSampleModel can be used with.  The new
153      * PixelInterleavedSampleModel/DataBuffer combination will represent
154      * an image with a subset of the bands of the original
155      * PixelInterleavedSampleModel/DataBuffer combination.
156      */
157     public SampleModel createSubsetSampleModel(int bands[]) {
158         int newBandOffsets[] = new int[bands.length];
159         for (int i=0; i<bands.length; i++) {
160             newBandOffsets[i] = bandOffsets[bands[i]];
161         }
162         return new PixelInterleavedSampleModel(this.dataType, width, height,
163                                                this.pixelStride,
164                                                scanlineStride, newBandOffsets);
165     }
166 
167     // Differentiate hash code from other ComponentSampleModel subclasses
168     public int hashCode() {
169         return super.hashCode() ^ 0x1;
170     }
171 }