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1   /*
2    * Copyright (c) 1998, 2012, 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 sun.java2d.pipe;
27  
28  import java.awt.Rectangle;
29  
30  /**
31   * This class defines the API for iterating through the bands
32   * of a region object.
33   */
34  public class RegionIterator {
35      Region region;
36      int curIndex;
37      int numXbands;
38  
39      RegionIterator(Region r) {
40          region = r;
41      }
42  
43      /**
44       * Returns a new RegionIterator object representing the same
45       * iteration state as this object to allow multiple iteration
46       * branches from the current position.
47       */
48      public RegionIterator createCopy() {
49          RegionIterator r = new RegionIterator(region);
50          r.curIndex = this.curIndex;
51          r.numXbands = this.numXbands;
52          return r;
53      }
54  
55      /**
56       * Copies the iteration state from this RegionIterator object
57       * into another RegionIterator object to allow multiple iteration
58       * branches from the current position.
59       */
60      public void copyStateFrom(RegionIterator ri) {
61          if (this.region != ri.region) {
62              throw new InternalError("region mismatch");
63          }
64          this.curIndex = ri.curIndex;
65          this.numXbands = ri.numXbands;
66      }
67  
68      /**
69       * Moves the iteration state to the beginning of the next
70       * Y range in the region returning true if one is found
71       * and recording the low and high Y coordinates of the
72       * range in the array at locations 1 and 3 respectively.
73       */
74      public boolean nextYRange(int range[]) {
75          curIndex += numXbands * 2;
76          numXbands = 0;
77          if (curIndex >= region.endIndex) {
78              return false;
79          }
80          range[1] = region.bands[curIndex++];
81          range[3] = region.bands[curIndex++];
82          numXbands = region.bands[curIndex++];
83          return true;
84      }
85  
86      /**
87       * Moves the iteration state to the beginning of the next
88       * X band in the current Y range returning true if one is
89       * found and recording the low and high X coordinates of
90       * the range in the array at locations 0 and 2 respectively.
91       */
92      public boolean nextXBand(int range[]) {
93          if (numXbands <= 0) {
94              return false;
95          }
96          numXbands--;
97          range[0] = region.bands[curIndex++];
98          range[2] = region.bands[curIndex++];
99          return true;
100     }
101 }