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11   * This code is distributed in the hope that it will be useful, but WITHOUT
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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 sun.java2d.pipe;
27  
28  /**
29   * This interface defines a general method for iterating through the
30   * rectangular "spans" that represent the interior of a filled path.
31   * <p>
32   * There can be many kinds of span iterators used in the rendering
33   * pipeline, the most basic being an iterator that scan converts a
34   * path defined by any PathIterator, or an nested iterator which
35   * intersects another iterator's spans with a clip region.
36   * Other iterators can be created for scan converting some of the
37   * primitive shapes more explicitly for speed or quality.
38   *
39   * @author Jim Graham
40   */
41  public interface SpanIterator {
42      /**
43       * This method returns the bounding box of the spans that the
44       * iterator will be returning.
45       * The array must be of length at least 4 and upon return, it
46       * will be filled with the values:
47       * <pre>
48       *     {PathMinX, PathMinY, PathMaxX, PathMaxY}.
49       * </pre>
50       */
51      public void getPathBox(int pathbox[]);
52  
53      /**
54       * This method constrains the spans returned by nextSpan() to the
55       * rectangle whose bounds are given.
56       */
57      public void intersectClipBox(int lox, int loy, int hix, int hiy);
58  
59      /**
60       * This method returns the next span in the shape being iterated.
61       * The array must be of length at least 4 and upon return, it
62       * will be filled with the values:
63       * <pre>
64       *     {SpanMinX, SpanMinY, SpanMaxX, SpanMaxY}.
65       * </pre>
66       */
67      public boolean nextSpan(int spanbox[]);
68  
69      /**
70       * This method tells the iterator that it may skip all spans
71       * whose Y range is completely above the indicated Y coordinate.
72       * This method is used to provide feedback from the caller when
73       * clipping prevents the display of any data in a given Y range.
74       * Typically it will only be called when this iterator has returned
75       * a span whose MaxY coordinate is less than the indicated Y and
76       * the calling mechanism wants to avoid unnecessary iteration work.
77       * While this request could technically be ignored (i.e. a NOP),
78       * doing so could potentially cause the caller to make this callback
79       * for each span that is being skipped.
80       */
81      public void skipDownTo(int y);
82  
83      /**
84       * This method returns a native pointer to a function block that
85       * can be used by a native method to perform the same iteration
86       * cycle that the above methods provide while avoiding upcalls to
87       * the Java object.
88       * The definition of the structure whose pointer is returned by
89       * this method is defined in:
90       * <pre>
91       *     src/share/native/sun/java2d/pipe/SpanIterator.h
92       * </pre>
93       */
94      public long getNativeIterator();
95  }