1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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15 * accompanied this code).
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24 */
25
26package 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 */
41public 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}
96