/[classpath]/classpath/java/awt/geom/PathIterator.java
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revision 1.2 by mark, Tue Jan 22 22:26:59 2002 UTC revision 1.3 by ericb, Thu Mar 21 07:58:00 2002 UTC
# Line 1  Line 1 
1  /* Copyright (C) 2000, 2002  Free Software Foundation  /* PathIterator.java -- describes a shape by iterating over its vertices
2       Copyright (C) 2000, 2002 Free Software Foundation
3    
4  This file is part of GNU Classpath.  This file is part of GNU Classpath.
5    
# Line 37  exception statement from your version. * Line 38  exception statement from your version. *
38  package java.awt.geom;  package java.awt.geom;
39    
40  /**  /**
41     * This interface provides a directed path over the boundary of a shape. The
42     * path can contain 1st through 3rd order Bezier curves (lines, and quadratic
43     * and cubic splines). A shape can have multiple disjoint paths via the
44     * MOVETO directive, and can close a circular path back to the previos
45     * MOVETO via the CLOSE directive.
46     *
47   * @author Tom Tromey <tromey@cygnus.com>   * @author Tom Tromey <tromey@cygnus.com>
48   * @date April 16, 2000   * @author Eric Blake <ebb9@email.byu.edu>
49     * @see Shape
50     * @see Stroke
51     * @see FlatteningPathIterator
52     * @since 1.2
53     * @status updated to 1.4
54   */   */
   
55  public interface PathIterator  public interface PathIterator
56  {  {
57    public static final int SEG_CLOSE = 4;    /**
58    public static final int SEG_CUBICTO = 3;     * The even-odd winding mode: a point is internal to the shape if a ray
59    public static final int SEG_LINETO = 1;     * from the point to infinity (in any direction) crosses an odd number of
60    public static final int SEG_MOVETO = 0;     * segments.
61    public static final int SEG_QUADTO = 2;     */
62    public static final int WIND_EVEN_ODD = 0;    int WIND_EVEN_ODD = 0;
63    public static final int WIND_NON_ZERO = 1;  
64      /**
65    public int currentSegment (double[] coords);     * The non-zero winding mode: a point is internal to the shape if a ray
66    public int currentSegment (float[] coords);     * from the point to infinity (in any direction) crosses a different number
67    public int getWindingRule ();     * of segments headed clockwise than those headed counterclockwise.
68    public boolean isDone ();     */
69    public void next ();    int WIND_NON_ZERO = 1;
70  }  
71      /**
72       * Starts a new subpath. There is no segment from the previous vertex.
73       */
74      int SEG_MOVETO = 0;
75    
76      /**
77       * The current segment is a line.
78       */
79      int SEG_LINETO = 1;
80    
81      /**
82       * The current segment is a quadratic parametric curve. It is interpolated
83       * as t varies from 0 to 1 over the current point (CP), first control point
84       * (P1), and final interpolated control point (P2):
85       * <pre>
86       *  P(t) = B(2,0)*CP + B(2,1)*P1 + B(2,2)*P2
87       *    0 <= t <= 1
88       *  B(n,m) = mth coefficient of nth degree Bernstein polynomial
89       *         = C(n,m) * t^(m) * (1 - t)^(n-m)
90       *  C(n,m) = Combinations of n things, taken m at a time
91       *         = n! / (m! * (n-m)!)
92       * </pre>
93       */
94      int SEG_QUADTO = 2;
95    
96      /**
97       * The current segment is a cubic parametric curve (more commonly known as
98       * a Bezier curve). It is interpolated as t varies from 0 to 1 over the
99       * current point (CP), first control point (P1), the second control point
100       * (P2), and final interpolated control point (P3):
101       * <pre>
102       *  P(t) = B(3,0)*CP + B(3,1)*P1 + B(3,2)*P2 + B(3,3)*P3
103       *    0 <= t <= 1
104       *  B(n,m) = mth coefficient of nth degree Bernstein polynomial
105       *         = C(n,m) * t^(m) * (1 - t)^(n-m)
106       *  C(n,m) = Combinations of n things, taken m at a time
107       *         = n! / (m! * (n-m)!)
108       * </pre>
109       */
110      int SEG_CUBICTO = 3;
111    
112      /**
113       * The current segment closes a loop by an implicit line to the previous
114       * SEG_MOVETO coordinate.
115       */
116      int SEG_CLOSE = 4;
117    
118      /**
119       * Returns the winding rule to determine which points are inside this path.
120       *
121       * @return the winding rule
122       * @see #WIND_EVEN_ODD
123       * @see #WIND_NON_ZERO
124       */
125      int getWindingRule();
126    
127      /**
128       * Tests if the iterator is exhausted. If this returns false, currentSegment
129       * and next may throw a NoSuchElementException (although this is not
130       * required).
131       *
132       * @return true if the iteration is complete
133       */
134      boolean isDone();
135    
136      /**
137       * Advance to the next segment in the iteration. It is not specified what
138       * this does if called when isDone() returns false.
139       *
140       * @throws NoSuchElementException optional when isDone() is true
141       */
142      void next();
143    
144      /**
145       * Returns the coordinates of the next point(s), as well as the type of
146       * line segment. The input array must be at least a float[6], to accomodate
147       * up to three (x,y) point pairs (although if you know the iterator is
148       * flat, you can probably get by with a float[2]). If the returned type is
149       * SEG_MOVETO or SEG_LINETO, the first point in the array is modified; if
150       * the returned type is SEG_QUADTO, the first two points are modified; if
151       * the returned type is SEG_CUBICTO, all three points are modified; and if
152       * the returned type is SEG_CLOSE, the array is untouched.
153       *
154       * @param coords the array to place the point coordinates in
155       * @return the segment type
156       * @throws NullPointerException if coords is null
157       * @throws ArrayIndexOutOfBoundsException if coords is too small
158       * @throws NoSuchElementException optional when isDone() is true
159       * @see #SEG_MOVETO
160       * @see #SEG_LINETO
161       * @see #SEG_QUADTO
162       * @see #SEG_CUBICTO
163       * @see #SEG_CLOSE
164       */
165      int currentSegment(float[] coords);
166    
167      /**
168       * Returns the coordinates of the next point(s), as well as the type of
169       * line segment. The input array must be at least a double[6], to accomodate
170       * up to three (x,y) point pairs (although if you know the iterator is
171       * flat, you can probably get by with a double[2]). If the returned type is
172       * SEG_MOVETO or SEG_LINETO, the first point in the array is modified; if
173       * the returned type is SEG_QUADTO, the first two points are modified; if
174       * the returned type is SEG_CUBICTO, all three points are modified; and if
175       * the returned type is SEG_CLOSE, the array is untouched.
176       *
177       * @param coords the array to place the point coordinates in
178       * @return the segment type
179       * @throws NullPointerException if coords is null
180       * @throws ArrayIndexOutOfBoundsException if coords is too small
181       * @throws NoSuchElementException optional when isDone() is true
182       * @see #SEG_MOVETO
183       * @see #SEG_LINETO
184       * @see #SEG_QUADTO
185       * @see #SEG_CUBICTO
186       * @see #SEG_CLOSE
187       */
188      int currentSegment(double[] coords);
189    } // interface PathIterator

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