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1   /*
2    * Copyright (c) 1998, 2007, 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.geom.PathIterator;
29  import java.awt.Rectangle;
30  import sun.awt.geom.PathConsumer2D;
31  
32  /**
33   * This class can iterate individual span elements generated by scan
34   * converting a Shape.
35   * This particular implementation flattens the incoming path and then
36   * performs simple polygon tracing to calculate the spans.
37   *
38   * Note that this class holds pointers to native data which must be
39   * disposed.  It is not marked as finalizable since it is intended
40   * to be very lightweight and finalization is a comparitively expensive
41   * procedure.  The caller must specifically use try{} finally{} to
42   * manually ensure that the object is disposed after use, otherwise
43   * native data structures might be leaked.
44   *
45   * Here is a code sample for using this class:
46   *
47   * public void fillShape(Shape s, Rectangle clipRect) {
48   *     ShapeSpanIterator ssi = new ShapeSpanIterator(false);
49   *     try {
50   *         ssi.setOutputArea(clipRect);
51   *         ssi.appendPath(s.getPathIterator(null));
52   *         int spanbox[] = new int[4];
53   *         while (ssi.nextSpan(spanbox)) {
54   *             int x = spanbox[0];
55   *             int y = spanbox[1];
56   *             int w = spanbox[2] - x;
57   *             int h = spanbox[3] - y;
58   *             fillRect(x, y, w, h);
59   *         }
60   *     } finally {
61   *         ssi.dispose();
62   *     }
63   * }
64   */
65  public final class ShapeSpanIterator
66      implements SpanIterator, PathConsumer2D
67  {
68      long pData;
69  
70      static {
71          initIDs();
72      }
73  
74      public static native void initIDs();
75  
76      public ShapeSpanIterator(boolean adjust) {
77          setNormalize(adjust);
78      }
79  
80      /*
81       * Appends the geometry and winding rule from the indicated
82       * path iterator.
83       */
84      public void appendPath(PathIterator pi) {
85          float coords[] = new float[6];
86  
87          setRule(pi.getWindingRule());
88          while (!pi.isDone()) {
89              addSegment(pi.currentSegment(coords), coords);
90              pi.next();
91          }
92          pathDone();
93      }
94  
95      /*
96       * Appends the geometry from the indicated set of polygon points.
97       */
98      public native void appendPoly(int xPoints[], int yPoints[], int nPoints,
99                                    int xoff, int yoff);
100 
101     /*
102      * Sets the normalization flag so that incoming data is
103      * adjusted to nearest (0.25, 0.25) subpixel position.
104      */
105     private native void setNormalize(boolean adjust);
106 
107     /*
108      * Sets the rectangle of interest for storing and returning
109      * span segments.
110      */
111     public void setOutputAreaXYWH(int x, int y, int w, int h) {
112         setOutputAreaXYXY(x, y, Region.dimAdd(x, w), Region.dimAdd(y, h));
113     }
114 
115     /*
116      * Sets the rectangle of interest for storing and returning
117      * span segments.
118      */
119     public native void setOutputAreaXYXY(int lox, int loy, int hix, int hiy);
120 
121     /*
122      * Sets the rectangle of interest for storing and returning
123      * span segments to the specified Rectangle.
124      */
125     public void setOutputArea(Rectangle r) {
126         setOutputAreaXYWH(r.x, r.y, r.width, r.height);
127     }
128 
129     /*
130      * Sets the rectangle of interest for storing and returning
131      * span segments to the bounds of the specified Region.
132      */
133     public void setOutputArea(Region r) {
134         setOutputAreaXYXY(r.lox, r.loy, r.hix, r.hiy);
135     }
136 
137     /*
138      * Sets the winding rule in the native data structures.
139      */
140     public native void setRule(int rule);
141 
142     /*
143      * Adds a single PathIterator segment to the internal list of
144      * path element structures.
145      */
146     public native void addSegment(int type, float coords[]);
147 
148     /*
149      * Gets the bbox of the available path segments, clipped to the
150      * OutputArea.
151      */
152     public native void getPathBox(int pathbox[]);
153 
154     /*
155      * Intersects the path box with the given bbox.
156      * Returned spans are clipped to this region, or discarded
157      * altogether if they lie outside it.
158      */
159     public native void intersectClipBox(int lox, int loy, int hix, int hiy);
160 
161     /*
162      * Fetches the next span that needs to be operated on.
163      * If the return value is false then there are no more spans.
164      */
165     public native boolean nextSpan(int spanbox[]);
166 
167     /**
168      * This method tells the iterator that it may skip all spans
169      * whose Y range is completely above the indicated Y coordinate.
170      */
171     public native void skipDownTo(int y);
172 
173     /**
174      * This method returns a native pointer to a function block that
175      * can be used by a native method to perform the same iteration
176      * cycle that the above methods provide while avoiding upcalls to
177      * the Java object.
178      * The definition of the structure whose pointer is returned by
179      * this method is defined in:
180      * <pre>
181      *     src/share/native/sun/java2d/pipe/SpanIterator.h
182      * </pre>
183      */
184     public native long getNativeIterator();
185 
186     /*
187      * Cleans out all internal data structures.
188      */
189     public native void dispose();
190 
191     public native void moveTo(float x, float y);
192     public native void lineTo(float x, float y);
193     public native void quadTo(float x1, float y1,
194                               float x2, float y2);
195     public native void curveTo(float x1, float y1,
196                                float x2, float y2,
197                                float x3, float y3);
198     public native void closePath();
199     public native void pathDone();
200     public native long getNativeConsumer();
201 }