1 /*
   2  * Copyright (c) 1998, 2016, 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.getLoX(), r.getLoY(), r.getHiX(), r.getHiY());
 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 }