| /* |
| * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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| */ |
| |
| package java.awt.geom; |
| |
| import java.lang.annotation.Native; |
| |
| /** |
| * The {@code PathIterator} interface provides the mechanism |
| * for objects that implement the {@link java.awt.Shape Shape} |
| * interface to return the geometry of their boundary by allowing |
| * a caller to retrieve the path of that boundary a segment at a |
| * time. This interface allows these objects to retrieve the path of |
| * their boundary a segment at a time by using 1st through 3rd order |
| * Bézier curves, which are lines and quadratic or cubic |
| * Bézier splines. |
| * <p> |
| * Multiple subpaths can be expressed by using a "MOVETO" segment to |
| * create a discontinuity in the geometry to move from the end of |
| * one subpath to the beginning of the next. |
| * <p> |
| * Each subpath can be closed manually by ending the last segment in |
| * the subpath on the same coordinate as the beginning "MOVETO" segment |
| * for that subpath or by using a "CLOSE" segment to append a line |
| * segment from the last point back to the first. |
| * Be aware that manually closing an outline as opposed to using a |
| * "CLOSE" segment to close the path might result in different line |
| * style decorations being used at the end points of the subpath. |
| * For example, the {@link java.awt.BasicStroke BasicStroke} object |
| * uses a line "JOIN" decoration to connect the first and last points |
| * if a "CLOSE" segment is encountered, whereas simply ending the path |
| * on the same coordinate as the beginning coordinate results in line |
| * "CAP" decorations being used at the ends. |
| * |
| * @see java.awt.Shape |
| * @see java.awt.BasicStroke |
| * |
| * @author Jim Graham |
| */ |
| public interface PathIterator { |
| /** |
| * The winding rule constant for specifying an even-odd rule |
| * for determining the interior of a path. |
| * The even-odd rule specifies that a point lies inside the |
| * path if a ray drawn in any direction from that point to |
| * infinity is crossed by path segments an odd number of times. |
| */ |
| @Native public static final int WIND_EVEN_ODD = 0; |
| |
| /** |
| * The winding rule constant for specifying a non-zero rule |
| * for determining the interior of a path. |
| * The non-zero rule specifies that a point lies inside the |
| * path if a ray drawn in any direction from that point to |
| * infinity is crossed by path segments a different number |
| * of times in the counter-clockwise direction than the |
| * clockwise direction. |
| */ |
| @Native public static final int WIND_NON_ZERO = 1; |
| |
| /** |
| * The segment type constant for a point that specifies the |
| * starting location for a new subpath. |
| */ |
| @Native public static final int SEG_MOVETO = 0; |
| |
| /** |
| * The segment type constant for a point that specifies the |
| * end point of a line to be drawn from the most recently |
| * specified point. |
| */ |
| @Native public static final int SEG_LINETO = 1; |
| |
| /** |
| * The segment type constant for the pair of points that specify |
| * a quadratic parametric curve to be drawn from the most recently |
| * specified point. |
| * The curve is interpolated by solving the parametric control |
| * equation in the range {@code (t=[0..1])} using |
| * the most recently specified (current) point (CP), |
| * the first control point (P1), |
| * and the final interpolated control point (P2). |
| * The parametric control equation for this curve is: |
| * <pre> |
| * P(t) = B(2,0)*CP + B(2,1)*P1 + B(2,2)*P2 |
| * 0 <= t <= 1 |
| * |
| * B(n,m) = mth coefficient of nth degree Bernstein polynomial |
| * = C(n,m) * t^(m) * (1 - t)^(n-m) |
| * C(n,m) = Combinations of n things, taken m at a time |
| * = n! / (m! * (n-m)!) |
| * </pre> |
| */ |
| @Native public static final int SEG_QUADTO = 2; |
| |
| /** |
| * The segment type constant for the set of 3 points that specify |
| * a cubic parametric curve to be drawn from the most recently |
| * specified point. |
| * The curve is interpolated by solving the parametric control |
| * equation in the range {@code (t=[0..1])} using |
| * the most recently specified (current) point (CP), |
| * the first control point (P1), |
| * the second control point (P2), |
| * and the final interpolated control point (P3). |
| * The parametric control equation for this curve is: |
| * <pre> |
| * P(t) = B(3,0)*CP + B(3,1)*P1 + B(3,2)*P2 + B(3,3)*P3 |
| * 0 <= t <= 1 |
| * |
| * B(n,m) = mth coefficient of nth degree Bernstein polynomial |
| * = C(n,m) * t^(m) * (1 - t)^(n-m) |
| * C(n,m) = Combinations of n things, taken m at a time |
| * = n! / (m! * (n-m)!) |
| * </pre> |
| * This form of curve is commonly known as a Bézier curve. |
| */ |
| @Native public static final int SEG_CUBICTO = 3; |
| |
| /** |
| * The segment type constant that specifies that |
| * the preceding subpath should be closed by appending a line segment |
| * back to the point corresponding to the most recent SEG_MOVETO. |
| */ |
| @Native public static final int SEG_CLOSE = 4; |
| |
| /** |
| * Returns the winding rule for determining the interior of the |
| * path. |
| * @return the winding rule. |
| * @see #WIND_EVEN_ODD |
| * @see #WIND_NON_ZERO |
| */ |
| public int getWindingRule(); |
| |
| /** |
| * Tests if the iteration is complete. |
| * @return {@code true} if all the segments have |
| * been read; {@code false} otherwise. |
| */ |
| public boolean isDone(); |
| |
| /** |
| * Moves the iterator to the next segment of the path forwards |
| * along the primary direction of traversal as long as there are |
| * more points in that direction. |
| */ |
| public void next(); |
| |
| /** |
| * Returns the coordinates and type of the current path segment in |
| * the iteration. |
| * The return value is the path-segment type: |
| * SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. |
| * A float array of length 6 must be passed in and can be used to |
| * store the coordinates of the point(s). |
| * Each point is stored as a pair of float x,y coordinates. |
| * SEG_MOVETO and SEG_LINETO types returns one point, |
| * SEG_QUADTO returns two points, |
| * SEG_CUBICTO returns 3 points |
| * and SEG_CLOSE does not return any points. |
| * @param coords an array that holds the data returned from |
| * this method |
| * @return the path-segment type of the current path segment. |
| * @see #SEG_MOVETO |
| * @see #SEG_LINETO |
| * @see #SEG_QUADTO |
| * @see #SEG_CUBICTO |
| * @see #SEG_CLOSE |
| */ |
| public int currentSegment(float[] coords); |
| |
| /** |
| * Returns the coordinates and type of the current path segment in |
| * the iteration. |
| * The return value is the path-segment type: |
| * SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. |
| * A double array of length 6 must be passed in and can be used to |
| * store the coordinates of the point(s). |
| * Each point is stored as a pair of double x,y coordinates. |
| * SEG_MOVETO and SEG_LINETO types returns one point, |
| * SEG_QUADTO returns two points, |
| * SEG_CUBICTO returns 3 points |
| * and SEG_CLOSE does not return any points. |
| * @param coords an array that holds the data returned from |
| * this method |
| * @return the path-segment type of the current path segment. |
| * @see #SEG_MOVETO |
| * @see #SEG_LINETO |
| * @see #SEG_QUADTO |
| * @see #SEG_CUBICTO |
| * @see #SEG_CLOSE |
| */ |
| public int currentSegment(double[] coords); |
| } |