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1: /* PathIterator.java -- describes a shape by iterating over its vertices 2: Copyright (C) 2000, 2002, 2003 Free Software Foundation 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 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) 48: * @author Eric Blake (ebb9@email.byu.edu) 49: * @see java.awt.Shape 50: * @see java.awt.Stroke 51: * @see FlatteningPathIterator 52: * @since 1.2 53: * @status updated to 1.4 54: */ 55: public interface PathIterator 56: { 57: /** 58: * The even-odd winding mode: a point is internal to the shape if a ray 59: * from the point to infinity (in any direction) crosses an odd number of 60: * segments. 61: */ 62: int WIND_EVEN_ODD = 0; 63: 64: /** 65: * The non-zero winding mode: a point is internal to the shape if a ray 66: * from the point to infinity (in any direction) crosses a different number 67: * of segments headed clockwise than those headed counterclockwise. 68: */ 69: 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 true, 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 true. 139: * 140: * @throws java.util.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 java.util.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 java.util.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