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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/java/awt/java2d/PolyEdge.java | |
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Diffstat (limited to 'libjava/classpath/gnu/java/awt/java2d/PolyEdge.java')
-rw-r--r-- | libjava/classpath/gnu/java/awt/java2d/PolyEdge.java | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/java/awt/java2d/PolyEdge.java b/libjava/classpath/gnu/java/awt/java2d/PolyEdge.java new file mode 100644 index 000000000..eb0cc7f8f --- /dev/null +++ b/libjava/classpath/gnu/java/awt/java2d/PolyEdge.java @@ -0,0 +1,171 @@ +/* PolyEdge.java -- An edge in a polygon, used for polygon filling + Copyright (C) 2006 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package gnu.java.awt.java2d; + +import gnu.java.math.Fixed; + +/** + * An edge in a polygon. + * + * @author Roman Kennke (kennke@aicas.com) + */ +final class PolyEdge + implements Comparable +{ + + /** + * The start and end coordinates of the edge. y0 is always smaller or equal + * than y1. + * + * These values are stored as fixed-point decimals. + */ + public int x0, y0, x1, y1; + + /** + * The slope of the edge. This is dx / dy. + * + * This is a fixed point decimal. + */ + private int slope; + + /** + * The intersection of this edge with the current scanline. + * + * This is a fixed point decimal. + */ + int xIntersection; + + /** + * Indicates whether this edge is from the clip or from the target shape. + */ + boolean isClip; + + /** + * Implements a linked list for the edge pool. + */ + PolyEdge poolNext; + + /** + * Implements a linked list for the scanline edge lists. + */ + PolyEdge scanlineNext; + + /** + * Create an uninitialized edge. + */ + PolyEdge() + { + // Nothing to do here. + } + + /** + * Creates a new PolyEdge with the specified coordinates. + * + * @param x0 the starting point, x coordinate + * @param y0 the starting point, y coordinate + * @param x1 the end point, x coordinate + * @param y1 the end point, y coordinate + */ + PolyEdge(int n, int x0, int y0, int x1, int y1, boolean clip) + { + init(n, x0, y0, x1, y1, clip); + } + + /** + * (Re-) Initializes this edge. + * + * @param x0 + * @param y0 + * @param x1 + * @param y1 + */ + void init(int n, int x0, int y0, int x1, int y1, boolean clip) + { + isClip = clip; + if (y0 < y1) + { + this.x0 = x0; + this.y0 = y0; + this.x1 = x1; + this.y1 = y1; + } + else + { + this.x0 = x1; + this.y0 = y1; + this.x1 = x0; + this.y1 = y0; + } + slope = Fixed.div(n, this.x1 - this.x0, this.y1 - this.y0); + } + + /** + * Sorts PolyEdges by the x coordinate from the minimum x value. + */ + public int compareTo(Object o) + { + PolyEdge other = (PolyEdge) o; + int comp = 0; + if (x0 < other.x0) + comp = -1; + else if (x0 > other.x0) + comp = 1; + return comp; + } + + /** + * Intersects this edge with the scanline at height y. The result is + * stored in {@link #xIntersection}. + * + * @param y the scanline + */ + void intersect(int n, int y) + { + int dy = y - y0; + int dx = Fixed.mul(n, slope, dy); + xIntersection = x0 + dx; + } + + public String toString() + { + return "Edge: " + x0 + ", " + y0 + ", " + x1 + ", " + y1 + ", slope: " + + slope + ", xIntersection: " + xIntersection + + ", isClip: " + isClip; + } +} |