Mega Code Archive
Clips the specified line to the given rectangle
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/*
* JFreeChart : a free chart library for the Java(tm) platform
*
*
* (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------------
* LineUtilities.java
* ------------------
* (C) Copyright 2008, by Object Refinery Limited and Contributors.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* Changes
* -------
* 05-Nov-2008 : Version 1 (DG);
*
*/
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;
/**
* Some utility methods for {@link Line2D} objects.
*
* @since 1.0.12
*/
public class LineUtilities {
/**
* Clips the specified line to the given rectangle.
*
* @param line the line (<code>null</code> not permitted).
* @param rect the clipping rectangle (<code>null</code> not permitted).
*
* @return <code>true</code> if the clipped line is visible, and
* <code>false</code> otherwise.
*/
public static boolean clipLine(Line2D line, Rectangle2D rect) {
double x1 = line.getX1();
double y1 = line.getY1();
double x2 = line.getX2();
double y2 = line.getY2();
double minX = rect.getMinX();
double maxX = rect.getMaxX();
double minY = rect.getMinY();
double maxY = rect.getMaxY();
int f1 = rect.outcode(x1, y1);
int f2 = rect.outcode(x2, y2);
while ((f1 | f2) != 0) {
if ((f1 & f2) != 0) {
return false;
}
double dx = (x2 - x1);
double dy = (y2 - y1);
// update (x1, y1), (x2, y2) and f1 and f2 using intersections
// then recheck
if (f1 != 0) {
// first point is outside, so we update it against one of the
// four sides then continue
if ((f1 & Rectangle2D.OUT_LEFT) == Rectangle2D.OUT_LEFT
&& dx != 0.0) {
y1 = y1 + (minX - x1) * dy / dx;
x1 = minX;
}
else if ((f1 & Rectangle2D.OUT_RIGHT) == Rectangle2D.OUT_RIGHT
&& dx != 0.0) {
y1 = y1 + (maxX - x1) * dy / dx;
x1 = maxX;
}
else if ((f1 & Rectangle2D.OUT_BOTTOM) == Rectangle2D.OUT_BOTTOM
&& dy != 0.0) {
x1 = x1 + (maxY - y1) * dx / dy;
y1 = maxY;
}
else if ((f1 & Rectangle2D.OUT_TOP) == Rectangle2D.OUT_TOP
&& dy != 0.0) {
x1 = x1 + (minY - y1) * dx / dy;
y1 = minY;
}
f1 = rect.outcode(x1, y1);
}
else if (f2 != 0) {
// second point is outside, so we update it against one of the
// four sides then continue
if ((f2 & Rectangle2D.OUT_LEFT) == Rectangle2D.OUT_LEFT
&& dx != 0.0) {
y2 = y2 + (minX - x2) * dy / dx;
x2 = minX;
}
else if ((f2 & Rectangle2D.OUT_RIGHT) == Rectangle2D.OUT_RIGHT
&& dx != 0.0) {
y2 = y2 + (maxX - x2) * dy / dx;
x2 = maxX;
}
else if ((f2 & Rectangle2D.OUT_BOTTOM) == Rectangle2D.OUT_BOTTOM
&& dy != 0.0) {
x2 = x2 + (maxY - y2) * dx / dy;
y2 = maxY;
}
else if ((f2 & Rectangle2D.OUT_TOP) == Rectangle2D.OUT_TOP
&& dy != 0.0) {
x2 = x2 + (minY - y2) * dx / dy;
y2 = minY;
}
f2 = rect.outcode(x2, y2);
}
}
line.setLine(x1, y1, x2, y2);
return true; // the line is visible - if it wasn't, we'd have
// returned false from within the while loop above
}
}
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