/* ===========================================================
* Orson Charts : a 3D chart library for the Java(tm) platform
* ===========================================================
*
* (C)opyright 2013-2016, by Object Refinery Limited. All rights reserved.
*
* http://www.object-refinery.com/orsoncharts/index.html
*
* This program 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 3 of the License, or
* (at your option) any later version.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* If you do not wish to be bound by the terms of the GPL, an alternative
* commercial license can be purchased. For details, please see visit the
* Orson Charts home page:
*
* http://www.object-refinery.com/orsoncharts/index.html
*
*/
package com.orsoncharts.graphics3d;
import java.awt.Dimension;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
/**
* A collection of utility methods for 2D geometry.
*/
public class Utils2D {
private Utils2D() {
// no need to instantiate
}
/**
* Returns {@code true} if the specified value is spanned by the
* two bounds, and {@code false} otherwise.
*
* @param value the value.
* @param bound1 the first boundary.
* @param bound2 the second boundary.
*
* @return A boolean.
*/
public static boolean spans(double value, double bound1, double bound2) {
return (bound1 < value && bound2 > value)
|| (bound1 > value && bound2 < value);
}
/**
* Calculates twice the area of a triangle for points specified in
* counter-clockwise order (if the points are specified in clockwise order
* the result will be negative).
*
* @param a the first point ({@code null} not permitted).
* @param b the second point ({@code null} not permitted).
* @param c the third point ({@code null} not permitted).
*
* @return The area x 2.
*/
public static double area2(Point2D a, Point2D b, Point2D c) {
double ax = a.getX();
double ay = a.getY();
double bx = b.getX();
double by = b.getY();
double cx = c.getX();
double cy = c.getY();
return (ax - cx) * (by - cy) - (ay - cy) * (bx - cx);
}
/**
* Returns the point in the center of the four supplied points.
*
* @param pt0 point 0 ({@code null} not permitted).
* @param pt1 point 1 ({@code null} not permitted).
* @param pt2 point 2 ({@code null} not permitted).
* @param pt3 point 3 ({@code null} not permitted).
*
* @return The center point (never {@code null}).
*/
public static Point2D centerPoint(Point2D pt0, Point2D pt1, Point2D pt2,
Point2D pt3) {
float x = (float) ((pt0.getX() + pt1.getX() + pt2.getX() + pt3.getX())
/ 4.0);
float y = (float) ((pt0.getY() + pt1.getY() + pt2.getY() + pt3.getY())
/ 4.0);
return new Point2D.Float(x, y);
}
/**
* Returns the dimensions of the smallest rectangle that could contain
* the supplied points.
*
* @param pts an array of points ({@code null} not permitted).
*
* @return The dimensions.
*/
public static Dimension findDimension(Point2D[] pts) {
double minx = Double.POSITIVE_INFINITY;
double maxx = Double.NEGATIVE_INFINITY;
double miny = Double.POSITIVE_INFINITY;
double maxy = Double.NEGATIVE_INFINITY;
for (Point2D pt : pts) {
minx = Math.min(minx, pt.getX());
maxx = Math.max(maxx, pt.getX());
miny = Math.min(miny, pt.getY());
maxy = Math.max(maxy, pt.getY());
}
return new Dimension((int) (maxx - minx), (int) (maxy - miny));
}
/**
* Creates and returns a line that is perpendicular to the specified line.
*
* @param line the reference line ({@code null} not permitted).
* @param b the base point, expressed as a percentage along the length of
* the reference line.
* @param size the size or length of the perpendicular line.
* @param opposingPoint an opposing point, to define which side of the
* reference line the perpendicular line will extend ({@code null}
* not permitted).
*
* @return The perpendicular line.
*/
public static Line2D createPerpendicularLine(Line2D line, double b,
double size, Point2D opposingPoint) {
double dx = line.getX2() - line.getX1();
double dy = line.getY2() - line.getY1();
double length = Math.sqrt(dx * dx + dy * dy);
double pdx = dy / length;
double pdy = -dx / length;
int ccw = line.relativeCCW(opposingPoint);
Point2D pt1 = new Point2D.Double(line.getX1() + b * dx,
line.getY1() + b * dy);
Point2D pt2 = new Point2D.Double(pt1.getX() - ccw * size * pdx,
pt1.getY() - ccw * size * pdy);
return new Line2D.Double(pt1, pt2);
}
/**
* Creates and returns a line that is perpendicular to the specified
* line.
*
* @param line the reference line ({@code null} not permitted).
* @param pt1 a point on the reference line ({@code null} not
* permitted).
* @param size the length of the new line.
* @param opposingPoint an opposing point, to define which side of the
* reference line the perpendicular line will extend ({@code null}
* not permitted).
*
* @return The perpendicular line.
*/
public static Line2D createPerpendicularLine(Line2D line, Point2D pt1,
double size, Point2D opposingPoint) {
double dx = line.getX2() - line.getX1();
double dy = line.getY2() - line.getY1();
double length = Math.sqrt(dx * dx + dy * dy);
double pdx = dy / length;
double pdy = -dx / length;
int ccw = line.relativeCCW(opposingPoint);
Point2D pt2 = new Point2D.Double(pt1.getX() - ccw * size * pdx,
pt1.getY() - ccw * size * pdy);
return new Line2D.Double(pt1, pt2);
}
/**
* Returns the angle of rotation (in radians) for the specified line.
*
* @param line the line ({@code null} not permitted).
*
* @return The angle of rotation (in radians).
*/
public static double calculateTheta(Line2D line) {
double dx = line.getX2() - line.getX1();
double dy = line.getY2() - line.getY1();
return Math.atan2(dy, dx);
}
/**
* Returns the length of the line.
*
* @param line the line ({@code null} not permitted).
*
* @return The length of the line.
*/
public static double length(Line2D line) {
double dx = line.getX2() - line.getX1();
double dy = line.getY2() - line.getY1();
return Math.sqrt(dx * dx + dy * dy);
}
}