Returns value of the angle at point B , given a line from point A to B and from point B to C - Java java.lang

Java examples for java.lang:Math Geometry Line

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Description

Returns value of the angle at point B , given a line from point A to B and from point B to C

Demo Code


import java.awt.geom.Line2D;
import java.awt.geom.Point2D;

public class Main{
    /** Returns value of the angle at point B , given a line from point A to B and from point B to C*/
    public static final double angle(Point2D pointA, Point2D pointB,
            Point2D pointC) {/*from  w ww  .j  av  a  2s  .c  om*/
        return angle(pointA.getX(), pointA.getY(), pointB.getX(),
                pointB.getY(), pointC.getX(), pointC.getY());
    }
    /** Returns value of the angle at vertice B(x,y) , given a line from vertice A(x,y) to vertice B(x,y) and from vertice B(x,y) to C(x,y)*/
    public static final double angle(double Ax, double Ay, double Bx,
            double By, double Cx, double Cy) {
        Vector BA = new Vector(Bx, Ax, By, Ay);
        Vector BC = new Vector(Bx, Cx, By, Cy);
        double cosB = Vector.scalarProduct(BA, BC)
                / (BA.getMagnitude() * BC.getMagnitude());
        return Math.acos(cosB);
    }
    /** This returns the value of x from the equation of this line given y*/
    public static double getX(Line2D line, double y) {
        return ((y - line.getP1().getY()) / gradient(line))
                + line.getP1().getX();
    }
    /** This returns the value of y from the equation of this line given x*/
    public static double getY(Line2D line, double x) {
        return (gradient(line) * (x - line.getP1().getX()))
                + line.getP1().getY();
    }
    public static double gradient(Line2D line) {
        return gradient(line.getP1(), line.getP2());
    }
    public static double gradient(Point2D p1, Point2D p2) {
        return gradient(p1.getX(), p1.getY(), p2.getX(), p2.getY());
    }
    public static double gradient(double x1, double y1, double x2, double y2) {
        return (y2 - y1) / (x2 - x1);
    }
}

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