Line java

line.java

package com.smallplanet.android.birdsandbees.math;

import android.graphics.PointF;

/**
 * Created by JBruchanov on 04/11/2015.
 */
public class Line implements Comparable<Line> {

    private PointF mPoint1;
    private PointF mPoint2;
    //ax + by + c = 0
    private float mA;
    private float mB;
    private float mC;

    //y = kx + q, tan(fi) = k
    private float mK;
    private float mQ;
    private float mFiDeg;


    public Line(float x1, float y1, float x2, float y2) {
        this(new PointF(Math.min(x1, x2), Math.min(y1, y2)), new PointF(Math.max(x1, x2), Math.max(y1, y2)));
    }

    private Line(PointF point1, PointF point2) {
        mPoint1 = point1;
        mPoint2 = point2;
        build();
    }

    private void build() {
        //u = X2 - X1 => (x2 - x1, y2 - y1)
        PointF u = new PointF(mPoint2.x - mPoint1.x, mPoint2.y - mPoint1.y);
        //n = u(u2, -u1) => ax+by+c=0 <=> u2x+u1y+c=0
        mA = u.y;
        mB = -u.x;

        //getting c => c = -ax -by =>
        float c1 = -(mA * mPoint1.x) - (mB * mPoint1.y);
        float c2 = -(mA * mPoint2.x) - (mB * mPoint2.y);

        assert c1 == c2;
        mC = c1;

        mK = -mA / mB;
        mQ = -mC / mB;
        mFiDeg = (float) Math.toDegrees(Math.atan(mK));
    }

    public float getY(float x) {
        if (inRange(x)) {

        }
        return Float.NaN;
    }

    public boolean inRange(float x) {
        return mPoint1.x <= x && x <= mPoint2.x;
    }

    public PointF getPoint1() {
        return new PointF(mPoint1.x, mPoint1.y);
    }

    public PointF getPoint2() {
        return new PointF(mPoint2.x, mPoint2.y);
    }

    public float getA() {
        return mA;
    }

    public float getB() {
        return mB;
    }

    public float getC() {
        return mC;
    }

    public float getK() {
        return mK;
    }

    public float getQ() {
        return mQ;
    }

    public float getFiDeg() {
        return mFiDeg;
    }

    @Override
    public int compareTo(Line another) {
        return Float.compare(mPoint1.x, another.mPoint1.x);
    }


    public String toGeneralForm() {
        StringBuilder sb = new StringBuilder();
        if (mA != 0) {
            sb.append(String.format("%.2fX", mA));
        }

        if (mB != 0) {
            sb.append(String.format(" %.2fY", mA));
        }

        if (mC != 0) {
            sb.append(String.format(" %.2f", mA));
        }
        sb.append(" = 0");
        return sb.toString().trim();
    }

    public String toInterceptForm() {
        StringBuilder sb = new StringBuilder();
        sb.append("Y = ");
        if (mK != 0) {
            sb.append(String.format("%.2fX", mA));
        }

        if (mQ != 0) {
            sb.append(String.format(" %.2fY", mA));
        }
        return sb.toString().trim();
    }
}