Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Apache License 

import android.graphics.PointF;

public class Main {
    /**
     * Gets the angle from P(center, p1) to P(center, p2), the value range is [-180, 180].
     *
     * @param center center point
     * @param p1     point 1
     * @param p2     point 2
     * @return angle
     */
    public static float calculateRotationDegree(PointF center, PointF p1, PointF p2) {
        double angle1 = Math.atan2(p1.y - center.y, p1.x - center.x);
        double angle2 = Math.atan2(p2.y - center.y, p2.x - center.x);
        float angle = (float) Math.toDegrees(angle2 - angle1);
        if (angle > 180) {
            angle -= 360;
        } else if (angle < -180) {
            angle += 360;
        }
        return angle;
    }
}