2.0-r1beta the new blackbox development will be continue here

app/src/main/java/top/niunaijun/blackboxa/util/MathUtil.java

@@ -0,0 +1,78 @@
+package top.niunaijun.blackboxa.util;
+
+import android.graphics.Point;
+import android.graphics.PointF;
+
+public class MathUtil {
+
+    public MathUtil() {
+    }
+
+    /**
+     * Get the distance between two points.
+     *
+     * @param A Point A
+     * @param B Point B
+     * @return the distance between point A and point B.
+     */
+    public static int getDistance(PointF A, PointF B) {
+        return (int) Math.sqrt(Math.pow(A.x - B.x, 2) + Math.pow(A.y - B.y, 2));
+    }
+
+    /**
+     * Get the distance between two points.
+     */
+    public static int getDistance(float x1, float y1, float x2, float y2) {
+        return (int) Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2));
+    }
+
+    /**
+     * Get the coordinates of a point on the line by cut length.
+     *
+     * @param A         Point A
+     * @param B         Point B
+     * @param cutLength cut length
+     * @return the point.
+     */
+    public static Point getPointByCutLength(Point A, Point B, int cutLength) {
+        float radian = getRadian(A, B);
+        return new Point(A.x + (int) (cutLength * Math.cos(radian)), A.y + (int) (cutLength * Math.sin(radian)));
+    }
+
+    /**
+     * Get the radian between current line(determined by point A and B) and horizontal line.
+     *
+     * @param A point A
+     * @param B point B
+     * @return the radian
+     */
+    public static float getRadian(Point A, Point B) {
+        float lenA = B.x - A.x;
+        float lenB = B.y - A.y;
+        float lenC = (float) Math.sqrt(lenA * lenA + lenB * lenB);
+        float radian = (float) Math.acos(lenA / lenC);
+        radian = radian * (B.y < A.y ? -1 : 1);
+        return radian;
+    }
+
+
+    /**
+     * angle to radian
+     *
+     * @param angle angle
+     * @return radian
+     */
+    public static double angle2Radian(double angle) {
+        return angle / 180 * Math.PI;
+    }
+
+    /**
+     * radian to angle
+     *
+     * @param radian radian
+     * @return angle
+     */
+    public static double radian2Angle(double radian) {
+        return radian / Math.PI * 180;
+    }
+}