content: package com.bihe0832.android.lib.media.image;
  
  import android.graphics.RectF;
  
  public class RectUtils {
  
      /**
       * Gets a float array of the 2D coordinates representing a rectangles
       * corners.
       * The order of the corners in the float array is:
       * 0------->1
       * ^        |
       * |        |
       * |        v
       * 3<-------2
       *
       * @param r the rectangle to get the corners of
       * @return the float array of corners (8 floats)
       */
      public static float[] getCornersFromRect(RectF r) {
          return new float[]{
                  r.left, r.top,
                  r.right, r.top,
                  r.right, r.bottom,
                  r.left, r.bottom
          };
      }
  
      /**
       * Gets a float array of two lengths representing a rectangles width and height
       * The order of the corners in the input float array is:
       * 0------->1
       * ^        |
       * |        |
       * |        v
       * 3<-------2
       *
       * @param corners the float array of corners (8 floats)
       * @return the float array of width and height (2 floats)
       */
      public static float[] getRectSidesFromCorners(float[] corners) {
          return new float[]{(float) Math.sqrt(Math.pow(corners[0] - corners[2], 2) + Math.pow(corners[1] - corners[3], 2)),
                  (float) Math.sqrt(Math.pow(corners[2] - corners[4], 2) + Math.pow(corners[3] - corners[5], 2))};
      }
  
      public static float[] getCenterFromRect(RectF r) {
          return new float[]{r.centerX(), r.centerY()};
      }
  
      /**
       * Takes an array of 2D coordinates representing corners and returns the
       * smallest rectangle containing those coordinates.
       *
       * @param array array of 2D coordinates
       * @return smallest rectangle containing coordinates
       */
      public static RectF trapToRect(float[] array) {
          RectF r = new RectF(Float.POSITIVE_INFINITY, Float.POSITIVE_INFINITY,
                  Float.NEGATIVE_INFINITY, Float.NEGATIVE_INFINITY);
          for (int i = 1; i < array.length; i += 2) {
              float x = Math.round(array[i - 1] * 10) / 10.f;
              float y = Math.round(array[i] * 10) / 10.f;
              r.left = (x < r.left) ? x : r.left;
              r.top = (y < r.top) ? y : r.top;
              r.right = (x > r.right) ? x : r.right;
              r.bottom = (y > r.bottom) ? y : r.bottom;
          }
          r.sort();
          return r;
      }
  
  }