Как установить контраст Уровни в гистограмме ImageView

class MaxFinder
{
    // finds the max and its index
    static int[] findMaxByIteration(int arr[], int start, int end)
    {
        int max, max_ndx; 

        max = arr[start];
        max_ndx = start;
        for (int i=start; i<end; i++)
        {
            if (arr[i] > max)
            {
                max = arr[i];
                max_ndx = i;
            }    
        }

        int result[] = {max, max_ndx};

        return result;
    }

    // optimized to skip iteration, when previous windows max element 
    // is present in current window
    static void optimizedPrintKMax(int arr[], int n, int k)
    {
        int i, j, max, max_ndx;

        // for first window - find by iteration.    
        int result[] = findMaxByIteration(arr, 0, k);

        System.out.printf("%d ", result[0]);

        max = result[0];
        max_ndx = result[1];   

         for (j=1; j <= (n-k); j++)
         {
            // if previous max has fallen out of current window, iterate and find
            if (max_ndx < j)  
            {
                result = findMaxByIteration(arr, j, j+k);
                max = result[0];
                max_ndx = result[1];   
            } 
            // optimized path, just compare max with new_elem that has come into the window 
            else 
            {
                int new_elem_ndx = j + (k-1);
                if (arr[new_elem_ndx] > max)
                {
                    max = arr[new_elem_ndx];
                    max_ndx = new_elem_ndx;
                }      
            }

            System.out.printf("%d ", max);
         }   
    }     

    public static void main(String[] args)
    {
        int arr[] = {10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
        //int arr[] = {1,5,2,6,3,1,24,7};
        int n = arr.length;
        int k = 3;
        optimizedPrintKMax(arr, n, k);
    }
}