text: import numpy as np
  import math
  
  previous_health = 0
  previous_damage = 0      # finding the edge of the thresh image
  
  def calculate(edges):
      ''' Calculating the damage by measuring the difference is length 
              of the total health bar and health bar after damage
              (remaing_health)'''
      remaing_health_percentage = 0
      # variable to keep track of previous remaing health
      global previous_health
      sum_of_white_pixel = 0
  
      # Total health bar height in numpy array (b)
      Total_vertical_pixel = len(edges)
      Total_horizontal_pixel = edges.shape[1] 
      # loop through all the (a) rows
      '''
  	   b
  	   ^
  	   |
  	   0000000000000000002550000000  <- a
  	   0000000000000000002550000000  <- a
  	   0000000000000000002550000000  <- a
  	   0000000000000000002550000000  <- a
  	   0000000000000000002550000000  <- a'''
  
      correctEdge = False
      for edge in edges:
          # detecting the white pixels(255) by eliminating the nonzero indices
          white_pixel = np.nonzero(edge)[0]
          no_pixel_in_one_row = len(white_pixel)
          if no_pixel_in_one_row < 1:
              continue
          else:
              if (white_pixel[0] - white_pixel[-1]) <= 4:
                  correctEdge = True
              else:
                  continue
          # if the multiple lines arises take the average of each (a) row
          avg_of_white_pixel = sum(white_pixel)/len(white_pixel)
  
          # if the image obtained has no edge set the average to 0
          if math.isnan(avg_of_white_pixel):
              avg_of_white_pixel = 0
  
          # taking sum of all white pixel in the (a) rows
          sum_of_white_pixel += int(avg_of_white_pixel)
  
      if(correctEdge):
          # remaing health is calculate by taking the average of white pixels vertical (b colums)
          remaing_health = int(sum_of_white_pixel/Total_vertical_pixel)
          remaing_health_percentage = remaing_health/Total_horizontal_pixel * 100
  
      return(int(remaing_health_percentage))
  