# Convert a color image into grayscale
from SimpleGraphics import *

# Load the image from the disk and display it
img = loadImage("Brickosaurus.gif")
drawImage(img, 0, 0)

# For each pixel in the image going down the rows and then across the 
# columns in each row
for y in range(0, getHeight(img)):
  for x in range(0, getWidth(img)):
    # Retrieve the red, green and blue values for the current pixel
    r, g, b = getPixel(img, x, y)

    # Compute the average
    avg = (r + g + b) / 3

    # Store the gray pixel in the image with average red, average green and
    # average blue
    putPixel(img, x, y, avg, avg, avg)

# Draw the image after it has been transformed
drawImage(img, 0, 0)