# Draw a smooth color gradient from black at the top of the window to gold
# (255, 192, 64) at the bottom of the window.  The gradient is drawn from
# bottom to top.
from SimpleGraphics import *

# For each row on the screen from bottom to top
for y in range(getHeight() - 1, -1, -1):
  # Compute the amount of red, green and blue for the current row
  r = int(y / (getHeight() - 1) * 255)
  g = int(y / (getHeight() - 1) * 192)
  b = int(y / (getHeight() - 1) * 64)
  # I have explicitly cast r, g and b to integers to deal with a change
  # made in Python 3.5.0 which does not allow the format operator (%) to
  # format a floating point number in hexadecimal using the %x format.  If you 
  # are running an earlier version then the integer casts are not necessary.

  # Set the current color
  setColor(r, g, b)

  # Draw a horizontal line in that color
  line(0, y, getWidth() - 1, y)