# QuadraticPlot.py
# Neal Nelson  2008.11.17

import string
from graphics import *

def main():

  # Introduction
  print "Plot points for quadratic y = a * x*x + b*x + c"

  a,b,c = input ("Enter parameters a,b,c; e.g. 2.0, -5.0, 2.0: ")

  # Display a scatter plot
  (xmin,xmax) = (-10,10)
  (ymin,ymax) = (-100,100)

  # Create a graphics window with (xmin,ymin) in lower left
  #win = GraphWin("Sample Scatter Plot", 320, 240)     # small drawing window
  win = GraphWin("Sample Line Plot", 640, 480)         # bigger drawing window
  win.setBackground("white")
  win.setCoords(xmin, ymin, xmax, ymax)

  # Draw x-axis and y-axis
  Line(Point(xmin,0), Point(xmax,0)).draw(win)      # x-axis
  Line(Point(0,ymin), Point(0,ymax)).draw(win)      # y-axis

  # Draw the (x,y) points
  for i in range(xmin,xmax+1):
    x = float(i)
    y = a*x*x + b*x + c
    print x,y                                  # for debugging
    Point(x,y).draw(win)
   

  # Hold window open
  #raw_input("Press <enter> to quit.")
  #win.close()

  # A better click-to-close technique
  text = Text(Point(xmax/2, ymax-5), 'Click to close')
  text.draw(win)
  win.getMouse()
  win.close()

main()