Wed Aug 12 23:27:54 CEST 2009

```Hello, I'm a new guy to this group, my professor recommend this group
to me, because I was boring him with questions.I'm new to python, and
I have problem plotting Quadratic Functions. Using module pygame.
Here is the code:

#!/usr/bin/env python
import pygame
def main():
import sys
import math
from math import sqrt
#Input equation coefficients
screen=pygame.display.set_mode((400,400))
pygame.display.set_caption( ' Ploting ' )
screen.fill((255,255,255))
pen=((0,0,255))
dark=(0,0,0)
ox=200
oy=200
a= int(raw_input('Input coefficient a ' ))
b= int(raw_input('Input coefficient b ' ))
c= int(raw_input('Input coefficient c ' ))
pygame.draw.aaline(screen,((255,0,0)),((200,0)) ,((200,400)))
pygame.draw.aaline(screen,((255,0,0)),((0,200)), ((400,200)))
if a==0:
if b==0:
print 'No solutions'
else:
x= -c/b
print x
else:
d=b*b-4*a*c
if d<0:
num=complex(-b/(2*a),sqrt(-d)/(2*a))
print num
else:
x1=(-b+sqrt(d))/(2*a)
x2=(-b-sqrt(d))/(2*a)
print 'x1= ' ,x1
print 'x2= ' ,x2
while 1:
for event in pygame.event.get():
if event ==pygame.QUIT:
print ' Quitting'
pygame.quit()
sys.exit(1)

x=-50;
while x<=50:
y=(a*(x**2) + b*x + c) *(-1)
screen.set_at(((x+ox),(y+oy)),dark)
pygame.display.flip()
x=x+1;

return 0

if __name__ == '__main__': main()

For now I'm plotting function only when Determinant >0. Or in other
words, when equation has two solutions,
x1,x2 e R... Now if you start my program you will see where problem
is. It's with function, It so bad drawn.
When I try to increment x in loop by 0.1 for every pass, I get
problems because method set_at() Which sets pixel requires integer...

Also I see I have problems with event handling here:
while 1:
for event in pygame.event.get():
if event ==pygame.QUIT:
print ' Quitting'
pygame.quit()
sys.exit(1)

When I click X, or exit on windows it doesn't exit.
What do you suggest I do...?
I don't have in this year Computer Graphics on my faculty. So this are
my first steps in this area of CS.

Regards,
S.I

```