from Tkinter import *

class BresenhamCanvas(Canvas):
 
     def draw_point(self, x, y, color="red"):
         self.create_line(x, y, x, y, fill=color)
 
 
     def draw_line(self, x0, y0, x1, y1, color="red"):
         steep = abs(y1 - y0) > abs(x1 - x0)
         if steep:
             x0, y0 = y0, x0  
             x1, y1 = y1, x1
 
 
         if x0 > x1:
             x0, x1 = x1, x0
             y0, y1 = y1, y0
 
         
         if y0 < y1: 
             ystep = 1
         else
             ystep = -1
 
             
         deltax = x1 - x0
         deltay = abs(y1 - y0)
         error = -deltax / 2
         y = y0
 
             
         for x in range(x0, x1 + 1): # We add 1 to x1 so that the range includes x1

      if steep:
         self.draw_point(y, x, color)
      else:
         self.draw_point(x, y, color)
              
        error = error + deltay
      if error > 0:
          y = y + ystep
          error = error - deltax
 
 
                 
    if __name__ == "__main__":
 
     import math
     CANVAS_SIZE = 600
 
     root = Tk()
     canvas = BresenhamCanvas(root, width=CANVAS_SIZE, height=CANVAS_SIZE)
     canvas.pack()
     
     margin = CANVAS_SIZE / 10
     
     xcenter = int(CANVAS_SIZE / 2)
     ycenter = int(CANVAS_SIZE / 2)
     line_length = ((CANVAS_SIZE / 2) - margin)
     
     n_lines = 100
     angle_step = (2 * math.pi) / n_lines
     
     for i in range(n_lines):
         theta = angle_step * i
         xstart = int(margin * math.cos(theta)) + xcenter
         ystart = int(margin * math.sin(theta)) + ycenter
         xend = int(line_length * math.cos(theta)) + xcenter
         yend = int(line_length * math.sin(theta)) + ycenter
         canvas.draw_line(xstart, ystart, xend, yend, color="blue")
         
     root.mainloop()