Cohen_Sutherland_Line_Cliping.py

from graphics import GraphWin,Rectangle,Point

INSIDE = 0 
LEFT = 1 
RIGHT = 2  
BOTTOM = 4  
TOP = 8	  


x_max = 600
y_max =600
x_min = 400
y_min = 400
win=GraphWin("Suderland Line CLipping",800,800)
def Bresenhams(x1,y1,x2,y2):
    x=x1
    y=y1
    dx=abs(x2-x1)
    dy=abs(y2-y1)
    if x2-x1>0:s1=1
    else : s1=-1

    if y2-y1>0:s2=1
    else :s2=-1

    if dy>dx:
        dx,dy=dy,dx
        interchange=1
    else :
        interchange = 0

    e_ = 2*dy - dx
    for i in range(dx):
        win.plot(x,y)
        while e_>0 :
            if interchange==1:
                x+=s1
            else :
                y+=s2
            e_-=2*dx
        if interchange==1:
            y+=s2
        else:
            x+=s1
        e_+=2*dy

def computeCode(x, y): 
	code = INSIDE 
	if x < x_min: 
		code |= LEFT 
	elif x > x_max:  
		code |= RIGHT 
	if y < y_min:	 
		code |= BOTTOM 
	elif y > y_max: 
		code |= TOP 
	print(code)
	return code 

def cohenSutherlandClip(x1, y1, x2, y2): 
	code1 = computeCode(x1, y1)
	code2 = computeCode(x2, y2)
	accept=False
	while True: 
		if code1 == 0 and code2 == 0: 
			accept = True
			break
		elif (code1 & code2) != 0: 
			break

		else: 
			x = 1.0
			y = 1.0
			if code1 != 0: 
				code_out = code1 
			else: 
				code_out = code2 
			if code_out & TOP:  
				x = x1 + (x2 - x1) * (y_max - y1) / (y2 - y1) 
				y = y_max 

			elif code_out & BOTTOM: 
				
				x = x1 + (x2 - x1) * (y_min - y1) / (y2 - y1) 
				y = y_min 

			elif code_out & RIGHT: 
				y = y1 + (y2 - y1) *  (x_max - x1) / (x2 - x1) 
				x = x_max 

			elif code_out & LEFT: 
				
				y = y1 + (y2 - y1) * (x_min - x1) / (x2 - x1) 
				x = x_min 

	
			if code_out == code1: 
				x1 = x 
				y1 = y 
				code1 = computeCode(x1,y1) 

			else: 
				x2 = x 
				y2 = y 
				code2 = computeCode(x2, y2) 
	if accept : 
		Bresenhams(x1,y1,x2,y2)
		print("(x1: %d , y1 : %d),(x2: %d , y2 : %d)"%(x1,y1,x2,y2))

	else: 
		print("Line rejected")
if __name__=="__main__": 

    window=Rectangle(Point(x_max,y_max),Point(x_min,y_min))
    window.draw(win)
    #Bresenhams(100,300,400,700)
    #Bresenhams(425,425,500,500)
    Bresenhams(50,375,700,600)
    win.getMouse()
    win.delete("all")
    window=Rectangle(Point(x_max,y_max),Point(x_min,y_min))
    window.draw(win)
    #cohenSutherlandClip(100,300,400,700) 
    #cohenSutherlandClip(425,425,500,500)
    cohenSutherlandClip(50, 375, 700, 600) 
    win.getMouse()
    win.close()