Line Clipping Algorithm

COHEN SUTHERLAND LINE CLIPPING ALGORITHM

1. Read the coordinates of line and draw a line

2. Read the coordinates of window xwmin, xwmax, yxmin, ywmax and draw a
window

3. Generate a vector C which determines whether the point is right, left, bottom or top
to window

4. Left if x < style=""> c[0]=1 else c[0]=0

Right if x < style=""> c[1]=1 else c[1]=0

Bottom if x < style=""> c[2]=1 else c[2]=0

Top if x < style=""> c[3]=1 else c[3]=0

5. To determine whether the entire line is inside the window Logically Or the vector
if the result is Zero the line is fully inside the window

6. To determine whether the entire line is outside the window logically AND the vectors if

result is ONE then entire line lies outside the window

1. If portion of line outside the window calculate the point where it intersects window and

suitably swapping pointsand vectors using following

Left c[0] = 1 y = y1 + ( x - x1 ) * m; x=xwmin

Right c[1] = 1 y = y2 + ( x - x2 ) * m; x=xwmax

Bottom ` c[2] = 1 x = x1 + ( y - y1 ) / m; y=xwmin

. Top c[3] = 1 x = x1 + ( y - y2 ) / m; y=xwmax

2. Draw the line using new points

3. STOP