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Nicholl-Lee-Nicholl(NLN) is a fast clipping algorithim that reduces the
chances of multiple clipping of a single line segment as may happen in
the Cohen-Sutherland algorithm. Here the area around the clipping window
is divided into a number of different areas depending on the position of
the initial point of the line to be clipped. This initial point should
be in the three predetermined areas, thus the line may have to be
translated and/or rotated to bring it into the desired region. The line
segment may then be re-translated and/or re-rotated to bring it to the
original position.After that, straight line segments are drawn from the
line end point, passing through the corners of the clipping window.
These areas are then designated as L,LT,LB,TR, depending on the location
of the initial point. Then the other end point of the line is checked
against these areas.
