In computer graphics, the Liang–Barsky algorithm (named after You-Dong Liang and Brian A. Barsky) is a line clipping algorithm.
The Liang–Barsky algorithm uses the parametric equation of a line and inequalities describing the range of the clipping window to determine the intersections between the line and the clip window.
With these intersections, it knows which portion of the line should be drawn.
The idea of the Liang–Barsky clipping algorithm is to do as much testing as possible before computing line intersections.
The algorithm uses the parametric form of a straight line: A point is in the clip window, if and which can be expressed as the 4 inequalities where To compute the final line segment: Algorithms used for the same purpose: