2 types of line clipping algorithm with example. Cohen-Sutherland Line Clipping and Liang-Barsky Line Clipping Algorithm By Shilpa. Liang-Barsky line clipping algorithm. ▫ Sutherland-Hogeman polygon clipping. 3. Pedher Johansson. Department of Computing Science, Umeå University. Liang – Barsky line clipping algorithm is faster line clipper algorithm based on analysis of the parametric equation of a line segment. Parametric equation of line .

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It basically avoids any unnecessary calculations if the line was already completely inside the edges to start with: Okay, now we’re ready to start. Now go to next edge.

Clipping: Liang-Barsky Line Clipping

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. To add a little context for those reading, the Liang-Barsky algorithm determines the segment of an infinite straight line that intersects an a,gorithm rectangle, if any.

Using these equations Cyrus and Beck developed an algorithm that is generated more efficient than the Cohen Sutherland algorithm. So the beginning of the line P 0 will be represented by 0and the end of the line P 1 by 1.

The Liang-Barsky line clipping algorithm in a nutshell! White onwards other than the code which you can freely use. Do the same for the other edges!

Example of Liang-Barsky Line Clipping

Now you’ve practically understood the whole algorithm because we can generalize what we’ve done for the left edge, to the other edges!


We hope you agree that the colour coding, examples, numerous diagrams pixel-precise and to scale! Since we don’t have LaTeX markup in this exchange, I’ll use bold to represent n-dimensional vectors. Well, we’ve outdone ourselves again, and present you with the easiest tutorial to the Liang Barsky line clipping algorithm on the whole net! At Skytopia, we pride ourselves in making some of the most difficult concepts as algroithm to understand as possible.

Amount you wish to contribute: Sign up or log in Sign up using Google. If the line is parallel to the X axis, for example then p1 and p2 must be zero.

Diagram 1b Left edge check: We need to find out some values before we proceed.

More values need calculating for our first check: Therefore we ignore it. Our hyperrectangle can be defined by two vectors, Least and Greatestexpressing the least and greatest values covered along each axis. Post as a guest Name. These two Xdelta and Ydelta are the most frequently used throughout the whole algorithm, so get them stuck into your brain: Also remember to take the new values for t0 and t1 into account the instructions above assume we’re starting out, and therefore think that t0 still equals 0 and t1 still equals 1, when that’ll change as we check each edge barsjy turn.

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Explain Liang Barsky line clipping algorithm. Maybe try out Computer Graphics Stack Exchange computergraphics. You get question papers, syllabus, subject analysis, kiang – all in one app.

Skytopia : The Liang Barsky line clipping algorithm in a nutshell

But bear with me, since the following algorithm will gradually clip it down, edge by edge. We can store these values in variables, as we will need to adjust them as the algorithm progresses.

Amount you wish to contribute:. Sign up using Facebook. Anyway, if this is the case which it is for uswe do this check: The parametric equation of our line is: Anyway, we start with a In the Liang-Barsky approach bagsky first the point clipping condition in parametric form: Diagram 1b Just for reference, remember that: Email Required, but never shown. Thus we would scrap everything don’t draw the line!

Liang-Barsky Clipping-Example

If P is more than zero however which it isn’t in this example btw – we’ve bagsky had the above executed, so the below boxout is only for future edge checks! And yes, it can be trivially extended to clipping lines against n-dimensional axis-aligned hyperrectangles pretty trivially.

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