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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We need to find out some values before we proceed. These two Xdelta and Ydelta are the most frequently used throughout the whole algorithm, so get them stuck into your brain: To add a little context for those reading, the Liang-Barsky algorithm determines the segment of an infinite straight line that intersects bafsky axis-aligned rectangle, if any.

### Liang-Barsky Clipping-Example

If P is more than zero however which it isn’t in this example btw – we’ve already had the above executed, so clippung below boxout is only for future edge checks!

So we ignore it. Diagram 1b Just for reference, remember that: In the Liang-Barsky approach we first the point clipping condition in parametric form: Well, we’ve outdone ourselves again, and present you with the easiest tutorial to the Liang Barsky line clipping algorithm on the whole net! Amount you wish to contribute: Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website barsmy subject to these policies.

Explain Liang Barsky line clipping algorithm. Home Questions Tags Users Unanswered. We can store these values in variables, as we will need to adjust them as the algorithm progresses.

## Liang–Barsky algorithm

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Using these equations Cyrus and Beck developed an algorithm that is generated more efficient than the Cohen Sutherland algorithm. Maybe try out Computer Graphics Stack Exchange computergraphics.

### Liang–Barsky algorithm – Wikipedia

If there is a segment of line inside the clip region, a alorithm of infinite line intersections must go entering, entering, exiting, and exiting as shown in figure There are slight differences though. We use slightly different values for P and Q R remains the same though: 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. White onwards other than the code which you can freely use.

Anyway, if this is the case which it is for uswe do this check: Do the same for the other edges!

Later Liang and Barsky independently devised an even faster parametric line clipping algorithm. Thus we would scrap everything don’t draw the line!

## Clipping: Liang-Barsky Line Clipping

Post as a guest Name. And yes, it can be trivially extended to clipping lines against n-dimensional axis-aligned hyperrectangles pretty trivially.

What we’ll do is go through each edge border in turn Left, Altorithm, Bottom, Topand at each stage we will either tweak t0 or t1, or we may find out that the line is outside the border completely, and therefore doesn’t need drawing – in which case we will cut the algorithm there and then! Since clippin don’t have LaTeX markup in this exchange, I’ll use bold to represent n-dimensional vectors.

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Email Required, but never shown. Liang — Barsky line clipping algorithm is faster line clipper algorithm based on analysis of the parametric equation of a line segment.

If the line is parallel to the X axis, for example then p1 and p2 must be zero. Engineering in your pocket Download our mobile app and study on-the-go. Anyway, we start with a More values need calculating for our first check: So the beginning of the line P 0 will be represented by 0and the end of the line P 1 by 1. The parametric equation of our line is: Parametric equation of line segment: By liangg our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.