Steps for clip a line segment-pq, Computer Graphics

Steps for clip a line segment-PQ

  • Initially, find all the points of intersections of the line segment PQ along with the edges of the polygonal window and describe them either as PE and PL points. Also find out the value of parameter t, by using equation (2) for respective PE's and PL's.

                                                            Or

If value of the normal to particular edges is not specified then, determine the value of normal to every edge of the window, then find out the value of parameter t, by using equation (2) for particular point of intersection among line segment and window edge then on the basis of the value of parameter t mark them like PE and PL given the value of t lies from 0 to 1 in magnitude.

  • Secondly, out of the diverse values of t for PE's find out the maximum value of t say it is tmax. Likewise, out of the diverse values of t for PL's find out the minimum value of t say it be tmin . Remember here that for clipping to be possible tmin > tmax.
  • at last, vary the parameter t from tmax to tmin and find out the clipped line as outcome.

For well understanding of steps here figure is shown below:

2071_Steps for clip a line segment-PQ.png

Figure: Steps of Cyrus Beck Clipping

During in case of Line 1: (PQ)

1) Point 1 is potentially entering (PE1) since as we move along PQ, the LHS of e1 is window and hence, it seems that we are entering the window.

2) Point 2 is again PE2 same as point 1.

3) Point 3 is potentially leaving (P4) ? as we move along PQ, the LHS of e2 is window and hence, it seems that we are leaving the window.

4) As the same, point 4 is also PL2.

Line 2 and 3 (PQ):

By using similar logic as for line 1 we determine p‾L and PE. Here, it is to be noted that for all points of intersection we have several value of t.

Say t1 is value of t for PE1

Say t2 is value of t for PE2

Say t3 is value of t for PL1

Say t4 is value of t for PL2

Posted Date: 4/3/2013 3:30:04 AM | Location : United States







Related Discussions:- Steps for clip a line segment-pq, Assignment Help, Ask Question on Steps for clip a line segment-pq, Get Answer, Expert's Help, Steps for clip a line segment-pq Discussions

Write discussion on Steps for clip a line segment-pq
Your posts are moderated
Related Questions

i want to learn how to programme

(a)  Voltage or Electro-Magnetic Field Tablet and Pointer: This has a grid of wires, embedded in the tablet surface along with various voltages or magnetic fields consequent to va

Sprite animation interactive, may be non rectangular (Computer games) In its simplest form it is a 2-D graphic object which moves across the display. Sprites frequently can hav

Perspective Distortion - Polygon Rendering and Ray Tracing Methods Anomalies are introduced since interpolation is performed after perspective transformation in the 3-D scree

Arguments made in favor of Digital Sound Dynamic range. Lower noise floor. Immunity to wow and flutter. Absence of generation loss. Capability to apply redu

2D Shape Primitives You have already learnt to plot a point or a pixel on any display device. In this unit, we shall introduce you to various devices available for data input o


Relation between 2-D Euclidean system and Homogeneous coordinate system Suppose that P(x,y) be any point in 2-D Euclidean system. In HCS, we add a third coordinate to the poin

Persistence (of phosphor) - Display devices Time it takes the emitted light from screen to decay to one-tenth of its original intensity. The point where an electron gun strikes