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# Finding the Intersection of Two Line Segments

IP.com Disclosure Number: IPCOM000091176D
Original Publication Date: 1969-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 12K

IBM

## Related People

Evangelisti, CJ: AUTHOR [+2]

## Abstract

In graphic data processing, the calculation of the intersection point of line segments is frequently required. An example of such required calculation is that of finding the hidden lines of a three-dimensional object when a two-dimensional representation is being depicted on a display device. At present, this calculation is effected by techniques employing software, such software being used to enable the calculations for displaying a figure rotating in real time. Another example of such calculation is in the determining as to whether a figure to be displayed lies inside a window boundary. In this situation, each line of the figure has to be compared with the window boundaries to ascertain whether an intersection exists.

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Finding the Intersection of Two Line Segments

In graphic data processing, the calculation of the intersection point of line segments is frequently required. An example of such required calculation is that of finding the hidden lines of a three-dimensional object when a two-dimensional representation is being depicted on a display device. At present, this calculation is effected by techniques employing software, such software being used to enable the calculations for displaying a figure rotating in real time. Another example of such calculation is in the determining as to whether a figure to be displayed lies inside a window boundary. In this situation, each line of the figure has to be compared with the window boundaries to ascertain whether an intersection exists.

In addition to such examples of applications, there are many problems in physics which are of a geometrical nature. For example, in some problems, particles are involved which have random directions of movements. To determine where the such movements intersect boundaries, the calculation of the intersection coordinates is required.

This device is for determining whether two line segments intersect and, if they do, to provide the coordinates of the intersection point, each line segment being defined by two X-Y endpoint coordinate pairs. The device which accepts the two X-Y endpoint coordinate pairs for each line segment and draws both line segments point by point. One line segment is drawn slowly while...