Tag Archives: intersection

Enlarge a polygon that has colinear vertices in C#

The example Enlarge a polygon in C# shows how you can expand a polygon. The basic idea is to offset each of the polygon’s edges away from the polygon’s center and then see where adjacent edges intersect as shown in … Continue reading

Perform set operations on enumerable lists in C#

To demonstrate set operations, this example creates two lists of Person objects. The Person class implements IEquatable. The code then uses the following code to display the lists and their intersection, union, difference, and exclusive or (xor). // Display the … Continue reading

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Calculate where a line segment and an ellipse intersect in C#

Finding the intersection between a line segment and an ellipse requires a lot of mathematics. It’s not particularly hard mathematics, but if you’d rather skip it, you can use the following links to jump to the other parts of this … Continue reading

Find the shortest distance between a point and a line segment in C#

This example treats the segment as parameterized vector where the parameter t varies from 0 to 1. It finds the value of t that minimizes the distance from the point to the line. If t is between 0.0 and 1.0, … Continue reading

Enlarge a polygon in C#

This example shows how you can enlarge a polygon by a certain distance. For example, you can use it to move the edges of the polygon outward by 10 pixels. The program lets you use the mouse to define the … Continue reading

Use set operators in C#

This example shows how you can add set operators to make working with sets slightly easier. The example Perform set operations in C# explains how to use the HashSet class to represent and manipulate sets. Unfortunately to manipulate the sets … Continue reading

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See where a line intersects a conic section in C#

This example shows how you can see where a line intersects a conic section. You can use the more general method described in the post See where two conic sections intersect in C#. This example takes advantage of the simpler … Continue reading

See where a parabola and hyperbola intersect in C#

This example shows how to see where a parabola and hyperbola intersect. The previous four-part example here, here, here, and here explains how to find the points of intersections between two conic sections. Although the posts focus on finding points … Continue reading

See where two ellipses intersect in C#, Part 4

This post explains why Newton’s method may not be the best way to find the roots of the difference equations used to see where two ellipses intersect. The final step in finding the points of intersection between two ellipses (or … Continue reading

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See where two ellipses intersect in C#, Part 3

This post summarizes the method you can use to see where two ellipses intersect. (Or any two conic sections, for that matter.) It also explains the example program. To find the points of intersection: Get the equations for the ellipses. … Continue reading

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