Category Archives: geometry

Use a custom dash pattern with WPF and XAML in C#

Posted on March 13, 2018 by RodStephens

My post Render dashed lines in a WPF program using C# explains how a WPF program can use C# code to render lines with a custom dash pattern onto a bitmap. This post shows how to use a custom dash … Continue reading →

Posted in drawing, geometry, graphics, wpf, XAML | Tagged C#, C# programming, custom dash pattern, dash, DashDot, dashed lines, dotted lines, draw strings, draw text, drawing, example, example program, geometry, graphics, OnRender, render, rendering, strings, text, Windows Forms programming, WPF, XAML | Leave a comment

Draw text on a circle in C#

Posted on February 14, 2018 by Rod Stephens

This example uses some of the techniques described in the post Measure character positions when drawing long strings in C# to draw text on a circle. The previous post explains how to determine where the characters in a string will … Continue reading →

Posted in algorithms, fonts, geometry, graphics, strings | Tagged algorithms, C#, C# programming, characters, circle, circular text, draw string, draw text, draw text on circle, example, example program, fonts, geometry, graphics, measure characters, MeasureCharacterRanges, strings, text on a circle, text on circle, Windows Forms programming | Leave a comment

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

Posted on August 3, 2017 by Rod Stephens

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 →

Posted in algorithms, drawing, geometry, graphics, mathematics | Tagged algorithms, C#, C# programming, drawing, ellipse, ellipse line intersection, ellipse/line intersection, example, example program, geometry, graphics, intersection, line, line ellipse intersection, line segment, line/ellipse intersection, mathematics, Windows Forms programming | 5 Comments

Generate random polygons in C#

Posted on July 7, 2017 by Rod Stephens

I needed a method for generating random polygons for a graphics program and the following code shows the result. // Make random polygons inside the bounding rectangle. private static Random rand = new Random(); public static PointF[] MakeRandomPolygon( int num_vertices, … Continue reading →

Posted in algorithms, geometry, graphics | Tagged algorithms, C#, C# programming, example, example program, geometry, graphics, random polygon, random polygons, Windows Forms programming | Leave a comment

Make silly eyes that track the mouse without flicker in C#

Posted on May 27, 2017 by Rod Stephens

The example Make silly eyes that track the mouse in C# shows how to make eyes track the mouse position, but if you look closely as that program runs you will see a noticeable flicker. The solution is quite simple: … Continue reading →

Posted in games, geometry, graphics | Tagged C#, C# programming, example, example program, games, geometry, graphics, mouse position, MousePosition, track mouse, track the mouse, unit vector, Windows Forms programming | 1 Comment

Make silly eyes that track the mouse in C#

Posted on May 26, 2017 by Rod Stephens

This example uses a Timer named tmrTick to track the mouse. Its Tick event handler, which is shown in the following code, updates the eyes. // The previous mouse location. private Point OldMousePos = new Point(-1, -1); // See if … Continue reading →

Make a 3D globe in WPF and C#

Posted on May 25, 2017 by RodStephens

This example shows how you can draw a 3D globe. More generally it shows how you can make a three-dimensional textured sphere in WPF. The example Draw smooth spheres using WPF and C# shows how to make smooth colored spheres. … Continue reading →

Posted in algorithms, drawing, geometry, graphics, mathematics, wpf, XAML | Tagged 3D, 3D globe, algorithms, C#, C# programming, drawing, example, example program, geometry, graphics, mathematics, sphere, tectured sphere, texture, Windows Forms programming, WPF, XAML | Leave a comment

Draw an interesting pattern of circles in C#

Posted on December 20, 2016 by RodStephens

This program simply draws an interesting arrangement of circles. I wrote it because a C# Helper post was mentioned on this Factal [sic] Patterns & Art page. This program uses the following code to draw the circles and connecting lines. … Continue reading →

Posted in algorithms, drawings, geometry, graphics, mathematics | Tagged algorithms, C#, C# programming, circles, drawing, example, example program, geometry, graphics, mandala, mathematics, patterns of circles, Windows Forms programming | Leave a comment

Circumscribe three tangent circles in C#

Posted on November 3, 2016 by Rod Stephens

The first step in the example Draw an Apollonian gasket in C# is to circumscribe three circles that all meet tangentially with a larger circle as shown in this example. In the previous example I glossed over how the program … Continue reading →

Posted in algorithms, drawing, geometry, graphics, mathematics | Tagged algorithms, Apollonian circles, Apollonian gasket, Apollonian packing, Apollonius, Apollonius' Problem, C#, C# programming, drawing, example, example program, geometry, graphics, mathematics, tangent cicles, Windows Forms programming | Leave a comment

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

Posted on September 21, 2016 by Rod Stephens

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 →