I wanted to create a random color generator.
The initial application was a plot color attribution for a graphic control.
I wanted to be able to put some weight to some color to ensure to stay away from them (like the background color). I haven’t found anything that does that. I decided to code it myself.
- Never the same color twice
- Each new color should be easily distinguishable from any previous one
- Be able to set inital colors to reject
- Be able to add a distance factor to any inital colors to reject in order to stay very far from them
I searched on the web for an already existing solution and I haven’t found any. I found many random generators but they didn’t keep tracks of already used colors and do not ensure to generate color far from used ones. Also, I needed to be able to add myself some color to reject. An additional nice feature would be to start generate color with very high distance between them and reduce the distance while color quantity increase (in order to introduce new ones).
After reading some article/code (like: http://www.codeproject.com/KB/recipes/colorspace1.aspx), I realized that it would be probably more easier/effective to work with HSB or HSL. I thought HSL would be better and go with it. Obtained results were sometimes with colors appearing to be too close to my eye. I decided to try to work with CieLab color distance and saw an improvement. The color appears to me to have a greater distance between them. This initial "Tips and tricks" was written with CieLab1997 algorithm. But Rob2412 (Thanks a lot Rob) give me the algorithm of CieLab2000 (http://www.codeproject.com/KB/recipes/colorspace1.aspx?msg=4018256#xx4018256xx) then I implemented it, tested it, and decided to update my code. Although, I haven’t seen a difference, the latest should give better results.
I started from the excellent code found here on code project from Guillaume Leparmentier
In fact, it was so good that I kept 99.9% of it and mainly just added 2 others classes (plus a Form to test).
I only added/modify:
- I changed
Color class used from WinForm (System.Drawing) to WPF (System.Windows.Media)
- I added Distance calculation in CIELab.cs
- I added a helper function
- I added
ColorRatio class and
The class is based on random color generation with auto adjustable distance tolerance. High distance tolerance at start but decrease while adding new colors.
The code references Framework.Net 4.0 (and WPF) and the project is VS2010.
The main usage is defined in the header comments of
ColorGenerator colorGenerator = new ColorGenerator();
colorGenerator.Speed = 50;
colorGenerator.UsedColors.Add(new ColorGenerator.ColorRatio(System.Windows.Media.Colors.Black, 4));
colorGenerator.UsedColors.Add(new ColorGenerator.ColorRatio(System.Windows.Media.Colors.White, 1.2));
colorGenerator.UsedColors.Add(new ColorGenerator.ColorRatio(System.Windows.Media.Colors.LightGray, 1));
System.Windows.Media.Color c = colorGenerator.GetNextColor();
Hope it helps some
Latest version of the code include (2011-10-05):
- CieLab2000 color distance calculation
- Corrections on D65 white reference constants – calculation
- Calculations are all made with D65 white reference
Thanks a lot to Rob2412 to bring me corrections and help me to understand a little bit better the color world (alternatives 4 and 5) .