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Determining Ideal Text Color Based on Specified Background Color

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4.43 (94 votes)
8 May 2007
A method for programatically determining the appropriate foreground color based on the specified background color

Introduction

Here's a little snippet for everyone that develops web pages. Today, my boss told me that the text color on a web page element did not contrast enough with the element's background color. Well, she changes her mind more often than Bush denies that Iraq is in the middle of a civil war. For that reason, we had to come up with a way that would preclude us from revisiting the code when she changes her mind about the background color.

Here's a link to an article that describes the VBScript version. I kept them separate (versus putting everything in the same article) so that a search of the appropriate code category would help you find the desired version a little faster.

The Snippet

We spent three hours trying different methods to determine whether or not the text in a HTML element should be black or white. Finally, we found a W3C compliant formula for weighting the lightness of a given color. Once we found that, the rest was fairly easy.

To determine the text color, we subtracted the bgDelta value from 255, and then tried arbitrary threshold values until the text was coming up in a reasonable color for all of our test cases. Your threshold may vary, so don't hesitate to change the value we're using.

using System.Graphics.Drawing;

public Color IdealTextColor(Color bg)
{
    int nThreshold = 105;
    int bgDelta = Convert.ToInt32((bg.R * 0.299) + (bg.G * 0.587) + 
                                  (bg.B * 0.114));

    Color foreColor = (255 - bgDelta < nThreshold) ? Color.Black : Color.White;
    return foreColor;
}

We put this function into a base class that is inherited by all of the pages on our site. If you're writing VB code, you should be able to easily port this to your site.

Disclaimers

This article is short because there's really nothing of any complexity associated with the method described herein. There's also no downloadable code because - well - this is all the code, and I'm not going to fight with VS2005 just to create a sample program for you to download.

Hopefully, it will save you a little time...

History

  • 08 May 2007 - included a link at the top of this article to the VBScript version of this article.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

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About the Author

#realJSOP
Software Developer (Senior) Paddedwall Software
United States United States
I've been paid as a programmer since 1982 with experience in Pascal, and C++ (both self-taught), and began writing Windows programs in 1991 using Visual C++ and MFC. In the 2nd half of 2007, I started writing C# Windows Forms and ASP.Net applications, and have since done WPF, Silverlight, WCF, web services, and Windows services.

My weakest point is that my moments of clarity are too brief to hold a meaningful conversation that requires more than 30 seconds to complete. Thankfully, grunts of agreement are all that is required to conduct most discussions without committing to any particular belief system.

Comments and Discussions

 
QuestionChanging text colour based on specific background colour Pin
Noel Macara19-Sep-18 23:43
memberNoel Macara19-Sep-18 23:43 
QuestionIN case of white background the label is white Pin
Member 1223840929-Nov-16 19:10
memberMember 1223840929-Nov-16 19:10 
GeneralI prefer this method Pin
Aiscrim28-Aug-08 3:15
memberAiscrim28-Aug-08 3:15 
GeneralRe: I prefer this method Pin
#realJSOP8-Jan-10 4:57
mve#realJSOP8-Jan-10 4:57 
GeneralRe: I prefer this method Pin
Hornwood5098-Dec-14 3:34
memberHornwood5098-Dec-14 3:34 
GeneralThanks, John Pin
Hans Dietrich20-Aug-08 22:47
mentorHans Dietrich20-Aug-08 22:47 
GeneralRe: Thanks, John Pin
#realJSOP20-Aug-08 23:15
mve#realJSOP20-Aug-08 23:15 
QuestionColor other than Black White Pin
a.mulay15-May-07 19:43
membera.mulay15-May-07 19:43 
AnswerRe: Color other than Black White Pin
#realJSOP17-May-07 2:10
mve#realJSOP17-May-07 2:10 
GeneralRe: Color other than Black White Pin
a.mulay17-May-07 2:31
membera.mulay17-May-07 2:31 
GeneralRe: Color other than Black White Pin
Liam O'Hagan15-Apr-08 17:27
memberLiam O'Hagan15-Apr-08 17:27 
Questionwhat's the C++ echivalent code? Pin
Mihai MOGA22-Dec-06 0:16
professionalMihai MOGA22-Dec-06 0:16 
AnswerRe: what's the C++ echivalent code? Pin
Pete O'Hanlon22-Dec-06 0:56
protectorPete O'Hanlon22-Dec-06 0:56 
AnswerRe: what's the C++ echivalent code? Pin
Dieter Hammer8-May-07 20:07
memberDieter Hammer8-May-07 20:07 
GeneralRe: what's the C++ echivalent code? Pin
#realJSOP14-May-07 2:04
mve#realJSOP14-May-07 2:04 
GeneralNot bad, but... Pin
ke4vtw7-Dec-06 6:50
memberke4vtw7-Dec-06 6:50 
GeneralRe: Not bad, but... Pin
#realJSOP7-Dec-06 12:54
mve#realJSOP7-Dec-06 12:54 
GeneralRe: Not bad, but... Pin
fwsouthern8-May-07 15:26
memberfwsouthern8-May-07 15:26 
GeneralYou got my 5 Pin
Tarakeshwar Reddy4-Dec-06 17:18
professionalTarakeshwar Reddy4-Dec-06 17:18 
GeneralNice Pin
Member 964-Dec-06 6:28
memberMember 964-Dec-06 6:28 
GeneralRe: Nice Pin
#realJSOP5-Dec-06 0:02
mve#realJSOP5-Dec-06 0:02 
GeneralCool trick Pin
Mike Brand4-Dec-06 6:22
memberMike Brand4-Dec-06 6:22 
GeneralRe: Cool trick Pin
#realJSOP8-Jan-10 4:56
mve#realJSOP8-Jan-10 4:56 
GeneralNow I remember... Pin
PJ Arends30-Nov-06 6:11
professionalPJ Arends30-Nov-06 6:11 
GeneralCP Is Just The Greatest Thing Pin
Ilíon29-Nov-06 3:28
memberIlíon29-Nov-06 3:28 

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Posted 28 Nov 2006

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