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Possible Duplicate:
given a background color, how to get a foreground color that make it readable on that background color?

I wonder, if there is any algorithm to determine the optimal fontcolor for readability by its background color.

For example: I create an icon with dynamic text and color. If the color is kinda dark, I want it to set the font color to white and if its fairly bright, I want it to be in black (or maybe even grayish).

  public DynamicIcon( String iconText, Color backgroundColor )
  {
    this.iconText = iconText;
    this.backgroundColor = backgroundColor;

    this.fontColor = determineFontColor( backgroundColor );
  }

  //This is what I need (Pseudocode):
  private fontColor determineFontColor( Color backgroundColor )
  {
    if( backgroundColor == bright )
      return Color.BLACK;
    if( backgroundColor == dark )
      return Color.WHITE;
    //If possible:
    if( backgroundColor == somethingInBetween )
      return Color.GRAYISH;
  }

Unfortunatly I didnt find any algorithm like that, eventhough I am kinda sure, that it already exists. Anyone has any ideas?

thanks, ymene

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crusam
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1 Answers1

1

We had to do something like that on our system: based on the background, we colour the font black or white. The solution we found is not perfect and chooses the wrong colour on some rare occasions, but we are very satisfied with it.

This is what we did:

int red = 0;
int green = 0;
int blue = 0;

if ( backgroundColor.red + backgroundColor.green + backgroundColor.blue < 383 ) {
    red = 255;
    green = 255;
    blue = 255;
}

And then we use red, green and blue values to create a new Color object.

The magical number 383 is the result of ( 255 + 255 + 255 ) / 2

Mario Marinato
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    thank you for sharing your idea. I'll try it. Might be good enough for me as well. – crusam Jan 05 '12 at 11:37
  • rgb(191,87,218) is a fairly darkish purple OSX uses for the list selection background colour (they use white for the text foreground colour.) 191+87+218=496, so this algorithm would determine it to be "light". The other solution I had, which was to convert to HSB and then use the B value as a cutoff, failed on the same example. – Hakanai Dec 16 '14 at 01:21