Weird color question for you...

[charris1980]

right now i have a user choose a background color and a lighter background color to show next to it on a data row i am displaying.

 

i was curious if there was a way that they could choose a background color (lets say blueish) and then through php code go about 4-6 shades lighter of the blueish color?

 

Or if there is a different way to accomplish this I am open ears.  I just want to eliminate users input as much as possible.

[laffin]

They say when it comes to colors, colors on the oppsite side of the color wheel will compliment the primary color chosen.

 

what better way than negate the color code?

 

bgcolor= <user input>

fgcolor = !<user input>

[frijole]

can you explain how the ! can do that? it will give the opposite color?

[laffin]

Yes, it will invert the numbers.

 

function negativeColor($color)
{
    //get red, green and blue
    $r = substr($color, 0, 2);
    $g = substr($color, 2, 2);
    $b = substr($color, 4, 2);
   
    //revert them, they are decimal now
    $r = 0xff-hexdec($r);
    $g = 0xff-hexdec($g);
    $b = 0xff-hexdec($b);
   
    //now convert them to hex and return.
    return dechex($r).dechex($g).dechex($b);
}

 

 

[frijole]

thats good to know. Thanks.

[charris1980]

yeah that is some good info about colors.  i'll test this tonight and see how it goes!  thanks!

[laffin]

Actually i did a test, and it did pretty well

<?php

function NegateColor($color)
{
return substr('000000'.dechex(~hexdec($color)),-6);
}

  $colors=array('FFFFFF','000000','3300FF','660033','444444','336633');
  echo "<TABLE>\n";
  foreach($colors as $color)
  {
  $bgc = NegateColor($color);
  echo "<TR><TD BGCOLOR=\"#$bgc\"><FONT color=\"#$color\">$color on $bgc</FONT></TD></TR>\n";
  }
  echo "</TABLE>";
  
?>

[laffin]

Went a little further to generate a random base color, and it works most of the time, some colors just blend into each other too well.

 

<?php

function NegateColor($color)
{
return substr('000000'.dechex(~hexdec($color)),-6);
}

  echo "<TABLE>\n";
  for($i=0;$i<10;$i++)
  {
  $color=dechex(mt_rand(0,hexdec('FFFFFF')));
  $bgc = NegateColor($color);
  echo "<TR><TD BGCOLOR=\"#$bgc\"><FONT color=\"#$color\">$color on $bgc</FONT></TD></TR>\n";
  }
  echo "</TABLE>";
  
?>