Creating an HTML hex color chart/table?

[random1]

How can you create a HTML Hex Color Chart using PHP to generate it?

 

Such as: http://www.immigration-usa.com/html_colors.html

 

So far I have the code:

 

<?php

function random_hex_color()
{
return sprintf("%02X%04X%02X", mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
}

echo('<table>' . "\n");

for($i = 0; $i < 500; $i++)
{
$hex = random_hex_color();
echo('<tr>' . "\n");
echo('<td bgcolor="#' . $hex . ';">#' . $hex . '</td>');
echo('</tr>');
}

echo("\n" . '</table>');

?>

 

but is not random enough. I'd like it so that is shades or each color ; red, yellow, blue, green, black.

[Tyche]

Its not random because you are using 4 zero filled spaces for the Green component in the sprintf format  , effectively fixing it as 00.

 

Change random_hex_color function to this

 

function random_hex_color()
{
   return sprintf("%02X%02X%02X", mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
}

[random1]

I ended up with:

 

<?php

function random_hex_color($max_r = 255, $max_g = 255, $max_b = 255)
{
// ensure that values are in the range between 0 and 255
if ($max_r > 255) { $max_r = 255; }
if ($max_g > 255) { $max_g = 255; }
if ($max_b > 255) { $max_b = 255; }
if ($max_r < 0) { $max_r = 0; }
if ($max_g < 0) { $max_g = 0; }
if ($max_b < 0) { $max_b = 0; }

// generate and return the random color
return dechex(rand(0, $max_r)) . dechex(rand(0, $max_g)) . dechex(rand(0, $max_b));
}

echo('<table>' . "\n");

for($i = 0; $i < 500; $i++)
{
$hex = random_hex_color();
echo('<tr height="40px">' . "\n");
echo('<td width="40px" bgcolor="#' . $hex . ';">    </td>');
echo('<td width="120px"> #' . $hex . '</td>');
echo('</tr>');
}

echo("\n" . '</table>');

?>

[Tyche]

You new method does produce random colors but there is still a bias in color selection . There are some possible colors which will never be produced and the bias is towards colors with higher red components and lower blue .

 

This is because you are dropping leading 0's  in your RGB color settings then concatenating them together.

 

So for instance  the 3 different  colours rgb(0F,FF,0F) rgb(0F,0F,FF) & rgb(FF,0F,0F) get returned as FFFF which is interpreted as rgb(FF,FF,00) . If you want your random colors to be uniformly distributed across all possible colors then just use the fix I gave you earlier.