How can I cycle through hex color codes in PHP?

Question

I want an array where each field in the array contains a color code

array(0 => \'#4CFF00\', 1 => \'#FFE97F\')

And I want this to go t

Answer 1

function list_colours($start, $end, $steps = 6)
{
    $return = array();

    $start_r = hexdec(substr($start, 1, 2));
    $start_g = hexdec(substr($start, 3, 2));
    $start_b = hexdec(substr($start, 5, 2));

    $end_r = hexdec(substr($end, 1, 2));
    $end_g = hexdec(substr($end, 3, 2));
    $end_b = hexdec(substr($end, 5, 2));

    $shift_r = ($end_r - $start_r) / $steps;
    $shift_g = ($end_g - $start_g) / $steps;
    $shift_b = ($end_b - $start_b) / $steps;

    for ($i = 0; $i < $steps; $i++)
    {
        $color = array();
        $color[] = dechex($start_r + ($i * $shift_r));
        $color[] = dechex($start_g + ($i * $shift_g));
        $color[] = dechex($start_b + ($i * $shift_b));

        // Pad with zeros.
        $color = array_map(function ($item) {
                return str_pad($item, 2, "0", STR_PAD_LEFT);
            },
            $color
        );

        $return[] = '#' . implode($color);
    }

    return $return;
}

// Examples
$spectrum = array();
$spectrum[] = list_colours("#000000", "#FFFFFF"); // grey
$spectrum[] = list_colours("#cc0033", "#FFFFFF"); // R
$spectrum[] = list_colours("#ff6600", "#FFFFFF"); // O
$spectrum[] = list_colours("#fdc710", "#FFFFFF"); // Y
$spectrum[] = list_colours("#cccc00", "#FFFFFF"); // G
$spectrum[] = list_colours("#339933", "#FFFFFF"); // G dark
$spectrum[] = list_colours("#339999", "#FFFFFF"); // B teal
$spectrum[] = list_colours("#14acde", "#FFFFFF"); // B light
$spectrum[] = list_colours("#0066cc", "#FFFFFF"); // B dark
$spectrum[] = list_colours("#663399", "#FFFFFF"); // I dark
$spectrum[] = list_colours("#990066", "#FFFFFF"); // I light
$spectrum[] = list_colours("#cc0066", "#FFFFFF"); // V pink