colors.php

<?php
//This script generates a color palette or gradient based on [hexadecimal, short-hex, rgb, color name] values sent through _GET['color'] or _GET['gradient]
$colors   = $_GET['color']; 
$gradient = $_GET['gradient'];

if (isset($colors)) { //added these to avoid sending a blank page with image headers. 
    header('Content-Type: image/png');
    $type = 'color';
} else if (isset($gradient)) {
    header('Content-Type: image/png');
    $type = 'gradient';
}

$colornames = array(
    "pink" => "FFC0CB",
    "lightpink" => "FFB6C1",
    "hotpink" => "FF69B4",
    "deeppink" => "FF1493",
    "palevioletred" => "DB7093",
    "mediumvioletred" => "C71585",
    "lightsalmon" => "FFA07A",
    "salmon" => "FA8072",
    "darksalmon" => "E9967A",
    "lightcoral" => "F08080",
    "indianred" => "CD5C5C",
    "crimson" => "DC143C",
    "firebrick" => "B22222",
    "darkred" => "8B0000",
    "red" => "FF0000",
    "orangered" => "FF4500",
    "tomato" => "FF6347",
    "coral" => "FF7F50",
    "darkorange" => "FF8C00",
    "orange" => "FFA500",
    "gold" => "FFD700",
    "yellow" => "FFFF00",
    "lightyellow" => "FFFFE0",
    "lemonchiffon" => "FFFACD",
    "lightgoldenrodyellow" => "FAFAD2",
    "papayawhip" => "FFEFD5",
    "moccasin" => "FFE4B5",
    "peachpuff" => "FFDAB9",
    "palegoldenrod" => "EEE8AA",
    "khaki" => "F0E68C",
    "darkkhaki" => "BDB76B",
    "cornsilk" => "FFF8DC",
    "blanchedalmond" => "FFEBCD",
    "bisque" => "FFE4C4",
    "navajowhite" => "FFDEAD",
    "wheat" => "F5DEB3",
    "burlywood" => "DEB887",
    "tan" => "D2B48C",
    "rosybrown" => "BC8F8F",
    "sandybrown" => "F4A460",
    "goldenrod" => "DAA520",
    "darkgoldenrod" => "B8860B",
    "peru" => "CD853F",
    "chocolate" => "D2691E",
    "saddlebrown" => "8B4513",
    "sienna" => "A0522D",
    "brown" => "A52A2A",
    "maroon" => "800000",
    "darkolivegreen" => "556B2F",
    "olive" => "808000",
    "olivedrab" => "6B8E23",
    "yellowgreen" => "9ACD32",
    "limegreen" => "32CD32",
    "lime" => "00FF00",
    "lawngreen" => "7CFC00",
    "chartreuse" => "7FFF00",
    "greenyellow" => "ADFF2F",
    "springgreen" => "00FF7F",
    "mediumspringgreen" => "00FA9A",
    "lightgreen" => "90EE90",
    "palegreen" => "98FB98",
    "darkseagreen" => "8FBC8F",
    "mediumseagreen" => "3CB371",
    "seagreen" => "2E8B57",
    "forestgreen" => "228B22",
    "green" => "008000",
    "darkgreen" => "006400",
    "mediumaquamarine" => "66CDAA",
    "aqua" => "00FFFF",
    "cyan" => "00FFFF",
    "lightcyan" => "E0FFFF",
    "paleturquoise" => "AFEEEE",
    "aquamarine" => "7FFFD4",
    "turquoise" => "40E0D0",
    "mediumturquoise" => "48D1CC",
    "darkturquoise" => "00CED1",
    "lightseagreen" => "20B2AA",
    "cadetblue" => "5F9EA0",
    "darkcyan" => "008B8B",
    "teal" => "008080",
    "lightsteelblue" => "B0C4DE",
    "powderblue" => "B0E0E6",
    "lightblue" => "ADD8E6",
    "skyblue" => "87CEEB",
    "lightskyblue" => "87CEFA",
    "deepskyblue" => "00BFFF",
    "dodgerblue" => "1E90FF",
    "cornflowerblue" => "6495ED",
    "steelblue" => "4682B4",
    "royalblue" => "4169E1",
    "blue" => "0000FF",
    "mediumblue" => "0000CD",
    "darkblue" => "00008B",
    "navy" => "000080",
    "midnightblue" => "191970",
    "lavender" => "E6E6FA",
    "thistle" => "D8BFD8",
    "plum" => "DDA0DD",
    "violet" => "EE82EE",
    "orchid" => "DA70D6",
    "fuchsia" => "FF00FF",
    "magenta" => "FF00FF",
    "mediumorchid" => "BA55D3",
    "mediumpurple" => "9370DB",
    "blueviolet" => "8A2BE2",
    "darkviolet" => "9400D3",
    "darkorchid" => "9932CC",
    "darkmagenta" => "8B008B",
    "purple" => "800080",
    "indigo" => "4B0082",
    "darkslateblue" => "483D8B",
    "slateblue" => "6A5ACD",
    "mediumslateblue" => "7B68EE",
    "white" => "FFFFFF",
    "snow" => "FFFAFA",
    "honeydew" => "F0FFF0",
    "mintcream" => "F5FFFA",
    "azure" => "F0FFFF",
    "aliceblue" => "F0F8FF",
    "ghostwhite" => "F8F8FF",
    "whitesmoke" => "F5F5F5",
    "seashell" => "FFF5EE",
    "beige" => "F5F5DC",
    "oldlace" => "FDF5E6",
    "floralwhite" => "FFFAF0",
    "ivory" => "FFFFF0",
    "antiquewhite" => "FAEBD7",
    "linen" => "FAF0E6",
    "lavenderblush" => "FFF0F5",
    "mistyrose" => "FFE4E1",
    "gainsboro" => "DCDCDC",
    "lightgray" => "D3D3D3",
    "lightgrey" => "D3D3D3",
    "silver" => "C0C0C0",
    "darkgray" => "A9A9A9",
    "darkgrey" => "A9A9A9",
    "gray" => "808080",
    "grey" => "808080",
    "dimgray" => "696969",
    "dimgrey" => "696969",
    "lightslategray" => "778899",
    "lightslategrey" => "778899",
    "slategray" => "708090",
    "slategrey" => "708090",
    "darkslategray" => "2F4F4F",
    "darkslategrey" => "2F4F4F",
    "black" => "000000"
);


function rgbFromHex($hexValue)
{
    if (strlen($hexValue) == 3) { //shorthand check
        $r = hexdec(str_repeat($hexValue[0], 2));
        $g = hexdec(str_repeat($hexValue[1], 2));
        $b = hexdec(str_repeat($hexValue[2], 2));
    } else if (strlen($hexValue) == 6) { //standard hex color
        $r = hexdec(substr($hexValue, 0, 2));
        $g = hexdec(substr($hexValue, 2, 2));
        $b = hexdec(substr($hexValue, 4, 2));
    } else {
        $r = 0;
        $g = 0;
        $b = 0;
    }
    
    $rgb = array(
        $r,
        $g,
        $b
    );
    return $rgb;
}

function getHexByName($name)
{
    global $colornames;
    if (isset($colornames[$name])) {
        return $colornames[$name];
    } else {
        return null;
    }
}

/*
 * $input - a string, possibly comma-separated list of HexValues and/or color names
 *
 * returns an array of [r, g, b] arrays
 */
function parseColors($input)
{
    $colorArray = array();
    $parts      = explode(",", $input);
    
    foreach ($parts as $color) {
        $byName = getHexByName($color);
        if (!isset($byName)) {
            array_push($colorArray, rgbFromHex($color));
        } else {
            if (strpos($byName, ",") !== FALSE) {
                // we're dealing with a multi-part name, eg: roygbiv
                foreach (parseColors($byName) as $col) {
                    array_push($colorArray, $col);
                }
            } else {
                array_push($colorArray, rgbFromHex($byName));
            }
        }
    }
    
    return $colorArray;
}

/* 
 * $colorArray - an array of [r, g, b] arrays. 
 *
 * returns an array of [r, g, b] arrays. 
 */
function interpolateGradient($colorArray)
{
    $steps        = 200;
    $arrLen       = count($colorArray) - 1;
    $stepsPerGrad = $steps / $arrLen;
    $output       = array();
    
    for ($step = 0; $step < $steps; $step++) {
        $index   = floor($step / $stepsPerGrad);
        $percent = $step / $stepsPerGrad - $index;
        $curr    = $colorArray[$index];
        $next    = $colorArray[$index + 1];
        
        array_push($output, array(
            $curr[0] + $percent * ($next[0] - $curr[0]),
            $curr[1] + $percent * ($next[1] - $curr[1]),
            $curr[2] + $percent * ($next[2] - $curr[2])
        ));
    }
    
    return $output;
}

/* 
 * $colorArray - an array of [r, g, b] arrays. 
 *
 * returns an image. 
 */
function createSwatch($colorArray)
{
    $img      = imagecreate(1200, 240);
    $colWidth = 1200 / count($colorArray);
    $x        = 0;
    foreach ($colorArray as $rgb) {
        $color = imagecolorallocate($img, $rgb[0], $rgb[1], $rgb[2]);
        imagefilledrectangle($img, $x, 0, $x + $colWidth, 240, $color);
        $x += $colWidth;
    }
    return imagepng($img);
}




if ($type == 'color') {
    $colorArray = parseColors(strtolower($colors));
} else if ($type == 'gradient') {
    $colorArray = interpolateGradient(parseColors(strtolower($gradient)));
} else {
    echo 'GO AWAY';
}

if (isset($colorArray)) {
    createSwatch($colorArray);
}

?>