- <?php
-
- * Performs color conversions.
- */
- class Color {
-
-
- * Validates whether a hexadecimal color value is syntactically correct.
- *
- * @param $hex
- * The hexadecimal string to validate. May contain a leading '#'. May use
- * the shorthand notation (e.g., '123' for '112233').
- *
- * @return bool
- * TRUE if $hex is valid or FALSE if it is not.
- */
- public static function validateHex($hex) {
-
- $valid = is_string($hex);
-
- $hex = ltrim($hex, '#');
-
- $length = backdrop_strlen($hex);
- $valid = $valid && ($length === 3 || $length === 6);
-
- $valid = $valid && ctype_xdigit($hex);
- return $valid;
- }
-
-
- * Parses a hexadecimal color string like '#abc' or '#aabbcc'.
- *
- * @param string $hex
- * The hexadecimal color string to parse.
- *
- * @return array
- * An array containing the values for 'red', 'green', 'blue'.
- *
- * @throws \InvalidArgumentException
- */
- public static function hexToRgb($hex) {
- if (!self::validateHex($hex)) {
- throw new \InvalidArgumentException("'$hex' is not a valid hex value.");
- }
-
-
- $hex = ltrim($hex, '#');
-
-
- if (strlen($hex) == 3) {
- $hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
- }
-
- $c = hexdec($hex);
-
- return array(
- 'red' => $c >> 16 & 0xFF,
- 'green' => $c >> 8 & 0xFF,
- 'blue' => $c & 0xFF,
- );
- }
-
-
- * Converts RGB color arrays and RGB strings in CSS notation to lowercase
- * simple colors like '#aabbcc'.
- *
- * @param array|string $input
- * The value to convert. If the value is an array the first three elements
- * will be used as the red, green and blue components. String values in CSS
- * notation like '10, 20, 30' are also supported.
- *
- * @return string
- * The lowercase simple color representation of the given color.
- */
- public static function rgbToHex($input) {
-
- if (is_array($input)) {
- $rgb = array_values($input);
- }
-
- elseif (is_string($input)) {
- preg_match('/(\d+), ?(\d+), ?(\d+)/', $input, $rgb);
- array_shift($rgb);
- }
-
- $out = 0;
- foreach ($rgb as $k => $v) {
- $out |= $v << (16 - $k * 8);
- }
-
- return '#' . str_pad(dechex($out), 6, 0, STR_PAD_LEFT);
- }
- }