Version 1

[yaffs-website] / web / core / lib / Drupal / Component / Utility / Color.php

diff --git a/web/core/lib/Drupal/Component/Utility/Color.php b/web/core/lib/Drupal/Component/Utility/Color.php
new file mode 100644 (file)
index 0000000..aa296e9
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+++ b/web/core/lib/Drupal/Component/Utility/Color.php
@@ -0,0 +1,97 @@
+<?php
+
+namespace Drupal\Component\Utility;
+
+/**
+ * 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) {
+    // Must be a string.
+    $valid = is_string($hex);
+    // Hash prefix is optional.
+    $hex = ltrim($hex, '#');
+    // Must be either RGB or RRGGBB.
+    $length = Unicode::strlen($hex);
+    $valid = $valid && ($length === 3 || $length === 6);
+    // Must be a valid hex value.
+    $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.");
+    }
+
+    // Ignore '#' prefixes.
+    $hex = ltrim($hex, '#');
+
+    // Convert shorthands like '#abc' to '#aabbcc'.
+    if (strlen($hex) == 3) {
+      $hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
+    }
+
+    $c = hexdec($hex);
+
+    return [
+      '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) {
+    // Remove named array keys if input comes from Color::hex2rgb().
+    if (is_array($input)) {
+      $rgb = array_values($input);
+    }
+    // Parse string input in CSS notation ('10, 20, 30').
+    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);
+  }
+
+}