CRM/Utils/Color.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 4.7                                                |
   5  +--------------------------------------------------------------------+
   6  | Copyright CiviCRM LLC (c) 2004-2017                                |
   7  +--------------------------------------------------------------------+
   8  | This file is a part of CiviCRM.                                    |
   9  |                                                                    |
  10  | CiviCRM is free software; you can copy, modify, and distribute it  |
  11  | under the terms of the GNU Affero General Public License           |
  12  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
  13  |                                                                    |
  14  | CiviCRM is distributed in the hope that it will be useful, but     |
  15  | WITHOUT ANY WARRANTY; without even the implied warranty of         |
  16  | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
  17  | See the GNU Affero General Public License for more details.        |
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  19  | You should have received a copy of the GNU Affero General Public   |
  20  | License and the CiviCRM Licensing Exception along                  |
  21  | with this program; if not, contact CiviCRM LLC                     |
  22  | at info[AT]civicrm[DOT]org. If you have questions about the        |
  23  | GNU Affero General Public License or the licensing of CiviCRM,     |
  24  | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
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  26  */
  27
  28 /**
  29  *
  30  * @package CRM
  31  * @copyright CiviCRM LLC (c) 2004-2017
  32  */
  33
  34 /**
  35  * Static utility functions for working with colors
  36  */
  37 class CRM_Utils_Color {
  38
  39   /**
  40    * Determine the appropriate text color for a given background.
  41    *
  42    * Based on YIQ value.
  43    *
  44    * @param string $hexcolor
  45    * @return string
  46    */
  47   public static function getContrast($hexcolor) {
  48     $hexcolor = trim($hexcolor, ' #');
  49     $r = hexdec(substr($hexcolor, 0, 2));
  50     $g = hexdec(substr($hexcolor, 2, 2));
  51     $b = hexdec(substr($hexcolor, 4, 2));
  52     $yiq = (($r * 299) + ($g * 587) + ($b * 114)) / 1000;
  53     return ($yiq >= 128) ? 'black' : 'white';
  54   }
  55
  56 }