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49f42e3c CW |
1 | <?php |
2 | /* | |
3 | +--------------------------------------------------------------------+ | |
fee14197 | 4 | | CiviCRM version 5 | |
49f42e3c | 5 | +--------------------------------------------------------------------+ |
6b83d5bd | 6 | | Copyright CiviCRM LLC (c) 2004-2019 | |
49f42e3c CW |
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. | | |
18 | | | | |
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 | | |
25 | +--------------------------------------------------------------------+ | |
26 | */ | |
27 | ||
28 | /** | |
29 | * | |
30 | * @package CRM | |
6b83d5bd | 31 | * @copyright CiviCRM LLC (c) 2004-2019 |
49f42e3c CW |
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 | |
8a52ae34 CW |
45 | * @param string $black |
46 | * @param string $white | |
49f42e3c CW |
47 | * @return string |
48 | */ | |
8a52ae34 CW |
49 | public static function getContrast($hexcolor, $black = 'black', $white = 'white') { |
50 | list($r, $g, $b) = self::getRgb($hexcolor); | |
49f42e3c | 51 | $yiq = (($r * 299) + ($g * 587) + ($b * 114)) / 1000; |
8a52ae34 CW |
52 | return ($yiq >= 128) ? $black : $white; |
53 | } | |
54 | ||
55 | /** | |
56 | * Convert hex color to decimal | |
57 | * | |
58 | * @param string $hexcolor | |
59 | * @return array | |
60 | * [red, green, blue] | |
61 | */ | |
62 | public static function getRgb($hexcolor) { | |
63 | $hexcolor = trim($hexcolor, ' #'); | |
64 | if (strlen($hexcolor) === 3) { | |
65 | $hexcolor = $hexcolor[0] . $hexcolor[0] . $hexcolor[1] . $hexcolor[1] . $hexcolor[2] . $hexcolor[2]; | |
66 | } | |
67 | return [ | |
68 | hexdec(substr($hexcolor, 0, 2)), | |
69 | hexdec(substr($hexcolor, 2, 2)), | |
70 | hexdec(substr($hexcolor, 4, 2)), | |
71 | ]; | |
72 | } | |
73 | ||
74 | /** | |
75 | * Calculate a highlight color from a base color | |
76 | * | |
77 | * @param $hexcolor | |
78 | * @return string | |
79 | */ | |
80 | public static function getHighlight($hexcolor) { | |
81 | $rgb = CRM_Utils_Color::getRgb($hexcolor); | |
82 | $avg = array_sum($rgb) / 3; | |
83 | foreach ($rgb as &$v) { | |
84 | if ($avg > 242) { | |
85 | // For very bright values, lower the brightness | |
86 | $v -= 50; | |
87 | } | |
88 | else { | |
89 | // Bump up brightness on a nonlinear curve - darker colors get more of a boost | |
90 | $v = min(255, intval((-.0035 * ($v - 242) ** 2) + 260)); | |
91 | } | |
92 | } | |
93 | return '#' . implode(array_map('dechex', $rgb)); | |
49f42e3c CW |
94 | } |
95 | ||
96 | } |