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<?php// This file is part of Moodle - http://moodle.org///// Moodle is free software: you can redistribute it and/or modify// it under the terms of the GNU General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// Moodle is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the// GNU General Public License for more details.//// You should have received a copy of the GNU General Public License// along with Moodle. If not, see <http://www.gnu.org/licenses/>.namespace tool_brickfield\local\htmlchecker\common;/*** Helper test base for tests dealing with color difference and luminosity.** @package tool_brickfield* @copyright 2020 onward: Brickfield Education Labs, www.brickfield.ie* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later*/class brickfield_accessibility_color_test extends brickfield_accessibility_test {/** @var string[] Define colour codes. */public $colornames = ['aliceblue' => 'f0f8ff','antiquewhite' => 'faebd7','aqua' => '00ffff','aquamarine' => '7fffd4','azure' => 'f0ffff','beige' => 'f5f5dc','bisque' => 'ffe4c4','black' => '000000','blanchedalmond' => 'ffebcd','blue' => '0000ff','blueviolet' => '8a2be2','brown' => 'a52a2a','burlywood' => 'deb887','cadetblue' => '5f9ea0','chartreuse' => '7fff00','chocolate' => 'd2691e','coral' => 'ff7f50','cornflowerblue' => '6495ed','cornsilk' => 'fff8dc','crimson' => 'dc143c','cyan' => '00ffff','darkblue' => '00008b','darkcyan' => '008b8b','darkgoldenrod' => 'b8860b','darkgray' => 'a9a9a9','darkgreen' => '006400','darkkhaki' => 'bdb76b','darkmagenta' => '8b008b','darkolivegreen' => '556b2f','darkorange' => 'ff8c00','darkorchid' => '9932cc','darkred' => '8b0000','darksalmon' => 'e9967a','darkseagreen' => '8fbc8f','darkslateblue' => '483d8b','darkslategray' => '2f4f4f','darkturquoise' => '00ced1','darkviolet' => '9400d3','deeppink' => 'ff1493','deepskyblue' => '00bfff','dimgray' => '696969','dodgerblue' => '1e90ff','firebrick' => 'b22222','floralwhite' => 'fffaf0','forestgreen' => '228b22','fuchsia' => 'ff00ff','gainsboro' => 'dcdcdc','ghostwhite' => 'f8f8ff','gold' => 'ffd700','goldenrod' => 'daa520','gray' => '808080','green' => '008000','greenyellow' => 'adff2f','grey' => '808080','honeydew' => 'f0fff0','hotpink' => 'ff69b4','indianred' => 'cd5c5c','indigo' => '4b0082','ivory' => 'fffff0','khaki' => 'f0e68c','lavender' => 'e6e6fa','lavenderblush' => 'fff0f5','lawngreen' => '7cfc00','lemonchiffon' => 'fffacd','lightblue' => 'add8e6','lightcoral' => 'f08080','lightcyan' => 'e0ffff','lightgoldenrodyellow' => 'fafad2','lightgrey' => 'd3d3d3','lightgreen' => '90ee90','lightpink' => 'ffb6c1','lightsalmon' => 'ffa07a','lightseagreen' => '20b2aa','lightskyblue' => '87cefa','lightslategray' => '778899','lightsteelblue' => 'b0c4de','lightyellow' => 'ffffe0','lime' => '00ff00','limegreen' => '32cd32','linen' => 'faf0e6','magenta' => 'ff00ff','maroon' => '800000','mediumaquamarine' => '66cdaa','mediumblue' => '0000cd','mediumorchid' => 'ba55d3','mediumpurple' => '9370d8','mediumseagreen' => '3cb371','mediumslateblue' => '7b68ee','mediumspringgreen' => '00fa9a','mediumturquoise' => '48d1cc','mediumvioletred' => 'c71585','midnightblue' => '191970','mintcream' => 'f5fffa','mistyrose' => 'ffe4e1','moccasin' => 'ffe4b5','navajowhite' => 'ffdead','navy' => '000080','oldlace' => 'fdf5e6','olive' => '808000','olivedrab' => '6b8e23','orange' => 'ffa500','orangered' => 'ff4500','orchid' => 'da70d6','palegoldenrod' => 'eee8aa','palegreen' => '98fb98','paleturquoise' => 'afeeee','palevioletred' => 'd87093','papayawhip' => 'ffefd5','peachpuff' => 'ffdab9','peru' => 'cd853f','pink' => 'ffc0cb','plum' => 'dda0dd','powderblue' => 'b0e0e6','purple' => '800080','red' => 'ff0000','rosybrown' => 'bc8f8f','royalblue' => '4169e1','saddlebrown' => '8b4513','salmon' => 'fa8072','sandybrown' => 'f4a460','seagreen' => '2e8b57','seashell' => 'fff5ee','sienna' => 'a0522d','silver' => 'c0c0c0','skyblue' => '87ceeb','slateblue' => '6a5acd','slategray' => '708090','snow' => 'fffafa','springgreen' => '00ff7f','steelblue' => '4682b4','tan' => 'd2b48c','teal' => '008080','thistle' => 'd8bfd8','tomato' => 'ff6347','turquoise' => '40e0d0','violet' => 'ee82ee','wheat' => 'f5deb3','white' => 'ffffff','whitesmoke' => 'f5f5f5','yellow' => 'ffff00','yellowgreen' => '9acd32'];/** @var string[] Define estimated relative font-size codes to pt values. */public $fontsizenames = ['xx-small' => 9,'x-small' => 10,'small' => 11,'smaller' => 11,'medium' => 12,'large' => 14,'larger' => 14,'x-large' => 18,'xx-large' => 24,];/*** Helper method that finds the luminosity between the provided* foreground and background parameters.* @param string $foreground The HEX value of the foreground color* @param string $background The HEX value of the background color* @return float The luminosity contrast ratio between the colors*/public function get_luminosity(string $foreground, string $background): float {if ($foreground == $background) {return 0;}$forergb = $this->get_rgb($foreground);$backrgb = $this->get_rgb($background);// If get_rgb returns null for either, return 0.if ($forergb === null || $backrgb === null) {return 0;}return $this->luminosity($forergb['r'], $backrgb['r'],$forergb['g'], $backrgb['g'],$forergb['b'], $backrgb['b']);}/*** Returns the luminosity between two colors* @param string $r The first Red value* @param string $r2 The second Red value* @param string $g The first Green value* @param string $g2 The second Green value* @param string $b The first Blue value* @param string $b2 The second Blue value* @return float The luminosity contrast ratio between the colors*/public function luminosity(string $r, string $r2, string $g, string $g2, string $b, string $b2): float {$rsrgb = $r / 255;$gsrgb = $g / 255;$bsrgb = $b / 255;$r3 = ($rsrgb <= 0.03928) ? $rsrgb / 12.92 : pow(($rsrgb + 0.055) / 1.055, 2.4);$g3 = ($gsrgb <= 0.03928) ? $gsrgb / 12.92 : pow(($gsrgb + 0.055) / 1.055, 2.4);$b3 = ($bsrgb <= 0.03928) ? $bsrgb / 12.92 : pow(($bsrgb + 0.055) / 1.055, 2.4);$rsrgb2 = $r2 / 255;$gsrgb2 = $g2 / 255;$bsrgb2 = $b2 / 255;$r4 = ($rsrgb2 <= 0.03928) ? $rsrgb2 / 12.92 : pow(($rsrgb2 + 0.055) / 1.055, 2.4);$g4 = ($gsrgb2 <= 0.03928) ? $gsrgb2 / 12.92 : pow(($gsrgb2 + 0.055) / 1.055, 2.4);$b4 = ($bsrgb2 <= 0.03928) ? $bsrgb2 / 12.92 : pow(($bsrgb2 + 0.055) / 1.055, 2.4);if ($r + $g + $b <= $r2 + $g2 + $b2) {$l2 = (.2126 * $r3 + 0.7152 * $g3 + 0.0722 * $b3);$l1 = (.2126 * $r4 + 0.7152 * $g4 + 0.0722 * $b4);} else {$l1 = (.2126 * $r3 + 0.7152 * $g3 + 0.0722 * $b3);$l2 = (.2126 * $r4 + 0.7152 * $g4 + 0.0722 * $b4);}// Increase round to 4 to avoid a 4.49 contrast being round up to a false pass of 4.5.$luminosity = round(($l1 + 0.05) / ($l2 + 0.05), 4);return $luminosity;}/*** Returns the decimal equivalents for a HEX color. Returns null if it cannot be determined.* @param string $color The hex color value* @return array|null An array where 'r' is the Red value, 'g' is Green, and 'b' is Blue*/public function get_rgb(string $color): ?array {$color = $this->convert_color($color);$c = str_split($color, 2);if (count($c) != 3) {return null;}$results = ['r' => hexdec($c[0]), 'g' => hexdec($c[1]), 'b' => hexdec($c[2])];return $results;}/*** Converts multiple color or background styles into a simple hex string* @param string $color The color attribute to convert (this can also be a multi-value css background value)* @return string A standard CSS hex value for the color*/public function convert_color(string $color): string {$color = trim($color);if (strpos($color, ' ') !== false) {$colors = explode(' ', $color);foreach ($colors as $backgroundpart) {if (substr(trim($backgroundpart), 0, 1) == '#' ||in_array(trim($backgroundpart), array_keys($this->colornames)) ||strtolower(substr(trim($backgroundpart), 0, 3)) == 'rgb') {$color = $backgroundpart;}}}// Normal hex color.if (substr($color, 0, 1) == '#') {if (strlen($color) == 7) {return str_replace('#', '', $color);} else if (strlen($color) == 4) {return substr($color, 1, 1) . substr($color, 1, 1) .substr($color, 2, 1) . substr($color, 2, 1) .substr($color, 3, 1) . substr($color, 3, 1);} else {return "000000";}}// Named Color.if (in_array($color, array_keys($this->colornames))) {return $this->colornames[$color];}// RGB values.if (strtolower(substr($color, 0, 3)) == 'rgb') {$colors = explode(',', trim(str_replace('rgb(', '', $color), '()'));if (count($colors) != 3) {return false;}$r = intval($colors[0]);$g = intval($colors[1]);$b = intval($colors[2]);$r = dechex($r < 0 ? 0 : ($r > 255 ? 255 : $r));$g = dechex($g < 0 ? 0 : ($g > 255 ? 255 : $g));$b = dechex($b < 0 ? 0 : ($b > 255 ? 255 : $b));$color = (strlen($r) < 2 ? '0' : '') . $r;$color .= (strlen($g) < 2 ? '0' : '') . $g;$color .= (strlen($b) < 2 ? '0' : '') . $b;return $color;}return '';}/*** Returns the WAIERT contrast between two colors* @param string $foreground* @param string $background* @return array* @see get_luminosity*/public function get_wai_ert_contrast(string $foreground, string $background): array {$forergb = $this->get_rgb($foreground);$backrgb = $this->get_rgb($background);// If get_rgb returns null for either, return 0.if ($forergb === null || $backrgb === null) {return [];}$diffs = $this->get_wai_diffs($forergb, $backrgb);return $diffs['red'] + $diffs['green'] + $diffs['blue'];}/*** Returns the WAI ERT Brightness between two colors* @param string $foreground* @param string $background* @return float|int*/public function get_wai_ert_brightness(string $foreground, string $background): float {$forergb = $this->get_rgb($foreground);$backrgb = $this->get_rgb($background);// If get_rgb returns null for either, return 0.if ($forergb === null || $backrgb === null) {return 0;}$color = $this->get_wai_diffs($forergb, $backrgb);return (($color['red'] * 299) + ($color['green'] * 587) + ($color['blue'] * 114)) / 1000;}/*** Get the wai differences.* @param array $forergb* @param array $backrgb* @return array*/public function get_wai_diffs(array $forergb, array $backrgb): array {$reddiff = ($forergb['r'] > $backrgb['r'])? $forergb['r'] - $backrgb['r']: $backrgb['r'] - $forergb['r'];$greendiff = ($forergb['g'] > $backrgb['g'])? $forergb['g'] - $backrgb['g']: $backrgb['g'] - $forergb['g'];$bluediff = ($forergb['b'] > $backrgb['b'])? $forergb['b'] - $backrgb['b']: $backrgb['b'] - $forergb['b'];return ['red' => $reddiff, 'green' => $greendiff, 'blue' => $bluediff];}/*** Helper method that finds the estimated font-size for the provided* string font-size parameter.* @param string $fontsize The css font-size, in various formats* @return int The estimated font-size*/public function get_fontsize(string $fontsize): int {$newfontsize = 12; // Default value, in pt, equivalent to 16px.// Search for rem, em, and px initially, typical font-size values.$pos1 = stripos($fontsize, 'rem');$pos2 = stripos($fontsize, 'em');$pos3 = stripos($fontsize, 'px');if ($pos1 !== false) {$rem = substr($fontsize, 0, -3);$newfontsize = $newfontsize * $rem;} else if ($pos2 !== false) {$em = substr($fontsize, 0, -2);$newfontsize = $newfontsize * $em;} else if ($pos3 !== false) {$px = substr($fontsize, 0, -2);$newfontsize = 0.75 * $px;} else if (in_array($fontsize, array_keys($this->fontsizenames))) {$newfontsize = $this->fontsizenames[$fontsize];} else {preg_match_all('!\d+!', $fontsize, $matches);$newfontsize = $matches[0][0] ?? $newfontsize;}return (int) $newfontsize;}}