name : wp-accessibility-contrast.php <?php /** * WP Accessibility Color Contrast testing * * @category Features * @package WP Accessibility * @author Joe Dolson * @license GPLv2 or later * @link https://www.joedolson.com/wp-accessibility/ */ if ( ! defined( 'ABSPATH' ) ) { exit; } /** * Measure the relative luminosity between two RGB values. * * @param int $r Red value 1. * @param int $r2 Red value 2. * @param int $g Green value 1. * @param int $g2 Green value 2. * @param int $b Blue value 1. * @param int $b2 Blue value 2. * * @return luminosity ratio. */ function wpa_luminosity( $r, $r2, $g, $g2, $b, $b2 ) { $rs_rgb = $r / 255; $gs_rgb = $g / 255; $bs_rgb = $b / 255; $r_new = ( $rs_rgb <= 0.03928 ) ? $rs_rgb / 12.92 : pow( ( $rs_rgb + 0.055 ) / 1.055, 2.4 ); $g_new = ( $gs_rgb <= 0.03928 ) ? $gs_rgb / 12.92 : pow( ( $gs_rgb + 0.055 ) / 1.055, 2.4 ); $b_new = ( $bs_rgb <= 0.03928 ) ? $bs_rgb / 12.92 : pow( ( $bs_rgb + 0.055 ) / 1.055, 2.4 ); $rs_rgb2 = $r2 / 255; $gs_rgb2 = $g2 / 255; $bs_rgb2 = $b2 / 255; $r2_new = ( $rs_rgb2 <= 0.03928 ) ? $rs_rgb2 / 12.92 : pow( ( $rs_rgb2 + 0.055 ) / 1.055, 2.4 ); $g2_new = ( $gs_rgb2 <= 0.03928 ) ? $gs_rgb2 / 12.92 : pow( ( $gs_rgb2 + 0.055 ) / 1.055, 2.4 ); $b2_new = ( $bs_rgb2 <= 0.03928 ) ? $bs_rgb2 / 12.92 : pow( ( $bs_rgb2 + 0.055 ) / 1.055, 2.4 ); if ( $r + $g + $b <= $r2 + $g2 + $b2 ) { $l2 = ( .2126 * $r_new + 0.7152 * $g_new + 0.0722 * $b_new ); $l1 = ( .2126 * $r2_new + 0.7152 * $b2_new + 0.0722 * $b2_new ); } else { $l1 = ( .2126 * $r_new + 0.7152 * $g_new + 0.0722 * $b_new ); $l2 = ( .2126 * $r2_new + 0.7152 * $g2_new + 0.0722 * $b2_new ); } $luminosity = round( ( $l1 + 0.05 ) / ( $l2 + 0.05 ), 2 ); return $luminosity; } /** * Convert an RGB value to a HEX value. * * @param int $r Red value. * @param int $g Green value. * @param int $b Blue value. * * @return Hexadecimal color equivalent. */ function wpa_rgb2hex( $r, $g = - 1, $b = - 1 ) { if ( is_array( $r ) && sizeof( $r ) === 3 ) { list( $r, $g, $b ) = $r; } $r = intval( $r ); $g = intval( $g ); $b = intval( $b ); $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; } /** * Convert a Hexadecimal color value to RGB. * * @param string $color Hexadecimal value for a color. * * @return array of RGB values in R,G,B order. */ function wpa_hex2rgb( $color ) { $color = str_replace( '#', '', $color ); if ( strlen( $color ) !== 6 ) { return array( 0, 0, 0 ); } $rgb = array(); for ( $x = 0; $x < 3; $x ++ ) { $rgb[ $x ] = hexdec( substr( $color, ( 2 * $x ), 2 ) ); } return $rgb; } /** * Calculate the luminosity ratio between two color values. */ function wpa_contrast() { if ( ! empty( $_POST ) ) { $nonce = $_REQUEST['_wpnonce']; if ( ! wp_verify_nonce( $nonce, 'wpa-nonce' ) ) { die( 'Security check failed' ); } if ( isset( $_POST['color'] ) && '' !== $_POST['color'] ) { $fore_color = $_POST['color']; if ( '#' === $fore_color[0] ) { $fore_color = str_replace( '#', '', $fore_color ); } if ( 3 === strlen( $fore_color ) ) { $color6char = $fore_color[0] . $fore_color[0]; $color6char .= $fore_color[1] . $fore_color[1]; $color6char .= $fore_color[2] . $fore_color[2]; $fore_color = $color6char; } if ( preg_match( '/^#?([0-9a-f]{1,2}){3}$/i', $fore_color ) ) { $echo_hex_fore = str_replace( '#', '', $fore_color ); } else { $echo_hex_fore = 'FFFFFF'; } if ( isset( $_POST['color2'] ) && '' !== $_POST['color2'] ) { $back_color = $_POST['color2']; if ( '#' === $back_color[0] ) { $back_color = str_replace( '#', '', $back_color ); } if ( 3 === strlen( $back_color ) ) { $color6char = $back_color[0] . $back_color[0]; $color6char .= $back_color[1] . $back_color[1]; $color6char .= $back_color[2] . $back_color[2]; $back_color = $color6char; } if ( preg_match( '/^#?([0-9a-f]{1,2}){3}$/i', $back_color ) ) { $echo_hex_back = str_replace( '#', '', $back_color ); } else { $echo_hex_back = 'FFFFFF'; } $color = wpa_hex2rgb( $echo_hex_fore ); $color2 = wpa_hex2rgb( $echo_hex_back ); $rfore = $color[0]; $gfore = $color[1]; $bfore = $color[2]; $rback = $color2[0]; $gback = $color2[1]; $bback = $color2[2]; $colors = array( 'hex1' => $echo_hex_fore, 'hex2' => $echo_hex_back, 'red1' => $rfore, 'green1' => $gfore, 'blue1' => $bfore, 'red2' => $rback, 'green2' => $gback, 'blue2' => $bback, ); return $colors; } else { return false; } } } return false; }