Custom color calculator based on the selected background color

actions-custom-output.php

<?php
/**
 * Actions.
 *
 * This file adds the required CSS to the front end to the Actions Pro Theme.
 *
 * @package Actions
 * @author  WPDevHQ
 * @license GPL-2.0+
 * @link    http://www.wpdevhq.com/
 */

/**
* Checks the settings for the link color, actions primary, actions secondary and button colors.
* If any of these value are set the appropriate CSS is output.
*
* @since 1.0.0
*/
function actions_pro_css() {
	if ( wp_get_theme()->get('Name') != 'Actions Pro' ) {
		$theme_style = 'actions-child-style';
	} else {
		$theme_style = 'actions-style';
	}
	$handle  = $theme_style;

	$color_link 			= get_theme_mod( 'actions_pro_link_color', actions_pro_customizer_get_default_link_color() );
	$color_link_hover		= get_theme_mod( 'actions_pro_link_hover_color', actions_pro_customizer_get_default_link_hover_color() );
	$color_accent_pri 		= get_theme_mod( 'actions_pro_accent_primary', actions_pro_customizer_get_default_accent_primary() );
	$color_accent_sec 		= get_theme_mod( 'actions_pro_accent_secondary', actions_pro_customizer_get_default_accent_secondary() );
	$color_button_pri 		= get_theme_mod( 'actions_pro_button_primary', actions_pro_customizer_get_default_button_primary() );
	$color_button_sec 		= get_theme_mod( 'actions_pro_button_secondary', actions_pro_customizer_get_default_button_secondary() );

	$css = '';
	//* Calculate Color Contrast
	function actions_color_contrast( $color ) {
	
		$hexcolor = str_replace( '#', '', $color );

		$red   = hexdec( substr( $hexcolor, 0, 2 ) );
		$green = hexdec( substr( $hexcolor, 2, 2 ) );
		$blue  = hexdec( substr( $hexcolor, 4, 2 ) );

		$luminosity = ( ( $red * 0.2126 ) + ( $green * 0.7152 ) + ( $blue * 0.0722 ) );

		return ( $luminosity > 128 ) ? '#333333' : '#ffffff';

	}
	
	//* Calculate Color Brightness
	function actions_color_brightness( $color, $change ) {

		$hexcolor = str_replace( '#', '', $color );

		$red   = hexdec( substr( $hexcolor, 0, 2 ) );
		$green = hexdec( substr( $hexcolor, 2, 2 ) );
		$blue  = hexdec( substr( $hexcolor, 4, 2 ) );
	
		$red   = max( 0, min( 255, $red + $change ) );
		$green = max( 0, min( 255, $green + $change ) );  
		$blue  = max( 0, min( 255, $blue + $change ) );

		return '#'.dechex( $red ).dechex( $green ).dechex( $blue );

	}

	$css .= ( actions_pro_customizer_get_default_link_color() !== $color_link ) ? sprintf( 'a,.site-content a{color: %s;}', $color_link ) : '';
	
	$css .= ( actions_pro_customizer_get_default_link_hover_color() !== $color_link_hover ) ? sprintf( 'a:hover,.site-content a:hover{color: %s;}', $color_link_hover ) : '';
	
	$css .= ( actions_pro_customizer_get_default_accent_primary() !== $color_accent_pri ) ? sprintf( '
		.site-header,.site-title a,.footer-area,.site-footer a,.archive-pagination li a:focus,
		.archive-pagination li a:hover,.site-title a:hover,.archive-pagination .active a {background-color: %s;color: %s;}
		', $color_accent_pri, actions_color_contrast( $color_accent_pri ) ) : '';
		
	$css .= ( actions_pro_customizer_get_default_accent_secondary() !== $color_accent_sec ) ? sprintf( '
		.site-header-menu,.main-navigation ul ul li,.site-header-menu a,.main-navigation li:hover > a,.main-navigation li.focus > a,
		.main-navigation .menu-item-has-children > a::after,.dropdown-toggle,.dropdown-toggle:hover,.dropdown-toggle:focus {background-color: %s; color: %s;}
		', $color_accent_sec, actions_color_contrast( $color_accent_sec ) ) : '';
		
	$css .= ( actions_pro_customizer_get_default_accent_secondary() !== $color_accent_sec ) ? sprintf( '
		.site-header-menu,.main-navigation .primary-menu,.main-navigation ul ul,.main-navigation li,.main-navigation ul ul li{border-color: %s;}', $color_accent_sec ) : '';
		
	$css .= ( actions_pro_customizer_get_default_button_primary() !== $color_button_pri ) ? sprintf( '
		input[type="submit"],input[type="button"],.header-elements .widget-area .button,.header-elements .widget-area a.button.small, 
		.header-elements .widget-area button.small,.enews-widget input[type="submit"],.comments-area input[type="submit"]{background-color: %s; color: %s;}
		', $color_button_pri, actions_color_contrast( $color_button_pri ) ) : '';
		
	$css .= ( actions_pro_customizer_get_default_button_secondary() !== $color_button_sec ) ? sprintf( '
		input[type="submit"]:hover,input[type="submit"]:focus,input[type="button"]:hover,input[type="button"]:focus,.header-elements .widget-area .button:hover,
		.header-elements .widget-area a.button.small:hover,.header-elements .widget-area button.small:hover,.header-elements .widget-area .button:focus,
		.header-elements .widget-area a.button.small:forcus,.header-elements .widget-area button.small:forcus,#secondary.enews-widget input:hover[type="submit"],
		.enews-widget input:focus[type="submit"],.comments-area input[type="submit"]:hover{background-color: %s; color: %s;}
		', $color_button_sec, actions_color_contrast( $color_button_sec ) ) : '';

	wp_add_inline_style( $handle, $css );

}
add_action( 'wp_enqueue_scripts', 'actions_pro_css', 9999 );