Hooking into register_admin_color_schemes

Question

I'm using WordPress 4.6.1, is it possible for us to hook into function register_admin_color_schemes() located in wp-includes/general-template.php? This way we can send or concatenate or bind the following code to that function:

wp_admin_css_color( 'ffa', _x( 'My Custom Color Combo', 'admin color scheme' ),
        admin_url( "/my-plugin=directory/css/colors/my-custom-color-combo/colors$suffix.css" ),
        array( '#ffffff', '#ffcd00', '#c7a589', '#9ea476' ),
        array( 'base' => '#f3f2f1', 'focus' => '#fff', 'current' => '#fff' )
    );

If possible, how can we do this dynamically?

FYI, I see that I can manually modify the general-template.php file, but I would have to do that every time I update WordPress.

Answer 1

No, you can't hook into that function since there is no do_action or apply_filters in it, the function itself hooks to admin_init. So if your goal is to add new color schemes you have to hook your code the same way, so using your example, the required code would be something like this:

// Define the function that registers the color schemes.
function wpse244982_register_admin_color_schemes() {
    wp_admin_css_color( 'ffa', _x( 'My Custom Color Combo', 'admin color scheme' ),
        admin_url( "/my-plugin=directory/css/colors/my-custom-color-combo/colors$suffix.css" ),
        array( '#ffffff', '#ffcd00', '#c7a589', '#9ea476' ),
        array( 'base' => '#f3f2f1', 'focus' => '#fff', 'current' => '#fff' )
    );

    // Maybe more colors schemes here
    // wp_admin_css_color(...);
    // wp_admin_css_color(...);
}

// Hook it to admin_init as WordPress does
add_action( 'admin_init', 'wpse244982_register_admin_color_schemes');

Answer 2

As far I understood your question you need a way where you can pass parameter and add multiple color schemes, right ? Well in that case you can call the function multiple times or you can write your own function like below-

function the_dramatist_admin_css_color( $args ) {
    wp_admin_css_color( $args['key'], $args['name'], admin_url( $args['url'] ), $args['color'], $args['last_el'] );
}

And call it passing your parameter like below-

$args = array(
    'key'       => 'ffa',
    'name'      => _x( 'My Custom Color Combo', 'admin color scheme' ),
    'url'       => '/my-plugin=directory/css/colors/my-custom-color-combo/colors.css',
    'color'     => array( '#ffffff', '#ffcd00', '#c7a589', '#9ea476' ),
    'last_el'   => array( 'base' => '#f3f2f1', 'focus' => '#fff', 'current' => '#fff' )

);

// Then call the function
the_dramatist_admin_css_color($args);

Hope that helps.