Custom logo sizes for multiple logos

Question

I am using

add_theme_support('custom-logo', array(
// The logo will be displayed with the following sizes:
    'width' => 200,
    'height' => 200,
));

to display a logo image in my sidebar.

in functions.php I have set the size for the large logo:

add_theme_support('custom-logo', array(
// The logo will be displayed with the following sizes:
    'width' => 200,
    'height' => 200,
));

However, I would also like to use the same logo in the header, but with a size of 80x80px. This means I need to set two different sizes for the_custom_logo. Is this possible? If so how?

I have tried using add_image_size but I believe this is wrong so I am not really sure how to do this.

Answer 1

It's possible to modify the size of the custom logo with:

// Modify the custom logo size
add_filter( 'image_downsize', 'wpse241257_new_custom_logo_size', 10, 3 );

// Display the custom logo
the_custom_logo();

where our filter callback is defined as (PHP 5.4+):

function wpse241257_new_custom_logo_size( $downsize, $id, $size )
{
    //-------------------
    // Edit to your needs
    $size = [80,80];          // Array of width and height
    // $size = 'thumbnail';   // String value of the image size name
    //-------------------

    remove_filter( current_filter(), __FUNCTION__ ); // Important to avoid recursive loop
    return image_downsize( $id, $size );
}