Extract url from next_image_link

Question

Is there a way to extract the url from next_image_link?

I want the image on the attachment page to link to the next image, but i didn't manage to figure out how to do it.

Answer 1

The function below is derived from adjacent_image_link() function. You can get both previous and next image source by this function. It can be used inside or outside loop.

Uses

 // get next image src
 $src = wpse145194_get_adjacent_image_link();


 // get previous image src
 $src = wpse145194_get_adjacent_image_link(true);

Function

function wpse145194_get_adjacent_image_link( $prev = false, $size = 'thumbnail', $post_id = false) {

    if(!$post_id)
        $post = get_post();
    else
        $post = get_post($post_id);


    $attachments = array_values( get_children( array( 'post_parent' => $post->post_parent, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => 'ASC', 'orderby' => 'menu_order ID' ) ) );


    foreach ( $attachments as $k => $attachment )
        if ( $attachment->ID == $post->ID )
            break;

    $k = $prev ? $k - 1 : $k + 1;

    $link = $attachment_id = null;

    if ( isset( $attachments[ $k ] ) ) {
        $attachment_id = $attachments[ $k ]->ID;
        // $link = wp_get_attachment_link( $attachment_id, $size, true, false, false );
        $link = get_attachment_link( $attachment_id);
    }

    return $link;
}

Code not tested

Answer 2

I solved my "problem" using a function from the twentyfourteen theme :

if ( ! function_exists( 'twentyfourteen_the_attached_image' ) ) :
/**
 * Print the attached image with a link to the next attached image.
 *
 * @since Twenty Fourteen 1.0
 */
function twentyfourteen_the_attached_image() {
    $post                = get_post();
    /**
     * Filter the default Twenty Fourteen attachment size.
     *
     * @since Twenty Fourteen 1.0
     *
     * @param array $dimensions {
     *     An array of height and width dimensions.
     *
     *     @type int $height Height of the image in pixels. Default 810.
     *     @type int $width  Width of the image in pixels. Default 810.
     * }
     */
    $attachment_size     = apply_filters( 'twentyfourteen_attachment_size', array( 810, 810 ) );
    $next_attachment_url = wp_get_attachment_url();

    /*
     * Grab the IDs of all the image attachments in a gallery so we can get the URL
     * of the next adjacent image in a gallery, or the first image (if we're
     * looking at the last image in a gallery), or, in a gallery of one, just the
     * link to that image file.
     */
    $attachment_ids = get_posts( array(
        'post_parent'    => $post->post_parent,
        'fields'         => 'ids',
        'numberposts'    => -1,
        'post_status'    => 'inherit',
        'post_type'      => 'attachment',
        'post_mime_type' => 'image',
        'order'          => 'ASC',
        'orderby'        => 'menu_order ID',
    ) );

    // If there is more than 1 attachment in a gallery...
    if ( count( $attachment_ids ) > 1 ) {
        foreach ( $attachment_ids as $attachment_id ) {
            if ( $attachment_id == $post->ID ) {
                $next_id = current( $attachment_ids );
                break;
            }
        }

        // get the URL of the next image attachment...
        if ( $next_id ) {
            $next_attachment_url = get_attachment_link( $next_id );
        }

        // or get the URL of the first image attachment.
        else {
            $next_attachment_url = get_attachment_link( array_shift( $attachment_ids ) );
        }
    }

    printf( '<a href="%1$s" rel="attachment">%2$s</a>',
        esc_url( $next_attachment_url ),
        wp_get_attachment_image( $post->ID, $attachment_size )
    );
}
endif;

Then use <?php twentyfourteen_the_attached_image(); ?> to output the image linking to the next image.