removing function from unknown hook

I have a question regarding a theme development issue. I’m trying to develop a child theme deprived from One Page Express Theme (https://onepageexpress.com).
It’s working fine so far, but now I want to replace a function in function.php.
As far as I have understood it, I have to remove it from an action or filter (is there a difference in this case?) to create a rewritten function. Otherwise the site gets broken. The problem is: I do not know the $tag string I i have to specify in the remove_action() function. I do not see where the original function was added by add_filter() or add_action().
Anyone an idea how to accomplish that?

The function is under inc/function.php in the theme folder line 2369.

Here is a listig of the code:

function one_page_express_background($inner = false)
{
    $attrs = array(
        'class' => $inner ? "header " : "header-homepage ",
    );

    $prefix = $inner ? "one_page_express_inner_header" : "one_page_express_header";
    $bgType = get_theme_mod($prefix . '_background_type', 'image');

    $header_type  = $inner ? "inner_header" : "header";
    $show_overlay = get_theme_mod("one_page_express_" . $header_type . "_show_overlay", true);
    if ($show_overlay) {
        $attrs['class'] .= " color-overlay ";
    }

    switch ($bgType) {

        case 'image':
            $bgImage        = $inner ? get_header_image() : get_theme_mod($prefix . '_image', get_template_directory_uri() . "/assets/images/home_page_header.jpg");
            $attrs['style'] = 'background-image:url("' . esc_url($bgImage) . '")';
            $parallax       = get_theme_mod("one_page_express_" . $header_type . "_parallax", true);
            if ($parallax) {
                $attrs['data-parallax-depth'] = "20";
            }
            break;

        case 'gradient':
 
           $bgGradient     = get_theme_mod($prefix . "_gradient", "plum_plate");
            $attrs['class'] .= $bgGradient;
            break;

        case 'slideshow':

            $js = get_template_directory_uri() . "/assets/js/libs/jquery.backstretch.js";
            wp_enqueue_script('one-page-express-backstretch', $js, array('jquery'), false, true);
            add_action('wp_footer', $prefix . '_slideshow_script');

            break;

        case 'video':
            $internalVideo = get_theme_mod($prefix . '_video', "");
            $video_url     = get_theme_mod($prefix . '_video_external', "https://www.youtube.com/watch?v=3iXYciBTQ0c");
            $videoPoster   = get_theme_mod($prefix . '_video_poster', get_template_directory_uri() . "/assets/images/Mock-up.jpg");

            if ($internalVideo) {
                $video_url = wp_get_attachment_url($internalVideo);
                $video_url = apply_filters('get_header_video_url', $video_url);
            }

            $video_type = wp_check_filetype($video_url, wp_get_mime_types());
            $header     = get_custom_header();
            $settings   = array(
                'mimeType'  => '',
                'videoUrl'  => $video_url,
                'posterUrl' => $videoPoster,
                'width'     => absint($header->width),
                'height'    => absint($header->height),
                'minWidth'  => 900,
                'minHeight' => 500,
                'l10n'      => array(
                    'pause'      => __('Pause', 'one-page-express'),
                    'play'       => __('Play', 'one-page-express'),
                    'pauseSpeak' => __('Video is paused.', 'one-page-express'),
                    'playSpeak'  => __('Video is playing.', 'one-page-express'),
                ),
            );

            if (preg_match('#^https?://(?:www\.)?(?:youtube\.com/watch|youtu\.be/)#', $video_url)) {
                $settings['mimeType'] = 'video/x-youtube';
            } else if ( ! empty($video_type['type'])) {
                $settings['mimeType'] = $video_type['type'];
            }

            $settings = apply_filters('header_video_settings', $settings);

            wp_enqueue_script('wp-custom-header');
            wp_localize_script('wp-custom-header', '_wpCustomHeaderSettings', $settings);
            wp_enqueue_script('cp-video-bg', get_template_directory_uri() . "/assets/js/video-bg.js", array('wp-custom-header'));
            $attrs['class'] .= " cp-video-bg";
            break;
    }

    $result = "";

    if ( ! isset($attrs['style'])) {
        $attrs['style'] = "";
    } else {
        $attrs['style'] .= ";";
    }

    if ( ! $inner) {
        $attrs['style'] .= " min-height:" . one_page_express_header_height();
    }

    $attrs = apply_filters('one_page_express_header_background_atts', $attrs, $bgType, $inner);

    foreach ($attrs as $key => $value) {
        $value  = trim(esc_attr($value));
        $result .= " {$key}='{$value}'";
    }

    return $result;
}

function one_page_express_header_slideshow_script()
{
    one_page_express_header_slideshow_script_();
}

• This topic was modified 8 years, 3 months ago by Steven Stern (sterndata).
• This topic was modified 8 years, 3 months ago by Steven Stern (sterndata).
• This topic was modified 8 years, 3 months ago by Jan Dembowski.