Generate image information

Key Features

• URL Validation and Update: The function validates the given URL and adjusts it to match the current domain of the WordPress site.
• Metadata Extraction: It retrieves metadata from the WordPress database, such as the image title, dimensions, and alternative text (alt) if available.
• Alt Text Generation: If no alt text is set in WordPress, it constructs one using the image title or a cleaned version of the image file name.

The result is a string containing the `alt`, `width`, and `height` attributes, ready to be used in an `img` tag for improved accessibility and SEO. This function is particularly useful for ensuring that all images have descriptive attributes without manual editing.

                            
                                /**
                                 * Generate alt, W and H attr for an image based on its URL or metadata.
                                 *
                                 * This function attempts to generate alt text for an image using the following methods:
                                 * 1: Construct a new URL with the home domain
                                 * 2. Get all information to the image from the metadata in WP
                                 * 3. Validate what type of alt will be set
                                 *
                                 * @since 2.0.0
                                 *
                                 * @param string $url The URL of the image.
                                 * @return string Alt text for the image.
                                 */
                                function generate_img_info($url)
                                {
                                    if (filter_var($url, FILTER_VALIDATE_URL)) {
                                        // Step 1: Construct a new URL with the home domain
                                        $parsed_url = parse_url($url);
                                
                                        if (!empty($parsed_url)) {
                                            $new_domain = parse_url(home_url());
                                            $new_image_url = $new_domain['scheme'] . "://" . $new_domain['host'] . $parsed_url['path'];
                                            // Now $new_image_url contains the URL updated with the new domain
                                
                                            // Step 2: Get all information to the image from the metadata
                                            $img_id = attachment_url_to_postid($new_image_url); // Tries to convert an attachment URL into a post ID
                                            $img_meta_data = get_post_meta($img_id)['_wp_attachment_metadata']; // Get the image information stored in the database
                                            $img_meta_data_uns = unserialize($img_meta_data[0]);
                                            $img_title = $img_meta_data_uns['image_meta']['title'];
                                            $img_w = $img_meta_data_uns['width'];
                                            $img_h = $img_meta_data_uns['height'];
                                            $alt_wp = get_post_meta($img_id, '_wp_attachment_image_alt', true); // Retrieve alt text from the WordPress attachment if available.
                                            $alt = '';
                                
                                            // Step 3: Validate what type of alt will be set
                                            if (!empty($alt_wp)) {
                                                $alt = $alt_wp;
                                            } elseif (!empty($img_title)) {
                                                $alt = $img_title;
                                            } else {
                                                $img_file = $img_meta_data_uns['file'];
                                                $img_name = pathinfo($img_file, PATHINFO_FILENAME);
                                                $cleaned_img_name = preg_replace('/[\d-]+/', ' ', $img_name);
                                                $final_result = ucwords(trim($cleaned_img_name));
                                
                                                // Set alt text based to the name of the filename
                                                $alt = $final_result;
                                            }
                                
                                            return "alt='{$alt}' width='{$img_w}' height='{$img_h}'";
                                        } else {
                                            return false;
                                        }
                                    }
                                }
                            
                        

Preview

Result