Add suffix to filename of uploaded images

Question

I registered 3 custom image sizes (Double sized, for retina displays) with add_image_size: thumbnail@2x, medium@2x and large@2x.

function retina_image_sizes() {
    $retina_sizes = array(
        'thumbnail@2x' => array(
        'width' => get_option( 'thumbnail_size_w' ) * 2,
        'height' => get_option( 'thumbnail_size_h' ) * 2,
        'crop' => get_option('thumbnail_crop'),
        ),
        'medium@2x' => array(
        'width' => get_option( 'medium_size_w' ) * 2,
        'height' => get_option( 'medium_size_h' ) * 2,
        'crop' => false,
        ),
        'large@2x' => array(
            'width' => get_option( 'large_size_w' ) * 2,
            'height' => get_option( 'large_size_h' ) * 2,
            'crop' => false,
        )
    );

    foreach ( $retina_sizes as $name => $data ) {
        add_image_size( $name, $data['width'], $data['height'], $data['crop'] );
    }
}
add_action( 'init', 'retina_image_sizes');

Wordpress's naming convention is filename-width x height.jpg. But I need them to be named in another fashion ( filename-originalwidth x originalheight@2x.jpg)

If I upload a picture, and the thumbnail has a size of 100x100, for example, I want the images to be named:

example-100x100.jpg
and
example-100x100@2x.jpg

I found ways to process pictures and save them under another name, but that is too much. This question explains, how to change the filename, but, not how to include with and height information. I tried to get it to work, but I only get a single file instead of seven and it throws some errors (probably because it tries to overwrite the file).

How can I change the filename in the above described fashion? Is the add_attachment hook the right one?

Answer 1

I did it in a different way. I just had to update the code from Gerasimos Tsiamalos Retina Plugin to Wordpress 3.5., using image editor instead of image resize.

This is how it looks like:

function nothing_image_make_retina_size($file, $width, $height, $crop=false) {
    if ( $width || $height ) {
        $resized_file = wp_get_image_editor($file);
        if ( ! is_wp_error( $resized_file ) ) {
            $resized_file->resize( $width*2, $height*2, $crop );
            $filename = $resized_file->generate_filename( $width . 'x' . $height . '@2x'  );
            $resized_file->save($filename);
        }
        if ( !is_wp_error($resized_file) && $resized_file && $info = getimagesize($filename) ) {
            $filename = apply_filters('nothing_retina_image_make_intermediate_size', $filename);
            return array(
                'file' => wp_basename( $filename ),
                'width' => $info[0],
                'height' => $info[1],
            );
        }
    }
    return false;
}

function nothing_generate_retina_image_metadata( $metadata, $attachment_id ) {
    $attachment = get_post( $attachment_id );   
    $file = get_attached_file($attachment_id);
    $old_metadata = $metadata;
    foreach ($metadata as $k => $v) {
        if (is_array($v)) {
            foreach ($v as $key => $val) {
                if (is_array($val)) {
                    nothing_image_make_retina_size($file, $val['width'], $val['height'], true);
                } 
            } 
        } 
    }
    return $old_metadata;
}
add_filter('wp_generate_attachment_metadata', 'nothing_generate_retina_image_metadata', 10, 2);

function nothing_delete_retina_images( $attachment_id ) {
    $nothing_metas = wp_get_attachment_metadata( $attachment_id );
    $nothing_updir = wp_upload_dir();
    $nothing_path = pathinfo($nothing_metas['file']);
    $nothing_path_name = $nothing_path['dirname'];
    $nothing_updir = wp_upload_dir();
    foreach ($nothing_metas as $nothing_meta => $nothing_meta_val) {
        if ($nothing_meta === "sizes") {
            foreach ($nothing_meta_val as $nothing_sizes => $nothing_size) {
                $nothing_original_filename = $nothing_updir['basedir'] . "/" . $nothing_path_name . "/" . $nothing_size['file'];
                $nothing_x2_filename = substr_replace($nothing_original_filename, "@2x.", strrpos($nothing_original_filename, "."), strlen("."));
                if (file_exists($nothing_x2_filename)) {
                    unlink($nothing_x2_filename);
                }
            }           
        }       
    }
}
add_filter('delete_attachment','nothing_delete_retina_images');