Cloudinary::generate_transformation_string PHP Method

    public static function generate_transformation_string(&$options = array())
    {
        $generate_base_transformation = "Cloudinary::generate_base_transformation";
        if (is_string($options)) {
            return $options;
        }
        if ($options == array_values($options)) {
            return implode("/", array_map($generate_base_transformation, $options));
        }
        $responsive_width = Cloudinary::option_consume($options, "responsive_width", Cloudinary::config_get("responsive_width"));
        $size = Cloudinary::option_consume($options, "size");
        if ($size) {
            list($options["width"], $options["height"]) = preg_split("/x/", $size);
        }
        $width = Cloudinary::option_get($options, "width");
        $height = Cloudinary::option_get($options, "height");
        $has_layer = Cloudinary::option_get($options, "underlay") || Cloudinary::option_get($options, "overlay");
        $angle = implode(Cloudinary::build_array(Cloudinary::option_consume($options, "angle")), ".");
        $crop = Cloudinary::option_consume($options, "crop");
        $no_html_sizes = $has_layer || !empty($angle) || $crop == "fit" || $crop == "limit" || $responsive_width;
        if (strlen($width) == 0 || $width && (substr($width, 0, 4) == "auto" || floatval($width) < 1 || $no_html_sizes)) {
            unset($options["width"]);
        }
        if (strlen($height) == 0 || $height && (floatval($height) < 1 || $no_html_sizes)) {
            unset($options["height"]);
        }
        $background = Cloudinary::option_consume($options, "background");
        if ($background) {
            $background = preg_replace("/^#/", 'rgb:', $background);
        }
        $color = Cloudinary::option_consume($options, "color");
        if ($color) {
            $color = preg_replace("/^#/", 'rgb:', $color);
        }
        $base_transformations = Cloudinary::build_array(Cloudinary::option_consume($options, "transformation"));
        if (count(array_filter($base_transformations, "is_array")) > 0) {
            $base_transformations = array_map($generate_base_transformation, $base_transformations);
            $named_transformation = "";
        } else {
            $named_transformation = implode(".", $base_transformations);
            $base_transformations = array();
        }
        $effect = Cloudinary::option_consume($options, "effect");
        if (is_array($effect)) {
            $effect = implode(":", $effect);
        }
        $border = Cloudinary::process_border(Cloudinary::option_consume($options, "border"));
        $flags = implode(Cloudinary::build_array(Cloudinary::option_consume($options, "flags")), ".");
        $dpr = Cloudinary::option_consume($options, "dpr", Cloudinary::config_get("dpr"));
        $duration = Cloudinary::norm_range_value(Cloudinary::option_consume($options, "duration"));
        $start_offset = Cloudinary::norm_range_value(Cloudinary::option_consume($options, "start_offset"));
        $end_offset = Cloudinary::norm_range_value(Cloudinary::option_consume($options, "end_offset"));
        $offset = Cloudinary::split_range(Cloudinary::option_consume($options, "offset"));
        if (!empty($offset)) {
            $start_offset = Cloudinary::norm_range_value($offset[0]);
            $end_offset = Cloudinary::norm_range_value($offset[1]);
        }
        $video_codec = Cloudinary::process_video_codec_param(Cloudinary::option_consume($options, "video_codec"));
        $overlay = Cloudinary::process_layer(Cloudinary::option_consume($options, "overlay"), "overlay");
        $underlay = Cloudinary::process_layer(Cloudinary::option_consume($options, "underlay"), "underlay");
        $if = Cloudinary::process_if(Cloudinary::option_consume($options, "if"));
        $params = array("a" => $angle, "b" => $background, "bo" => $border, "c" => $crop, "co" => $color, "dpr" => $dpr, "du" => $duration, "e" => $effect, "eo" => $end_offset, "fl" => $flags, "h" => $height, "l" => $overlay, "so" => $start_offset, "t" => $named_transformation, "u" => $underlay, "vc" => $video_codec, "w" => $width);
        $simple_params = array("ac" => "audio_codec", "af" => "audio_frequency", "ar" => "aspect_ratio", "br" => "bit_rate", "cs" => "color_space", "d" => "default_image", "dl" => "delay", "dn" => "density", "f" => "fetch_format", "g" => "gravity", "o" => "opacity", "p" => "prefix", "pg" => "page", "q" => "quality", "r" => "radius", "vs" => "video_sampling", "x" => "x", "y" => "y", "z" => "zoom");
        foreach ($simple_params as $param => $option) {
            $params[$param] = Cloudinary::option_consume($options, $option);
        }
        $param_filter = function ($value) {
            return $value === 0 || $value === '0' || trim($value) == true;
        };
        $params = array_filter($params, $param_filter);
        ksort($params);
        if (isset($if)) {
            $params = array_merge(array("if" => $if), $params);
        }
        $join_pair = function ($key, $value) {
            return $key . "_" . $value;
        };
        $transformation = implode(",", array_map($join_pair, array_keys($params), array_values($params)));
        $raw_transformation = Cloudinary::option_consume($options, "raw_transformation");
        $transformation = implode(",", array_filter(array($transformation, $raw_transformation)));
        array_push($base_transformations, $transformation);
        if ($responsive_width) {
            $responsive_width_transformation = Cloudinary::config_get("responsive_width_transformation", Cloudinary::$DEFAULT_RESPONSIVE_WIDTH_TRANSFORMATION);
            array_push($base_transformations, Cloudinary::generate_transformation_string($responsive_width_transformation));
        }
        if (substr($width, 0, 4) == "auto" || $responsive_width) {
            $options["responsive"] = true;
        }
        if (substr($dpr, 0, 4) == "auto") {
            $options["hidpi"] = true;
        }
        return implode("/", array_filter($base_transformations));
    }

 protected static function build_responsive_breakpoints($breakpoints)
 {
     if (!$breakpoints) {
         return NULL;
     }
     $breakpoints_params = array();
     foreach (\Cloudinary::build_array($breakpoints) as $breakpoint_settings) {
         if ($breakpoint_settings) {
             $transformation = \Cloudinary::option_consume($breakpoint_settings, "transformation");
             if ($transformation) {
                 $breakpoint_settings["transformation"] = \Cloudinary::generate_transformation_string($transformation);
             }
             array_push($breakpoints_params, $breakpoint_settings);
         }
     }
     return json_encode($breakpoints_params);
 }