Image resizing function

    /**
    * Images scaling
    * @param string  $ini_path Path to initial image.
    * @param string $dest_path Path to save new image.
    * @param array $params [optional] Must be an associative array of params
    * $params['width'] int New image width.
    * $params['height'] int New image height.
    * $params['constraint'] array.$params['constraint']['width'], $params['constraint'][height]
    * If specified the $width and $height params will be ignored.
    * New image will be resized to specified value either by width or height.
    * $params['aspect_ratio'] bool If false new image will be stretched to specified values.
    * If true aspect ratio will be preserved an empty space filled with color $params['rgb']
    * It has no sense for $params['constraint'].
    * $params['crop'] bool If true new image will be cropped to fit specified dimensions. It has no sense for $params['constraint'].
    * $params['rgb'] Hex code of background color. Default 0xFFFFFF.
    * $params['quality'] int New image quality (0 - 100). Default 100.
    * @return bool True on success.
    */
    function resize($ini_path, $dest_path, $params = array()) {
        $width = !empty($params['width']) ? $params['width'] : null;
        $height = !empty($params['height']) ? $params['height'] : null;
        $constraint = !empty($params['constraint']) ? $params['constraint'] : false;
        $rgb = !empty($params['rgb']) ?  $params['rgb'] : 0xFFFFFF;
        $quality = !empty($params['quality']) ?  $params['quality'] : 100;
        $aspect_ratio = isset($params['aspect_ratio']) ?  $params['aspect_ratio'] : true;
        $crop = isset($params['crop']) ?  $params['crop'] : true;

        if (!file_exists($ini_path)) return false;


        if (!is_dir($dir=dirname($dest_path))) mkdir($dir);

        $img_info = getimagesize($ini_path);
        if ($img_info === false) return false;

        $ini_p = $img_info[0]/$img_info[1];
        if ( $constraint ) {
            $con_p = $constraint['width']/$constraint['height'];
            $calc_p = $constraint['width']/$img_info[0];

            if ( $ini_p < $con_p ) {
                $height = $constraint['height'];
                $width = $height*$ini_p;
            } else {
                $width = $constraint['width'];
                $height = $img_info[1]*$calc_p;
            }
        } else {
            if ( !$width && $height ) {
                $width = ($height*$img_info[0])/$img_info[1];
            } else if ( !$height && $width ) {
                $height = ($width*$img_info[1])/$img_info[0];
            } else if ( !$height && !$width ) {
                $width = $img_info[0];
                $height = $img_info[1];
            }
        }

        preg_match('/\.([^\.]+)$/i',basename($dest_path), $match);
        $ext = strtolower($match[1]);
        $output_format = ($ext == 'jpg') ? 'jpeg' : $ext;

        $format = strtolower(substr($img_info['mime'], strpos($img_info['mime'], '/')+1));
        $icfunc = "imagecreatefrom" . $format;

        $iresfunc = "image" . $output_format;

        if (!function_exists($icfunc)) return false;

        $dst_x = $dst_y = 0;
        $src_x = $src_y = 0;
        $res_p = $width/$height;
        if ( $crop && !$constraint ) {
            $dst_w  = $width;
            $dst_h = $height;
            if ( $ini_p > $res_p ) {
                $src_h = $img_info[1];
                $src_w = $img_info[1]*$res_p;
                $src_x = ($img_info[0] >= $src_w) ? floor(($img_info[0] - $src_w) / 2) : $src_w;
            } else {
                $src_w = $img_info[0];
                $src_h = $img_info[0]/$res_p;
                $src_y    = ($img_info[1] >= $src_h) ? floor(($img_info[1] - $src_h) / 2) : $src_h;
            }
        } else {
            if ( $ini_p > $res_p ) {
                $dst_w = $width;
                $dst_h = $aspect_ratio ? floor($dst_w/$img_info[0]*$img_info[1]) : $height;
                $dst_y = $aspect_ratio ? floor(($height-$dst_h)/2) : 0;
            } else {
                $dst_h = $height;
                $dst_w = $aspect_ratio ? floor($dst_h/$img_info[1]*$img_info[0]) : $width;
                $dst_x = $aspect_ratio ? floor(($width-$dst_w)/2) : 0;
            }
            $src_w = $img_info[0];
            $src_h = $img_info[1];
        }

        $isrc = $icfunc($ini_path);
        $idest = imagecreatetruecolor($width, $height);
        if ( ($format == 'png' || $format == 'gif') && $output_format == $format ) {
            imagealphablending($idest, false);
            imagesavealpha($idest,true);
            imagefill($idest, 0, 0, IMG_COLOR_TRANSPARENT);
            imagealphablending($isrc, true);
            $quality = 0;
        } else {
            imagefill($idest, 0, 0, $rgb);
        }
        imagecopyresampled($idest, $isrc, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h);
        $res = $iresfunc($idest, $dest_path, $quality);

        imagedestroy($isrc);
        imagedestroy($idest);

        return $res;
    }