//DEBUG_IMG_TEMP
                //debugpng
                if (defined("DEBUGPNG") && DEBUGPNG) {
                    print 'trouble writing file from GD';
                }
            }

            if ($error) {
                $this->addMessage('PNG error - (' . $file . ') ' . $errormsg);

                return;
            }
        }  //End isset($this->imagelist[$file]) (png Duplicate removal)

        $this->addPngFromBuf($data, $file, $x, $y, $w, $h, $is_mask, $mask);
    }

    /**
     * @param $file
     * @param $x
     * @param $y
     * @param $w
     * @param $h
     * @param $byte
     */
    protected function addImagePngAlpha($file, $x, $y, $w, $h, $byte)
    {
        // generate images
        $img = @imagecreatefrompng($file);

        if ($img === false) {
            return;
        }

        // FIXME The pixel transformation doesn't work well with 8bit PNGs
        $eight_bit = ($byte & 4) !== 4;

        $wpx = imagesx($img);
        $hpx = imagesy($img);

        imagesavealpha($img, false);

        // create temp alpha file
        $tempfile_alpha = @tempnam($this->tmp, "cpdf_img_");
        @unlink($tempfile_alpha);
        $tempfile_alpha = "$tempfile_alpha.png";

        // create temp plain file
        $tempfile_plain = @tempnam($this->tmp, "cpdf_img_");
        @unlink($tempfile_plain);
        $tempfile_plain = "$tempfile_plain.png";

        $imgalpha = imagecreate($wpx, $hpx);
        imagesavealpha($imgalpha, false);

        // generate gray scale palette (0 -> 255)
        for ($c = 0; $c < 256; ++$c) {
            imagecolorallocate($imgalpha, $c, $c, $c);
        }

        // Use PECL gmagick + Graphics Magic to process transparent PNG images
        if (extension_loaded("gmagick")) {
            $gmagick = new \Gmagick($file);
            $gmagick->setimageformat('png');

            // Get opacity channel (negative of alpha channel)
            $alpha_channel_neg = clone $gmagick;
            $alpha_channel_neg->separateimagechannel(\Gmagick::CHANNEL_OPACITY);

            // Negate opacity channel
            $alpha_channel = new \Gmagick();
            $alpha_channel->newimage($wpx, $hpx, "#FFFFFF", "png");
            $alpha_channel->compositeimage($alpha_channel_neg, \Gmagick::COMPOSITE_DIFFERENCE, 0, 0);
            $alpha_channel->separateimagechannel(\Gmagick::CHANNEL_RED);
            $alpha_channel->writeimage($tempfile_alpha);

            // Cast to 8bit+palette
            $imgalpha_ = @imagecreatefrompng($tempfile_alpha);
            imagecopy($imgalpha, $imgalpha_, 0, 0, 0, 0, $wpx, $hpx);
            imagedestroy($imgalpha_);
            imagepng($imgalpha, $tempfile_alpha);

            // Make opaque image
            $color_channels = new \Gmagick();
            $color_channels->newimage($wpx, $hpx, "#FFFFFF", "png");
            $color_channels->compositeimage($gmagick, \Gmagick::COMPOSITE_COPYRED, 0, 0);
            $color_channels->compositeimage($gmagick, \Gmagick::COMPOSITE_COPYGREEN, 0, 0);
            $color_channels->compositeimage($gmagick, \Gmagick::COMPOSITE_COPYBLUE, 0, 0);
            $color_channels->writeimage($tempfile_plain);

            $imgplain = @imagecreatefrompng($tempfile_plain);
        }
        // Use PECL imagick + ImageMagic to process transparent PNG images
        elseif (extension_loaded("imagick")) {
            // Native cloning was added to pecl-imagick in svn commit 263814
            // the first version containing it was 3.0.1RC1
            static $imagickClonable = null;
            if ($imagickClonable === null) {
                $imagickClonable = true;
                if (defined('Imagick::IMAGICK_EXTVER')) {
                    $imagickVersion = \Imagick::IMAGICK_EXTVER;
                } else {
                    $imagickVersion = '0';
                }
                if (version_compare($imagickVersion, '0.0.1', '>=')) {
                    $imagickClonable = version_compare($imagickVersion, '3.0.1rc1', '>=');
                }
            }

            $imagick = new \Imagick($file);
            $imagick->setFormat('png');

            // Get opacity channel (negative of alpha channel)
            if ($imagick->getImageAlphaChannel()) {
                $alpha_channel = $imagickClonable ? clone $imagick : $imagick->clone();
                $alpha_channel->separateImageChannel(\Imagick::CHANNEL_ALPHA);
                // Since ImageMagick7 negate invert transparency as default
                if (\Imagick::getVersion()['versionNumber'] < 1800) {
                    $alpha_channel->negateImage(true);
                }
                $alpha_channel->writeImage($tempfile_alpha);

                // Cast to 8bit+palette
                $imgalpha_ = @imagecreatefrompng($tempfile_alpha);
                imagecopy($imgalpha, $imgalpha_, 0, 0, 0, 0, $wpx, $hpx);
                imagedestroy($imgalpha_);
                imagepng($imgalpha, $tempfile_alpha);
            } else {
                $tempfile_alpha = null;
            }

            // Make opaque image
            $color_channels = new \Imagick();
            $color_channels->newImage($wpx, $hpx, "#FFFFFF", "png");
            $color_channels->compositeImage($imagick, \Imagick::COMPOSITE_COPYRED, 0, 0);
            $color_channels->compositeImage($imagick, \Imagick::COMPOSITE_COPYGREEN, 0, 0);
            $color_channels->compositeImage($imagick, \Imagick::COMPOSITE_COPYBLUE, 0, 0);
            $color_channels->writeImage($tempfile_plain);

            $imgplain = @imagecreatefrompng($tempfile_plain);
        } else {
            // allocated colors cache
            $allocated_colors = [];

            // extract alpha channel
            for ($xpx = 0; $xpx < $wpx; ++$xpx) {
                for ($ypx = 0; $ypx < $hpx; ++$ypx) {
                    $color = imagecolorat($img, $xpx, $ypx);
                    $col = imagecolorsforindex($img, $color);
                    $alpha = $col['alpha'];

                    if ($eight_bit) {
                        // with gamma correction
                        $gammacorr = 2.2;
                        $pixel = round(pow((((127 - $alpha) * 255 / 127) / 255), $gammacorr) * 255);
                    } else {
                        // without gamma correction
                        $pixel = (127 - $alpha) * 2;

                        $key = $col['red'] . $col['green'] . $col['blue'];

                        if (!isset($allocated_colors[$key])) {
                            $pixel_img = imagecolorallocate($img, $col['red'], $col['green'], $col['blue']);
                            $allocated_colors[$key] = $pixel_img;
                        } else {
                            $pixel_img = $allocated_colors[$key];
                        }

                        imagesetpixel($img, $xpx, $ypx, $pixel_img);
                    }

                    imagesetpixel($imgalpha, $xpx, $ypx, $pixel);
                }
            }

            // extract image without alpha channel
            $imgplain = imagecreatetruecolor($wpx, $hpx);
            imagecopy($imgplain, $img, 0, 0, 0, 0, $wpx, $hpx);
            imagedestroy($img);

            imagepng($imgalpha, $tempfile_alpha);
            imagepng($imgplain, $tempfile_plain);
        }

        $this->imageAlphaList[$file] = [$tempfile_alpha, $tempfile_plain];

        // embed mask image
        if ($tempfile_alpha) {
            $this->addImagePng($imgalpha, $tempfile_alpha, $x, $y, $w, $h, true);
            imagedestroy($imgalpha);
            $this->imageCache[] = $tempfile_alpha;
        }

        // embed image, masked with previously embedded mask
        $this->addImagePng($imgplain, $tempfile_plain, $x, $y, $w, $h, false, ($tempfile_alpha !== null));
        imagedestroy($imgplain);
        $this->imageCache[] = $tempfile_plain;
    }

    /**
     * add a PNG image into the document, from a file
     * this should work with remote files
     *
     * @param $file
     * @param $x
     * @param $y
     * @param int $w
     * @param int $h
     * @throws Exception
     */
    function addPngFromFile($file, $x, $y, $w = 0, $h = 0)
    {
        if (!function_exists("imagecreatefrompng")) {
            throw new \Exception("The PHP GD extension is required, but is not installed.");
        }

        if (isset($this->imageAlphaList[$file])) {
            [$alphaFile, $plainFile] = $this->imageAlphaList[$file];

            if ($alphaFile) {
                $img = null;
                $this->addImagePng($img, $alphaFile, $x, $y, $w, $h, true);
            }

            $img = null;
            $this->addImagePng($img, $plainFile, $x, $y, $w, $h, false, ($plainFile !== null));
            return;
        }

        //if already cached, need not to read again
        if (isset($this->imagelist[$file])) {
            $img = null;
        } else {
            $info = file_get_contents($file, false, null, 24, 5);
            $meta = unpack("CbitDepth/CcolorType/CcompressionMethod/CfilterMethod/CinterlaceMethod", $info);
            $bit_depth = $meta["bitDepth"];
            $color_type = $meta["colorType"];

            // http://www.w3.org/TR/PNG/#11IHDR
            // 3 => indexed
            // 4 => greyscale with alpha
            // 6 => fullcolor with alpha
            $is_alpha = in_array($color_type, [4, 6]) || ($color_type == 3 && $bit_depth != 4);

            if ($is_alpha) { // exclude grayscale alpha
                $this->addImagePngAlpha($file, $x, $y, $w, $h, $color_type);
                return;
            }

            //png files typically contain an alpha channel.
            //pdf file format or class.pdf does not support alpha blending.
            //on alpha blended images, more transparent areas have a color near black.
            //This appears in the result on not storing the alpha channel.
            //Correct would be the box background image or its parent when transparent.
            //But this would make the image dependent on the background.
            //Therefore create an image with white background and copy in
            //A more natural background than black is white.
            //Therefore create an empty image with white background and merge the
            //image in with alpha blending.
            $imgtmp = @imagecreatefrompng($file);
            if (!$imgtmp) {
                return;
            }
            $sx = imagesx($imgtmp);
            $sy = imagesy($imgtmp);
            $img = imagecreatetruecolor($sx, $sy);
            imagealphablending($img, true);

            // @todo is it still needed ??
            $ti = imagecolortransparent($imgtmp);
            if ($ti >= 0) {
                $tc = imagecolorsforindex($imgtmp, $ti);
                $ti = imagecolorallocate($img, $tc['red'], $tc['green'], $tc['blue']);
                imagefill($img, 0, 0, $ti);
                imagecolortransparent($img, $ti);
            } else {
                imagefill($img, 1, 1, imagecolorallocate($img, 255, 255, 255));
            }

            imagecopy($img, $imgtmp, 0, 0, 0, 0, $sx, $sy);
            imagedestroy($imgtmp);
        }
        $this->addImagePng($img, $file, $x, $y, $w, $h);

        if ($img) {
            imagedestroy($img);
        }
    }

    /**
     * add a PNG image into the document, from a file
     * this should work with remote files
     *
     * @param $file
     * @param $x
     * @param $y
     * @param int $w
     * @param int $h
     */
    function addSvgFromFile($file, $x, $y, $w = 0, $h = 0)
    {
        $doc = new \Svg\Document();
        $doc->loadFile($file);
        $dimensions = $doc->getDimensions();

        $this->save();

        $this->transform([$w / $dimensions["width"], 0, 0, $h / $dimensions["height"], $x, $y]);

        $surface = new \Svg\Surface\SurfaceCpdf($doc, $this);
        $doc->render($surface);

        $this->restore();
    }

    /**
     * add a PNG image into the document, from a memory buffer of the file
     *
     * @param $data
     * @param $file
     * @param $x
     * @param $y
     * @param float $w
     * @param float $h
     * @param bool $is_mask
     * @param null $mask
     */
    function addPngFromBuf(&$data, $file, $x, $y, $w = 0.0, $h = 0.0, $is_mask = false, $mask = null)
    {
        if (isset($this->imagelist[$file])) {
            $data = null;
            $info['width'] = $this->imagelist[$file]['w'];
            $info['height'] = $this->imagelist[$file]['h'];
            $label = $this->imagelist[$file]['label'];
        } else {
            if ($data == null) {
                $this->addMessage('addPngFromBuf error - data not present!');

                return;
            }

            $error = 0;

            if (!$error) {
                $header = chr(137) . chr(80) . chr(78) . chr(71) . chr(13) . chr(10) . chr(26) . chr(10);

                if (mb_substr($data, 0, 8, '8bit') != $header) {
                    $error = 1;

                    if (defined("DEBUGPNG") && DEBUGPNG) {
                        print '[addPngFromFile this file does not have a valid header ' . $file . ']';
                    }

                    $errormsg = 'this file does not have a valid header';
                }
            }

            if (!$error) {
                // set pointer
                $p = 8;
                $len = mb_strlen($data, '8bit');

                // cycle through the file, identifying chunks
                $haveHeader = 0;
                $info = [];
                $idata = '';
                $pdata = '';

                while ($p < $len) {
                    $chunkLen = $this->getBytes($data, $p, 4);
                    $chunkType = mb_substr($data, $p + 4, 4, '8bit');

                    switch ($chunkType) {
                        case 'IHDR':
                            // this is where all the file information comes from
                            $info['width'] = $this->getBytes($data, $p + 8, 4);
                            $info['height'] = $this->getBytes($data, $p + 12, 4);
                            $info['bitDepth'] = ord($data[$p + 16]);
                            $info['colorType'] = ord($data[$p + 17]);
                            $info['compressionMethod'] = ord($data[$p + 18]);
                            $info['filterMethod'] = ord($data[$p + 19]);
                            $info['interlaceMethod'] = ord($data[$p + 20]);

                            //print_r($info);
                            $haveHeader = 1;
                            if ($info['compressionMethod'] != 0) {
                                $error = 1;

                                //debugpng
                                if (defined("DEBUGPNG") && DEBUGPNG) {
                                    print '[addPngFromFile unsupported compression method ' . $file . ']';
                                }

                                $errormsg = 'unsupported compression method';
                            }

                            if ($info['filterMethod'] != 0) {
                                $error = 1;

                                //debugpng
                                if (defined("DEBUGPNG") && DEBUGPNG) {
                                    print '[addPngFromFile unsupported filter method ' . $file . ']';
                                }

                                $errormsg = 'unsupported filter method';
                            }
                            break;

                        case 'PLTE':
                            $pdata .= mb_substr($data, $p + 8, $chunkLen, '8bit');
                            break;

                        case 'IDAT':
                            $idata .= mb_substr($data, $p + 8, $chunkLen, '8bit');
                            break;

                        case 'tRNS':
                            //this chunk can only occur once and it must occur after the PLTE chunk and before IDAT chunk
                            //print "tRNS found, color type = ".$info['colorType']."\n";
                            $transparency = [];

                            switch ($info['colorType']) {
                                // indexed color, rbg
                                case 3:
                                    /* corresponding to entries in the plte chunk
                                     Alpha for palette index 0: 1 byte
                                     Alpha for palette index 1: 1 byte
                                     ...etc...
                                    */
                                    // there will be one entry for each palette entry. up until the last non-opaque entry.
                                    // set up an array, stretching over all palette entries which will be o (opaque) or 1 (transparent)
                                    $transparency['type'] = 'indexed';
                                    $trans = 0;

                                    for ($i = $chunkLen; $i >= 0; $i--) {
                                        if (ord($data[$p + 8 + $i]) == 0) {
                                            $trans = $i;
                                        }
                                    }

                                    $transparency['data'] = $trans;
                                    break;

                                // grayscale
                                case 0:
                                    /* corresponding to entries in the plte chunk
                                     Gray: 2 bytes, range 0 .. (2^bitdepth)-1
                                    */
                                    //            $transparency['grayscale'] = $this->PRVT_getBytes($data,$p+8,2); // g = grayscale
                                    $transparency['type'] = 'indexed';
                                    $transparency['data'] = ord($data[$p + 8 + 1]);
                                    break;

                                // truecolor
                                case 2:
                                    /* corresponding to entries in the plte chunk
                                     Red: 2 bytes, range 0 .. (2^bitdepth)-1
                                     Green: 2 bytes, range 0 .. (2^bitdepth)-1
                                     Blue: 2 bytes, range 0 .. (2^bitdepth)-1
                                    */
                                    $transparency['r'] = $this->getBytes($data, $p + 8, 2);
                                    // r from truecolor
                                    $transparency['g'] = $this->getBytes($data, $p + 10, 2);
                                    // g from truecolor
                                    $transparency['b'] = $this->getBytes($data, $p + 12, 2);
                                    // b from truecolor

                                    $transparency['type'] = 'color-key';
                                    break;

                                //unsupported transparency type
                                default:
                                    if (defined("DEBUGPNG") && DEBUGPNG) {
                                        print '[addPngFromFile unsupported transparency type ' . $file . ']';
                                    }
                                    break;
                            }

                            // KS End new code
                            break;

                        default:
                            break;
                    }

                    $p += $chunkLen + 12;
                }

                if (!$haveHeader) {
                    $error = 1;

                    //debugpng
                    if (defined("DEBUGPNG") && DEBUGPNG) {
                        print '[addPngFromFile information header is missing ' . $file . ']';
                    }

                    $errormsg = 'information header is missing';
                }

                if (isset($info['interlaceMethod']) && $info['interlaceMethod']) {
                    $error = 1;

                    //debugpng
                    if (defined("DEBUGPNG") && DEBUGPNG) {
                        print '[addPngFromFile no support for interlaced images in pdf ' . $file . ']';
                    }

                    $errormsg = 'There appears to be no support for interlaced images in pdf.';
                }
            }

            if (!$error && $info['bitDepth'] > 8) {
                $error = 1;

                //debugpng
                if (defined("DEBUGPNG") && DEBUGPNG) {
                    print '[addPngFromFile bit depth of 8 or less is supported ' . $file . ']';
                }

                $errormsg = 'only bit depth of 8 or less is supported';
            }

            if (!$error) {
                switch ($info['colorType']) {
                    case 3:
                        $color = 'DeviceRGB';
                        $ncolor = 1;
                        break;

                    case 2:
                        $color = 'DeviceRGB';
                        $ncolor = 3;
                        break;

                    case 0:
                        $color = 'DeviceGray';
                        $ncolor = 1;
                        break;

                    default:
                        $error = 1;

                        //debugpng
                        if (defined("DEBUGPNG") && DEBUGPNG) {
                            print '[addPngFromFile alpha channel not supported: ' . $info['colorType'] . ' ' . $file . ']';
                        }

                        $errormsg = 'transparency alpha channel not supported, transparency only supported for palette images.';
                }
            }

            if ($error) {
                $this->addMessage('PNG error - (' . $file . ') ' . $errormsg);

                return;
            }

            //print_r($info);
            // so this image is ok... add it in.
            $this->numImages++;
            $im = $this->numImages;
            $label = "I$im";
            $this->numObj++;

            //  $this->o_image($this->numObj,'new',array('label' => $label,'data' => $idata,'iw' => $w,'ih' => $h,'type' => 'png','ic' => $info['width']));
            $options = [
                'label'            => $label,
                'data'             => $idata,
                'bitsPerComponent' => $info['bitDepth'],
                'pdata'            => $pdata,
                'iw'               => $info['width'],
                'ih'               => $info['height'],
                'type'             => 'png',
                'color'            => $color,
                'ncolor'           => $ncolor,
                'masked'           => $mask,
                'isMask'           => $is_mask
            ];

            if (isset($transparency)) {
                $options['transparency'] = $transparency;
            }

            $this->o_image($this->numObj, 'new', $options);
            $this->imagelist[$file] = ['label' => $label, 'w' => $info['width'], 'h' => $info['height']];
        }

        if ($is_mask) {
            return;
        }

        if ($w <= 0 && $h <= 0) {
            $w = $info['width'];
            $h = $info['height'];
        }

        if ($w <= 0) {
            $w = $h / $info['height'] * $info['width'];
        }

        if ($h <= 0) {
            $h = $w * $info['height'] / $info['width'];
        }

        $this->addContent(sprintf("\nq\n%.3F 0 0 %.3F %.3F %.3F cm /%s Do\nQ", $w, $h, $x, $y, $label));
    }

    /**
     * add a JPEG image into the document, from a file
     *
     * @param $img
     * @param $x
     * @param $y
     * @param int $w
     * @param int $h
     */
    function addJpegFromFile($img, $x, $y, $w = 0, $h = 0)
    {
        // attempt to add a jpeg image straight from a file, using no GD commands
        // note that this function is unable to operate on a remote file.

        if (!file_exists($img)) {
            return;
        }

        if ($this->image_iscached($img)) {
            $data = null;
            $imageWidth = $this->imagelist[$img]['w'];
            $imageHeight = $this->imagelist[$img]['h'];
            $channels = $this->imagelist[$img]['c'];
        } else {
            $tmp = getimagesize($img);
            $imageWidth = $tmp[0];
            $imageHeight = $tmp[1];

            if (isset($tmp['channels'])) {
                $channels = $tmp['channels'];
            } else {
                $channels = 3;
            }

            $data = file_get_contents($img);
        }

        if ($w <= 0 && $h <= 0) {
            $w = $imageWidth;
        }

        if ($w == 0) {
            $w = $h / $imageHeight * $imageWidth;
        }

        if ($h == 0) {
            $h = $w * $imageHeight / $imageWidth;
        }

        $this->addJpegImage_common($data, $img, $imageWidth, $imageHeight, $x, $y, $w, $h, $channels);
    }

    /**
     * common code used by the two JPEG adding functions
     * @param $data
     * @param $imgname
     * @param $imageWidth
     * @param $imageHeight
     * @param $x
     * @param $y
     * @param int $w
     * @param int $h
     * @param int $channels
     */
    private function addJpegImage_common(
        &$data,
        $imgname,
        $imageWidth,
        $imageHeight,
        $x,
        $y,
        $w = 0,
        $h = 0,
        $channels = 3
    ) {
        if ($this->image_iscached($imgname)) {
            $label = $this->imagelist[$imgname]['label'];
            //debugpng
            //if (DEBUGPNG) print '[addJpegImage_common Duplicate '.$imgname.']';

        } else {
            if ($data == null) {
                $this->addMessage('addJpegImage_common error - (' . $imgname . ') data not present!');

                return;
            }

            // note that this function is not to be called externally
            // it is just the common code between the GD and the file options
            $this->numImages++;
            $im = $this->numImages;
            $label = "I$im";
            $this->numObj++;

            $this->o_image(
                $this->numObj,
                'new',
                [
                    'label'    => $label,
                    'data'     => &$data,
                    'iw'       => $imageWidth,
                    'ih'       => $imageHeight,
                    'channels' => $channels
                ]
            );

            $this->imagelist[$imgname] = [
                'label' => $label,
                'w'     => $imageWidth,
                'h'     => $imageHeight,
                'c'     => $channels
            ];
        }

        $this->addContent(sprintf("\nq\n%.3F 0 0 %.3F %.3F %.3F cm /%s Do\nQ ", $w, $h, $x, $y, $label));
    }

    /**
     * specify where the document should open when it first starts
     *
     * @param $style
     * @param int $a
     * @param int $b
     * @param int $c
     */
    function openHere($style, $a = 0, $b = 0, $c = 0)
    {
        // this function will open the document at a specified page, in a specified style
        // the values for style, and the required parameters are:
        // 'XYZ'  left, top, zoom
        // 'Fit'
        // 'FitH' top
        // 'FitV' left
        // 'FitR' left,bottom,right
        // 'FitB'
        // 'FitBH' top
        // 'FitBV' left
        $this->numObj++;
        $this->o_destination(
            $this->numObj,
            'new',
            ['page' => $this->currentPage, 'type' => $style, 'p1' => $a, 'p2' => $b, 'p3' => $c]
        );
        $id = $this->catalogId;
        $this->o_catalog($id, 'openHere', $this->numObj);
    }

    /**
     * Add JavaScript code to the PDF document
     *
     * @param string $code
     */
    function addJavascript($code)
    {
        $this->javascript .= $code;
    }

    /**
     * create a labelled destination within the document
     *
     * @param $label
     * @param $style
     * @param int $a
     * @param int $b
     * @param int $c
     */
    function addDestination($label, $style, $a = 0, $b = 0, $c = 0)
    {
        // associates the given label with the destination, it is done this way so that a destination can be specified after
        // it has been linked to
        // styles are the same as the 'openHere' function
        $this->numObj++;
        $this->o_destination(
            $this->numObj,
            'new',
            ['page' => $this->currentPage, 'type' => $style, 'p1' => $a, 'p2' => $b, 'p3' => $c]
        );
        $id = $this->numObj;

        // store the label->idf relationship, note that this means that labels can be used only once
        $this->destinations["$label"] = $id;
    }

    /**
     * define font families, this is used to initialize the font families for the default fonts
     * and for the user to add new ones for their fonts. The default bahavious can be overridden should
     * that be desired.
     *
     * @param $family
     * @param string $options
     */
    function setFontFamily($family, $options = '')
    {
        if (!is_array($options)) {
            if ($family === 'init') {
                // set the known family groups
                // these font families will be used to enable bold and italic markers to be included
                // within text streams. html forms will be used... <b></b> <i></i>
                $this->fontFamilies['Helvetica.afm'] =
                    [
                        'b'  => 'Helvetica-Bold.afm',
                        'i'  => 'Helvetica-Oblique.afm',
                        'bi' => 'Helvetica-BoldOblique.afm',
                        'ib' => 'Helvetica-BoldOblique.afm'
                    ];

                $this->fontFamilies['Courier.afm'] =
                    [
                        'b'  => 'Courier-Bold.afm',
                        'i'  => 'Courier-Oblique.afm',
                        'bi' => 'Courier-BoldOblique.afm',
                        'ib' => 'Courier-BoldOblique.afm'
                    ];

                $this->fontFamilies['Times-Roman.afm'] =
                    [
                        'b'  => 'Times-Bold.afm',
                        'i'  => 'Times-Italic.afm',
                        'bi' => 'Times-BoldItalic.afm',
                        'ib' => 'Times-BoldItalic.afm'
                    ];
            }
        } else {

            // the user is trying to set a font family
            // note that this can also be used to set the base ones to something else
            if (mb_strlen($family)) {
                $this->fontFamilies[$family] = $options;
            }
        }
    }

    /**
     * used to add messages for use in debugging
     *
     * @param $message
     */
    function addMessage($message)
    {
        $this->messages .= $message . "\n";
    }

    /**
     * a few functions which should allow the document to be treated transactionally.
     *
     * @param $action
     */
    function transaction($action)
    {
        switch ($action) {
            case 'start':
                // store all the data away into the checkpoint variable
                $data = get_object_vars($this);
                $this->checkpoint = $data;
                unset($data);
                break;

            case 'commit':
                if (is_array($this->checkpoint) && isset($this->checkpoint['checkpoint'])) {
                    $tmp = $this->checkpoint['checkpoint'];
                    $this->checkpoint = $tmp;
                    unset($tmp);
                } else {
                    $this->checkpoint = '';
                }
                break;

            case 'rewind':
                // do not destroy the current checkpoint, but move us back to the state then, so that we can try again
                if (is_array($this->checkpoint)) {
                    // can only abort if were inside a checkpoint
                    $tmp = $this->checkpoint;

                    foreach ($tmp as $k => $v) {
                        if ($k !== 'checkpoint') {
                            $this->$k = $v;
                        }
                    }
                    unset($tmp);
                }
                break;

            case 'abort':
                if (is_array($this->checkpoint)) {
                    // can only abort if were inside a checkpoint
                    $tmp = $this->checkpoint;
                    foreach ($tmp as $k => $v) {
                        $this->$k = $v;
                    }
                    unset($tmp);
                }
                break;
        }
    }
}