pdf-api

long time ago i used PDFlib to create pdf-files. when i started my own business i started to create a clone of PDFlib for my free use. this is my updated project to create pdf-file like PDFlib but without restrictions. this project follows a different strategy of collecting and storing data. all data is stored inside an array for easy access. each element is accessible, changeable and removable at any time.

supported filters

• /ASCIIHexDecode
• /ASCII85Decode
• /FlateDecode
• /LZWDecode

supported image formats

• GIF (PNG)
• JPG
• PNG
• others (JPG from convert)

supported fonts

• /Type1 (14 core fonts)
• /TrueType (/Type2 in theory)
• /Type3 (experimental, self defined)

feature

the internal list of loaded resources is stored the same way like /Resources of a single page. whenever a resource is loaded, it is applied to the internal list of loaded resources. whenver a resource is used by a page, it is applied to /Resources of the page. this makes it possible to let users have real-time access to all key, values and elements at any time. this prevent multiple loadings of identical fonts. the list of loaded resources can be read from "resources" of the pdf-array created with pdf_new() at any time.

print_r($mypdf["resources"]);

example

see pdf-api-test.php for a working example. more examples can be found in manual-pages of PDFlib.

$pdf = pdf_new();

pdf_begin_document($pdf, "");

	# returns /Fx where x is integer
	# $font = pdf_load_font($pdf, "Verdana", "winansi");
	$font = pdf_load_font($pdf, "Courier", "winansi");

	# returns /Fx where x is integer but returns error on unloaded font.
	# $font = pdf_findfont($pdf, "Verdana");

	# returns /Xx where x is integer
	$image = pdf_load_image($pdf, "png", "pdf-api-test.png");

	foreach(range(1, 1) as $i)
		{
		pdf_begin_page($pdf, 595, 842);

			# use return value of _pdf_add_font as fontname
			pdf_setfont($pdf, $font, 72);

			pdf_set_leading($pdf, 12);
			pdf_show_xy($pdf, "ABC " . $i, 3, 3);

			pdf_fit_image($pdf, $image, 20, 20, array("scale" => 10));

		# store loaded resources
		$page = pdf_end_page($pdf);

		$outline = pdf_add_outline($pdf, "page " . $i, "", $page);
		}

pdf_end_document($pdf);

$data = pdf_get_buffer($pdf);

header("Content-Type: application/pdf");
header("Content-Disposition: inline; filename=parse-test.pdf");
header("Content-Length: " . strlen($data));

print($data);

keep in mind that some functions may work different than in the original PDFlib.

explanaitions

this library stores any information inside a single multi-dimensional array. the most important elements are named objects, resources and stream. resources will contain short names and pointers to images and fonts loaded by pdf_load_image and pdf_load_font. pdf_set_font and pdf_place_image or pdf_fit_image will copy this information into the resources-dictionary of a page. objects will contains all objects of the document. all resources are stored in real-time as they are and can be accessed at any time. stream contains the stream of the page.

compatibility

this project can be used to replace PDFlib since basic functionality is implemented.

recommendation

you should read pdf-reference carfully and learn how to write pdf-files by hand, to understand the concept of pdf-format. understanding the concept of pdf-format makes it much easier to create pdf-files in general. the concept of drawing lines in pdf-files is similar to drawing lines in svg-files.

requirements

there are no special requirements to run this script. php's builtin functions gzcompress and gzuncompress are used for compression. it could be useful to have convert installed, which is part of image magik, for additional image support. the following functions and operators and kewords are used inside this script:

• array, array_reverse, array_slice, as
• basename, break
• case, chr, continue, cos, count
• define, die, do
• else, elseif, explode
• fclose, feof, filesize, file_get_contents, file_put_contents, fopen, for, foreach, fread, function
• getimagesize, gzcompress, gzuncompress
• header
• iconv, iconv_set_encoding, if, imagecreatefromgif, imagedestroy, imageinterlace, imagepng, imagettfbbox, implode, in_array, isset
• list
• ord
• preg_replace, preg_match_all, print
• range
• sin, sprintf, sscanf, strlen, strpos, strtolower, str_replace, substr, system (convert)
• tan, tempnam
• ucfirst, unlink, unset
• while

note

the precision of floating-numbers, for sprintf and such functions, is set to one digit. this sems to be enough for most drawings and saves a lot of space too. a regular page got a size of 595 x 842 pixel which is 210 x 297 millimeter. in this case 1 pixel is equal to (0.1 : 72 x 2.54) 0.35 millimeter. from this point of view, there is no need for 6 digits precision, under normal circumstances. if more precission is needed sprintf("%.1f", ...) needs to be replaced with sprintf("%.f", ...) inside this script. this script is able to parse pdf files but stream content for pages can not be parsed.

references

• [convert] (https://wiki.ubuntuusers.de/ImageMagick/)
• [fpdf] (http://www.fpdf.org/)
• [pdf] (https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf)
• [pdflib] (https://www.php.net/manual/en/ref.pdf.php)
• [php] (https://www.php.net/)
• [png] (http://www.libpng.org/pub/png/spec/1.2/PNG-Contents.html)