PDFlib & PHP - (1) HELLO WERLD

I need to take baby-steps; myself described in the PDFlib manual as a PHP Web Programmer.
NOTE: The API listing/real documentation for PDFlib lives here under Reference

In the example here I sometimes say, "see: ...php.net/some-documentation," and there is a distinct and notable difference between the php.net and usage below. That is, in all "see:" comments it works like this:

• PHP.NET says:
  float PDF_stringwidth ( resource $p , string $text , int $font , float $fontsize )


• Where usage below is always going to replace the PDF_ with the PDFlib object $p.


• ...and the first parameter in the PHP.NET documentaion is never resource, but the next, i.e. for the above mentioned PDF_stringwidth we have:
  $p->stringwidth(string $text, int $font, float $fontsize)

This will be:

1. Make a PDF delivered to browser that was crafted using PDFlib usage of PHP.


2. Throw in a (centered-to-doc) line of text, in the PDF.

try{
 # number reflect an A4 sized document.
 $doc_width = 595;
 $doc_height = 842;
 # create a new instance of PDFlib.
 $p = new PDFlib();
 # extras here. in cookbook examples these are not mentioned.
 # but, for error logging add logging and set errorpolicy to exception. 
 #   (thanks PDFLib support for these setting info)
 $p->set_parameter("logging", "filename {PDFlib.log}");
 $p->set_parameter("errorpolicy", "exception");
 # set textformat, or try without and watch log:
 # [Warning message 2592: "Glyph for Unicode value U+6548 not 
 #    found in font 'Helvetica' (Unicode will be replaced in text)"]
 $p->set_parameter("textformat", "utf8");
 # begin document, see:  
 #   http://www.php.net/manual/en/function.pdf-begin-document.php
 if ($p->begin_document("", "") == 0) 
    throw new Exception("Error@begin_document: " . $p->get_errmsg());
 # loading font (that most will have)
 $font = $p->load_font("Helvetica", "unicode", "");
 # make/begin page, see: 
 #   http://www.php.net/manual/en/function.pdf-begin-page-ext.php
 $p->begin_page_ext($doc_width, $doc_height, "");
 # setfont before adding text, see: 
 #   http://www.php.net/manual/en/function.pdf-setfont.php
 if ($p->setfont($font, 24) == 0) 
    throw new Exception("Error@setfont: " . $p->get_errmsg());
 # add line of text, to center of page, approximately :)
 # doing a few things here to center the width and then place text.
 $message = "Hello Werld!";
 $message_width = $p->stringwidth($message, $font, 24);
 $p->show_xy($message, ($doc_width*.5)-($message_width*.5), $doc_height*.5);
 # end page...
 $p->end_page_ext("");
 #
 $p->end_document("");
 # get and send buffer
 $buf = $p->get_buffer();
 $len = strlen($buf);
 header("Content-type: application/pdf");
 header("Content-Length: $len");
 header("Content-Disposition: inline; filename=blog_1.pdf");
 print $buf;
} catch (PDFlibException $e) {
 die("PDFlib exception occurred:\n".
 "[" . $e->get_errnum() . "] " . $e->get_apiname() .
 ": " . $e->get_errmsg() . "\n");
} catch (Exception $e) {
 die($e->getMessage());
}

Props to this person for the pretty-print on blogger, blog:
Pretty Print Blog by Luka Marinko