Inserting Blocks of Text - PHP

As you know, more and more web sites try to engage their visitors by delivering their database contents in several formats, such as Adobe’s Portable Document Format (PDF). The good news regarding this topic is that you, as a PHP developer, can take advantage of this language’s versatility and get started quickly building PDF files directly from your own scripts.

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By: Alejandro Gervasio

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November 27, 2007

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Inserting blocks of text into an existing PDF file: working with the versatile “show_xy()” method

As you saw in the earlier articles of this series, several times I used the “show()” method to insert a string of text into a sample PDF file, which hopefully demonstrated how easy it is to work with. However, it should be noticed here that this method itself is rather useless, particularly in those cases where a determined string must be positioned using a pair of X,Y coordinates.

Of course, you may say that this accurate positioning procedure can be achieved with the “set_text_pos()” method, which was also reviewed previously, but this implies having to work with two different methods. Fortunately, the “PDFlib” library comes equipped with a handy method, named “show_xy()”, which can be used to display a given string in any position of a PDF document, in this way replacing the two methods referenced above.

Having explained in theory how the “show_xy()” method works, it’s time to analyze it from a practical point of view. So below I coded an illustrative example that shows its considerable functionality. Here it is:

try{

// example creating a basic PDF document and display a
basic text using the 'show_xy()' method

// create new instance of the 'PDFlib' class

$pdf=new PDFlib();

// open new PDF file

if(!$pdf->begin_document("","")){

throw new PDFlibException("Error creating PDF document. ".$pdf-
>get_errmsg());

}

$pdf->set_info("Creator","example.php");

$pdf->set_info("Author","Alejandro Gervasio");

$pdf->set_info("Title","Example on using PHP to create PDF
docs");

$pdf->begin_page_ext(421,595,"");

$font=$pdf->load_font("Helvetica-Bold","winansi","");

$pdf->setfont($font,24.0);

$pdf->show_xy("PHP is great for creating PDFs!",30,500);

// end page

$pdf->end_page_ext("");

// end document

$pdf->end_document("");

// get buffer contents

$buffer=$pdf->get_buffer();

// get length of buffer

$len=strlen($buffer);

// display PDF document

header("Content-type: application/pdf");

header("Content-Length: $len");

header("Content-Disposition: inline; filename=example.pdf");

echo $buffer;

}

catch (PDFlibException $e){

echo 'Error Number:'.$e->get_errnum()."n";

echo 'Error Message:'.$e->get_errmsg();

exit();

}

As you can see, the above hands-on example demonstrates quite clearly how to use the “show_xy()” method to display a trivial string of text on a given PDF document. In this concrete situation, the method in question was instructed to show the respective text using an offset of 30 for the X coordinate and a value of 500 for the respective Y axis.

If you analyze in detail the previous code sample, it’s quite evident how useful the “show_xy()” method can be, particularly when the PDF file being created includes only some strings of text and nothing else. Pretty good, right?

In addition, with the purpose of completing even more of the previous explanation of this handy method, below I included a picture that shows the output generated by the prior hands-on example:

So far, so good. At this stage you hopefully learned the basics of utilizing the helpful “show_xy()” method to display different blocks of text using a predefined pair of X,Y coordinates. However, if you’re anything like me, then you might want to see some additional examples regarding the implementation of this method in concrete cases.

Thus, bearing this in mind, in the course of the upcoming section, I’m going to set up another practical example, aimed at providing you with more material on using the “show_xy()” method.

To learn how this example will be developed, go ahead and read the next few lines. They’re just one click away.

Next: Going One Step Further >>