Producing a simple bar graph in a PDF document - PHP

Now that you know the basics of generating a PDF document, you can start playing with the whole suite of PDFlib functions as listed in the PHP Manual.

Below is another sample code that outputs a simple bar graph to a PDF document as shown below:

I have sprinkled many comments in the code, so it should be quite self-explanatory.

<?php

# pdf_example4

# a simple bar graph

// create a new pdf document

$pdf = pdf_new();

$filename = 'c:pdf_example4.pdf';

pdf_open_file($pdf, $filename);

// start a new page (Letter size)

pdf_begin_page($pdf, 612, 792);

// setup font and print hello world

pdf_set_parameter($pdf, 'FontOutline',

'Arial=c:windowsfontsarial.ttf');

$font = pdf_findfont($pdf, "Arial", "host", 1);

pdf_setfont($pdf, $font, 16);

pdf_show_xy($pdf, "Simple Bar Graph", 50, 720);

// draw the x and y axis

pdf_moveto($pdf, 50, 690);

pdf_lineto($pdf, 50, 520);

pdf_lineto($pdf, 400, 520);

pdf_stroke($pdf);

// draw the bar chart

$x = 80;

$y = 520;

$w = 40;

// the data and color for each column

$data = array('120','160','300','240');

$color = array('#4EC3BC', '#DAA876', '#E29CC8', '#FDE0C6');

// get into some meat now, cheese for vegetarians;

for ($i=0;$i<count($data);$i++){

// calculate the height of the bar

$y_ht = ($data[$i]/max($data))* 100;

// set the color for each bar

list($r, $g, $b) = hex2rgb($color[$i]);

pdf_setcolor($pdf, "fill", "rgb", $r, $g, $b, 0);

// draw the bar

pdf_rect($pdf, $x, $y, $w, $y_ht);

pdf_fill_stroke($pdf);

// write the bar label

pdf_setcolor($pdf, "fill", "rgb", 0, 0, 0, 0);

pdf_setfont($pdf, $font, 10);

pdf_show_xy($pdf, $data[$i], $x+12, $y-16);

// go to the next bar

$x = $x+$w+40;

}

// done

pdf_end_page($pdf);

pdf_close($pdf);

pdf_delete($pdf);

// send it to browser

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

header("Content-Disposition: inline; filename=pdf_example3.pdf");

readfile($filename);

unlink($filename);

// function to convert a standard rgb from hex to float

function hex2rgb($hex) {

$color = str_replace('#','',$hex);

$r = hexdec(substr($color,0,2))/255;

$g = hexdec(substr($color,2,2))/255;

$b = hexdec(substr($color,4,2))/255;

return array($r, $g, $b);

}

?>

Final Words

We’ve come to the end of this article. In this tutorial I’ve shown you how to generate PDF documents on the Windows platform. I’ve also given you a number of complete sample codes that should give you a head start in generating your own PDF documents.

Take some time to explore that various PDFlib functions as listed in the PHP Manual. Just bear in mind that of some of the sample codes there might not work because they might have been written for higher versions of PDFlib.

Have lots of fun generating PDF documents with PHP!