The data entered into the form is passed to the "mypie.php" script via a variable named $data; this data is then split into its individual components with the explode() function, and each individual value is placed in the $slices array. A loop then converts these numbers into degrees of a circle, and draws arcs for each slice. In each iteration of the loop, the coordinate of the end point of the arc is also calculated and a line segment in drawn to demarcate the arc from the rest of the circle. Once the pie segment has been drawn, the pdf_fill_stroke() function is used to fill it with colour; this colour is obtained from the $colours array.
The output :
Here's the script for html form
<html>
<head>
<basefont face=arial>
</head>
<body>
<h3>Pie Chart Generator</h3>
<table cellspacing="5" cellpadding="5">
<form action="mypie.php" method=POST>
<tr>
<td>Enter numeric values (pie segments), separated by commas</td> </tr> <tr> <td><input type=text name=data></td> </tr> <tr> <td><input name="submit" type=submit value="Generate PDF Pie Chart"></td> </tr> </form> </table>
</body>
</html>
Here's the script that does all the work:
<?php
// raw data
$data = $_POST['data'];
$slices = explode(",", $data);
// initialize some variables
$sum = 0;
$degrees = Array [10]();
$diameter = 200;
$radius = $diameter/2;
// set up colours array for pie slices (rgb, as percentages of intensity) // add more to these if you like $colours = array(
array(0,0,0),
array(0,0,1),
array(0,1,0),
array(1,0,0),
array(0,1,1),
array(1,1,0),
array(1,0,1),
);
// calculate sum of slices
$sum = array_sum($slices);
// convert each slice into corresponding percentage of 360-degree circle for ($y=0; $y<sizeof($slices); $y++) {
$degrees[$y] = ($slices[$y]/$sum) * 360;
}
// start building the PDF document
// create handle for new PDF document
$pdf = pdf_new();
// open a file
pdf_open_file($pdf, "chart.pdf");
// start a new page (A4)
pdf_begin_page($pdf, 500, 500);
// set a stroke colour
pdf_setcolor($pdf, "stroke", "rgb", 1, 1, 0);
// draw baseline
pdf_moveto($pdf, 250, 250);
pdf_lineto($pdf, 350, 250);
pdf_stroke($pdf);
for ($z=0; $z<sizeof($slices); $z++)
{
// set a fill colour
pdf_setcolor($pdf, "fill", "rgb", $colours[$z][0], $colours[$z][1], $colours[$z][2]);
// calculate coordinate of end-point of each arc by obtaining
// length of segment and adding radius
// remember that cos() and sin() return value in radians
// and have to be converted back to degrees!
$end_x = round(250 + ($radius * cos($last_angle*pi()/180)));
$end_y = round(250 + ($radius * sin($last_angle*pi()/180)));
// demarcate slice with line
pdf_moveto($pdf, 250, 250);
pdf_lineto($pdf, $end_x, $end_y);
// calculate and draw arc corresponding to each slice
pdf_arc($pdf, 250, 250, $radius, $last_angle, ($last_angle+$degrees[$z]));
// store last angle
$last_angle = $last_angle+$degrees[$z];
// fill slice with colour
pdf_fill_stroke($pdf);
}
// redraw the circle outline
pdf_circle($pdf, 250, 250, 100);
pdf_stroke($pdf);
// end page
pdf_end_page($pdf);
// close and save file
pdf_close($pdf);
?>
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