drawing graphs in php
- by user434885
i am using php to generate graphs from arrays. I wish to create multiple graphs on the same page as i need to design a summary report from answers extracted from a database.
Currently i am using this code and am only able to get one single graph. what additions to the code do i need to make to get multiple graphs?
<?php
function draw_graph($values)
{
// Get the total number of columns we are going to plot
$columns = count($values);
// Get the height and width of the final image
$width = 300;
$height = 200;
// Set the amount of space between each column
$padding = 5;
// Get the width of 1 column
$column_width = $width / $columns ;
// Generate the image variables
$im = imagecreate($width,$height);
$gray = imagecolorallocate ($im,0xcc,0xcc,0xcc);
$gray_lite = imagecolorallocate ($im,0xee,0xee,0xee);
$gray_dark = imagecolorallocate ($im,0x7f,0x7f,0x7f);
$white = imagecolorallocate ($im,0xff,0xff,0xff);
// Fill in the background of the image
imagefilledrectangle($im,0,0,$width,$height,$white);
$maxv = 0;
// Calculate the maximum value we are going to plot
for($i=0;$i<$columns;$i++)$maxv = max($values[$i],$maxv);
// Now plot each column
for($i=0;$i<$columns;$i++)
{
$column_height = ($height / 100) * (( $values[$i] / $maxv) *100);
$x1 = $i*$column_width;
$y1 = $height-$column_height;
$x2 = (($i+1)*$column_width)-$padding;
$y2 = $height;
imagefilledrectangle($im,$x1,$y1,$x2,$y2,$gray_dark);
}
header ("Content-type: image/png");
imagepng($im);
imagedestroy($im);
}
$values = array("23","32","35","57","12");
$values2 = array("123","232","335","157","102");
draw_graph($values2);
draw_graph($values);//no output is coming
draw_graph($values2);//no output is coming
draw_graph($values);//no output is coming
?>
