php pagina die buiten joomla goed werkt, werkt niet in joomla

Als ik onderstaande pagina test in een php pagina op de site werkt hij uitstekend, als ik hem op joomla plaats binnen {source} tags, geeft hij allemaal rare tekentjes

[PHP]<?php

// PHP Graph - find updates and more at: www.puremango.co.uk/2005/08/php_graph_18/



$loginstring = "";
$host = "localhost";

$database = "algen23_crowd";
$user="algen23";
$password = "xxxxxx";

$t = @mysql_connect ($host, $user, $password) ;
//mysql_select_db( $database )or die('connection');
//$res=mysql_query($select);
//$optieA=7000;
//while($row = mysql_fetch_array($select)){
// $optieA=$optieA + $row[$'bedragbetaald'];
// }

$seed = 500;
// for the demo:
$amounts = Array(
"Optie A: "=> 60,
"Optie B: "=>rand(0,$seed),
"Optie C: "=>rand(0,$seed),
"Optie "=>rand(0,$seed),
"Optie E: "=>rand(0,$seed),
"TOTAAL : "=>rand(0,$seed),

);

// or for 'real' use:
// $amounts = $_SESSION;
// where the page with the <img src="graph.php"> sets up the $amounts array and stores in the session.

// sort amounts (lowest>highest)
//if(rand(0,1)>0.5) {
// asort($amounts);
//}

// user defined vars:
// all measurements are in pixels

// any less than 12 will cut off the text
$bar_height = 50;

// how many pixels to leave between bars (vertically)
$bar_spacing = 50;

// set grid spacing, any less than 25 will fudge the text. min 50 is preferable.
$valid_spacings = Array(50,100,150);
$grid_space = $valid_spacings[rand(0,count($valid_spacings)-1)];

// amount of space to give for bar titles (horizontally)
$bar_title_space = 70;

// (optional) title of graph
$graph_title = "Resultaat.";

// vertical space to leave for title
$graph_title_space = 40;


// vertical space to leave for footer
$graph_footer_space = 20;

// colour of bars
// 0=red, 1=green, 2=blue, 3=random
$bar_colour = 2;

// end setup

// calculate required width and height of image
$pic_width = $bar_title_space+max($amounts)+($grid_space*1.5);
$pic_height = ($bar_height+$bar_spacing+2)*sizeof($amounts)+20+$graph_title_space+$graph_footer_space;

// create image
$pic = ImageCreate($pic_width+1,$pic_height+1);

// allocate colours
$white = ImageColorAllocate($pic,255,255,255);
$grey = ImageColorAllocate($pic,200,200,200);
$lt_grey = ImageColorAllocate($pic,210,210,210);
$black = ImageColorAllocate($pic,0,0,0);

// fill background of image with white
ImageFilledRectangle($pic,0,0,$pic_width,$pic_height,$white);

// draw graph title
ImageString($pic,5,($pic_width/2)-(strlen($graph_title)*5),0,$graph_title,$black);

// draw graph footer
ImageString($pic, 2,($pic_width/2)-(strlen($graph_footer)*3),$pic_height-$graph_footer_space, $graph_footer, $grey);

// draw grid markers
for($x_axis=$bar_title_space ; ($x_axis-$bar_title_space)<max($amounts)+$grid_space ; $x_axis+=$grid_space) {
// draw vertical grid marker
ImageLine($pic,$x_axis,$graph_title_space,$x_axis,$pic_height-$graph_footer_space,$grey);

// draw horizontal line above grid numbers
ImageLine($pic,$x_axis,($pic_height-$graph_footer_space-25),$x_axis-($bar_title_space+$grid_space),($pic_height-$graph_footer_space-25),$grey);

// draw grid numbers
ImageString($pic, 3, $x_axis+5, ($pic_height-$graph_footer_space-20), $x_axis-($bar_title_space), $black);
}

// draw bars
$y_axis=$graph_title_space;

if($bar_colour!) {
// for a nice smooth fade of colour.
$col = 180;
$decrement = intval($col/count($amounts));
}

foreach($amounts as $key=>$amount) {
// write the bar title
ImageString($pic, 2, ($bar_title_space-(strlen($key)*6)), $y_axis, $key, $black);

// allocate a colour for this bar
if($bar_colour=) {
// random colour
$tempCol = ImageColorAllocate($pic,rand(50,200),rand(50,200),rand(50,200));
} else {

$col -= $decrement;
if($bar_colour==0) {
// faded red
$tempCol = ImageColorAllocate($pic,255,$col,$col);
} else if($bar_colour==1) {
// faded green
// 200 because green just looks too bright otherwise
$tempCol = ImageColorAllocate($pic,$col,200,$col);
} else if($bar_colour==2) {
// faded blue
$tempCol = ImageColorAllocate($pic,$col,$col,255);
}
}

// draw the bar
ImageFilledRectangle($pic,($bar_title_space+1),$y_axis,$amount+$bar_title_space,($y_axis+$bar_height),$tempCol);

if(($amount)<15) {
// if it's a tiny amount, write the amount outside the bar in black
ImageString($pic, 2, ($amount+3)+$bar_title_space, $y_axis, $amount, $black);
} else {
// or if over 20, write the amount inside the bar in white
// the strlen stuff is to ensure number is aligned with the end of the bar. works quite well, too.
ImageString($pic, 2, ($amount-(strlen($amount)*6))+$bar_title_space, $y_axis, $amount, $white);
}

// move down
$y_axis+$bar_spacing+1)+$bar_height;
}

header("Content-type: image/png");

// output image
ImagePNG($pic);

// remove image from memory
ImageDestroy($pic);
?>[/PHP]

Kan je een voorbeeld geven van de rare tekentjes? Waarom is het database gedeelte half uitgecomment?

Ik vermoed dat het komt door header("Content-type: image/png");
Als je het bestand in een losse php-pagina runt dan is er nog geen uitvoer naar de browser en krijg je een .png-bestand.
Joomla heeft daarentegen al headers om een pagina gezet, het menu is al opgebouwd etc. Omdat er al een html-uitvoer is gemaakt kun je header("Content-type: image/png"); niet meer gebruiken