Problems with GD

[748323]

Every time I use GD, its impossible for me to use any other scripts. For example, I wrote this 'Scribble generator' when I was bored

<?

$image = imagecreate(500,500);
$back = imagecolorallocate($image, 0,0,0);

for ($x = 0; $x < rand(3,7); $x++ ) {
$arrayx = array();
$points = rand(100, 300);
for ($i = 0; $i < $points; $i++) {
$arrayx[] = rand(0, 500);
$arrayx[] = rand(0, 500);
}
$color = imagecolorallocate($image, rand(0,255) ,rand(0,255),rand(0,255));
imagepolygon($image, $arrayx, $points, $color);
}


Header("Content-type: image/png");
imagepng($image);

?>

This will create a new PNG image, and put a ton of random scribbles in there. Now, when I try to echo something before or after that script, it gives me an error. For example:

<?
echo "sa";

$image = imagecreate(500,500);
$back = imagecolorallocate($image, 0,0,0);
Header("Content-type: image/png");
imagepng($image);

?>

That script will give me an error saying that the Headers cannot be modified. Help? Thanks!

 

[kenrbnsn]

Think about what you are doing here.

You're creating an image an displaying it. One image per invocation of your script. Just invoke your script via the <img> tag in HTML then you can do whatever you like before and after.

<?
echo 'something';
echo '<img src=yourscript.php>';
echo 'something else';
?>

Ken

 

[Olavxxx]

Just a general tip:
Header() and session_start() are two functions that *must* be called *before* anything is parsed!

You also can not echo anything in the image-generating script, as that will not work!

When you call the image-making-script, it will make an image for the client (web-browser) and show that image.
If you however try to echo or do anything else, before the header, it will not work, as then the headers are already sent. (as you then make text, not image).

btw. use quotes in your html tags:
<img src="yourscript.php" alt="foo" />

Olav Alexander Mjelde

http://www.volvo-power.net

Admin & Webmaster

 

[748323]

http://scorpion.titanboards.com/scribble/

Sweet. Thanks a lot!