Can't find image in GD (PHP)

I'm trying to put a watermark on my images, but the script can't find my watermark image. I'm doing this dynamically, so for each user there is a watermark in the watermarks folder. When trying to use this code:

session_start();
$username = $_SESSION['_user_login'];

// Set the path to the image to watermark
$input_image = $target开发者_运维技巧Path.$newName; 
// Read in the text watermark image
$watermark = imagecreatefrompng("../watermarks/$username.png");

Nothing happens. I tried printing the user name variable and it works fine. I even tried to just print the image and it works also. But when using imagecreatefrompng, the watermark image is never found. Looking in my log I see the following error:

Warning: imagecreatefrompng(../watermarks/.png) [function.imagecreatefrompng]: failed to open stream: No such file or directory

I don't get it. What am I doing wrong?

Thanks.

You would need to use:

$watermark = imagecreatefrompng(dirname(dirname(__FILE__)) . "/watermarks/" . $username . ".png");

(You can print dirname(__FILE__) to check your directory structure before using this method).

The clue's in the warning:

imagecreatefrompng(../watermarks/.png)

It's looking for a file called .png, so obviously your $username = $_SESSION['_user_login']; isn't actually returning the username, or the string isn't getting created properly.

Have you tried using braces in the string like this: "../watermarks/{$username}.png"? If that doesn't work then you've got a problem with your username.

$username appears to be blank. Hence, "imagecreatefrompng(../watermarks/.png)"

I'd suggest debugging starting with making sure the file path you're requesting is valid.

session_start();
$username = $_SESSION['_user_login'];

// Set the path to the image to watermark
$input_image = $targetPath.$newName; 
// Read in the text watermark image
$filestring = "../watermarks/$username.png";
echo "LOOKING FOR $filestring";
$watermark = imagecreatefrompng($filestring);

.. is resolved from PHP's current working directory. Presumably, this is the directory that the PHP file is currently in.

Generally, it's a better idea to resolve directories from $_SERVER['DOCUMENT_ROOT'] so that they are absolute* directories rather than relying on nothing doing a chdir before your file is opened.

$watermark = imagecreatefrompng($_SERVER['DOCUMENT_ROOT'] . "/watermarks/$username.png");

*For a given definition of absolute.

Well the $username variable is blank according to that error. Do a var_dump($_SESSION) in your script to double check your are properly storing the _user_login variable.

Also I would suggest using curly braces when putting variables in strings.

$watermark = imagecratefrompng("../watermarks/{$username}.png"); 

This will make it easy to see your variables and prevent php from using the wrong variable name.

Tried everything but for some reason the SESSION variable just doesn't work in the imagecreatefrompng function.

To solve this I just post the username as a hidden variable. This seems to work fine for the moment.

Thanks everyone for the help. It's appreciated.

mw