pagination within image - IF problem

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Views: 401 | Replies: 2 | Solved

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Join Date: Apr 2008

Posts: 48

Reputation: helraizer is an unknown quantity at this point

Rep Power: 1

Solved Threads: 3

helraizer

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Light Poster

pagination within image - IF problem

Jun 2nd, 2008

Hey folks,

I have made an image-based shoutbox and now users can view older and newer message on the shoutbox depending on the $_GET['page'] - pagination - that works. However, since it's image based and can be linked in forums etc. on the Internet I only want it to save the gif image if $page == 1, so the newest shouts are saved onto the image. Yet the users can still view the other messages on site without it changing the saved gif image.

What I've tried so far is this:

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
<?php
 
if (isset($_GET['page']) && is_numeric($_GET['page'])) {
 
    $page = mysql_real_escape_string(htmlspecialchars($_GET['page']));
 
} else {
    $page = 1;
}
 
//other code - not relevant for this purpose
 
if ($page == 1) {
	imagegif($image); // paint the image in browser
    imagegif($image, "user/" . $user . ".gif"); //export as gif file
} elseif(!isset($filter) && $page == 1) {
	imagegif($image); // paint the image in browser
	imagegif($image, "user/" . $user . ".gif"); //export as gif file
} elseif($page != 1) {
	imagegif($image); // paint the image in browser
} elseif(isset($filter)) {
	imagegif($image); // paint the image in browser
} else {
 
}
?>
<?php

if (isset($_GET['page']) && is_numeric($_GET['page'])) {

    $page = mysql_real_escape_string(htmlspecialchars($_GET['page']));

} else {
    $page = 1;
}

//other code - not relevant for this purpose

if ($page == 1) {
	imagegif($image); // paint the image in browser
    imagegif($image, "user/" . $user . ".gif"); //export as gif file
} elseif(!isset($filter) && $page == 1) {
	imagegif($image); // paint the image in browser
	imagegif($image, "user/" . $user . ".gif"); //export as gif file
} elseif($page != 1) {
	imagegif($image); // paint the image in browser
} elseif(isset($filter)) {
	imagegif($image); // paint the image in browser
} else {
	
}
?>

Which, to me means that when $page == 1 then it loads the image in the browser and also saves user/helraizer.gif and if $page != 1 then it only loads it to the browser and doesn't save the gif. But even if $page == 3 then it saves that as the image and therefore the image hosted on a forum will keep changing as each user views a different thing.

I know that $page works because it changes the contents of the image, but it doesn't work within the if statement.

Can you see what's/if anything's wrong with the code? Would a switch statement be a better solution?

Thanks,
Sam

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Join Date: Mar 2008

Location: Praha, Czech Republic, Europe

Posts: 99

Reputation: petr.pavel is an unknown quantity at this point

Rep Power: 1

Solved Threads: 14

petr.pavel petr.pavel is offline

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Junior Poster in Training

Re: pagination within image - IF problem

Jun 10th, 2008

Hi there,
the bug is in this if statement. Try using parentheses to make your intentions more clear:

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
if ( (!isset($filter)) && ($page == 1) )
if ( (!isset($filter)) && ($page == 1) )

Frankly I would just write this instead of the whole if/else if bunch:

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
if ($page == 1)
  imagegif($image, "user/" . $user . ".gif");
imagegif($image);
if ($page == 1)
  imagegif($image, "user/" . $user . ".gif");
imagegif($image);

Also, you could make the initial testing a bit more simple:

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
$page = max(intval($_GET['page']), 1);
$page = max(intval($_GET['page']), 1);

I guess you start paging with 1, which is a bit impractical.
If you start with zero you could do with a plain intval($_GET['page']);

Last edited by petr.pavel : Jun 10th, 2008 at 6:13 am.

Petr 'PePa' Pavel

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Join Date: Apr 2008

Posts: 48

Reputation: helraizer is an unknown quantity at this point

Rep Power: 1

Solved Threads: 3

helraizer

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Light Poster

Re: pagination within image - IF problem

Jun 10th, 2008

Hey, thanks for the input.

I found a solution a while ago.

 Help with Code Tags 
 PHP Syntax (Toggle Plain Text) 
if (isset($filter))
{
 
        imagepng($image);
 
}
elseif ($page == 1)
{
 
        imagepng($image);
        imagepng($image, "./user/".$user.".png");
 
 
 
 
}
else
{
        imagepng($image);
 
}
if (isset($filter))
{
    
        imagepng($image);
    
}
elseif ($page == 1)
{

        imagepng($image);
        imagepng($image, "./user/".$user.".png");
    



}
else
{
        imagepng($image);
    
}

•

if ($page == 1)
imagegif($image, "user/" . $user . ".gif");
imagegif($image);

$page is always set, even if filter is on. Since it's for use as a signature, with the code above, if someone uses the filter then it'll change the image in the signature, which isn't good. Therefore if filter is set (regardless of whether page is set) then the image isn't saved; if filter isn't saved but page is, then it is saved and if $page != 1 then it isn't saved either.