[Resolved] Random Image Pairs.. How does one grab a matching pair of images at random?

[mr_bean]

Hello all,

I am learning, please be gentle as I try to get better.

I have a page with two different images that are pulled at random for display on the page in different locations. That works fine. However, I want the images to be a matching pair, like a headline and matching banner.

I don't know how to do that or where to find a tutorial on what the technique would be.

In pseudo-code:

Execute random image script
 and grab banner image from folder "banner."

Grab matching image N from folder "headline."

Essentially, two matching images both named N.gif but pulled from different folders could be displayed. They could be in the same folder, I just want both images N1.gif and N2.gif to display at once.

my php random pull starts like this

<?php


$folder = "banner";

$fileList = array();
$handle = opendir($folder); 
while (false !== ($file = readdir($handle) ) ) {
	if ( substr($file, -4) == ".gif" || substr($file, -4) == ".jpg" ) {
		$fileList[count($fileList)] = $file;
	}
}
closedir($handle);
$randNum = rand( 0, (sizeOf($fileList) -1) );
if ( substr($fileList[$randNum], -4) == ".gif" ) {
	header ("Content-type: image/gif");
} elseif ( substr($fileList[$randNum], -4) == ".jpg" ) {
	header ("Content-type: image/jpeg");
}
readfile($fileList[$randNum]);
?>

I am learning, albeit slowly.

[cafrow]

I am not sure what you are having a problem with. Let me see if I get you right.

You have 2 banner locations on your site, you want them to randomly show up but you want both the banners to be for the same theme / type / company. Well what i could do is the fallowing.

Make 2 folders, Banners and Headlines both folders are Exactly the same, so for every file that is in Headlines there is the same filename in Banners. Then i would write a script that goes thru the Healines folder and puts the file names of each Headline Image into an array, then do a random number to pick which filename out of the array I want to randomly grab. Then just pull the images headlines/ARRAY[3] and banners/ARRAY[3].

Not sure if that was what you where asking for, but that seems to be a nice way of doing it, it is dynamic so that if you want to add or remove new banners/headlines, then you just do so in the folder.

[mr_bean]

that is basically exactly what I am talking about Cafrow. I just don't know how to do it right yet. My attempts just don't cut it yet.

$folder1 = "banner"; 
$folder2 = "promo";

$fileList = array(); 
$handle = opendir($folder1);  
while (false !== ($file = readdir($handle) ) ) { 
    if ( substr($file, -4) == ".gif" || substr($file, -4) == ".jpg" ) { 
        $fileList[count($fileList)] = $file; 
    } 
} 
closedir($handle); 
$randNum = rand( 0, (sizeOf($fileList) -1) ); 

okay, so at this point I have gone through folder banner and taken the names, subtracted the extensions and generated the random number to which one I should be using.

I don't know how to store that name and then look into folder2 for the same name and then how to print them into the page at two separate places in the html page. Thank you for any insight you have. PHP is just a little less like greek for me every day.

[swr]

Looking at the script in your first post (using header() and readfile() to spit out an image), it sounds like you have a page that does something like this:

<img src="headline.php">
<img src="banner.php">

and want the two image-generating scripts to coordinate. Don't do it that way if you can avoid it! Both scripts will be run independently, and you'd have to jump through all kinds of hoops to get them coordinated. Instead, have the page that outputs those img tags take care of it all.

Suppose you have 20 images, numbered 1 through 20...

$n = rand(1, 20);
echo '<img src="/images/headline'.$n.'.jpg">';
echo '<img src="/images/banner'.$n.'.jpg">';

Your second post shows some more complicated logic (checking the directory to see what images are there) and that is fine, but if at all possible handle it when the HTML is served rather than when the images are served.

[mr_bean]

Thanks for the input swr. You are right about what the original script did and you are correct in your question about where I hope to go. I get what you are saying but am not sure how I ensure the code is served when the html is beyond writing the php markup directly into my page rather than calling it separately. I am also not sure how to now (with this revised technique you recommend) get the list of files form folder one, independent of their quantity because folder two will always have the same number whatever is is.

I am a ittle closer each time but baby steps because I am in the wading pool of php know how.

This would all in my php page directly that is called.

<?php 
$folder1 = images/banner
$folder2 = images/promo   

$fileList = array(); 
$makelist = opendir($folder1);  

/* somehow now get the list of files into an array, minus their extension */

closedir($folder1); 
$randNum = rand( 0, (sizeOf($fileList) -1) ); 

/*somehow now say, pick a random file and assign it value $chosenfile */

/* and then place the value of the random file name in the page */

echo '<img src="$folder1'.$chosenfile.'.jpg">'; 
echo '<img src="$folder2'.$chosenfile.'.jpg">';

   ?>

Am I getting closer to an efficient solution?

[swr]

Yes, you're very nearly there. The "get the list of files into an array" part you seem to have worked out earlier. The "pick a random file" part can be done with:
$chosenfile = $fileList[$randNum];

A few minor things...

In your echo statements, you have $folder1 and $folder2 inside single-quotes, so they won't be evaluated as variables (the literal string $folder1 will end up on the page). They need to be outside, like $chosenfile is.

In the code you posted earlier, this:
$fileList[count($fileList)] = $file;
could be written more simply as this:
$fileList[] = $file;
By using [] with no index php will infer that you want to add to the end of the array.

[mr_bean]

<?php  

$folder1 = images/banner 
$folder2 = images/promo    

$fileList = array();  
$makelist = opendir($folder1);
while (false !== ($file = readdir($makelist) ) ) 
{ if ( substr($file, -4) == ".jpg" )
{ $fileList[] = $file;
}
}

closedir($folder1);  

$randNum = rand( 0, (sizeOf($fileList) -1) );
$chosenfile = $fileList[$randNum];

echo '<img src="'.$folder1.''.$chosenfile.'.jpg">';  

echo '<img src="'.$folder2.''.$chosenfile.'.jpg">';

?>

Soooo close, that might be it. Thanks for the tips and the nonpatronizing effort to help me out in this conundrum.

[mr_bean]

well, I think it is safe to say that latest attempt was a complete failure. I am trying to diagnose the error messages right now.

I have four errors like this,

Warning: Division by zero in /home/username/domains/domain.com/public_html/index.php on line 13

and one final error to tie it all bakc up stating,
Fatal error: Unsupported operand types ...

sigh

[swr]

That's because of this:

$folder1 = images/banner
$folder2 = images/promo

Which should be this:

$folder1 = "images/banner";
$folder2 = "images/promo";

[mr_bean]

I have wasted way too much time on this script. Swr, I appreciate you taking the time to provide me insight.

The error in my code you picked out was quite true, however, fixing it didn't fix the functionality. Ack!

No end of rewriting the way I format the directory variables seems to fix this following bug. Does anyone have insight?

Warning: closedir(): supplied argument is not a valid Directory resource in /home/user/domains/domain.com/public_html/projects/index.php on line 18

Warning: closedir(): supplied argument is not a valid Directory resource in /home/user/domains/domain.com/public_html/projects/index.php on line 23

Lines 18 and 23:

while (false !== ($file = readdir($folder1) ) ) { 

closedir($folder1); 

PHP humbles me. I should add that I am not opposed to starting over if this is not the best approach. I have spent hours pouring over old posts in the forum and php.net to no avail in getting a functioning script.

[mr_bean]

I finally got all my bugs squashed and have a functional script. It works althoug I already see that it smacks of amateur workmanship. Any tips would be appreciated as I continue learning. Thanks for the previous feedback

<?php  

$folder1 = '/home/user/domains/domain.com/public_html/projects/assets/images/banner/';
$folder2 = '/home/user/domains/domain.com/public_html/projects/assets/images/bannerbox/';

$fileList = array();  
$makelist = opendir($folder1);
	while (false !== ($file = readdir($makelist) ) ) { 
    if ( substr($file, -4) == ".gif" || substr($file, -4) == ".jpg" ) { 
        $fileList[count($fileList)] = $file; 
    }
}
closedir($makelist);  

$randNum = rand( 0, (sizeOf($fileList) -1) );
$chosenfile = $fileList[$randNum];

?>

<?php echo '<img src="http://www.domain.com/projects/assets/images/bannerbox/'.$chosenfile.'" alt="Promotional Image" width="367" height="246" border="0" />' ?>