Ok... here comes the wrap-up and summary.
Goal: To have a page show thumbnails of the images stored in a folder. Number of images is likely to change but they will always have the same format and resolution.
Means: To have a base HTML page calling a PHP script that counts the images in a specific folder and then returns the paths to these to another function that renders thumbnails of them on-the-fly. When you press a thumbnail, the real existing full-scale image is supposed to be shown to the right of the thumbnails.
Ideas: Constructing a script that counts the images in a folder was fairly easy. I used the following loop:
Code:
foreach(glob('images/'.$cat.'/*') as $img)
{
$imgArray[]=$img;
}
When calling the scipt I sent a variable which completed the path as above so that the script knows which images to take.
Once $imgArray had all the images, it was time to convert them to thumbnails without storing them anywhere. This is a script I call thumbnail.php:
Code:
<?php
$src=$_GET["img"];
$source_image = imagecreatefromjpeg($src);
$virtual_image = imagecreatetruecolor(50,50);
imagecopyresampled($virtual_image, $source_image,0,0,0,0,50,50,260,260);
imagejpeg($virtual_image);
imagedestroy($virtual_image);
imagedestroy($source_image);
?>
It works in a little strange manner though. It's part of the PHP GD extension and using it like a separate script and opening it in a browser generates a white page with an image and no HTML code (of course). I guess I think it's strange because it can't act in a context with other code, you don't SEND the image anywhere and tell someone what to do with it. As soon as you use the function 'imagejpeg' the script outputs a representation of an image. Therefore, echoing this script, returning 'imagejpeg' from this script or just executing this script should generally generate the same code since it ALWAYS outputs the image. Trying to output several images at once using the above script several times in the same file makes the browser just generate the first one. I guess I would have expected it to either show all three of them in a fast changing order or show them side by side but it's like wherever you use it, it just stops at the first imagejpeg. I must sound dumb but there's something I don't reall grip with this fairly easy to use script.... (Note: Using it separately in a browser requires including an image header at the top.)
My initial idea was to include this as a function in the script counting the images.
But how to include the image?
FIRST THOUGHT: The HTML written expects a source for the image. And the source should be a valid path which including this as a function could never make. Having the getThumbs('image') was hard to know where to put and my logical thought was to just put it inside of two <TD>-tags since including it in an IMG-tag would be illogical (what I supply is really not a path to an image but the image itself). Also, would it be correct to just put the function itself there or should I put 'echo' or 'return' in front of it? I mixed around a bit and the most common result was with a lot of strange letters inside the TD-tags at the place of the image and it all started with some familiar words containing 'JPEG Creator'. Apparently it was the image being processed in clear text. I tried to fix this by changing the headers for image (so that the browser would know to output it as an image) however this resulted in an error about "Headers already sent". During one output, for example when you send a HTML-file to a client, you can't change headers in the middle of output and that was what I was trying to do. From the moment my server sent out the first '<' in the opening <HTML> tag, that output was destined to be of type text/html and not image/jpeg which made it impossible to make the browser understand what I was trying to do.
SECOND THOUGHT: At first I thought that the above about output meant the PHP file's output to the HTML file which made me try a different approach. The approach involved the HTML page first being written with new code including info on the number of pictures it found, but ALSO new PHP code about how to get the thumbnails. My intention was that the web server would somehow feel that there were new PHP to execute and then execute that, now in a different output to the HTML file and thus rendering the images with the proper headers as it should.
Two mistakes though, first of all, the server literally thinks it's gonna send out the newly written PHP code so it doesn't execute that (like Xyro said) and second of all, I misunderstood the thing about output where output it actually the entire output from webserver to browser.
THIRD APPROACH: I constructed the function as a separate script that took a variable in the URL. This is the above posted script and it tells the script the path to the image it's supposed to make a thumbnail out of. I didn't like this method at first because it forced me to have one more file in my scripts folder (not that bad after all) and it also forced me to show that I have a script named thumbnail.php (I was being paranoid and not familiar with PHP, now I realize it's not that dangerous a script and also that PHP isn't THAT vulnerous).
However, when thinking about this, I realize it's the only way to do it.
FACT: Output has to be separate to the browser so it can render it as an image, therefore it cannot be included in the stream with the rest of the code and therefore it has to be a separate file and it has to take a variable as input.
CONCLUSION: I'm happy with the way of doing this now. Also, after applying some Javascript, it's now working super good. Only remaining question mark is about exactly how the 'imagejpeg' function works but I guess I can learn about that in the future
Thanks all of you!
