Dynamic Image problem...

kendaile

Greetings,

I'm rather new to the boards, but thought that perhaps you all might be able to help with a slight problem we're having at work...

To sum up, at work we're dynamically creating png images for the web - using the GD package - from an input string sent at the time of page instantiation.

It works beautifully now, as per spec on single images. However my requirements have changed near the end of the project, and I'm to add a new feature that shows multiple images, from multiple input strings, using the same script on the same page. The code itself was not difficult to impliment of itself, however we've found an very difficult error.

(I'm rather new to the actual dynamics of the web, so please correct me of I'm wrong..) As far as I can tell, HTML browsers load images last on webpages... This creates a timing problem, because each image is created dynamically and called in real-time. -- So we're seeing the same picture, the very last one created, shown in every image.

One possible solution involves Javascript, I believe, but one of our requirements is the specific exclusion of Javascript if at all possible. If there is no other possibility, we're allowed.. but only after all other possible avenues have been exhausted.

My question: is there a way to create each of these individual images using the same script, without using javascript?

Any help would be greatly appreciated.
Thanks,
Kendaile

Marqis

Worth a try... Something I found in the YAPPA project from Freshmeat.

Basically, something like this:
Make a file called showimage.php
Call it like this from your main page <img src="showimage.php?str=data">

showimage.php
header("Content-type: image/png");
process $str
create image in a file or in ram or whatever
binary stream said file

Voila...

kendaile

Thanks for the Repsonse..

I'll try it when I get back to work Monday - however that is nearly what I am doing anyway.. though in a bit different order..

We're getting an image out perfectly with only one image to display.. it is the problem of multiple calls to the same script that we're having problems with.

We're using object oriented php.. in this case, for example, I have a class that receieves the raw input string and needs to return an array of strings as well, for one of the features.. (exclusion of parts of that image for the next time..)

My problem is that if you attempt to call that same script in the img src for different pictures (from different input strings).. you get only the very last picture created. We're wanting all of them individually.

This isn't verbatum, but it looks something like this at the moment:

<?php

foreach ($inputArray as $inString){

// create the image
$Pic = new Image($inString, $otherArguments);

// store it for use in the called script page
$_SESSION['Pic'] = $Pic;

// get the information we need from the image's
// class before it's destroyed
$returnedArray = $Pic->get_returnedArray();

// .... create the html/css to surround the picture, then:
// the ImageScript file only calls the GD specific functions
// to return the image, like create the headers and
// call GD's image creation and destroying mechanism.
echo "<img src=\"ImageScript.php\">";

} // end foreach

... and so on.

It's quite a change from what we had planned and how this type of thing is normally used.. However, as long as you don't destroy the image by creating it, you can treat the image as an object with it's own data and functions.

... To define the problem another way, our classes are being created and destroyed before the browser goes and gets any of the pictures, leaving us with only the output of the final image for each one called, and not seperate images for each one.

It may not be a php problem, but we're looking for a php solution just in case.

Thanks for your time and for bearing with me, my friends.. it is appreciated.

Have a good one!
K.

Marqis

Since I haven't done any session programming before I can't say for sure, but to me this looks like a simple problem (too simple which is why I think I'm wrong on this one).

foreach ($inputArray as $inString){

// create the image
$Pic = new Image($inString, $otherArguments);

// store it for use in the called script page
$_SESSION['Pic'] = $Pic;

You're storing each new picture to the same variable.
ie:
for(i=0; i < 5; i++)
j=i;

Why is j always the same value (5)?

It looks like you should be doing:
foreach ($inputArray as $inString)
{
$Pic = new Image($inString, $otherArguments);
$_SESSION['Pic'][] = $Pic; // note the []
}

Then afterwards iterate over $SESSION['Pic']
foreach($SESSION['Pic'] as $pic)
dostuff($pic);

My 2 cents.

kendaile

Actually, you have the same idea that we had, in a way..

After doing a little testing, however, the session variable seems to be getting everything correct. At least, I can get it to return and display the inputString and some other variables to make sure that the stored session variable is still unique for each picture.

Along the same vein of thought, I now think that it is not the session variable, but the actual script name being calledthat is the same at each calling.. and because HTML calls the script after it has loaded everything else, (just like it would plain .png's) it calls the same image repeatedly instead of a unique one each time the script is called.

... and one possibility we've thought of to fix this is to make a number of uniquely named scripts that all are the same image creating script.. Just copying the name of the script and adding sequential numbers; then we could just changing the code to concatinate the original script name and the new number.

Personally, I would rather have a more eloquent solution, but if that is what it takes, then it will work.

Thank you yet again for your time, it is appreciated!
K.