PHP image GD library not outputting visuals until loop is complete

Question

I am trying to have this function output data and the rescaled image after every loop but it doesn't display anything until it is finished looping through the complete array. I am assuming that this has something to do with the PHP image functions but is there a workaround?

function resize_images($images_l){
echo "Resizing Images<br>";
$new_height = 200;
$new_width = 200;
$c = 1;

foreach($images_l as $filename) {
 echo "Image" . $c . "<br>";
 $c++;


 // Get the new dimensions
 list($width, $height) = getimagesize($filename);
 echo $new_width . ", " . $new_height . "<br>";

 // Create the new image
 $image_blank = imagecreatetruecolor($new_width, $new_height);
 $baseimage = imagecreatefromjpeg($filename);
 imagecopyresampled($image_blank, $baseimage, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

 // Save the file
 imagejpeg($image_blank, 's_' . $filename , 100);

 echo "<img src=\"s_$filename\">";
}
return TRUE; }

Thanks

Answer 1

I assume this is on your web server? Your server only sends a web page to the client once, when it's done running. If you want to show all the intermediate stages you need to build a page that automatically refreshes or use javascript to reload the image at an interval.

If this is on CLI then how are you viewing the images. You post doesn't really make sense.

Answer 2

I suggest you take a look at Output Control Functions, you could flush each image after its been re-scaled.

EXAMPLE

<?php

function gradual_output()
{
    # start using the output buffer.
    ob_start();

    for ($i = 0; $i <= 10; $i++) {
        echo "loop count: " . $i . "<br />\n";

        # flush the buffer to the user.
        ob_flush(); flush();

        # do something that takes a while...
        sleep(2);
    }

    # were done with the buffer, clean up.
    ob_end_clean();
}

gradual_output();

?>

Anything you echo out after calling ob_start() will be put into a buffer, you can decide when you want to flush this buffer to the user.