Returning Data From Php Back To Ajax Without Using Echo

[thecommonthread]

So traditionally you use "echo json_encode(array of data to return)" to return data to AJAX, but the problem is my PHP file is a PNG image -

 

header("Content-type: image/png");

imagepng($image);

 

 

So I can't echo anything or else the image based from a PHP file will just fail. Is there an alternative way to return data to AJAX without echoing anything? I sure appreciate any help anyone could give me. Thanks!

[Jessica]

No. Whatever you're doing you are going about it in the wrong way.

[thecommonthread]

Lol, thanks for the reply. So you're saying I can use an echo in an image then and I'm missing something? Let's just use the example from the PHP Manual (php.net/imagettftext) to create a very simple image with only a text phrase in it:

 

<?php
// Set the content-type
header('Content-Type: image/png');
// Create the image
$im = imagecreatetruecolor(400, 30);
// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 29, $white);
// The text to draw
$text = 'Testing...';
// Replace path by your own font path
$font = 'arial.ttf';
// Add some shadow to the text
imagettftext($im, 20, 0, 11, 21, $grey, $font, $text);
// Add the text
imagettftext($im, 20, 0, 10, 20, $black, $font, $text);
// Using imagepng() results in clearer text compared with imagejpeg()
imagepng($im);
imagedestroy($im);
?>

 

If the $font you are loading in this code exists on the server, this will just load a PNG image with the word "Testing..." Now try using a simple echo statement. Echo anything. Now try and run the PHP and it will just load as a broken image. This is why I'm looking for an alternative to echoing a json_encode(). Thanks.

[Christian F.]

No, what she's saying is that there is no way to mix image-data and non-image data. Your PHP code outputs into one format, and one format only, at a time.

What you'll need to do is to shell out the image generation into a script of its own, then set that script as the source of the image element you want to show it in. The JSON bit, and anything else, needs to come from a separate file. Normally you'll call that file with the AJAX.

 

If you want to generate an image based upon the AJAX call, then you will still need to to this in two operations: First the AJAX call, to get the data you need (including the image name). Then set the image src to the image-generation script, using the data you've just retrieved from the AJAX call.