php - creating img watermark

Question

<img id='imgt' src='../img/crop00.jpg' alt='img'>
<img id='imgtest' src='../img/crop00.jpg' alt='img'>

js

...
$.ajax({
    url: 'pro20.php',
    type: 'post',
    data: {...},
    success: function(data) {
        $('#imgtest').attr('src', data);
    }
});

php

error_reporting(E_ALL);
ini_set('display_errors', 1);

GD library is turned on - checked with print_r(gd_info());

pro20.php

I'm trying to run this code

$stamp = imagecreatefrompng('img/wmark.png');
$im = imagecreatefromjpeg('img/test.jpg');

$marge_right = 10;
$marge_bottom = 10;
$sx = imagesx($stamp);
$sy = imagesy($stamp);

imagecopy($im, $stamp, imagesx($im) - $sx - $marge_right, imagesy($im) - $sy - $marge_bottom, 0, 0, imagesx($stamp), imagesy($stamp));

header('Content-type: image/png');
imagepng($im);
imagedestroy($im);

echo imagepng($im);  // my added line 28

Result:
- #imgtest is blank,
- in file system there is nowhere new img created
- error log:

[:error] [pid 2736:tid 1580] [client ::1:59185] PHP Warning: imagepng(): supplied resource is not a valid Image resource in ... pro20.php on line 28,

you should probably use this http://image.intervention.io/ makes life way easier — Raj Nandan Sharma, Mar 14 '17 at 12:48
@RajSharma, thanks for the info, but I need to know what is wrong with the above code. — qadenza, Mar 14 '17 at 12:52
Could it be that you `imagedestroy($im);` and then try and use `$im` in an `echo imagepng($im);` ??? — RiggsFolly, Mar 14 '17 at 13:00
You dont have to post to get the image because if you look at the php code you will see it is returning an image. You can just do this $('#imgtest').attr('src', 'url/of/your/pro20.php'); But in case you want to make it dynamic. Use get parameters instead of post. Pass the names of image in the url (if you pass url then urlencode them in client side) $('#imgtest').attr('src', 'url/of/your/pro20.php?png=stamp&jpg=main'); — Raj Nandan Sharma, Mar 14 '17 at 13:05
@RajSharma, Is there a way to echo the url of new created img inside `pro20.php`? — qadenza, Mar 14 '17 at 15:21
yes, and also delete the complete `imagedestroy($im);` line. — qadenza, Mar 14 '17 at 15:27
For that you will have to save the image using file. And return the URL to where you have saved — Raj Nandan Sharma, Mar 14 '17 at 15:47

Niraj Shah · Answer 1 · 2017-03-15T12:11:11.473

There is nothing wrong with the code. The issue is likely that one (or both of the images) aren't being loaded correctly:

$stamp = imagecreatefrompng('img/wmark.png');
$im = imagecreatefromjpeg('img/test.jpg');

Check that img/wmark.png and img/test.jpg exist and are valid images.

I've tested your code (with some slight modification):

<?php

$stamp = imagecreatefrompng('wmark.png');
$im = imagecreatefromjpeg('img.jpg');

$marge_right = 10;
$marge_bottom = 10;
$sx = imagesx($stamp);
$sy = imagesy($stamp);

imagecopy($im, $stamp, imagesx($im) - $sx - $marge_right, imagesy($im) - $sy - $marge_bottom, 0, 0, imagesx($stamp), imagesy($stamp));

header('Content-type: image/png');
imagepng($im);
imagedestroy($im);

echo imagepng($im);

And I got this:

Nothing wrong with your code. The likely issue is that your images may not be valid png / jpg images. Please verify this.

Nothing wrong with your code. The likely issue is that your images may not be valid png / jpg images. Please verify this. — Niraj Shah, Mar 15 '17 at 12:11

php - creating img watermark

1 Answers1