Improve GD library hook_requirements() for color and image modules

This is what I think is going on. You've got GD installed, though it is not the version bundled with PHP. As a result some of the image effects will work (scale for example), and some will not. Desaturate and rotate. Do you get watchdog messages to the tune of "The image %file could not be desaturated because the imagefilter() ..."?

If so, you've got a partially functioning version of GD.

I think we should adjust the _requirements hook to test for existence of imagefilter() and imagerotate() and if they are missing return a warning. Image styles will still function without them, and we're already checking if the function exists before trying to use it. We just need to make it more obvious to the user that they're missing some functionality.

We might want to consider hiding the desaturate and rotate effects for system that do not support them as well. Not sure if that would get in for D7 or not though.

I think the new checks should go in image.install instead of color.install.

1. Color module doesn't make use of either imagefilter() or imagerotate().
2. Its possible to have color disabled and image enabled which would lead to inaccurate status reports and people getting confused when desaturate doesn't work.

I would also like to see the warning be a little more explicit about what exactly is missing. This is important because it gives people a little head start when they are trying to figure out what is wrong with their GD. Perhaps something along the lines of:

The GD Library for PHP is enabled, but was compiled without support for functions used by the rotate and desaturate effects. It was probably compiled using the official GD libraries from http://www.libgd.org instead of the GD library bundled with PHP. You should recompile PHP --with-gd using the bundled GD library. See: http://www.php.net/manual/book.image.php

That link in color.module to the PHP docs should change to, it points to the function reference page, not very useful for people who are trying to debug installation/configuration problems. That's for another issue though.

Thanks for the patch.

The bad thing is that basically two separate modules are implementing the need for gd. That means that if GD isn't there, there will be two separate warnings about it. And if GD is there (but broken, as in my case) then one requirement will say it's OK, the other not.

True, but accurate. As we would rather have more clues than less, and the requirements are from two different modules - and technically are requiring different functionality, then I'd vote for the two slightly different warnings. Your fix is fine, I think.

I'm okay with keeping the requirements checks separate. Otherwise, we could put them in system_requirements(). Which, is already checking for the existence of the GD PHP extension. And since the GD toolkit we're using for image manipulation is provided by system.module I think this would be an okay place as well.

Picky, but can we change the link in the second requirements error to http://www.php.net/manual/book.image.php as per #5. Again, I just think it is a more useful place to send the user when trying to resolve this issue.

See also
#747042: Rotate effect
#752276: Image Style Previews Not Working - marked as duplicate of this.

I'm okay with this method, but would still like to see the link changed as per #9.

If we're going this route I would also like to change the title of the color.module requirement to something like 'GD Library PNG Support'. This makes it clear that the requirement in this instance is for a specific GD functionality and not just GD in general.

If you want to re-roll your patch I would be happy to summarize the issue and RTBC.

Yeah! Thanks rfay.

Committed to CVS HEAD. Thanks.

This should just be a warning - I'm sure a lot of people wont need rotate or desaturate, but don't want a permanent error at the top of the configuration page.

I'm okay with this just being a warning. Both of the image api functions that use the GD functions in question check for their existence before using them and log errors via watchdog. So we're not likely to get any WSOD or Fatal errors.

I still think we should consider hiding the rotate/desaturate effects if they don't work. But that can be discussed here #747042: Rotate effect

I have the same issue.
I can't even publish pictures anymore.
When i upload them, i see them for a short time. When i refresh my page the images are gone.

Does anyone know what may cause this?

Thanks in advance

Can someone please summarize a resolution this for major distros.

I'm thinking an
# apt-get install php5-gd

or something like that is inline here.

If it's not part of the major Linux distros then really it's rather annoying that Drupal's asking us to build an app for scratch not to get a nasty red error message on the status page.

RE documenting:
It may not always be turned on automatically in hand-compiled raw distros, but it is usually enabled as a matter of course by hosting providers. And is in most domestic/developer precompiled default binary installs of PHP, and XAMPP and MAMPP. (but not OSX)

Folk who have the authority to run apt-get are expected to have the knowledge to run apt-get.
So it's a documentation matter if the current recommendation "An image library for PHP such as the GD library is needed for image manipulation needs to have an extra line added "And to do that you run apt-get install php5-gd"
Some hand-holding is good, when the instruction is just a short copy-paste like that. I know I always forget, and try "apt-get install gd" unless I remember right. So it'll be handy to be documented there.

So ...

If you have administrator rights on a Debian/Ubuntu server, and GD is not already available (see your phpinfo) it can usually be installed by going:
sudo apt-get install php5-gd
See the ImageMagick install instructions for your platform if you want that.

has now been added to the (already huge) system requirements. The system requirements should not IMO turn into a HOWTO - which is better left to the install instructions themselves, but this small one is short.

Ok, but sadly that's only as good as the repository you're working with. Doesn't seem to work with stable debian.

$ sudo apt-get install php5-gd
[sudo] password for me:
Reading package lists... Done
Building dependency tree
Reading state information... Done
php5-gd is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 7 not upgraded.

I don't have a debian box to test this one but I'm not sure that the standard php5-gd will actually fix the problem. My understanding is that the issue stems from the fact that debian uses the "official" libgd package though as of 5.x PHP has it's own forked version of the GD library (built in, and with a number of changes that haven't been contributed upstream as of yet). Image Styles/Effects depends on some of the functions that exist in the PHP version of GD but not the libgd version. Debian doesn't build with bundled libraries as per their policies ... and thus chaos ensues.

In order to get a fully functioning version of PHP + GD working on Debian you need to re-compile php using the --with-gd flag, just using 'php5-gd' won't actually do you any good.

At least that's my understanding of the situation. @rfay may be able to confirm or shed some more light on this as he alerted me to the problem originally.

I was having the original problem described. I found this ticket because I did a web search for "drupal GD library rotate and desaturate effects". I know this ticket is about changing the messages and warnings that are displayed, but in case anyone else is looking to solve this problem on their install... I followed the link in #25 (thanks @rfay) and eventually ended up on this page: http://drupal.org/node/540838 . I followed the directions and it works. (I'm running Ubuntu Server 8.04.)

Seems like the Debian folks aren't going to be making it easy to install GD the way Drupal wants to. "php5-gd is already the newest version" and we're still getting the error "GD library rotate and desaturate effects" even though the phpinfo() reports that "GD Version 2.0 or higher".

According to the system requirements we should have the option of using ImageMagick too "ImageMagick is also supported for basic image manipulations in Drupal core", but sadly this doesn't get rid of this error.

Also according to the phpinfo() results "imagick module version 2.1.1-rc1" so this should give me the power to rotate images or do other stuff that core's worried about.

So either D7 needs to be updated to support imagemagick or (in a worse case senario) the docs need to be changed. Also it should be clear that other than recompiling PHP yourself, the only approach to do this is to use non-core sources.

Ubuntu 10.04 seems to take care of it out of the box, but not sure when the Debian community will.

I had to take a look at this a bit further. Seems silly that it's giving an error, especially since I've never used Drupal to either rotate or filter an image since I've been using it. So if I look for the instances where it's used:

$ grep -ir imagefilter *
modules/simpletest/tests/image.test:    // Systems using non-bundled GD2 don't have imagefilter. Test if available.
modules/simpletest/tests/image.test:    if (function_exists('imagefilter')) {
modules/simpletest/tests/image.test:        // Transparent GIFs and the imagefilter function don't work together.
modules/image/image.install:      if (function_exists('imagefilter') && function_exists('imagerotate')) {
modules/system/image.gd.inc:  // PHP installations using non-bundled GD do not have imagefilter.
modules/system/image.gd.inc:  if (!function_exists('imagefilter')) {
modules/system/image.gd.inc:    watchdog('image', 'The image %file could not be desaturated because the imagefilter() function is not available in this PHP installation.', array('%file' => $image->source));
modules/system/image.gd.inc:  return imagefilter($image->resource, IMG_FILTER_GRAYSCALE);

$ grep -ir imagerotate *
modules/simpletest/tests/image.test:    // Systems using non-bundled GD2 don't have imagerotate. Test if available.
modules/simpletest/tests/image.test:    if (function_exists('imagerotate')) {
modules/image/image.install:      if (function_exists('imagefilter') && function_exists('imagerotate')) {
modules/system/image.gd.inc:  // PHP installations using non-bundled GD do not have imagerotate.
modules/system/image.gd.inc:  if (!function_exists('imagerotate')) {
modules/system/image.gd.inc:    watchdog('image', 'The image %file could not be rotated because the imagerotate() function is not available in this PHP installation.', array('%file' => $image->source));
modules/system/image.gd.inc:  $image->resource = imagerotate($image->resource, 360 - $degrees, $background);

It really boils down to two lines that require it for one module. I think these are the Imagemagick equivalents:

http://ca2.php.net/manual/en/function.imagick-medianfilterimage.php
http://ca2.php.net/manual/en/function.imagick-rotateimage.php

So shouldn't we just allow for that if it's a matter of two functional lines in the code? This is just a partial patch, as it just deals with proposed changes to include rotateimage support and doesn't deal with the a lot of stuff. Just a proof of concept at this point.

Either way I support this being made a warning and not an error on the Status page as per:
http://drupal.org/node/758628#comment-2805856

I should probably make a new issue to talk about imagemagick support.

Attached is a patch which basically makes these warnings instead of errors as per #16 but including Randy's request that this apply to both image.install and color.install

My anecdotal opinion, I've run dozens if not hundreds of sites now and never used image rotation or desaturation effects, but even for those who do use such effects, this shouldn't be an error, it should be a warning, otherwise you get confused users (which you will find in the issue queue) wondering why they have this even though it in no way prevents them from installing Drupal. We had so much hubbub in the D7 release process about issues not being critical if they don't affect the core usage of Drupal, and I think we should apply the same standards to what the Status Report is outputting. You can run a Drupal site without needing these GD effects, and moreover you may never need them.

My reason for wanting this is so I can use drush nagios-check requirements for a sanity check, but now looks like I'll have to reproduce that functionality (in lieu of hacking core).

Patch applies nicely. Looks better.

+1 & Thanks!

Thanks!

Makes sense to have these not be as severe as they are now. Rotate, especially, is just showing off. :)

Committed to 8.x and 7.x. Thanks!