Watermarking module.

I'm thinking about adding a few features to watermarking.

1) Ability to watermark text instead of an image.
2) Ability to add a Watermark based on groups.
3) Ability to manager permissions based on groups.
A) allow only admins to turn watermarks on and off.
4) Better compatibility with Safari (dragging the image around only works for a few pixels at a go).

I noticed the watermark module is not without bugs, so I just want to make sure I'm not working on features that are already planned/begun.

One bug I noticed in CVS (as of 10/14/2004) :
Hitting save on the "Edit A Watermark" page always results in an error.
Error (ERROR_BAD_PARAMETER) : Controller results are missing status, error or (redirect,delegate)
in main.php at line 172 (gallerystatus::error)
in main.php at line 47
in main.php at line 40

Joseph Elwell.

A bigger thing:
Watermark a photo, go to site/user admin and delete the watermark.. now go back to the album with the watermarked photo and do rebuild thumbs (or rotate the photo if original is watermarked).. the thumb and/or preferred derivative now show our broken image image.

It was in edit photo / Watermark where I saw the listbox not using the watermark names.. I hadn't looked at the watermark option in add items.

Removing existing watermarks seems like the right thing, as long as the user is warned that watermarks are being removed when they delete the watermark image.

(fyi, quote= requires quotes around the name, for some reason..)

I think I've misunderstood this feature somewhat.

But let me start with the bug.

This is with Safari on the Mac. If I go to the "Site Administration" page for "Watermarks" and I click on "edit" in the Action column of one of my watermarks I get sent to the "Edit A Watermark" page. If I just leave the defaults and click on the "Save" button, I get an error on the next page:

Error (ERROR_BAD_PARAMETER) : Controller results are missing status, error or (redirect,delegate)
in main.php at line 172 (gallerystatus::error)
in main.php at line 47
in main.php at line 40

On Internet Explorer (on the Mac) when I get to the "Edit A Watermark" page there's not even a "Save" button, nor a "Cancel" button. *shrug* This isn't so important to me since I only fired up Internet Explorer because I thought it might be a browser issue.

On Camino hitting save doesn't cause any problems. But then I can't drag the watermark at all.

I'll work on these compatibility issues for now.

As for me not understanding the module, the whole component simply doesn't seem to work (under Safari), so I was just guessing at the functionality. Anyways, what I want to do - in particular - is add systemwide watermarks to images that are loaded outside of the Gallery framework. That means if someone embeds a gallery image into another website the image will be automatically watermarked. Groups come into play because I want to set it up to watermark or not based on whether the owner is in a certain group. Anyways, I can handle all this code myself, I was just trying to figure out if these kind of features are something you'd want integrated into this module. I'm going to hold off on this work until I can figure out the Safari issues.
Joseph Elwell.

I like his idea of a feature to only watermark images that are hotlinked. That would be groovey. Btw, since g2 does image firewalling... how WOULD you hotlink if you wanted to?

fryfrog, you would have to check the request referrer ($_SERVER["HTTP_REFERER"]) if it comes from your site or from an unknown site and do the switch. I think it could be an interesting feature.

I accomplished this with a patch to modules/core/DownloadItem.inc:

$path = $data['derivativePath'];
$mimeType = $data['mimeType'];
if (!isset($_SERVER['HTTP_REFERER']) || strpos($_SERVER['HTTP_REFERER'], 'mydomain.com') === false) {
  // Bad referer.. watermark the image:
  list ($ret, $toolkit) = GalleryCoreApi::getToolkitByOperation($mimeType, 'composite');
  if ($ret->isError()) {
    return array($ret->wrap(__FILE__, __LINE__), null);
  }
  if (!isset($toolkit)) {
    return array(GalleryStatus::error(ERROR_PERMISSION_DENIED, __FILE__, __LINE__), null);
  }
  $tmpFile = $platform->tempnam($gallery->getConfig('data.gallery.tmp'), 'wmk_');
  list ($ret, $mimeType) = $toolkit->performOperation(
    $mimeType, 'composite', $path, $tmpFile, array('watermark/watermark_png', 'image/png',
                                                   96, 39, 'bottom-right', 0, 0));
  if ($ret->isError()) {
    return array($ret->wrap(__FILE__, __LINE__), null);
  }
  $path = $tmpFile;
}

...

if (isset($tmpFile)) {
  @$platform->unlink($tmpFile);
}

This is in renderShortcut().. then I changed a few more lines to use $path and $mimeType where appropriate. Similar code is needed in renderImmediate() so the same logic applies when the permissions aren't already cached. You can see above that I hardcoded the parameters for the watermark... with this code in place I can browse my G2 fine, but if I do "view image" in mozilla for anything I see the image with a watermark (mozilla doesn't send any referer when you do "view image").
The referer check could be a little more robust, so other websites can't put their page at theirdomain.com/mydomain.com/page.php.. ;) It should probably also check that it's working with an image.. for other items types my code above will give PERMISSION_DENIED because it won't find a toolkit that can apply 'composite' to movies, mp3s, etc

I'm not sure how the same can be accomplished in a module...

yeah, I thought the same about caching.. either by managing its own file cache or by creating actual DerivativeImage entities. (I also figured, who cares if it's slow for someone using my images on their site!) Using derivatives is probably better since it will automatically benefit from cache expiration if the source is modified.

but, how can this fit in as a module? the only code the runs before renderShortcut() is GalleryUrlGenerator::parseCurrentUrl().. (for mapping short urls to the right view).

Keep in mind there's Gallery 1 code for preventing deep linking, with caching already. Don't know if that will help, it includes code for watermarking with Text instead of an image. But I'm sure you all know that already. ;)

http://gallery.menalto.com/index.php?name=PNphpBB2&file=viewtopic&p=55547#55547

http://gallery.menalto.com/index.php?name=PNphpBB2&file=viewtopic&t=12926&highlight=htaccess

As for the Safari issue, I emailed the author of the library. I don't know how much can be done to support Safari. The issue is, in particular, with dragging images. Safari lets you download an image from a website by dragging the image from Safari and dropping on your desktop. So after a few pixels of movement the image "comes off the page" and the javascript library stops registering the drag.

My suggestion to the library author was to add a dhtml div (for Safari only) to pure image divs that's sort of a border, that allows for dragging in Safari. If I don't hear from the author I might try to add this, but it's not terribly important for me, since I don't intend on installing any watermarking module other than a site admin utility to deal with deep linking.
Joseph Elwell.

mindeless,
Could you please help me extending the watermark module so that an album can have a watermark assigned to it? Now only individual photos can get watermarks. My goal is to just upload photos, for example by using the publishXP method, and have the watermarks assigned to the photos. I haven't got a clue where to start, so any help greatly appreciated!

I've been trying to implement this with help from #gallery@IRC, but then valiant told me that it existed already in the latest nightly build Gallery 2.1 (Blackjack). And indeed in the changes highlist is "PublishXP module now supports add-options such as watermarks and applying size limits or quotas."

I'm a happy user now, instead of a developer wannabee with a headache