Use real HTML-Diff algorithm in Drupal Diff module

I had a detailed look at daisydiff and started integrating it into the diff module. The problem is that the PHP implementation of daisydiff is very slow when documens are longer (>4 screen pages). I talked to Guy, the developer of daisydiff and he confirmed this. The comparison does not deliver good results for longer documents. Therefore, I can not recommend using daisydiff for the diff module.

Thanks for this evaluation - please feel free to make active again if/when the performance of this library is improved.

PHP API http://code.google.com/p/daisydiff/source/browse/trunk/daisydiff-php/HTM...

PHP version developed for Wikipedia : http://www.mediawiki.org/wiki/Visual_Diff

Daisydiff's output does look nice, however including this might be a non-starter due to license issues.

Given that Drupal is released under GPL 2 and Daisydiff Apache 2

From Various Licenses and Comments about Them - GNU Project
http://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenses

Apache License, Version 2.0
This is a free software license, compatible with version 3 of the GPL.
Please note that this license is not compatible with GPL version 2

like many other drupal modules it can be used as an optional third party. It does not have to be bounded with this module. it might also be possible to use the java version as well

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I've been playing around with a couple diff packages. I'm hoping to have a test patch of one of them up and running soon. Hopefully, I'll post back within a few days.

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I've created a modified version that uses PEAR's Text_Diff package, which needs to already be installed on your system beforehand.

It's still quite kludgy at the moment, but it appears to work decently enough (but only for nodes in the current version).

I've attached a screenshot along with the patch files.

Also, it might be worthwhile to combine this with http://drupal.org/node/372957 to create a simple configuration screen to toggle between the diff engines and whether or not to include markup.

If you're interested you might also want to look at:
http://drupal.org/project/lifewire_diff

It's only available for 5, but it also uses PEAR Text_diff and I used it as a jumping off point for my experiment. It also allows users to select between the 2 column and single column diff views.

Bumping to 3.x branch. See #1630062: Developmental Roadmap.

Marked #304618: HTML Filtering (How?) as a duplicate.

Re #10: There's now an issue to #1826156: Move to Text_Diff library.

HTML-Diff support seems like it should be easy to handle after looking at #10, #304618-3: HTML Filtering (How?), Lifewire Diff, and http://stackoverflow.com/questions/1360610/how-to-show-a-comparison-of-2... .

Does that mean we can close out or postpone this issue?

Patch in #10 works in 6.x-2.3 (with some offsets.)

I agree, it's a little clunky, especially when links change, but works well enough. Thanks.

Any progress with this feature? It would be awesome!
Nvm, found it pushed in dev (https://drupal.org/node/372957).
Thanks a lot!

#372957: HTML Strip for Diff, WYSIWYG Friendly

Closing as major developments in 7.x are not going to be continued and 8.x provides a base that includes VisualInlineDiffLayout that uses mkalkbrenner/php-htmldiff-advanced that provides a nice inline diff.