A visual diff compares and shows differences between rendered (or displayed) documents, as opposed to showing the text (or markup) that is used to format such documents.
The main approach for visual diffs in MediaWiki is the visual diffs system (pictured) provided by the VisualEditor extension, which compares the HTML of two documents. It provides visual diffs in VisualEditor's editing preview, as well as (still as a beta feature) in MediaWiki's standard diff display.
Another option for visual diffs is the VisualDiff extension, which adds visual diffs directly to the history page.
Previous attempts at visual diffs in MediaWiki include:
- Wiki Edit History Analyzer was another apparently-abandoned attempt at visual diffs; its development was discussed in the 2010 paper "What Did They Do? Deriving High-Level Edit Histories in Wikis".
- IBM's history flow as an alternative concept
- Replay edits tool shows some visual diffs