04 · Diff visualizations

Whenever reviewing changes to a document, it’s essential to have a way of seeing what changed: a “diff view.”

Diff views appear in source control tools, such as the red/green line-based view in the diff unix utility. Writers have seen the blue (added) and red+strikethrough (removed) syntax found in word processors.

But two common problems we’ve noticed ourselves and heard from others about existing diff views for prose:

  1. They’re often very noisy, making it hard to review (e.g. suggested edits in Google Docs).
  2. It can be hard to get a high-level glance of what’s changed, in addition to the details.

Here are some small experiments we tried in this area to improve legibility and utility.

First, diff visualization in the full-size document editor:

Additions are highlighted green, deletions are shown with a backspace key glyph.

We also used the right-side gutter, traditionally used for comments, to call out additions and deletions. Most promising here was showing replaced text, which is a common operation in copyediting but can get noisy with strikethrough-based diff views.

Replaced text shows as “before → after” in the margin.

There’s another type of diff visualization we need, which is a summary or thumbnail view. Git shows a commit summary in the style of “+added/-removed,” but no such thing exists for prose writing.

Some experiments we tried for a summary diff:

Summary diff visualization micro-experments. On the left is a simple set of additions to two sections. On the right is a more complex whole-document edit. Breaking these down top to bottom:

Our team’s favorites so far are the hover-to-show-deleted (full document) and the minibar (summary). What directions do you think we should try next?

Next entry: 05 · Edit groups

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