Kaleidoscope 6: Collapse Unchanged Text for Faster Comparisons

Our latest feature required more development effort than expected: Kaleidoscope can now hide equal blocks of text by collapsing them into a single expandable line. This significantly shortens text comparisons when most of the text in A and B is identical. Collapsing unchanged lines lets you quickly focus on the differences, assuming familiarity with the text. A collapsed area looks like this:

A sample Text Diff, comparing two revisions of a storyboard file. Storyboards tend to have a lot of common areas. This excerpt shows 4 areas of Collapsed Lines as a result, showing you more changes at a glance.

While the new functionality is mostly self-explanatory, this article will provide basic information, one caveat to be aware of and some hints for best use.

Enable Collapsing

As collapsing unchanged lines can makes many comparisons look quite different, it’s off by default. To enable it by default for new comparisons, go to Kaleidoscope > Settings > Text.

Kaleidoscope > Settings > Text controls default behavior for new comparisons.

Toggle Collapsing

After a comparison loads and unchanged line ranges are detected, you can choose to hide or reveal those unchanged ranges. The initial state depends on your default setting (see above).

Global Controls

You can toggle collapsing globally using a menu command in the View menu and a button in the bottom toolbar:

The **Expand Unchanged Lines** toolbar button.

Controlling a Single Pair

In addition to globally toggling all unchanged areas, you can quickly expand a single pair of collapsed areas to reveal more context for a change. Click the ellipsis button inside a collapsed area. It changes color on hover to indicate its interactivity.

Clicking the **ellipsis button** expands a single collapsed area.

Caveat

Kaleidoscope is a text comparison tool, not a compiler or syntax parser. Since Kaleidoscope doesn’t understand language constructs like functions or blocks, collapsing is based solely on matching lines between changes.

Hints

Expanding individual areas doesn’t change the global state. The toolbar button will still expand all other collapsed areas. To quickly collapse everything when some areas are expanded, hold Option (⌥) while clicking the toolbar button.
Holding Option (⌥) while clicking the ellipsis button expands all collapsed areas, not just the one you click.
If you are printing comparisons or sharing via PDF, collapsing unchanged areas is a godsend. Put the comparison in the state you want to share, then go to File > Print… to print or share.