DiffineStrings

The words both views put on the screen. DiffineCommonStrings, which the two tables under it extend.Flutter keeps one table, and this is the part of it both widgets read.

Key	English default
before	Before
after	After
empty	Nothing to compare yet.
identical	The two are the same.
previousChange	Previous change
nextChange	Next change
changePosition	Change {position} of {total}

What the document comparison adds. DiffineTextStrings, which is what TextDiff takes.Read by TextDiff.

Key	English default
placeholder	Type or paste a document here.
added	Added
removed	Removed
changed	Changed
folded	{lines} unchanged lines
expand	Show {lines} unchanged lines
applyChange	Take this change into {label}
format	{before} → {after}
mixedEndings	mixed
noFinalNewline	no final newline
language	Syntax highlighting
summary	{changes} changes, {inserted} lines added, {deleted} lines removed
documentSize	{label}: {characters} characters, {size}
search	Find
searchIn	Find in {label}
searchPrevious	Previous match
searchNext	Next match
searchClose	Close find
searchPosition	Match {position} of {total}
searchEmpty	No matches
matchCase	Match case
wholeWord	Whole word
regex	Regular expression
replace	Replace
replaceWith	Replace with
replaceAll	Replace all

What the picture comparison adds. DiffineImageStrings, which is what ImageDiff takes. DiffineStrings is the two together, for an application that keeps one table for both.Read by ImageDiff.

Key	English default
imageSize	{label}: {width} × {height}, {size}
imageSummary	{regions} changed areas, {percent}% of the picture
choose	Choose an image
chooseIn	Choose an image for {label}
unsupported	That file is not an image.
loading	Opening the picture
zoomOut	Zoom out
zoomIn	Zoom in
zoomFit	Fit to the pane
zoomLevel	{percent}%
fade	Fade between the two
wipe	Drag to wipe between the two
at	At
loupeMove	Drag to move the magnified pixels
loupeSize	Drag to show more pixels

added, removed, changed, summary, documentSize, changePosition, searchPosition, searchEmpty and imageSummary are read by a screen reader rather than shown. language names the editor's menu of languages to one.

The placeholders are filled in as follows. searchIn and chooseIn fill {label} with the name of the side the button belongs to, so two of the same button on one componentwidget are told apart. summary fills {changes}, {inserted} and {deleted} with the counts. documentSize fills {label} with the name of a side and {characters} and {size} with numbers already written in the reader's own language, and imageSize fills {width}, {height} and {size} the same way. imageSummary takes {regions} and {percent}, and zoomLevel takes {percent}. at is what goes before the coordinates under the magnified pixels, and loupeMove and loupeSize name the handle that moves that panel and the corner that shows more pixels in it. placeholder is what an empty field in the editor says.

strings is a partial table, so an application changing one word passes one word — Partial<DiffineTextStrings> on TextDiff and Partial<DiffineImageStrings> on ImageDiff.

strings is a whole DiffineStrings rather than a partial one, because Dart has no partial. Start from the locale's own and replace what you mean to change:

TextDiff(
  before: saved,
  after: draft,
  strings: baseStringsFor(DiffineLocale.en).copyWith(before: 'Saved', after: 'Draft'),
);