Transcript DiffView

DiffView

A file diff: one row per line, added lines on the constructive tint, removed lines on the danger tint with the text struck through, context on the surface-2 well. It is the body that a file edit row opens into.

import 'package:agent_kit/agent_kit.dart';

Demo

A diff with two hunks, from the _modified() fixture in the gallery: the hunk at line 24, then a break marked "…", then the hunk at line 183. The crop is the second DiffView in the scene (index 1), the one under the "Diff view" label. The first DiffView is inside the open file edit row.

Parameters

Parameter	Type	Notes
diff	FileDiff	Required, positional. Its hunks are drawn in order; path, added and removed feed the semantics label.
lineNumbers	bool	Default true. When true, draws the number gutter. When false, the rows start 8 px in and no numbers are drawn.

Line numbers come from the new file. Numbering starts at each hunk's newStart. Context and added lines take the next number; a removed line has none and does not advance the count.

Line types (DiffOp):

Op	Row fill	Text	Sign
add	constructive	constructiveInk	+
del	danger	dangerInk, struck through	−
ctx	surface2	muted	none (faint)

An empty line is drawn as a space, so the row keeps its height. A hunk break is a 16 px row on surface2 with a faint …; it is indented to clear the gutter (44 px, or 8 px without numbers).

Theme roles

constructive, constructiveInk, danger, dangerInk, surface2, muted, faint (numbers, signs and the hunk break), and radii.sm (the clip corners).

The text is 12.5/20 mono, set through monoStyle from a fixed TypeSpec in the file, not from typeScale.code.

Size classes

Does not read the size class. The diff lays out at the width its parent gives it. The inner Column is an IntrinsicWidth, and a horizontal scroll takes over when a line is wider than the viewport. Lines do not wrap (softWrap: false).

Accessibility

• Semantics(container: true, label: 'Diff of <path>, +<added> −<removed>'). The rows underneath are not given their own labels.
• No focusable controls. Scrolling is the default of SingleChildScrollView; no key handling is added.

Gallery and tests

• Gallery scene: Components. Specimen "Diff view" in TranscriptSpecimens (apps/gallery/lib/components/transcript.dart, lines 108 to 109), built from _modified().diff.
• Golden: apps/gallery/test/component_shots_test.dart writes diff_view from DiffView index 1, light and dark.
• Other tests, in packages/agent_kit/test/transcript/transcript_test.dart:
  • "counts, callbacks and the diff" (line 349);
  • "the diff numbers lines and strikes removals" (line 420).
• Transcript goldens in packages/agent_kit/test/goldens/transcript_turn_*.png and transcript_states_*.png.

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Generated from docs/components/transcript/DiffView.md. Edit the file there; changes made on the wiki are overwritten.