TextApi

Decorations

Decorations attach metadata to character ranges — squiggles, syntax highlights, search highlights, bookmarks, and custom data. They automatically track text edits: an insert before a decoration shifts its offsets; a delete that encompasses the decoration removes it.

Navigation: Overview

TextDocument

Examples

Search

Quick Reference

using TextAPI.Core.Decorations;

// Add an error squiggle on chars 10–20
Guid id = doc.AddDecoration(start: 10, end: 20, DecorationType.ErrorSquiggle, tag: "CS0101");

// Remove it later
doc.RemoveDecoration(id);

// Query decorations overlapping a range
foreach (var d in doc.GetDecorationsInRange(0, 100))
	Console.WriteLine($"{d.Type} [{d.Start},{d.End}) tag={d.Tag}");

DecorationType Enum

Value	Typical Use
SyntaxHighlight	Token colouring from the active tokeniser.
ErrorSquiggle	Red underline for errors.
WarningSquiggle	Yellow underline for warnings.
InfoSquiggle	Blue underline for informational hints.
Selection	Current cursor selection highlight.
SearchMatch	Find-and-replace match highlights.
Bookmark	Named bookmark on a range.
Custom	Application-defined decorations.

Decoration Properties

Property	Type	Description
Id	Guid	Unique identifier. Use this to remove the decoration later.
Start	int	Start offset (inclusive). Updated automatically on edits.
End	int	End offset (exclusive). Updated automatically on edits.
Length	int	End - Start.
Type	DecorationType	Category of this decoration.
Tag	string?	Short string label (e.g. error code, token type).
Data	object?	Caller-supplied payload (e.g. diagnostic object, tooltip).

TextDocument Decoration API

Method	Returns	Description
AddDecoration(start, end, type, tag?, data?)	Guid	Add a decoration and return its ID.
RemoveDecoration(id)	void	Remove decoration by ID.
GetDecorationsInRange(start, end)	IEnumerable<Decoration>	All decorations that overlap the given range.

Offset Tracking

Decorations automatically update their offsets when the document is edited:

• Insert before: offsets shift right
• Insert inside: decoration grows (end shifts right)
• Delete that encompasses: decoration is removed automatically
• Delete that partially overlaps: end shifts left proportionally

var id = doc.AddDecoration(10, 20, DecorationType.Custom);
doc.Insert(5, "hello");  // +5 chars before the decoration
var d = doc.GetDecorationsInRange(0, 100).FirstOrDefault();
Console.WriteLine(d.Start);  // 15 (was 10, shifted by +5)