Paint.NET

Paint.NET palettes (.txt) contain eight-digit hexadecimal colour entries in AARRGGBB order, including alpha.

Details about the format can be found in the Paint.NET palette documentation.

API

Class	Description
PaintNetFormat	Singleton format for reading and writing palettes.
PaintNetFile	Palette file with typed components.
PaintNetColourEntry	Byte-backed colour entry.

Reading and Writing

using var input = File.OpenRead("palette.txt");
PaintNetFile file = PaintNetFormat.Instance.Read(input);

using var output = File.Create("output.txt");
file.Write(output);

Loading and saving preserves the original UTF-8 bytes, optional BOM, line endings and whitespace. Comments, ordering and duplicate colours are retained. Invalid UTF-8 and palettes without colour entries are rejected. The format also supports asynchronous I/O and compression; see Reading, Writing and Converting.

Components

Paint.NET has no required header. The ordered Lines collection retains every line, with colour lines represented by PaintNetColourEntry. Each entry exposes its decoded Colour, including alpha. Lines starting with ; are comments.

The model retains all actual entries without padding or truncation. Paint.NET's UI displays 96 slots, filling missing slots with white and ignoring additional colours; this UI behaviour is not applied to stored file data.

Entries exposes colour entries in palette order. Body lines expose their original Data, decoded Text and LineEnding. Palette derives a shared PaletteData view from the entries rather than storing an independent copy.

Creating Palettes

var palette = new PaletteData([new Colour(255, 0, 0), new Colour(0, 255, 0)]);
var file = new PaintNetFile(palette);
byte[] bytes = file.ToByteArray();

Constructors produce canonical UTF-8 without a BOM, using LF line endings. Creation retains alpha and writes uppercase hexadecimal entries, preceded by a ; Paint.NET Palette File comment.

Conversions

GplFile gpl = IOFileConversion.Convert<GplFile>(file);
JascFile jasc = IOFileConversion.Convert<JascFile>(file);

Conversions preserve colour values, order and duplicates without quantization. Comments and source-format metadata are not transferred; GPL output uses its constructor defaults. Conversion to GPL or JASC rejects non-opaque colours with ArgumentException rather than losing alpha. See Reading, Writing and Converting for the conversion API.