An idiomatic Kotlin Multiplatform RTF reader and writer.

RtfParserKmp is a port of RTFParserKit by Jon Iles (Apache 2.0) — its proven, SAX-style Standard parser, re-homed into commonMain so it runs on the JVM, JS, WebAssembly, and every Kotlin/Native target with no platform code in the hot path. The parsing engine and the entire command dictionary are faithful translations of the original; the public API is reshaped to be idiomatic Kotlin (sealed event types, listener interfaces with default methods, a dependency-free byte source).

Acknowledgement. This library is a derivative work of RTFParserKit, © 2013 Jon Iles, used under the Apache License 2.0. See NOTICE. New code is © 2026 The RtfParserKmp contributors.

Each module publishes as its own Maven artifact under the group com.darkrockstudios, so you depend only on what you use.

A non-published sample-cli (Kotlin/Native) demonstrates the stack end to end. rtf-compose targets the Compose-supported subset (JVM, Android, wasmJs, iOS, macOS); the other modules cover the full matrix.

dependencies {
    implementation("com.darkrockstudios:rtf-reader:0.1.0")
    implementation("com.darkrockstudios:rtf-writer:0.1.0")        // optional, for export
    implementation("com.darkrockstudios:rtf-io-kotlinx:0.1.0")    // optional, for streaming I/O
}

JVM · Android · JS (IR, browser + node) · wasmJs · wasmWasi · iOS (x64/arm64/simulatorArm64) · macOS (x64/arm64) · tvOS · watchOS · Linux (x64/arm64) · Windows (mingwX64).

Core parsing — including \uN Unicode, all single-byte codepages (Windows-125x, CP437/850/874, Mac Roman and friends), and UTF-8 — runs identically on every target with zero platform code.

import com.darkrockstudios.libs.rtfparserkmp.parser.parseRtf
import com.darkrockstudios.libs.rtfparserkmp.converter.extractPlainText
import com.darkrockstudios.libs.rtfparserkmp.converter.convertToMarkdown

val bytes: ByteArray = /* your .rtf */
val text: String = extractPlainText(bytes)
val markdown: String = convertToMarkdown(bytes)

// Or drive the event stream yourself:
for (event in parseRtf(bytes)) { /* RtfEvent.Text, .Command, GroupStart, ... */ }

Implement RtfListener (every method has a no-op default) for streaming, or when over the sealed RtfEvent from parseRtf.

import com.darkrockstudios.libs.rtfparserkmp.writer.convertMarkdownToRtf
import com.darkrockstudios.libs.rtfparserkmp.writer.writeRtf
import com.darkrockstudios.libs.rtfparserkmp.model.*

val rtf: String = convertMarkdownToRtf("This is **bold** and _italic_.")

// Or from the styled-text model directly:
val doc = StyledDocument(listOf(Paragraph(listOf(TextRun("Hello", CharacterStyle(bold = true))))))
val rtf2: String = writeRtf(doc)

The writer emits 7-bit ASCII (non-ASCII as \uN), so it has no charset dependency and round-trips cleanly with the reader.

For authoring rich documents — fonts, colors, headings, page breaks, hyperlinks, bookmarks, and paragraph layout — build an RtfDocument and serialize it with RtfDocumentWriter. See Writing rich RTF.

import com.darkrockstudios.libs.rtfparserkmp.io.asRtfSource          // kotlinx-io or okio
import com.darkrockstudios.libs.rtfparserkmp.parser.StandardRtfParser

StandardRtfParser().parse(source.asRtfSource(), myListener)   // source: kotlinx-io Source / okio BufferedSource

import com.darkrockstudios.libs.rtfparserkmp.compose.rtfToAnnotatedString
import androidx.compose.foundation.text.BasicText

val styled: AnnotatedString = rtfToAnnotatedString(bytes)   // bold/italic/underline -> SpanStyle
// BasicText(styled)

val rtf: String = annotatedStringToRtf(styled)             // and back the other way

rtfcli <input> [--text | --markdown | --rtf] [-o <out>]

.rtf input → --text (default) or --markdown; .md input → --rtf.

The 22 real-world .rtf fixtures from upstream (Word, LibreOffice, Pages, encodings, \upr, negative Unicode, …) are embedded and compared byte-for-byte against their expected event dumps — green on JVM, and on every target for the single-byte/UTF-8 subset. CI runs the suite across Linux, macOS, and Windows runners.

• Legacy multibyte CJK (codepages 932/936/949/950 via \'xx) decodes on JVM, Android, JS, wasmJs, and all Apple targets (web via TextDecoder, Apple via CFString). Only the remaining native targets — Linux, Windows (mingw), and wasmWasi — throw for those legacy bytes. \uN Unicode (what modern Word/LibreOffice/Pages emit) and all single-byte codepages work on every target.

Apache License 2.0 — see LICENSE and NOTICE.