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MDI

Android / Kotlin

The Android binding is an AAR-shaped Kotlin interface over a small JNI façade. It passes complete UTF-8 source directly to mdi-core; Android code does not tokenize Markdown or MDI, repair delimiter fallback, or render document semantics.

Contract

Section titled “Contract”
  • minSdk is 23 and the library compiles against API 36. The consuming app owns its target SDK (API 36 for current Google Play submissions).
  • arm64-v8a is provided for devices and x86_64 for emulators. Android v1 deliberately excludes 32-bit ARM.
  • parse, HTML, canonical MDI serialization, TXT, EPUB, and DOCX delegate to Rust. EPUB and DOCX return ByteArray; apps write those bytes with the Storage Access Framework.
  • Parse results reject unsupported IR versions and preserve diagnostics and UTF-8 byte spans.
  • Kotlin unit coverage has an enforced 90% line threshold; the acceptance command generates its JaCoCo XML and HTML reports before running device tests.
  • PDF is not an Android API. The Rust PDF path requires an executable Chromium process; Android apps should display Rust HTML in a WebView or use Android’s print framework instead.
val result = Mdi.parse("{東京|とうきょう}で第^12^話を読む。")
val html = Mdi.renderHtml("# 題\n\n{東京|とうきょう}")

See android/README.md for local Rust target setup, native-library generation, and the acceptance command.

Automatic warichu layout

Section titled “Automatic warichu layout”

Rust is the only splitting implementation. Layout uses two lines at half the body font size with zero line gap. The first fragment can use remaining body-line capacity; later fragments use full capacity. Capacity and widths are half-em units at note size, using character-width estimates rather than exact proportional-font balancing.

val fragments = Mdi.layoutWarichuJson(
    """[{"type":"text","value":"一二三四五六"}]""", capacity = 4, firstCapacity = 2)

Results include lines, html, widths, overflow, hardBreakAfter and sources. Source paths are child indices relative to the input array; startUtf8 and endUtf8 are half-open byte offsets in visible leaf text. Indivisible group IDs keep clusters across formatting boundaries together. Ruby, tcy and no-break stay whole. Hard breaks are retained; automatic splits do not change canonical MDI or plain text. Static HTML/EPUB readers may reflow differently. DOCX uses native combination groups; XML and importer checks are not a claim of Microsoft Word rendering tests.

Editorial comments in MDI 2.1

Section titled “Editorial comments in MDI 2.1”
Mdi.parse(source, includeComments = true)

MDI 2.1 recognizes <!-- note --> in all documents, including declared 2.0 and unversioned source. Comments can be empty, multiline or Unicode; the nearest --> closes them and their contents are not interpreted. Code, front matter, link destinations and plain-text MDI parameters remain literal. Escape an opener as \<!--.

Source saving retains comments. Default parse/prepare/mdast APIs omit them with IR 1.0; { includeComments: true } returns positional comment nodes and IR 1.1. Both report syntax 2.1. Existing front-matter declarations are retained. Public body projections and layout exclude comments even with an inclusive tree, and their source-map runs preserve the gaps.

Every publication format always omits valid comments. This intentionally changes old 2.0 output that displayed them as HTML text. Unterminated comments remain literal and return mdi.comment.unterminated: export is allowed, so intended private text may be visible.

Use source serialization or an inclusive IR for lossless comment retention. A filtered external IR cannot restore omitted comments.

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