designcraft/docs/file-format-parity.md

File format parity

Last reviewed: 2026-10-10 · Last updated: 2026-10-15 · Change: minor (IDML liquid guide types, #872) · Target: Adobe InDesign 2026 (21.6)

Every format InDesign 2026 reads or writes, with DesignCraft's support, fidelity and tests. The InDesign list comes from its bundle's Info.plist (CFBundleDocumentTypes, UTExportedTypeDeclarations), its import/export filter folder names and its File menus; ours from the open/place/export filters in apps/designcraft/src/main.rs and the file.* commands. Overall numbers: target-app-parity.md; open problems: gaps.md.

Dimension score: ~40% ready (estimated), 150–250 h + 20–60 h for INDD integration. The single largest gap is that .indd can't be opened.

Read/Write: ✓ supported · ~ partial · ✗ missing · — InDesign doesn't either. Weight: what share of an InDesign professional's file traffic the format carries (used for the score below).

Documents and interchange

Format	Ext	InDesign	DesignCraft read	DesignCraft write	Fidelity / tests	Weight
InDesign document	.indd	read/write (native)	✗ (#21; converters proposed in #98, #114)	✗	—	30%
InDesign template	.indt	read/write	✗	✗	—	2%
InDesign Markup	.idml	read/write	✓	✓	Synthetic fixtures in crates/idml/src/tests.rs (49 tests); exported files verified by opening in InDesign 2026 by hand; indd-utils' 98-document run imports 811 spreads / 2,866 stories / 5,812 items. Open: #193, #338, #339, #340, #211. No real-file corpus test	20%
DesignCraft native	.designcraft	—	✓	✓	zip + JSON, versioned; round-trip tests. Asset loading and compaction index by content hash, then confirm byte equality; equal-sized distinct files no longer all share one search bucket (#727). Separate links, MIME types and PDF pages retain their identity	—
InDesign book	.indb	read/write	✗ (own .dcbook)	✗	Books are shallow (see gaps.md)	2%
InDesign library	.indl, .inlx	read/write	✗ (own .dclib)	✗		1%
Snippet	.idms	read/write	✗ (own snippets)	✗		1%
InCopy story / assignment	.icml, .icma, .incx, .inca	read/write	✗	✗	InCopy workflow out of scope; ICML story import would still help	1%
InDesign Interchange (legacy)	.inx	read	✗	—		<1%
PageMaker	.pmd, .p65, .t65, .pmt	read	✗	—		<1%
QuarkXPress	.qxd, .qxt	read (old versions)	✗ (#73)	—		<1%

IDML preserves stored page liquid rules and distinguishes liquid guides from ordinary ruler guides on document and parent pages. Guide positions, orientation, Fit to Page, lock state and layer survive interchange; literal XML and round-trip tests are in crates/idml/src/tests/liquid_guides.rs. Object liquid pins and resize constraints remain unmapped (#872); this is not full liquid-layout interchange support.

Output

Format	Ext	InDesign	DesignCraft	Fidelity / tests	Weight
PDF (print)	.pdf	✓ all presets, PDF/X-1a/3/4, PDF/A, PDF/UA	✓ krilla: real text with subset fonts, DeviceCMYK/RGB, spot Separations, bleed/slug, marks, spreads, compression options, remembered settings (#196); PDF/X-4 with output intent and a validator (#223, #200); PDF/A-2b; tagged PDF	53 tests in crates/pdf; no PDF/X-1a or X-3 (needs flattening to PDF 1.3/1.4); no presets / .joboptions; no external validator (veraPDF / callas) in CI	18%
PDF (interactive)	.pdf	✓	✓ links, bookmarks, buttons, AcroForm fields, page transitions, object states		2%
JPEG / PNG	.jpg, .png	✓	PNG from the UI; JPEG from the CLI only	no resolution / colour space options dialog for JPEG	3%
EPUB reflowable	.epub	✓	✓ stories in article order, tables, footnotes and endnotes, CSS from styles, images, nav		2%
EPUB fixed layout	.epub	✓ (live HTML/CSS)	~ page images with text kept for search	not live text	1%
HTML	.html	✓	~ one self-contained page (#314)		1%
HTML5 ZIP / Publish Online		✓	✗ (Publish Online out of scope)		<1%
SVG export	.svg	✓ (via plug-in)	✗		<1%
EPS export	.eps	✓	✗		<1%
Text Only / RTF / Tagged Text	.txt, .rtf	✓	✓ (file.exportText txt, rtf, tagged)		1%
XML	.xml	✓	✓ export and import, DTD validate	depth unmeasured	1%
Print / PostScript		✓ printers, PPDs, separations	~ PDF to CUPS/Windows (craft-print; no PostScript)		3%
Package	folder	✓ fonts, links, IDML, PDF, report	✓ (#340: IDML inside links to absolute paths)		2%

Placed and imported content

Format	Ext	InDesign	DesignCraft	Notes	Weight
PDF / AI (PDF-compatible)	.pdf, .ai	✓ page boxes, layers, pages	✓ rendered with hayro, embedded as vector in PDF export, crop to page boxes	layer visibility depth; editable vectors not offered (#227)	3%
JPEG, PNG, GIF, BMP, WebP		✓	✓	CMYK JPEG/TIFF keep inks in PDF (#35)	2%
TIFF	.tif	✓ incl. CMYK, alpha, indexed colour, paths	✓ incl. CMYK	clipping paths from 8BIM resources unverified	1%
PSD	.psd	✓ layers, comps, alpha, paths	~ composite + Object Layer Options	layer comps partial	1%
EPS	.eps	✓ (PostScript)	~ preview only (no interpreter)		<1%
SVG	.svg	✓	✓ (usvg)		<1%
HEIC	.heic	✓	✗		<1%
Word	.docx	✓ styles, footnotes, tables, track changes, options	✓ styles by name, footnotes, tables, tabs, breaks, moved text (#257), bullets and numbering from numbering.xml (#626; parent levels in a label are fixed text), style mapping and conflicts	.doc not supported (InDesign reads it)	2%
RTF	.rtf	✓	✓		<1%
Excel	.xlsx, .xls	✓	~ .xlsx first sheet's used range	no sheet/range options; .xls ✗	<1%
Plain text, Markdown	.txt, .md	✓ (txt)	✓		<1%
InDesign Tagged Text	.txt	✓	✓ import and export		<1%
CSV / TSV (Data Merge)		✓	✓ (+ Excel)		<1%
Audio / video	.mp4, .mp3, …	✓ placeholders for EPUB/PDF	~ placed as media objects	no in-app playback	<1%

Resources and settings

Format	Ext	InDesign	DesignCraft
Adobe Swatch Exchange	.ase	read/write	✓ load and save
Colour books	.acb	read (17 libraries ship)	✗ (licensed libraries; Pantone etc. out of scope, own libraries possible)
ICC profiles	.icc, .icm	read	✓
Colour settings	.csf	read/write	✗
PDF presets	.joboptions, .pdfs	read/write	✗
Print / flattener / document presets	.prst, .flst, .dcst	read/write	✗
Preflight profiles	.idpp	read/write	✗ (own profiles in the document)
Keyboard shortcut sets	.indk	read/write	✗ (own JSON)
User dictionary	.udc	read/write	✗ (own, in the document and prefs)
Fonts	OTF, TTF, TTC, variable	✓	✓ (Type 1 retired by both)

Score

Weighted by the Weight column (documents, output and placed tables; resources unweighted), counting ✓ = 1, ~ = 0.5, and IDML at 0.6 until a real-file corpus proves it: ~45% present. Taking fidelity into account (no INDD, IDML unproven, PDF/X-1a and presets missing), ~40% ready for real work (estimated). INDD alone moves this dimension by up to 30 points.

Remaining effort

Work	Opus 5.5 h
INDD import via a clean-room converter (owner decision, #114)	20–60
IDML real-file corpus, metric, fixes (#193, #338, #339, #340)	60–100
PDF/X-1a and X-3 (transparency flattener), PDF presets and .joboptions, external validator	40–70
Print fidelity, PostScript level 3 output and print presets	25–45
ICML story import, IDMS snippets, INDT templates (once INDD reads)	15–25
HTML / fixed-layout EPUB with live text	20–35
JPEG export dialog, SVG export, EPS export	10–20
Total	190–355 (150–250 excluding INDD and PostScript output)

Revision history

Date	Change	Summary
2026-10-15	minor	IDML retains liquid versus ruler guide types on document and parent pages, with literal XML and mixed-guide round-trip coverage; object liquid constraints remain unsupported (#872)
2026-10-13	minor	Asset loading and compaction use content fingerprints with exact equality checks; tests cover equal-sized distinct buffers, shared copies, independent links and missing data (#727)
2026-10-10	major	Created from InDesign 2026's declared document types and filters, plan/indesign/08-file-formats.md and the code