.RM V6 Support #392

joagonca · 2025-10-29T14:10:22Z

Supports rendering reMarkable v6 files w/ colour and all pen types, including text.
Rendering is supported in Go, using go-cairo to produce the PDF contents (implementation in this library: https://github.com/joagonca/rmc-go). Highly based on rmscene, with added functionality (like colour support).
Ability to export/download to PDF the .RM file.
[CAVEAT] For now it only supports rendering the first page.

Trying to address issue #255 .

baflo · 2025-10-31T10:59:13Z

Awesome work @joagonca 🥳
However, am I doing something wrong? It always shows just one page and it's not deterministic which one is rendered...

joagonca · 2025-10-31T11:04:55Z

Thanks!
That is correct, it's a limitation of the current integration. There is already support for a multipage render on the library, but I wanted to keep this initial PR simple (just v6 support).

The "randomness", I intend to fix that, and support all pages in a subsequent PR. The rmc-go library already exports the multipage PDF using the .content files from reMarkable, in the correct order.

joagonca · 2025-11-03T10:42:24Z

It should now support multipage rendering in the correct order.
Still one caveat: some pages might appear cropped (I'm calculating the PDF page size based on the first .rm file).

@baflo

baflo · 2025-11-03T11:24:12Z

@joagonca I actually came up with a solution myself, too. I looks quite similar to yours, but it stitches the single pages together with unipdf, so all pages maintain their original size. Maybe it is of help to you:

baflo@15de3ca#diff-fc741d1c044272840de20d525e88fb8068c4737e42703b589317c2f981502d12

joagonca · 2025-11-03T11:33:38Z

@baflo Nice one. For the sake of this PR, it might make more sense to go with yours, as it provides best functionality out of the box.

For the final one, I might ditch go-cairo and go with unipdf in the library. That way the whole packaging will use just one Go PDF renderer, and we'd remove the cgo requirement.

Thoughts?

baflo · 2025-11-03T12:29:41Z

Sound good to me ;)

@ddvk what do you think?

Copilot

Pull Request Overview

This PR adds native support for reMarkable v6 file format (introduced in software 3.0+) to rmfakecloud. The implementation integrates the rmc-go library with Cairo renderer to enable in-process rendering of v6 files without external dependencies.

Key changes:

Added version detection logic to differentiate between v3/v5/v6 .rm file formats
Integrated rmc-go library for native v6 file rendering using Cairo
Updated document export paths to route v5 files to rmapi and v6 files to rmc-go

Reviewed Changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
internal/storage/models/archive.go	Modified to detect and store v6 page data separately in V6PageData map instead of attempting to parse with rmapi
internal/storage/fs/documents.go	Added version detection and routing logic to use rmc-go for v6 files and rmapi for v5 files
internal/storage/fs/blobstore.go	Implemented v6 blob export path with direct .rm file extraction and rmc-go rendering
internal/storage/exporter/version.go	New file with version detection logic for .rm files
internal/storage/exporter/version_test.go	Comprehensive tests for version detection functionality
internal/storage/exporter/rmc_go.go	New file with wrapper functions for rmc-go library PDF/SVG export
internal/storage/exporter/myarchive.go	Added V6PageData field to store raw v6 page bytes
internal/config/config.go	Updated help text to document v6 support and formatting fix
go.mod	Added rmc-go dependency and upgraded Go version to 1.25.1
go.sum	Updated with new dependencies (rmc-go and go-cairo)
README.md	Added comprehensive v6 support documentation
Makefile	Added build-cairo targets for building with Cairo support
Dockerfile	Updated to include Cairo dependencies for v6 rendering

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Copilot · 2025-11-03T12:34:17Z

internal/storage/fs/blobstore.go

+	if len(arch.Pages) == 0 {
+		return exporter.VersionUnknown, fmt.Errorf("no pages in archive")
+	}
+
+	// Try to marshal first page and detect from header
+	if arch.Pages[0].Data != nil {
+		data, err := arch.Pages[0].Data.MarshalBinary()
+		if err != nil {
+			return exporter.VersionUnknown, fmt.Errorf("failed to marshal page data: %w", err)
+		}
+		return exporter.DetectRmVersion(bytes.NewReader(data))
+	}
+
+	return exporter.VersionUnknown, fmt.Errorf("no page data available")


The function 'detectBlobArchiveVersion' is identical to 'detectArchiveVersion' in documents.go (lines 227-243). This is duplicated code. Consider extracting this to a shared utility function or moving it to the exporter package to avoid duplication.

Suggested change

if len(arch.Pages) == 0 {

return exporter.VersionUnknown, fmt.Errorf("no pages in archive")

}

// Try to marshal first page and detect from header

if arch.Pages[0].Data != nil {

data, err := arch.Pages[0].Data.MarshalBinary()

if err != nil {

return exporter.VersionUnknown, fmt.Errorf("failed to marshal page data: %w", err)

}

return exporter.DetectRmVersion(bytes.NewReader(data))

}

return exporter.VersionUnknown, fmt.Errorf("no page data available")

return exporter.DetectArchiveVersionFromMyArchive(arch)

Copilot · 2025-11-03T12:34:17Z

README.md

+
+### Known Limitations
+
+- Multi-page v6 documents: Currently exports first page only


The documentation states 'Multi-page v6 documents: Currently exports first page only' in Known Limitations, but the code in documents.go (lines 122-127) and blobstore.go (lines 194-212) clearly iterates through all pages and uses ExportV6MultiPageToPdfNative to export all pages. This limitation appears to be incorrect or outdated.

Suggested change

- Multi-page v6 documents: Currently exports first page only

- Multi-page v6 documents: Fully supported

Copilot · 2025-11-03T12:34:18Z

internal/storage/fs/documents.go

+			for i := 0; i < len(arch.V6PageData); i++ {
+				if data, ok := arch.V6PageData[i]; ok {
+					pages = append(pages, data)
+				}
+			}


This loop assumes that V6PageData keys are sequential from 0 to len(V6PageData)-1, but if there are gaps in the page indices (e.g., missing page 2 in a 5-page document), the loop will still iterate 5 times but may skip entries. This could result in pages being collected out of order or missing pages. Consider using a sorted iteration over the map keys instead.

internal/storage/fs/documents.go

ddvk · 2025-11-03T12:38:35Z

nice work!

unipdf is no longer agpl and has to be removed

joagonca · 2025-11-03T13:00:03Z

Hmm, if that's the case, we might be better off trying to fix it using current go-cairo implementation. I can take that task on the library side. Then see if updating the package here fixes the issue.

Moreover, I'll address the comments made by co-pilot.

joagonca · 2025-11-03T15:51:48Z

I've bumped the rmc-go library to v1.1.1 which already supports multi-size multi-page PDF rendering using go-cairo. I think I've also addressed the co-pilot comments.

rmitchellscott · 2025-11-10T19:03:56Z

A quick look seems to indicate that this also will support CRDT IDs needed for the handwriting search branch I'm working on 👍

internal/storage/fs/documents.go

ericchianti · 2025-12-19T04:46:28Z

Do we have an estimate on how long is left on this PR before it gets merged? I am so thrilled for this ticket I check several times a week.

baflo · 2026-01-06T09:54:38Z

@ddvk I would like to help rectify any problems that still exist with this PR. Would you give me a hint what's missing so this can be merged?

ddvk · 2026-01-06T09:55:44Z

just the merge conflicts i guess

joagonca · 2026-01-06T09:57:11Z

This is held back by the unipdf PR. It breaks some stuff.

…

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On Tuesday, 01/06/26 at 09:56 ddvk ***@***.***> wrote: ddvk left a comment [(ddvk/rmfakecloud#392)](#392 (comment)) just the merge conflicts i guess — Reply to this email directly, [view it on GitHub](#392 (comment)), or [unsubscribe](https://github.com/notifications/unsubscribe-auth/AB35UWQ6S4M4HPSY2GEER7T4FOBDLAVCNFSM6AAAAACKR2C6VGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTOMJUGAYTANJTHA). You are receiving this because you were mentioned.Message ID: ***@***.***>

joagonca added 9 commits September 30, 2025 15:32

Added support to v6 format using external rmc tool

c40a7e1

Prior detection of format

262f700

Added debug logging lines

7092b5a

Updated Dockerfile to add Python packages

3183b7a

Merge branch 'ddvk:master' into v6_rmc

fb6a3a4

Implemented support for rmc-go library

558e4bb

Removed Python legacy code

d160991

Removed implementation details files

3cc43ec

Mod tidy

1c1cac4

joagonca mentioned this pull request Oct 29, 2025

.RM V6 Support #255

Open

joagonca added 2 commits November 3, 2025 10:31

Multipage v6 support

5886605

Fix page ordering

732bd9e

ddvk requested a review from Copilot November 3, 2025 12:31

Copilot AI reviewed Nov 3, 2025

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github-advanced-security bot found potential problems Nov 3, 2025

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joagonca added 2 commits November 3, 2025 15:34

Bump rmc-go to v1.1.1

326d317

Addressing PR comments

88fc73c

github-advanced-security bot found potential problems Nov 16, 2025

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internal/storage/fs/documents.go Dismissed Show dismissed Hide dismissed

internal/storage/fs/documents.go Dismissed Show dismissed Hide dismissed

internal/storage/fs/documents.go Dismissed Show dismissed Hide dismissed

internal/storage/fs/documents.go Dismissed Show dismissed Hide dismissed

ddvk self-assigned this Nov 16, 2025

joagonca mentioned this pull request Dec 17, 2025

Removes the unipdf and rmapi library dependencies #403

Draft


		### Known Limitations

		- Multi-page v6 documents: Currently exports first page only

	- Multi-page v6 documents: Currently exports first page only
	- Multi-page v6 documents: Fully supported

.RM V6 Support #392

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.RM V6 Support #392

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