rm

Documentation

Overview

Package rm provides primitives for encoding and decoding the .rm format which is a proprietary format created by Remarkable to store the data of a drawing made with the device.

Axel Huebl has made a great job of understanding this binary format and has written an excellent blog post that helped a lot for writting this package. https://plasma.ninja/blog/devices/remarkable/binary/format/2017/12/26/reMarkable-lines-file-format.html As well, he has its own implementation of this decoder in C++ at this repository. https://github.com/ax3l/lines-are-beautiful

To mention that the format has since evolve to a new version labeled as v3 in the header. This implementation is targeting this new version.

As Ben Johnson says, "In the Go standard library, we use the term encoding and marshaling for two separate but related ideas. An encoder in Go is an object that applies structure to a stream of bytes while marshaling refers to applying structure to bounded, in-memory bytes." https://medium.com/go-walkthrough/go-walkthrough-encoding-package-bc5e912232d

We will follow this convention and refer to marshaling for this encoder/decoder because we want to transform a .rm binary into a bounded in-memory representation of a .rm file.

To try to be as idiomatic as possible, this package implements the two following interfaces of the default encoding package (https://golang.org/pkg/encoding/).

• BinaryMarshaler
• BinaryUnmarshaler

The scope of this package is defined as just the encoding/decoding of the .rm format. It will only deal with bytes and not files (one must take care of unzipping the archive taken from the device, extracting and providing the content of .rm file as bytes).

This package won't be used for retrieving metadata or attached PDF, ePub files.

Index

• Constants
• type BrushColor
• type BrushSize
• type BrushType
• type Layer
• type Line
• type Point
• type Rm
  • func New() *Rm
  • func (rm *Rm) MarshalBinary() (data []byte, err error)
  • func (rm Rm) String() string
  • func (rm *Rm) UnmarshalBinary(data []byte) error
• type Version

Constants

const (
	HeaderV3  = "reMarkable .lines file, version=3          "
	HeaderV5  = "reMarkable .lines file, version=5          "
	HeaderLen = 43
)

Header starting a .rm binary file. This can help recognizing a .rm file.

const (
	Width  int = 1404
	Height int = 1872
)

Width and Height of the device in pixels.

Types

type BrushColor

type BrushColor uint32

BrushColor defines the 3 colors of the brush.

const (
	Black BrushColor = 0
	Grey  BrushColor = 1
	White BrushColor = 2
)

Mapping of the three colors.

type BrushSize

type BrushSize float32

BrushSize represents the base brush sizes.

const (
	Small  BrushSize = 1.875
	Medium BrushSize = 2.0
	Large  BrushSize = 2.125
)

3 different brush sizes are noticed.

type BrushType

type BrushType uint32

BrushType respresents the type of brush.

The different types of brush are explained here: https://blog.remarkable.com/how-to-find-your-perfect-writing-instrument-for-notetaking-on-remarkable-f53c8faeab77

const (
	BallPoint   BrushType = 2
	Marker      BrushType = 3
	Fineliner   BrushType = 4
	SharpPencil BrushType = 7
	TiltPencil  BrushType = 1
	Brush       BrushType = 0
	Highlighter BrushType = 5
	Eraser      BrushType = 6
	EraseArea   BrushType = 8

	// v5 brings new brush type IDs
	BallPointV5   BrushType = 15
	MarkerV5      BrushType = 16
	FinelinerV5   BrushType = 17
	SharpPencilV5 BrushType = 13
	TiltPencilV5  BrushType = 14
	BrushV5       BrushType = 12
	HighlighterV5 BrushType = 18
)

Mappings for brush types.

type Layer

type Layer struct {
	Lines []Line
}

A Layer contains lines.

type Line

type Line struct {
	BrushType  BrushType
	BrushColor BrushColor
	Padding    uint32
	Unknown    float32
	BrushSize  BrushSize
	Points     []Point
}

A Line is composed of points.

type Point

type Point struct {
	X         float32
	Y         float32
	Speed     float32
	Direction float32
	Width     float32
	Pressure  float32
}

A Point has coordinates.

type Rm

type Rm struct {
	Version Version
	Layers  []Layer
}

A Rm represents an entire .rm file and is composed of layers.

func New

func New() *Rm

New helps creating an empty Rm page. By mashaling an empty Rm page and exporting it to the device, we should generate an empty page as if it were created using the device itself. TODO

func (*Rm) MarshalBinary

func (rm *Rm) MarshalBinary() (data []byte, err error)

MarshalBinary implements encoding.MarshalBinary for transforming a Rm page into bytes TODO

func (Rm) String

func (rm Rm) String() string

String implements the fmt.Stringer interface The aim is to create a textual representation of a page as in the following image. https://plasma.ninja/blog/assets/reMarkable/2017_12_21_reMarkableAll.png TODO

func (*Rm) UnmarshalBinary

func (rm *Rm) UnmarshalBinary(data []byte) error

UnmarshalBinary implements encoding.UnmarshalBinary for transforming bytes into a Rm page

type Version

type Version int

Version defines the version number of a remarkable note.

const (
	V3 Version = iota
	V5
)