Zettlr [ˈset·lər]

A Markdown Editor for the 21^st century.

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With Zettlr, writing professional texts is easy and motivating: Whether you are a college student, a researcher, a journalist, or an author — Zettlr has the right tools for you. Watch the video or continue reading to see what they are!

Visit our Website.

Features

• Available in over a dozen languages
• Tight and ever-growing integration with your favourite reference manager (such as Zotero or JabRef)
• Cite with Zettlr using citeproc and your existing literature database
• Five themes and dark mode support
• File-agnostic writing: Enjoy full control over your own files
• Keep all your notes and texts in one place — searchable and accessible
• Code highlighting for many languages
• Simple and beautiful exports with Pandoc, LaTeX, and Textbundle
• Support for state of the art knowledge management techniques (Zettelkasten)
• A revolutionary search algorithm with integrated heatmap

… and the best is: Zettlr is Open Source (FOSS)!

Installation

To install Zettlr, just download the latest release for your operating system! Currently supported are macOS, Windows, and most Linux distributions (via Debian- and Fedora-packages as well as AppImages).

All other platforms that Electron supports are supported as well, but you will need to build the app yourself for this to work.

Please also consider becoming a patron or making a one-time donation!

Getting Started

After you have installed Zettlr, head over to our documentation to get to know Zettlr. Refer to the Quick Start Guide, if you prefer to use software heads-on.

Contributing

Zettlr is an Electron-based app, so to start developing, you'll need to have:

1. A NodeJS-stack installed on your computer. Make sure it's at least Node 14 (lts/fermium). To test what version you have, run node -v.
2. Yarn installed. Yarn is the required package manager for the project, as we do not commit package-lock.json-files and many commands require yarn. You can install this globally using npm install -g yarn or Homebrew, if you are on macOS.

Then, simply clone the repository and install the dependencies on your local computer:

$ git clone https://github.com/Zettlr/Zettlr.git
$ cd Zettlr
$ yarn install --frozen-lockfile

The --frozen-lockfile flag ensures that yarn will stick to the versions as listed in the yarn.lock and not attempt to update them.

During development, hot module reloading is active so that you can edit the renderer's code easily and hit F5 after the changes have been compiled by electron-forge. You can keep the developer tools open to see when HMR has finished loading your changes.

What Should I Know To Contribute Code?

In order to provide code, you should have basic familiarity with the following topics and/or manuals (ordered by importance descending):

• JavaScript (especially asynchronous code) and TypeScript
• Node.js
• Electron
• Vue.js (2.x) and Vuex
• CodeMirror (5.x)
• ESLint
• LESS
• Webpack 5.x
• Electron forge
• Electron builder

Note: See the "Directory Structure" section below to get an idea of how Zettlr specifically works.

Development Commands

This section lists all available commands that you can use during application development. These are defined within the package.json and can be run from the command line by prefixing them with yarn. Run them from within the base directory of the repository.

start

Starts electron-forge, which will build the application and launch it in development mode. This will use the normal settings, so if you use Zettlr on the same computer in production, it will use the same configuration files as the regular application. This means: be careful when breaking things. In that case, it's better to use test-gui.

package

Packages the application, but not bundle it into an installer. Without any suffix, this command will package the application for your current platform and architecture. To create specific packages (may require running on the corresponding platform), the following suffixes are available:

• package:mac-x64 (Intel-based Macs)
• package:mac-arm (Apple Silicon-based Macs)
• package:win-x64 (Intel-based Windows)
• package:win-arm (ARM-based Windows)
• package:linux-x64 (Intel-based Linux)
• package:linux-arm (ARM-based Linux)

The resulting application packages are stored in ./out.

release:{platform-arch}

Packages the application and then bundles it into an installer for the corresponding platform and architecture. To create such a bundle (may require running on the corresponding platform), one of the following values for {platform-arch} is required:

• release:mac-x64 (Intel-based Macs)
• release:mac-arm (Apple Silicon-based Macs)
• release:win-x64 (Intel-based Windows)
• release:win-arm (ARM-based Windows)
• release:linux-x64 (Intel-based Linux)
• release:linux-arm (ARM-based Linux)

The resulting setup bundles are stored in ./release.

Please note that, while you can package directly for your platform without any suffix, for creating a release specifying the platform is required as electron-builder would otherwise include the development-dependencies in the app.asar, resulting in a bloated application.

lang:refresh

This downloads the four default translations of the application from Zettlr Translate, with which it is shipped by default. It places the files in the static/lang-directory. Currently, the default languages are: German (Germany), English (USA), English (UK), and French (France).

Please note, that this command is intended for an automated workflow that runs from time to time on the repository to perform this action. This means: Do not commit updated files to the repository. Instead, the updated files will be downloaded whenever you git fetch.

csl:refresh

This downloads the Citation Style Language (CSL) files with which the application is shipped, and places them in the static/csl-locales- and static/csl-styles-directories respectively.

Please note, that this command is intended for an automated workflow that runs from time to time on the repository to perform this action. This means: Do not commit updated files to the repository. Instead, the updated files will be downloaded whenever you git fetch.

lint

This simply runs ESLint. Apps such as Atom or Visual Studio Code will automatically run ESLint in the background, but if you want to be extra-safe, make sure to run this command prior to submitting a Pull Request.

This command will run automatically on each Pull Request to check your code for inconsistencies.

reveal:build

This re-compiles the source-files needed by the exporter for building reveal.js-presentations. Due to the nature of how Pandoc creates such presentations, Zettlr needs to modify the output by Pandoc, which is why these files need to be pre-compiled.

Please note, that this command is intended for an automated workflow that runs from time to time on the repository to perform this action. This means: Do not commit updated files to the repository. Instead, the updated files will be downloaded whenever you git fetch.

test

This runs the unit tests in the directory ./test. Make sure to run this command prior to submitting a Pull Request, as this will be run every time you commit to the PR, and this way you can make sure that your changes don't break any tests, making the whole PR-process easier.

test-gui

Use this command to carefree test any changes you make to the application. This command will start the application as if you ran yarn start, but will provide a custom configuration and a custom directory.

The first time you start this command, pass the --clean-flag to copy a bunch of test-files to your ./resources-directory, create a test-config.yml in your project root, and start the application with this clean configuration. Then, you can adapt the test-config.yml to your liking (so that certain settings which you would otherwise always set will be pre-set without you having to open the preferences).

Whenever you want to reset the test directory to its initial state (or you removed the directory, or cloned the whole project anew), pass the flag --clean to the command in order to create or reset the directory. This is also necessary if you changed something in test-config.yml.

You can pass additional command-line switches such as --clear-cache to this command as well. They will be passed to the child process.

Attention: Before first running the command, you must run it with the --clean-flag to create the directory in the first place!

Additionally, have a look at our full development documentation.

Directory Structure

Zettlr is a mature app that has amassed hundreds of directories over the course of its development. Since it is hard to contribute to an application without any guidance, we have compiled a short description of the directories with how they interrelate.

.
├── resources                      # Contains resource files
│   ├── NSIS                       # Images for the Windows installer
│   ├── icons                      # Icons used to build the application
│   ├── screenshots                # The screenshots used in this README file
├── scripts                        # Scripts that are run by the CI and some YARN commands
│   ├── assets                     # Asset files used by some scripts
│   └── test-gui                   # Test files used by `yarn test-gui`
├── source                         # Contains the actual source code for the app
│   ├── app                        # Contains service providers and the boot/shutdown routines
│   ├── common                     # Common files used by several or all renderer processes
│   │   ├── fonts                  # Contains the font files (note: location will likely change)
│   │   ├── img                    # Currently unused image files
│   │   ├── less                   # Contains the themes (note: location will likely change)
│   │   ├── modules                # Contains renderer modules
│   │   │   ├── markdown-editor    # The central CodeMirror markdown editor
│   │   │   ├── preload            # Electron preload files
│   │   │   └── window-register    # Run by every renderer during setup
│   │   ├── util                   # A collection of utility functions
│   │   └── vue                    # Contains Vue components used by the graphical interface
│   ├── main                       # Contains code for the main process
│   │   ├── assets                 # Static files (note: location will likely change)
│   │   ├── commands               # Commands that perform user-actions, run from within zettlr.ts
│   │   └── modules                # Main process modules
│   │       ├── document-manager   # The document manager handles all open files
│   │       ├── export             # The exporter converts Markdown files into other formats
│   │       ├── fsal               # The File System Abstraction Layer provides the file tree
│   │       ├── import             # The importer converts other formats into Markdown files
│   │       └── window-manager     # The window manager manages all application windows
│   ├── win-about                  # Code for the About window
│   ├── win-custom-css             # Code for the Custom CSS window
│   ├── win-defaults               # Code for the defaults file editor
│   ├── win-error                  # The error modal window
│   ├── win-log-viewer             # Displays the running logs from the app
│   ├── win-main                   # The main window
│   ├── win-paste-image            # The modal displayed when pasting an image
│   ├── win-preferences            # The preferences window
│   ├── win-print                  # Code for the print and preview window
│   ├── win-quicklook              # Code for the Quicklook windows
│   ├── win-stats                  # Code for the general statistics window
│   ├── win-tag-manager            # Code for the tag manager
│   └── win-update                 # The dedicated update window
├── static                         # Contains static files, cf. the README-file in there
└── test                           # Unit tests

On the Distinction between Modules and Service Providers

You'll notice that Zettlr contains both "modules" and "service providers". The difference between the two is simple: Service providers run in the main process and are completely autonomous while providing functionality to the app as a whole. Modules, on the other hand, provide functionality that must be triggered by user actions (e.g. the exporter and the importer).

The Application Lifecycle

Whenever you run Zettlr, the following steps will be executed:

0. Execute source/main.ts
1. Environment check (source/app/lifecycle.ts::bootApplication)
2. Boot service providers (source/app/lifecycle.ts::bootApplication)
3. Boot main application (source/main/zettlr.ts)
4. Load the file tree and the documents
5. Show the main window

And when you shut down the app, the following steps will run:

1. Close all windows except the main window
2. Attempt to close the main window
3. Shutdown the main application (source/main/zettlr.ts::shutdown)
4. Shutdown the service providers (source/app/lifecycle.ts::shutdownApplication)
5. Exit the application

During development of the app (yarn start and yarn test-gui), the following steps will run:

1. Electron forge will compile the code for the main process and each renderer process separately (since these are separate processes), using TypeScript and webpack to compile and transpile.
2. Electron forge will put that code into the directory .webpack, replacing the constants you can find in the "create"-methods of the window manager with the appropriate entry points.
3. Electron forge will start a few development servers to provide hot module reloading (HMR) and then actually start the application.

Whenever the app is built, the following steps will run:

1. Electron forge will perform steps 1 and 2 above, but instead of running the app, it will package the resulting code into a functional app package.
2. Electron builder will then take these pre-built packages and wrap them in a platform-specific installer (DMG-files, Windows installer, or Linux packages).

Electron forge will put the packaged applications into the directory ./out while Electron builder will put the installers into the directory ./release.

Command-Line Switches

The Zettlr binary features a few command line switches that you can make use of for different purposes.

--clear-cache

This will direct the File System Abstraction Layer to fully clear its cache on boot. This can be used to mitigate issues regarding changes in the code base. To ensure compatibility with any changes to the information stored in the cache, the cache is also automatically cleared when the version field in your config.json does not match the one in the package.json, which means that, as long as you do not explicitly set the version-field in your test-config.yml, the cache will always be cleared on each run when you type yarn test-gui.

--data-dir=path

Use this switch to specify custom data directory, which holds your configuration files. Without this switch data directory defaults to %AppData%/Zettlr (on Windows 10), ~/.config/Zettlr (on Linux), etc. The path can be absolute or relative. Basis for the relative path will be either the binary's directory (when running a packaged app) or the repository root directory (when running an app that is not packaged). If the path contains spaces, do not forget to escape it in quotes. ~ to denote home directory does not work. Due to the bug in Electron an empty Dictionaries subdirectory is created in the default data directory, but it does not impact functionality.

--disable-hardware-acceleration

This switch causes Zettlr to disable hardware acceleration, which could be necessary in certain setups. For more information on why this flag was added, see issue #2127.

VSCode Extension Recommendations

This repository makes use of Visual Studio Code's recommended extensions feature. This means: If you use VS Code and open the repository for the first time, VS Code will tell you that the repository recommends to install a handful of extensions. These extensions are recommended if you work with Zettlr and will make contributing much easier. The recommendations are specified in the file .vscode/extensions.json.

Since installing extensions is sometimes a matter of taste, we have added short descriptions for each recommended extension within that file to explain why we recommend it. This way you can make your own decision whether or not you want to install any of these extensions (for example, the SVG extension is not necessary if you do not work with the SVG files provided in the repository).

If you choose not to install all of the recommended extensions at once (which we recommend), VS Code will show you the recommendations in the extensions sidebar so you can first decide which of the ones you'd like to install and then manually install those you'd like to have.

Using the same extensions as the core developer team will make the code generally more consistent since you will have the same visual feedback.

License

This software is licensed via the GNU GPL v3-License.

The brand (including name, icons and everything Zettlr can be identified with) is excluded and all rights reserved. If you want to fork Zettlr to develop another app, feel free but please change name and icons. Read about the logo usage.