Katvan

A bare-bones graphical editor for Typst files, with a strong bias for Right-to-Left editing.

Screenshot

Motivation

For University, I have a need to write documents that are mainly in Hebrew but also heavily incorporate math and inline English terms. For me, any solution is preferably offline, efficient to write (i.e. does not require building equations by selecting parts from a toolbar) and runs on Linux natively. I ran across Typst, a typesetting system which ticks all of these boxes and has very good BiDi support right out of the box, which makes it very attractive.

The question is now which text editor to use with it? Typesetting input files are a bit weird in that they are source code, but primarily consist of natural language. When that language is written from right to left, code editors typically don't display that too well - even if the final result looks good, it is hard to write and harder to edit. Even the better ones don't align different parts to their natural order. Plain text editors tend to be better, but lack many conveniences that make working on source nicer.

Therefore Katvan is a new editor application, with a very specific focus on this particular use case; starting with a plain text editor that gets the basics right (at least for me), and goes from there.

Features

Not a whole lot so far, but for now we have:

• Reasonably good RTL editing
  • Mostly thanks the Qt Rich Text Framework
  • But also specific additional functionality, for example:
    • Toggling between logical and visual cursor movement
    • Manually flipping paragraph direction (using both Windows style Ctrl+RShift/LShift, or Firefox style Ctrl+Shift+X)
    • Handy commands to insert BiDi control marks and isolates for when the algorithm doesn't quite lead to the right result (e.g. for inline math)
• Live-ish previews¹
• Syntax highlighting
• Syntax-aware spell checking
• Supported on Linux and Windows 10/11

Installation

Regardless of how Katvan is installed, it is required to install the typst CLI and make it available via the system path or by placing it next to the katvan executable. Without it previews and PDF export will not work. See here for details.

Linux

A pre-built AppImage for the x86_64 architecture is available from the project releases page. If it isn't suitable, you'll need to compile from source. Note that it contains the spell checker library, but not any dictionaries; install any required hunspell dictionaries system-wide from your distribution's repositories.

Windows

A build for 64-bit Windows 10/11 is available from the project releases page. Note that this is a portable build, which will store settings and the personal dictionary file in the same directory as the main executable, so make sure to extract the archive in a writable location. To write settings to the registry instead, run the katvan.exe binary with the --no-portable flag.

This build does not include spell checking dictionaries. You'll need to download hunsepll dictionaries for any desired languages (as a pair of .dic and .aff files), and save them to the hunspell sub-directory next to the main executable file. See the hunspell README page for locations to get dictionaries from.

From Source

To compile and install Katvan from source code, you'll need:

• A C++ compiler toolchain that supports C++20, and is supported by Qt
• Development files for Qt 6.5 (or a later 6.x release)
• CMake 3.16 or later
• A working pkg-config
• hunspell
• GoogleTest (optional, for running unit tests)

Get those from your distribution repositories, vcpkg, or wherever.

To build, perform a usual CMake invocation. For example, on Linux this might look like:

  mkdir build
  cmake -S . -B build -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local
  cmake --build build
  sudo cmake --build build -t install

Contributing

Contributions aren't really expected. Issues and PRs in Github are open to create, but please don't expect much. This exists to scratch my personal need, and made available in hope it is useful for others with similar needs.

License

GPL v3

Roadmap

A few things I'd like and may happen at some point, in no particular order:

• Ability to view BiDi control characters
• Better integration with typst (incremental previews, highlight errors)
• Editor configuration with modelines
• Dark theme support

Footnotes

1. Previews are currently rendered by running the entire file through the Typst CLI after each change. It is plenty fast at least for smaller documents, so good enough for now. ↩