Phantom

A multi-tab Markdown editor with live preview

Build

Dependencies:

• Qt6
• Qt6-webengine
• cmark-gfm
• CMake (build only)
• ImageMagick (Windows-build only)

Build instructions:

Clone the repository

git clone --recurse-submodules https://codeberg.org/ItsZariep/Phantom
cd Phantom

Build/Install

Linux

• Build

cmake -B build-linux  -DCMAKE_BUILD_TYPE=Release
cmake --build build-linux -- -j$(nproc)

• Install

cmake --install build-linux

• Windows (MinGW)

cmake -G Ninja -B build-windows -DWITH_QTWEBENGINE=OFF

MSVC is untested, but it should be able to build with Qt WebEngine

Packaging

dpkg/rpm packagers can use:

cpack -G DEB --config build/CPackConfig.cmake # or -G RPM 

Why?

Most Markdown editors I’ve used only allow opening a single file per application instance. This becomes inefficient when working with multiple documents, as each instance consumes a significant amount of system resources.

Phantom solves this problem by supporting multiple tabs and using a shared preview widget, keeping memory usage low even with the more demanding QtWebEngine backend.

So, even with 100+ files opened, Phantom will likely use less than 500MB, or less than 1GB with 1000+ files opened (Extreme: not recommended) cases.

Preview Backends

Phantom supports two preview rendering backends:

• QTextEdit

  • Lightweight and fast
  • Minimal resource usage
  • Limited Markdown feature support

• QtWebEngine

  • Heavier and slower
  • Much better Markdown compatibility
  • Utilizes cmark-gfm for rendering

Backend Switching

Only one backend can be active at a time: Users must restart Phantom when switching backends.

This limitation avoids using unnecessary ram since only one backend is loaded to memory.

QtWebEngine can consume up to 300% more memory than QTextEdit.

Why the Name “Phantom”?

Before developing Phantom, my preferred Markdown editor was KDE Ghostwriter. Phantom is a direct reference to that.