Skribidi

Skribidi is nimble bidirectional text stack for building UIs.

Features

• bidirectional text layout
• bidirectional text editing
• font collections with CSS inspired font selection
• color emojis
• line breaking
• text attributes
  • size, weight, style, stretch, letter spacing, word spacing, line spacing, baseline align, horizontal align)
• icons
  • PicoSVG or procedural
• glyph, emoji and icon rasterization
  • color, SDF and alpha
• render cache with image atlas for glyphs and icons
• layout cache for immediate mode use
• lean dependencies

Motivation

Text rendering is hard, text editing is hard too, font selection is hard, text alignment is hard. Everything text related is hard, and messy, and full of nuances.

If you wanted to have bidirection text display and input for you project, there are not many options. There are a lot of great projects that cover parts of the text stack, but there's still a huge amount of work left to piece things together. A lot of the wisdom is scattered all over old browser bugs, blogs that might not exists anymore, or bits of code scattered all over the world.

Many text stacks are part of larger projects, like browsers or game engines, or have licenses that are not permissive, or require huge dependecies.

Skribidi tries to solve the text stack for UIs without dragging in large dependencies. Text layout, text input, and font rasterization, with features that you'd expect to build an UI.

Skribidi leans heavily on Harfbuzz for text shaping and accessing font data, SheenBidi for bidirectional segmentation, libunibreak for grapheme and linebreak detection, and budouxc for East Asian word boundary detection. All permissively licensed and quite lean dependencies.

Status

Skribidi just got started. There are bugs and the API is very likely to change.

Building

• Install CMake
• Ensure CMake is in the user PATH
• mkdir build
• cd build
• Generate the build files:
  • cmake ..
• Compile:
  • Windows: Open and build build/skribidi.sln
  • Linux: use cmake --build . -j$(nproc)
  • macOS: use cmake --build . -j$(sysctl -n hw.ncpu)

When running the example or test, the working directory should be the build binary directory (/build/bin). On Windows, the example data direction is copied there and on Linux or macOS there's a symlink for the data directory.

When generating the build files, you can provide options to using the -D flag (for example cmake .. -D SKRIBIDI_UNIT_TESTS=OFF). Skribidi provides a number of options:

• BUILD_SHARED_LIBS determines whether Skribidi and it's dependencies are built as a static library or as a shared library. This is disabled by default, producing a static library.

• SKRIBIDI_LIBRARY_TYPE is the library type to build only Skribidi as and doesn't effect Skribidi's dependencies. It must be a valid CMake library type. Set it to STATIC to build as a static library, SHARED to build as a shared library, or OBJECT to build as a CMake object library.

• SKRIBIDI_EXAMPLE determines whether the examples are built along with the library. Disabled by default when Skribidi is build as a subproject of a larger CMake project.

• SKRIBIDI_UNIT_TESTS determines whether the unit tests are build along with the library. Disabled by default when Skribidi is build as a subproject of a larger CMake project.

Dependencies

The project uses CMake, but you dont need to. If you handle dependecies yourself you can just add the include and src to your project and you're good to go. If you are using Skdribidi as a shared library, you must define SKB_DLL, otherwise it must not be defined. The CMake is used to fetch the right deps and to build the examples and tests, making development simpler.

• Harfbuzz - 11.0.0
• SheenBidi - 83f77108a2873600283f6da4b326a2dca7a3a7a6
• libunibreak - libunibreak_6_1.zip
• budouxc - a044d49afc654117fac7623fff15bec15943270c

License

Skribidi is developed by Mikko Mononen and uses the MIT license.

Similar or Related Projects

• Pango (C)
• Cosmic Text (Rust)
• Harfbuzz
• SheenBidi
• libunibreak
• budouxc

Example fonts

The examples use following fonts:

• IBM Plex Sans (Latin, Arabic, Devanagari, Hebrew, Japanese, Korean)
• Noto (Bengali, Brahmi, Tamil, Thai, Balinese)
• Noto Color Emoji
• OpenMoji