xbanan

A portable X11 compatibility layer. There are 2 officially supported platforms: banan-os's native GUI windowing system and SDL3.

Running on linux

Prerequisites

You need to have SDL3 development library and X11 headers installed on your system.

Building

git clone --recursive https://git.bananymous.com/Bananymous/xbanan.git
cd xbanan

cmake -B build -S . -DPLATFORM=SDL3
cmake --build build --parallel $(nproc)

Running

To start xbanan, run the following command in project root

./build/xbanan/xbanan

To run X11 apps, specify DISPLAY=:69 environment variable. For example

DISPLAY=:69 xeyes

Porting to a new platform

Add your platform to the VALID_PLATFORMS list in the root CMakeLists.txt file. Create a directory for your platform in xbanan/<your platform> and define the needed source files and libraries in xbanan/CMakeLists.txt based on your platform.

Barebones

For the simplest port, you need to implement 3 functions: initialize, create_window and invalidate. Define the variable g_platform_ops declared in xbanan/Platform.h with function pointers to the your functions. You can look at the existing platforms and the xbanan/Platform.h header for help.

Events

To handle events, you have to hook an event receiver fd for your platform using register_event_fd declared in xbanan/Events.h and define the poll_events function in g_platform_ops. When the registered fd becomes readable, xbanan will call your platform's poll_events function. This function should drain all of the pending events and call appropriate on_*_event function declared in the events header. If your platform does not expose fd(s) that can be polled for events, you can do what the SDL3 port does and create an eventfd/pipe that gets signaled periodically.

Installation

To install xbanan to sysroot, just copy the build/xbanan/xbanan to the destination. xbanan is statically linked against the libraries from this repository so you don't have to care about those. DO NOT use the cmake's install target, as that installs banan-os libraries to the root of the sysroot. You also need to have the x11 misc fonts at FONT_PATH/misc in your sysroot if you want server side font support. The fonts are shipped (public domain) with xbanan, so you can just copy fonts/misc into FONT_PATH. You can specify the FONT_PATH with cmake using -DFONT_PATH=... when configuring.