OpenRenderBox

OpenRenderBox is an open source implementation of Apple's Private framework - RenderBox.

RenderBox is a high performance rendering engine written in C++.

And it powers the underlying rendering of SwiftUI.

The project is for the following purposes:

• Add RB support for non-Apple platform (eg. Linux, WASI and Windows)
• Diagnose and debug RB issues on Apple platform

Currently, this project is in early development.

Build

The current suggested toolchain to build the project is Swift 6.3.3 / Xcode 26.6.

Shims

The OpenRenderBoxShims product provides Swift aliases and a C header for path APIs. Swift clients use:

import OpenRenderBoxShims

C, C++, and Objective-C clients use:

#include <OpenRenderBoxShims/OpenRenderBoxShims.h>

The C module is OpenRenderBoxShimsCxx; its public header uses the product name.

The package selects the public header directory for the configured backend. Clients use ORB names with either backend and do not need to define OPENRENDERBOX_RENDERBOX in their preprocessor settings.

Supported platforms

CI Status

License

See LICENSE file - MIT