CXX-Qt - Getting Started

In comparison to other Qt-Rust-bindings, CXX-Qt does not aim to simply expose Qt functionality to Rust, but rather to completely integrate Rust into the Qt ecosystem.

In this guide we'll go through a minimal example that uses CXX-Qt to create your own QObject in Rust and integrate it with a small QML-based GUI.

Prerequisites

This guide won't be able to explain everything to you, but it will try its best to make sure everyone can follow along. However, there are a few things you should be familiar with before reading this guide. It may be confusing otherwise!

Firstly, you should be familiar with Rust. There are many great resources for learning Rust, like the book.

As CXX-Qt aims to integrate Rust into the existing Qt ecosystem, you should have basic knowledge of Qt and QML. If you're not familiar with Qt/QML yet, take a look at the Qt Getting started guide or the QML intro respectively.

CXX-Qt (as the name suggests) is built on top of CXX. You should have a basic idea of how CXX works before attempting to follow this guide. Take a look at the CXX documentation here: https://cxx.rs/

Installation

You'll need to have the following tools installed:

⚠️ It is vital that the qmake executable can be found by CXX-Qt. On Windows, you may have to manually add it to your PATH in order for this to work automatically.

To check that qmake can indeed be found, run:

$ qmake --version
QMake version 3.1
Using Qt version 6.5.1 in /usr/lib64

If you don't want to add QMAKE to your path you can always provide Cargo with the right path by using the QMAKE environment variable.
e.g.: QMAKE=/usr/bin/qmake cargo build

We unfortunately cannot list every way to install these tools on all platforms. Please make sure you have installed the right toolchains before following this guide!

What this guide covers

During this getting started guide we'll first take a look at how CXX-Qt integrates with Qt's object system to allow the definition of QObjects in Rust. Then we'll dive straight into practice and define our first QObject in Rust. Followed by actually defining our GUI using QML.

We will show two different ways to build the project. First we will build the CXX-Qt code as a Rust executable without requiring a C++ build system. Additionally, we will show how to integrate CXX-Qt into a C++ application by building with CMake.

📝 Note: CXX-Qt is tested on CI on Linux, Windows, and macOS (all on x86_64). wasm32 is compiled, but not tested on CI. It should work on other platforms that Qt and Rust both support, however, these are not tested regularly.

So, without further ado - let's Get Started