What exactly is Microsoft’s Project Reunion?

At last month’s Build 2020 conference, Microsoft announced Project Reunion, which outlines how it can be used to build a unified Windows application that better breaks down the barriers between Win32 (the Windows API) and the Universal Windows Platform (UWP) API. But many developers don’t know what it does and what it can do. As a result, Microsoft recently updated a document for Project Reunion in more detail.

What exactly is Microsoft's Project Reunion?

According to Microsoft’s recent introduction, “Project Reunion is a set of libraries, frameworks, components, and tools that you can use in your applications to experience powerful Windows platform capabilities from a variety of applications.” Project Reunion combines the capabilities of Win32 native applications with modern API usage techniques, so these applications can be used on different Windows platforms. “

From this point of view, developers don’t need to rewrite their apps if they want to publish their apps to different Windows platforms, through Project Reunion. Project Reunion automatically adapts to the preferred application model and deployment mechanism.

Project Reunion’s functionality is divided into three main categories — new APIs, aggregation APIs, and a subset of APIs. Developers can use each of the different levels of functionality as they need.

Currently, the components already in Project Reunion include:

WinUI 3 for XAML leverages XAML’s capabilities to help developers build smooth UX for a variety of applications.

The local projection of the language of the custom type is provided by the C?/WinRT, the C?/WinRT, making it easier for C?/Rust/C?developers to invoke the Windows API and make it easier to build a variety of Windows apps and components in their familiar languages.

MSIX-Core is used to package applications to distribute to Windows desktop computers through the store or through their own delivery pipeline.

Microsoft says there are many more components in the plan, such as:

Edge/Chromium-enabled WebView2 brings with it the convenience of writing applications in HTML-JS at once and reusing them across all platforms.

Modern Lifecycle helpers make applications more sensitive to power consumption and react to changes in power consumption management and user state in runtime systems.

Startup Tasks lets applications start working without overusing resources, or are ready to be active when you’re ready to use them quickly.

Update Scan Integration helps keep your applications up-to-date while performing with other system maintenance tasks.

As Project Reunion evolves, it will provide functionality that will not be limited to merging existing Win32 and UWP models, but will provide additional functionality for all applications to use.

Project Reunion is completely open source, and Microsoft says it wants to rely on the power of the community to better grow it.