September 9, 2021 by Olivier Goffart and Simon Hausmann

SixtyFPS 0.1.2 Released

Today we're releasing SixtyFPS version 0.1.2, which contains important bug fixes and some new features. This blog post highlights some of theses new features since the last release, 0.1.1. This release maintains backwards source compatibility. Applications developed with previous releases in the 0.1.x series will continue to run with version 0.1.2.

SixtyFPS 0.1.2

API to access Global singletons

Structures in .60 markup can be instantiated as global singletons throughout your design. To make it easier to share data and callbacks between the UI design and your native code, you can now also access global singletons from Rust and C++. Use the export syntax in your entry point .60 file and the global() function on the main instance to get a reference. In the C++ and Rust interpreter APIs, globals are accessed by name, for example using set_global_property().

For example, consider this global in a .60 file:

export global Logic := {
    property <string> player-name;
    callback to-uppercase(string) -> string;

// ... more component that can use Logic ...

MyApplication := Window { /* ... */ }

It is possible to access the global singleton from native code in the following ways:

In Rust:

let app = MyApplication::new();<Logic>().set_player_name(
    |arg| arg.to_uppercase().into()

In C++:

auto app = MyApplication::create();
  [](std::string a) {
    std::transform(a.begin(), a.end(),
        a.begin(), toupper);
    return a;

For more information, check out the online Rust docs or C++ docs.

Multi-line Input

We're continuously improving our support for text input on desktop platforms. New in this release is a basic TextEdit widget, which supports multi-line text editing.

SixtyFPS Gallery TextEdit Screenshot

Semantic Syntax Highlighting

Our IDE integration, which includes Visual Studio Code, is backed by a Language Server Protocol process. In this release we've added Semantic highlighting to provide an even more refined coloring of .60 markup.

Without semantic highlighting:

Screenshot of .60 code shown in VS code with semantic highlighting off

With semantic highlighting:

Screenshot of .60 code shown in VS code with semantic highlighting on


We hope that you'll enjoy upgrading to this new version. If you're using SixtyFPS with Rust and Cargo, just run cargo update to update your application to the latest release. If you're using our CMake integration with FetchContent, update the GIT_TAG entry in your CMakeLists.txt to specify v0.1.2.

For a detailed list of all changes, check out the


Slint is a declarative GUI toolkit to build native user interfaces for desktop and embedded applications written in Rust, C++, or JavaScript. Find more information at or check out the source code at