This week in SixtyFPS

8th of November 2021 to 14th of November 2021

Posted on November 15, 2021

SixtyFPS is a toolkit to efficiently develop fluid graphical user interfaces for any display: embedded devices and desktop applications. We support multiple programming languages, such as Rust, C++, and JavaScript. Find more information at or go straight to github at

SixtyFPS UI Library

De-Inlining Status Update

The de-inlining work has been integrated this week and the compiler will now produce de-inlined code by default with commit 61202c.

The environment variable SIXTYFPS_INLINING can be used to still force inlining in the compiler.

Here are some results of compiling the SixtyFPS Printer demo

C++ generated header sizeC++ binary sizeCompilation time
Before (all inlined) 1.4M 2.3M 40 seconds
Now (de-inlined) 852K 1.4M 21 seconds

Rust generated code sizeRust binary sizeCompilation time
Before (all inlined) 2.9M 6.9M 85 seconds
Now (de-inlined) 1.9M 6.4M 67 seconds

These numbers are all for a release build. The Compilation time is measured by the incremental time of just changing the .60 file.

The C++ binary is dynamically linked to the SixtyFPS library and reads its resources from disk. The rust binary on the other hand is statically linked to the SixtyFPS library and has its image resources baked into the binary. So the binary sizes are not directly comparable between the two languages.


  • Fix the maximization button in the window decoration when a window has a fixed size (PR #642, thanks @Aursen)

Improvements and Refactorings

  • Move more of the winit related code from PlatformWindow impl into WinitWindow (51469b)

    This will allow code sharing with the simulator in the future.

  • Make the GL backends' winit driven event loop a reusable module (3c0607)

    Abstract away the dependency to the former GraphicsWindow by

    (1) Renaming GraphicsWindow to GLWindow (2) Introducing a WinitWindow trait

  • Const propagation (a3adfd)

    Inline access to constant properties

  • Start doing some constant evaluation (de43f0)

    There was a warning in the C++ generated code in the tests: (in test_cpp_image_geometry)

    /tmp/AMWqZ.cpp:307:85: error: self-comparison always evaluates to true [-Werror,-Wtautological-compare]
    this->image_in_layout_fit_ok.set((sixtyfps::cbindgen_private::ImageFit::contain == sixtyfps::cbindgen_private::ImageFit::contain));

    Doing some simple evaluation prevent this warning at least

  • handle tab key-code in backend (PR #639, thanks @phi-gamma)

    Treating the Tab key as text disallows handling Shift-Tab because the shift modifier will not be passed down. This makes the handling of Tab analogous to Escape, Return and other non-text key-codes.


46 patches were committed by 4 authors.