GNOME Sushi Updated with GTK4 Support and Dark Mode

The file previewer “Sushi,” integrated into GNOME Files (Nautilus), has finally made the transition to GTK4, which had been in the works for a long time. According to a report by Phoronix on June 6, 2026, this update is part of the GNOME 51 development cycle and includes numerous visual and functional enhancements, such as support for dark mode and the addition of floating toolbars.

What is Sushi?

Sushi is a lightweight tool in the GNOME desktop environment that allows users to preview files in Nautilus simply by pressing the spacebar. It supports a wide variety of file formats, including images, text, videos, audio, and PDFs, enabling users to quickly preview content without launching an application. Its design philosophy is similar to Quick Look in macOS, making it a popular feature among GNOME users.

With its migration to GTK4, Sushi can now benefit from the modern UI toolkit. Compared to GTK3, GTK4 offers improved rendering performance, more flexible CSS-based styling, and enhanced compatibility with Wayland. This transition aligns with the GNOME desktop’s broader evolution towards modernizing its components.

The Background and Significance of the GTK4

Migration

Since the stable release of GTK4 in 2020, it has gradually been adopted across GNOME’s core components. While major applications such as GNOME Text Editor (formerly gedit), GNOME Console, and Builder have already made the transition, Sushi is a relatively late addition to this migration. According to the Phoronix article, this long-awaited move was described as “finally,” reflecting the anticipation within the community.

The migration to GTK4 is not merely a change of toolkit; it also contributes to reducing GNOME’s overall maintenance burden. With GTK3 nearing the end of its support, minimizing the number of GTK3-based applications has been a priority for the GNOME development team. With Sushi’s transition, most components included in the GNOME 51 release are expected to be unified under GTK4.

Details of Dark Mode Support

One of the most noticeable changes for users in this update is the addition of dark mode support. Since GNOME 42, system-wide dark mode switching has been a standard feature, but some applications required individual adjustments. Sushi was one such application, but with the GTK4 migration, it now properly follows the system’s theme settings.

According to Phoronix, the GNOME OS Nightly build has been used to confirm the functionality, and the UI is rendered correctly in dark mode. The floating toolbar introduced in this update is also compatible with dark mode, ensuring good visibility.

Other Improvements

Beyond the adoption of GTK4 and dark mode, several other enhancements have been made. These include initial support for Blueprint and Glycin. Blueprint is GNOME’s UI design language, which simplifies application interface descriptions. Glycin, on the other hand, is an image processing library that enables more efficient image previews.

Additionally, the preview layouts for various file types have been redesigned, with notable improvements in how information is displayed for video and document previews. The floating toolbar replaces the previous fixed toolbar, appearing as an overlay on the preview area to maximize usable space.

These updates have been detailed in GNOME’s weekly newsletter, “This Week in GNOME.” Michael Larabel of Phoronix praised the improvements, stating, “GNOME Sushi has been significantly enhanced, offering a more comfortable preview experience.”

Sushi’s Role in the GNOME 51 Cycle

The current GNOME 51 development cycle began following the stable release of GNOME 50. While GNOME 50 focused on major UI overhauls, GNOME 51 emphasizes fine-tuning and performance optimization. The GTK4 migration of Sushi fits perfectly into this ongoing effort.

Although the official release date for GNOME 51 has not yet been announced, based on previous patterns, it is likely to arrive in the fall of 2026. By then, Sushi’s improvements are expected to be further refined.

Community Reactions

Phoronix’s article has received six comments so far, with many users expressing positive feedback. There is a particularly warm reception for the dark mode support, and some commenters have expressed anticipation for similar updates to other GNOME components now that Sushi’s GTK4 migration is complete.

On the other hand, attention is also focused on when these updates will be adopted in GNOME-based distributions such as Ubuntu 26.10. Given Ubuntu’s release cycle, it often does not immediately adopt the latest GNOME updates, raising questions about how Sushi’s improvements will influence the plans for a context-aware desktop in Ubuntu 26.10.

Editorial Perspective

At first glance, the Sushi update may seem like a minor change, but it serves as an important milestone in the evolution of the GNOME desktop. In the short term, the migration to GTK4 is likely to reduce Sushi’s maintenance costs and accelerate future feature additions. Furthermore, dark mode support enhances the overall cohesiveness of the desktop environment, helping GNOME differentiate itself from macOS and Windows. For users, particularly engineers working late hours, a consistent dark mode experience can significantly boost productivity.

In the long term, unifying all first-party GNOME applications under GTK4 will stabilize the platform for extension and theme developers. This will, in turn, enhance the overall health of the GNOME ecosystem and encourage the development of third-party applications. However, since Sushi’s migration to GTK4 lagged behind other components, attention must now shift to the progress of similar transitions for remaining applications such as GNOME Software and Evince. It is also worth monitoring how migrations will be managed for components relying on external dependencies, such as WebKitGTK, as the GNOME roadmap progresses.

References

• Phoronix: GNOME File Previewer Finally Switches To GTK4, Adds Dark Mode — Published on June 6, 2026
• Official GNOME Project Website (Related Information)