GTK now has two new renderers called “ngl” and “vulkan” which are built from the same source, making them unified renderers. The advantage of these renderers is that they can share infrastructure and maintain both Vulkan and GL renderers easily. The unified renderer implementation is focused on correctness and maintainability and can handle more varied rendernode trees. The new renderers also bring new capabilities such as antialiasing, fractional scaling, arbitrary gradients, and dmabuf support. However, there are some potential issues to be aware of, such as the lack of support for glshader nodes and the possibility of unintended consequences with fractional positions. The new renderers are not faster than the old GL renderer yet, but they bring exciting features and correctness. The ngl renderer is now the new default, but the Vulkan renderer is not yet due to integration issues. The new renderers provide a foundation for future improvements such as proper color handling, path rendering on the GPU, and off-the-main-thread rendering. Users are encouraged to try out the new renderers and provide feedback.
https://blog.gtk.org/2024/01/28/new-renderers-for-gtk/