Flinger of widgets adds a digit: Qt 5.15 completes 5.x series

After a slight postponement, version 5.15 of C++ GUI building library Qt is now available. The long-term support release especially looks to improve the graphics side of the project, revamping the underlying graphics stack and finally fully supporting Qt Quick 3D.

Not much has changed since the first alpha, which came out in February, but for those who haven’t given it a try already, here’s a reminder of what the new version has in store for cross-platform app developers.

Since Qt 5.15 was often described as a stepping stone to Qt 6, a major release supposed to land later this year, most of the additions to this release provide some sort of foundation for the big 6.0. Like the opt-in new graphics stack, that comes with a new abstraction layer to work with 3D graphics APIs that have popped up to replace OpenGL and Direct 3D. Qt Rendering Hardware Interface is said to let devs run Qt Quick applications on Metal and Vulkan in addition to the older interfaces. For now, it can be enabled through an environment variable before it becomes the norm in Qt 6.

Works on supporting Qt Quick 3D, a tool to let users quickly integrate 3D content into their Qt projects, have also continued, so that devs now have access to APIs for quaternion-based rotations and custom geometries, and a slew of post processing effects. 

The Qt modeling language has meanwhile been extended with the concept of required properties, which users have to set for components, and a way to specify components inline in a QML file. Devs having trouble adhering to Qt’s QML coding style guidelines can now make use of a qmlformat tool to get their code into shape.

The release goes along with updates to Qt Design Studio and Qt Quick. Quick now comes with a PathText element for its shapes and a cursorShape property to style the mouse cursor on desktop systems, while Design Studio’s outstanding features seem to be a 3D editor, a docking system for workspace customisation, item annotation and an editor for application flows.

Qt 5.15 is the last of the Qt 5 series and a LTS release, meaning commercial users will receive bug fixes for the next three years. Speaking of which, support for Qt 5.9, a LTS release which came out in May 2017, will end on Sunday. Qt chief maintainer Lars Knoll therefore used the announcement to point out again that updating to the new LTS version should be relatively easy, though extended support seems to be available for those willing to pay for it.