The last post from my colleague Marc Mutz about deprecating Q_FOREACH caused quite an uproar amongst the Qt developers who follow this blog. I personally feel that this was caused fundamentally by a perceived threat: there is a cost associated to porting away a codebase from a well-known construct (Q_FOREACH) to a new and yet-undiscovered […]

In this article, I will take a look at one of the fundamental concepts introduced in Alex Stepanov and Paul McJones’ seminal book "Elements of Programming" (EoP for short) — that of a (Semi-)Regular Type and Partially-Formed State. Using these, I shall try to derive rules for C++ implementations of what are commonly called "value […]

Android Things is Google’s answer to creating an environment for IoT devices. Take a slimmed down Android build, add some sensor-specific APIs, and provide it on a number of powerful pre-integrated micro-boards and you have a ready-made platform for building a host of upcoming IoT devices. Android Things can take advantage of many existing Android […]

On December 1st, KDAB’s Kévin Ottens and David Faure co-hosted a one day Meet Qt in Lyons, with The Qt Company and Witekio. The event was booked out with 50 people attending, confirming the growing community of Qt users in France. Participants were given plenty of opportunities for questions throughout the day and much appreciated […]

Functional Safety is the term used for systems designed to minimize risk to human health. But there’s a dilemma in today’s tech-driven world. We are more reliant than ever on software to control our planes, trains, cars, and boats, to operate our medical equipment, to process our food, to clean our water, and to power […]

For today's blog I would like to share with you the little adventure I had when fixing a very strange bug in Qt. Pop quiz Don't think about this too much, just guess: what does this QML snippet print? There are no JavaScript semantic tricks involved; and using either == or === does not change […]

GammaRay is a high-level runtime introspection tool for Qt applications. In this talk we will look at a number of real-world debugging and profiling problems and how the capabilities provided by GammaRay help you with those. When creating applications we strive to use higher-level frameworks to obtain results quickly and reduce development effort and long-term […]

This talk introduces you to the fundamentals of threading in Qt. We will discuss how threads, QObjects and events interact together; how a thread affinity of a QObject has a play in signals and slots connections; and how you can leverage the modern C++11 threading capabilities in your Qt application. Cross-platform thread support was introduced […]

This talk will introduce you to various effective strategies of drawing raw OpenGL content inside a Qt Quick 2 scene. After a brief introduction to how the Qt Quick 2 renderer works, we will see the APIs in Qt 5.6 that allow us to integrate existing OpenGL code and QML. One of the foundation pillars […]

Are you a Qt developer and do you use Linux as your development platform of choice? Then this talk is for you: I will introduce you to perf, the Linux tool suite for performance analysis. The talk will not only cover a broad part of what perf has to offer, it will also dive into […]

Qt Quick and QML provide an easy way to rapidly develop customized, reusable components entirely within QML. As these components grow in complexity, performance and maintainability often suffer, a drawback that is especially noticeable on low-powered embedded and mobile devices. In addition, some specialized components simply cannot be implemented by combining existing Qt Quick items […]

Having 3D scenes in your application is becoming a clear trend and is likely to become even more important in the future with the growth of Virtual Reality and Augmented Reality. So far Qt was allowing you to integrate with Open GL fairly easily, but managing the rendering code itself was still a very challenging […]

Using OpenGL code with Qt is a long love story... long enough that there might be skeletons in the closet. Indeed, the OpenGL code of your Qt application could have been written before the modernization of the OpenGL API to exploit better GPUs. In this talk, we will walk through a technique to help refactor […]

A retrospective on the KDE community from 20 years ago and how things were done back then, with an emphasis on community spirit and fun facts. Over time, the KDE community has seen many people join and leave, as with any open source community, which means that very few people in the current community still […]

The past year was very important for the KDE PIM community. We released the first Qt5-based version, restructured our code base and set ourselves more ambitious goals. Let's look a bit deeper into some of the important changes that have happened in KDE PIM in the past year, and peak a little into the future. […]

In this session we'll see real life examples of using JNI on Android. We'll start by checking the Qt 5.7 goodies which will make our lives easier, then we'll see simple examples that you'll need to use in almost any Qt on Android application, and we'll end up with an Android Service made with Qt. […]

Physics Based Rendering (PBR) is the latest and greatest trend in real-time rendering yielding much more visually believable images than the traditional Phong or ad-hoc lighting models. The underlying concept is that the shaders should use physical principles in the encoded models - chief of which are conservation of energy and the Fresnel effect. PBR […]

Many KDAB engineers are part of the Qt Security Team. The purpose of this team is to get notified of security-related issues, and then decide the best course of action for the Qt project. Most of the time, this implies identifying the problem, creating and submitting a patch through the usual Qt contribution process, waiting […]

Design, Technical Excellence and Superb User Experience Why does a tipper truck need an app? Meiller is the leading manufacturer of tippers in Europe. KDAB software developers and UI/UX designers worked with Meiller to create a mobile app that interacts with embedded hardware on the truck, allowing drivers to diagnose and fix problems - even […]

Quick: When you design C++ APIs, when and how should you use pair and tuple? The answer is as simple as it is surprising: Never. Ever. When we design APIs, we naturally strive for qualities such as readability, ease-of-use, and discoverability. Some C++ types are enablers in this regard: std::optional, std::variant, std::string_view/gsl::string_span, and, of course, […]