Book Image

Hands-On High Performance Programming with Qt 5

By : Marek Krajewski
5 (1)
Book Image

Hands-On High Performance Programming with Qt 5

5 (1)
By: Marek Krajewski

Overview of this book

Achieving efficient code through performance tuning is one of the key challenges faced by many programmers. This book looks at Qt programming from a performance perspective. You'll explore the performance problems encountered when using the Qt framework and means and ways to resolve them and optimize performance. The book highlights performance improvements and new features released in Qt 5.9, Qt 5.11, and 5.12 (LTE). You'll master general computer performance best practices and tools, which can help you identify the reasons behind low performance, and the most common performance pitfalls experienced when using the Qt framework. In the following chapters, you’ll explore multithreading and asynchronous programming with C++ and Qt and learn the importance and efficient use of data structures. You'll also get the opportunity to work through techniques such as memory management and design guidelines, which are essential to improve application performance. Comprehensive sections that cover all these concepts will prepare you for gaining hands-on experience of some of Qt's most exciting application fields - the mobile and embedded development domains. By the end of this book, you'll be ready to build Qt applications that are more efficient, concurrent, and performance-oriented in nature
Table of Contents (14 chapters)

Stalls when displaying widget with QML contents

This problem was already solved when I joined the project at hand, but it is a rather typical scenario, so we will have a look at it here.

Context

In one Qt 5 project, we had a rather complicated GUI displaying an image in several different processing stages. As is often the case in image-processing applications, the user could define a region of interest (ROI) typically a circle or a rectangle to restrict an image operation to some part of the image. The ROI was displayed over the image and could be interactively moved and resized.

The ROI was implemented in QML because of the ease with which moving and resizing could be programmed. It was embedded into the...