KDAB TV – Recent Videos KDAB's YouTube Channel: Qt, C++ and 3D tutorials, news and more

Qt Container in Qt 5 and Qt 6 - QVarLengthArray

QVarLengthArray is a container class with interesting semantics, not found in any container from the Standard Library. Like an array, it stores elements contiguously in memory. Like a vector, it has dynamic size. But unlike a vector, it does not necessarily store them in heap-allocated memory.

How does it work then? Well, watch the video to learn more!

All Qt Container in Qt 5 and Qt 6 videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6jrZFWcB1HK5cJ_nvViBuRu

All Qt Widgets and More videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

About the host:
Giuseppe is a senior software engineer and trainer at KDAB. He has almost two decades of Qt experience, and has contributed to Qt since the very beginning of the Qt project. He regularly presents at Qt and C++ conferences.

Every month our newsletter is featuring technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing, and innovative software across embedded, mobile, and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D, and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL, and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK, and the USA. https://www.kdab.com/about/contact/

8 1

KDAB News 09/10 - Interview about codebrowser.dev; Qt Insight Beta; CXX-Qt 0.4.0 released and more

Welcome to KDAB News, the monthly update for developers working with Qt, C++ and 3D technologies.

In this edition, we have:

0:00 Intro
0:33 10 years of Meeting C++
0:55 codebrowser.dev
1:37 Interview with Miłosz Kosobucki (KDAB) about codebrowser.dev
7:42 CXX-Qt 0.4.0 released
8:38 Qt Insight Beta
9:18 Announcements
10:02 Ressources

**

Here you find all the links mentioned in the news:

Meeting C++ website
http://meetingcpp.com/

codebrowser.dev website
https://codebrowser.dev/

Release of CXX-Qt 0.4.0
https://www.kdab.com/cxx-qt-0-4/
https://github.com/kdab/cxx-qt/releases/tag/v0.4.0

Qt Insight Beta
https://www.qt.io/blog/introducing-qt-insight-beta-program

Announcements
https://cpponsea.uk/
https://www.kdab.com/software-services/scheduled-training/schedule/

Ressources
https://www.youtube.com/watch?v=5GegZvv4fOM

9 0

Qt Container in Qt 5 and Qt 6 - Qt Containers or Standard Library Containers?

A question that always comes up when working with Qt is: "Should I be using Qt containers, or should I be using the Standard Library containers?".

The answer to this question is not easy, because it's not merely a binary choice. It's not just about the feature set: ease to use, convenience, familiarity, interoperability all play a role.

In this video I'll try to illustrate pros and cons of Qt containers versus the Standard Library ones, and let you make an informed decision.

I mention Hyrum's law: all observable properties of an API, whether documented or not, will eventually be relied upon by someone. You can read more about it here https://www.hyrumslaw.com/ . This is what makes changing behavior of low-level classes a somewhat scary affair.

All Qt Container in Qt 5 and Qt 6 videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6jrZFWcB1HK5cJ_nvViBuRu

All Qt Widgets and More videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

About the host:
Giuseppe is a senior software engineer and trainer at KDAB. He has almost two decades of Qt experience, and has contributed to Qt since the very beginning of the Qt project. He regularly presents at Qt and C++ conferences.

Every month our newsletter is featuring technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing, and innovative software across embedded, mobile, and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D, and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL, and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK, and the USA. https://www.kdab.com/about/contact/

15 0

Qt Container in Qt 5 and Qt 6 - Associative Containers: QMap, QHash

In this episode we'll talk about associative containers: containers that map arbitrary keys to values.

What are the ones that are provided by Qt? Are there differences between their Qt 5 versions and their Qt 6 versions? Which one should one pick for a given use case? No spoilers – watch until the end (Lächeln)

In the video, we mention a couple of blog posts about how to implement hashing functions. Here they are:
https://www.kdab.com/how-to-declare-a-qhash-overload/
https://www.kdab.com/qt-6-1-stdhash-support/

All Qt Container in Qt 5 and Qt 6 videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6jrZFWcB1HK5cJ_nvViBuRu

All Qt Widgets and More videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

About the host:
Giuseppe is a senior software engineer and trainer at KDAB. He has almost two decades of Qt experience, and has contributed to Qt since the very beginning of the Qt project. He regularly presents at Qt and C++ conferences.

Every month our newsletter is featuring technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing, and innovative software across embedded, mobile, and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D, and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL, and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK, and the USA. https://www.kdab.com/about/contact/

16 2

Qt Container in Qt 5 and Qt 6 - Sequence Containers: QList and QVector

In this video we discuss the two most used Qt containers: QList and QVector. How do they work? Are they similar to the std counterparts? What has changed in Qt 6 regarding them?

Links:
* Interview to watch in advance to this episode: https://www.youtube.com/watch?v=-CM45D0QBfc

All Qt Container in Qt 5 and Qt 6 videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6jrZFWcB1HK5cJ_nvViBuRu

All Qt Widgets and More videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

About the host:
Giuseppe is a senior software engineer and trainer at KDAB. He has almost two decades of Qt experience, and has contributed to Qt since the very beginning of the Qt project. He regularly presents at Qt and C++ conferences.

Every month our newsletter is featuring technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing, and innovative software across embedded, mobile, and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D, and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL, and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK, and the USA. https://www.kdab.com/about/contact/

19 1

Qt Container in Qt 5 and Qt 6 - Implicit Sharing

All Qt containers have a specific feature: they are "implicitly shared", also known as "copy on write". What does that mean exactly? What are the advantages for developers who use these containers? Are there any downsides?

This video will (hopefully) answer all of your questions!

Links:
* Video about the 'but' syndrome: "The LED Traffic Light and the Danger of "But Sometimes!"": https://www.youtube.com/watch?v=GiYO1TObNz8
* QWAM episode and interview about "Understanding qAsConst / std::as_const": https://www.youtube.com/watch?v=-CM45D0QBfc
* Video about "Clazy - An open source Clang plugin allowing it to understand Qt semantics": https://www.youtube.com/watch?v=vXhWbP0vfzw&list=PL6CJYn40gN6jVzEv9MCklItl4tfqjQTQ7
* GitHub link to Clazy: https://github.com/KDE/clazy

All Qt Container in Qt 5 and Qt 6 videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6jrZFWcB1HK5cJ_nvViBuRu

All Qt Widgets and More videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

About the host:
Giuseppe is a senior software engineer and trainer at KDAB. He has almost two decades of Qt experience, and has contributed to Qt since the very beginning of the Qt project. He regularly presents at Qt and C++ conferences.

Every month our newsletter is featuring technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing, and innovative software across embedded, mobile, and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D, and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL, and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK, and the USA. https://www.kdab.com/about/contact/

21 8

KDAB News 08/2022 – Interview with New Qt Chief Maintainer Volker Hilsheimer; Qt WS 2022 and more

Welcome to KDAB News, the monthly update for developers working with Qt, C++ and 3D technologies.

In this edition, we have:

0:00 Intro
0:30 News new feature
0:50 Interview with new Qt Chief Maintainer Volker Hilsheimer
12:25 Qt World Summit 2022
13:14 Tip of the month
15:00 Announcements

**

Here you find all the links mentioned in the news:

Qt World Summit 2022
https://www.qt.io/qtws_2022

Tip of the month
https://www.kdab.com/c-cpp-debugging-tools/
Sign up now for our newsletter https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

Announcements
https://meetingcpp.com/2022/
https://br.qtcon.org

8 0

Qt Container in Qt 5 and Qt 6 - Introduction and Common Features

What's a container? Maybe you know them under another name (collections, sequences, ...): they are data structures that can hold (arbitrary) amounts of data. Think about lists, associative arrays (maps), and so on. For various reasons, detailed in these videos, Qt ships with its own family of containers, even if you're using Qt with a language (C++, Python) that also has them!

So what are the features of Qt containers? Should you use them? How are they different from the ones coming from the C++ Standard Library? Have the Qt containers changed between Qt 5 and Qt 6? This video series will give answers to these questions.

"Who cares about containers, anyways?" That's a fair point; one may as well answer: "everybody!". Any non-trivial application needs to use some container to hold data. Maybe most of the time a developer won't care about picking a specific one... except in the cases where they do, and then the knowledge that these videos will provide will be useful 🙂

This first video acts as an introduction to the whole series. We will discuss what are the history and the common features of the Qt containers.

All Qt Container in Qt 5 and Qt 6 videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6jrZFWcB1HK5cJ_nvViBuRu

All Qt Widgets and More videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

About the host:
Giuseppe is a senior software engineer and trainer at KDAB. He has almost two decades of Qt experience, and has contributed to Qt since the very beginning of the Qt project. He regularly presents at Qt and C++ conferences.

Every month our newsletter is featuring technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing, and innovative software across embedded, mobile, and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D, and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL, and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK, and the USA. https://www.kdab.com/about/contact/

34 1

From One Man's Vision for His Kids to Global Teaching Aid: The Story of GCompris

In this video for our 'Insights' series, we talk to Bruno Coudoin, the creator and founder of GCompris software, about what inspired him and how GCompris became so successful.

GCompris is a free and open source, high quality, educational software suite for kids aged 2 – 10, that’s built with Qt.

00:00 Intro
00:50 What inspired you to get started on GCompris? What was the point?
02:20 Why did you make GCompris open source from the start?
03:46 Was all the development made in your spare time?
04:11 Did you get some help from your family?
07:12 Why was the gauge in the submarine activity added?
07:40 What were the biggest challenges along the way?
13:00 How can a new Contributor get started?
15:00 Why did you end up handing over the project?
16:21 How does it feel now to see full country governments making GCompris part of their school curriculum?

Link to download GCompris: https://gcompris.net/downloads-en.html

About the host:
Currently working as a Software Architect in his home town of Toulouse, Bruno Coudoin is the creator and was the main developer on GCompris, an open source educational software suite with numerous Activities for children aged 2 - 10 years old.

More about GCompris:
GCompris is a free and open source, high quality, educational software suite for kids aged 2 – 10, that’s built with Qt.

It was originally written in C and Python using the GTK+ widget toolkit, but a rewrite in C++ and QML using the Qt widget toolkit was initiated by Bruno Coudoin in 2014.

GCompris is used as a teaching aid worldwide. It is available in multiple languages and has global users estimated to be in the millions. With its multiple datasets, GCompris Activities can be adjusted to fit pupil’s learning needs, and fitted into their existing lesson plans, individually or in groups.

Aside from its benefit as an addition to any teaching curriculum, GCompris is proven to be especially helpful for children with learning difficulties or neurological differences. Its content is non violent, quieter, and free from distractions like pop-ups or advertisements. It has also been designed to be non-addictive. https://gcompris.net/index-en.html

These days, GCompris is a project under the umbrella of KDE, a long-term partner of KDAB.

GCompris Contributor’s site wiki: https://gcompris.net/wiki/New_contributor

Patreon donation site for GCompris: https://gcompris.net/donate-en.html

GTK: https://www.gtk.org/

Gnome: https://www.gnome.org/get-involved/

Python: https://www.python.org/

Google Summer of Code: https://summerofcode.withgoogle.com/

About KDE:
KDE is an international community supporting the cooperative development and distribution of Free, Open Source Software for desktop and portable computing: https://kde.org/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing, and innovative software across embedded, mobile, and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D, and more: https://www.kdab.com/software-services

Keep in touch with KDAB developments by signing up for our monthly newsletter featuring news and technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL, and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK, and the USA. https://www.kdab.com/about/contact/

25 2

Checking for Regression via Screenshots

When you make larger changes to your code base, you likely want to validate there are no side effects.

Unit testing the complete code base is of course the golden standard, but somewhat unrealistic in most cases.
The next best is a comprehensive set of Squish test cases, but when you are about to make a large change to your application, your focus might likely not be towards building that.

A solution that comes from the box "better than nothing" is to run your original and modified applications side by side and comparing them.
For that I create a small application which makes it easy to take a screenshot of each and compares them.

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv/tree/master/Qt-Widgets-and-more/screenshot-comparison

All QML tips and tricks videos : https://www.youtube.com/playlist?list=PL6CJYn40gN6jWHP5krsQrVGyYtKh3A3be

All Qt Widgets and more videos:
https://www.youtube.com/playlist?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

About the host:
The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

Every month our newsletter is featuring technical blogs on Qt, C++ and 3D topics: https://www.kdab.com/development-resources/sign-up-for-our-newsletter/

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrolment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

6 0