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KDAB News 06/2022 - Interview with KDE's Adam Szopa; Qt Creator 8; KDE Akademy; CppCon 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
0:27 KDE Goals and KDE Akademy - Interview with Adam Szopa
3:40 Qt Creator 8 released
4:54 Tip of the month - Android Shared Storage Qt Wrapper
6:09 Announcements

**

Here you find all the links mentioned in the news:

KDE Goals and KDE Akademy - Interview with Adam Szopa

KDE Goals announcement: https://dot.kde.org/2022/06/23/submit-goal-and-help-shape-future-kde
KDE Goals workboard: https://phabricator.kde.org/project/view/322/

Akademy website: https://akademy.kde.org/2022
Akademy schedule announcement: https://dot.kde.org/2022/08/08/akademy-2022-talk-schedule-now-live

Qt Creator 8
https://www.qt.io/blog/qt-creator-8-released

Tip of the month - Android Shared Storage Qt Wrapper
https://www.kdab.com/android-shared-storage-qt-wrapper/

Announcements
KDE Akademy, 1-7 October in Barcelona, Spain
https://akademy.kde.org

CppCon, 11-16 September in Aurora, Colorado
https://cppcon.org

Meeting C++, 17-19 in Berlin, Germany
https://meetingcpp.com/2022/

KDAB Training Schedule
https://www.kdab.com/software-services/scheduled-training/schedule/

QtDevCon22 – Qt 6.3 and Beyond

With the first long term support version of Qt 6 out of the door, it is time to reflect on the updates within the recent releases. Qt 6 brought many new items to help developers creating compelling applications and products.

Furthermore, the speaker will provide an outlook on what the next steps will be, exploring new use-cases and scenarios, but also focus on how to maintain the already huge feature set that Qt provides on the desktop, mobile and embedded.

About the speaker:
Maurice Kalinowski works as Product Director for the Qt Company, heading the Technical Product Management. He has a long history in the development of Qt, maintaining various embedded Windows variants, IoT protocols and developer offering in general.

All QtDevCon22 Videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6h5jKSLw0cEsKficprxd2iX

QtDevCon22 Website:
https://www.qtdevcon.com/

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/

20 1

QtDevCon22 – The Journey to the Cloud Has to Go through the Edge

Secular trends like Cloud and 5G are shifting the focus more and more towards IoT, AI and in general towards software. With technology evolving at a faster rate than ever, keeping up to speed is becoming more and more difficult – the speed of change outpaces the reaction capabilities of most companies.

This is a story about how a traditional hardware company ended up listing on the Italian stock exchange with a proposition entirely based on AI. It is a story about startups, about change, about the edge… and about Qt. If it is true that technology is merely a mean to achieve something great, it is also true that harnessing great technology is the main driver to a company’s success – today more than ever.

About the speaker:
Dario started his involvement with Qt more than 10 years as a member of the KDE community, for which is yet today a big advocate.

After bouncing back and forth between big companies, startups, and more, Dario is the CEO of SECO Mind, and leads SECO Group’s transition to a software company.

All QtDevCon22 Videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6h5jKSLw0cEsKficprxd2iX

QtDevCon22 Website:
https://www.qtdevcon.com/

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/

5 1

QtDevCon22 – Welcome Note

About the speaker:
Founder, president and CEO of KDAB, Matthias Dalheimer

All QtDevCon22 Videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6h5jKSLw0cEsKficprxd2iX

QtDevCon22 Website:
https://www.qtdevcon.com/

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/

10 1

Qt Item Delegates - A Framework

QListView, QTableView and QTreeView can all be configured via a number of roles from the models, e.g. BackgroundRole, ForegroundRole, FontRole, and TextAlignmentRole. This often means that no additional configurations of the views are needed.

However, if you want more control over how the data is presented, you can get that by implementing a delegate.

The question, however, is: Which delegate should you subclass from - QItemDelegate or QStyledItemDelegate? The documentation argues the latter, but the answer isn't so black and white. In this video I'll look into many details, and at the end implement a new super class which is super easy to extend.

0:00 Introduction
0:47 When do you /not/ need a delegate?
2:33 Rendering Money instances in a delegate without a custom delegate
4:21 Difference between QItemDelegate and QStyledItemDelegate
6:56 QStyledItemDelegate with Oxygen style
7:59 Subclassing QStyledItemDelegate
11:00 Debugging into QStyledItemDelegate
15:00 Subclassing QItemDelegate
19:06 Paint negative numbers in red
20:55 QWAMDelegate
22:49 What's in the next two episodes?

Links:
* Avoid wrapping the money instance in QVariant::fromValue() - https://youtu.be/rL8gYFPcFlE?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

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

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/

12 3

The Making of the Cluster Demo - Data Driven 3D Apps With Kuesa 3D 2.0

When your 3D model provides different features and you want to reflect those in your application, you would try to avoid doing all those variants in code. You would strive for a data driven approach instead.
This is where the glTF file format we use for Kuesa 3D comes into play. We show you how we realized such a data driven approach for our cluster demo using Kuesa 3D.

How to Replace a 3D Model without Modifying the Application: https://www.youtube.com/watch?v=EqOSD-ciALc

All of 'The Making of the Cluster Demo' videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6j6iZQK2QeZQTYl-RhytlaZ

All KUESA 3D videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6hVdcXHTtzzltmSvZ6eG590

Music credits:
Music by Little Glass Men - Logrthythm (CC BY) from freemusicarchive.org
'The Age of Insignificance' Album https://freemusicarchive.org/music/Little_Glass_Men/The_Age_of_Insignificance
licencing information: https://freemusicarchive.org/FAQ_For_Videos/

About the host:
Timo Buske has his roots in the mobile gaming industry, working on several 3D engines and tools. He's the product manager of KUESA™ 3D.

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/

3 0

Inline Headers in Qt View Classes (Take 2)

In a previous episode on inline headers in tables and trees, I left on a cliff hanger saying, "and then you need to connect to some change signals from the models".
I'll make things right in this episode by implementing those signals.

HOWEVER, I won't stop there, I'll continue with some discussion on class design, and how to avoid duplicating code for setting up a table view and a tree view.

0:00 Introduction
0:40 The original code
2:14 The basic idea - a drop in replacement for QTableView and QTreeView with row span support
2:51 Step 0 - Basic implementation
3:42 clazy warning
4:04 Step 1 - Signal connections
9:01 Step 2 - Introducing the superclass RowSpanHelper
14:57 Step 3 - RowSpanHelper as a templerized super class
18:48 Step 4 - subclassing from a private class
22:58 Step 5 - Implementing the template methods in C++

Links:
Original video explaining the table rows https://youtu.be/qLnX_yfSZAU?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

Episode on clang-tidy and clazy: https://youtu.be/gO3KCzdmcrQ?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

Here is why you should always include the Q_OBJECT macro: https://youtu.be/KkJfkrIO29Y?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI&t=279

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

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/

7 0

How to Replace a 3D Model without Modifying the Application

Handling the needs of different 3D models in the same application over the lifetime of your project can be time consuming.
Watch this video to learn about an easier way to replace a 3D model with another one in the same code base.

How to quickly change the 3D scene in your application with Kuesa: https://www.youtube.com/watch?v=DyjWOBhTDXM&list=PL6CJYn40gN6hVdcXHTtzzltmSvZ6eG590&index=2

All KUESA 3D videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6hVdcXHTtzzltmSvZ6eG590

About the host:
Kirsi Sutherland provided the voice over for this video. She is a Scottish technical artist, photographer, programmer and UI designer.

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/

6 1

Migrating to Qt6 - QVariant

We are currently working on migrating an in-house tool to Qt6. While doing so there were some run time issues relating to QVariant. In this episode I'll discuss these.

0:00 Introduction
1:00 Recap of the episode on combo boxes in Qt Designer
2:17 The problem in Qt6
4:04 Debugging the code to see the underlying problem
8:33 Adding QVariant::fromValue to solve the problem
9:54 Just be carefull
10:41 Problems with QVariant::toString()
13.36 operator<()(QVariant, QVariant) is gone
14:46 QVariant::compare
18:47 Improved Money comparison in Qt5
20:10 Improved Money comparison in Qt6

Links:
Original episode on combo box setup: https://youtu.be/X3cb5RtfsFo?list=PL6CJYn40gN6gf-G-o6syFwGrtq3kItEqI

More details on QMetaType: https://www.qt.io/blog/whats-new-in-qmetatype-qvariant

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv/tree/master/Qt-Widgets-and-more/Qt6Migration

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/

27 11

The Making of the Cluster Demo - Rigging up the Car

In this new series, Timo will show you how to create a Cluster demo using Kuesa 3D.

This second video is showing you how to rig up the car (i.e. preparing it so animation, lighting... are easier to do).

Music credits:
Music by Little Glass Men - Logrthythm (CC BY) from freemusicarchive.org
'The Age of Insignificance' Album https://freemusicarchive.org/music/Little_Glass_Men/The_Age_of_Insignificance
licencing information: https://freemusicarchive.org/FAQ_For_Videos/

All KUESA 3D videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6hVdcXHTtzzltmSvZ6eG590

All of 'The Making of the Cluster Demo' videos: https://www.youtube.com/playlist?list=PL6CJYn40gN6j6iZQK2QeZQTYl-RhytlaZ

About the host:
Timo Buske has his roots in the mobile gaming industry, working on several 3D engines and tools. He's the product manager of KUESA™ 3D.

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/

4 0