What's New in Qt 6.2

New and Restored Modules in Qt 6.2

Qt 6.2 adds the following module:

• QtQuick.Dialogs - A QML module that provides native dialogs with a Qt Quick fallback on platforms where Qt does not provide a native one. FileDialog and FontDialog are available in this release.

Qt 6.2 reintroduces the following modules that were not present in Qt 6.1. All listed modules were ported to Qt 6 and the CMake build system.

A more detailed list of changes to each module can be found in Changes to Qt Modules in Qt 6.

• Qt Bluetooth
  • BlueZ 4 support was removed.
  • Win32 backend was removed. As a consequence, there is no longer support for Qt Bluetooth using Mingw-w64.
  • The QML API was removed.
  • QBluetoothTransferManager and related classes were removed.
  • Functionality related to pairing agents was removed from QBluetoothLocalDevice.
• Qt Multimedia
  • Qt Multimedia public API consists of five large functional blocks. Each API has undergone significant changes compared to Qt 5:
    • Device discovery
    • Low level audio
    • Playback and decoding
    • Capture and recording
    • Video output pipeline
  • Currently supported backends:
    • Linux: GStreamer
    • Windows: WMF
    • macOS/iOS: AVFoundation
    • Android: MediaPlayer and Camera APIs
• Qt NFC
  • Removed support for Linux/NearD.
  • Added support for iOS.
• Qt Positioning
  • Many of the properties were made bindable.
  • Renamed QGeoPolygon::path() to QGeoPolygon::perimeter.
  • QGeoLocation now uses QGeoShape instead of QGeoRectangle as a bounding area.
  • The error() signal in multiple positioning classes was renamed to errorOccurred().
  • QGeoPositionInfoSourceFactoryV2 was removed, and QGeoPositionInfoSourceFactory now supports custom parameters for the created objects.
  • NMEA support was redesigned. The serialnmea plugin was renamed to nmea and now supports reading the input stream from a TCP socket or a raw file. The nmeaSource property was removed.
• Qt Remote Objects
  • The local connection backend now supports abstract namespaces (this is a Linux-specific extension), achieved by using the new localabstract schema in the URL.
  • .rep-files now support:
    • Class enums.
    • QFlags.
    • Multiline comments (C-style).
  • Enums and flags are now supported in POD-types and as keys for QMap and QHash properties in .rep files.
• Qt Sensors
  • Most QML facing properties are now bindable.
  • Sensor::type and QSensor::type properties are now marked as constant.
  • Added parameter to QSensorBackend::sensorBusy() to be able to also clear the busy state.
  • Deleted typedef for qtimestamp.
  • Renamed sensor type string to sensorType.
  • Windows: We can now require Windows 10 API, thereby extending the number of sensors supported.
  • TI Sensor Tag as supported platform has been removed.
  • The Linux sysfs backend has been removed.
  • The sensor gesture support has been removed (input welcomed here: QTBUG-97066).
  • Sensorfw as a platform was removed due to Sensorfw itself not yet ported to Qt 6.
  • Sensor types that had only Sensorfw backend (IRProximity, Lid, and Tap) are not listed as supported anymore.
  • Sensor types without any backend have been removed (Altimeter, Distance, and Holster).
• Qt Serial Bus
  • QCanBusFactory was removed and QCanBusFactoryV2 was renamed to QCanBusFactory.
  • QModbusRtuSerialSlave and QModbusRtuSerialMaster were renamed to QModbusRtuSerialServer and QModbusRtuSerialClient.
• Qt Serial Port
• Qt WebChannel
  • QWebChannel properties were made bindable.
  • The property update interval of QWebChannel can now be configured. 50ms update interval remains the default.
  • QWebChannel now supports property updates for BINDABLE properties. However, the client side does not provide a generic callback mechanism if the host property does not have a NOTIFY signal.
  • Signals from objects living in a different thread are now handled correctly (QTBUG-51366).
• Qt WebEngine
  • The submodule for Qt Quick has been renamed from QtWebEngine to QtWebEngineQuick.
  • Several classes were moved from QtWebEngineWidgets to QtWebEngineCore, including QWebEnginePage.
  • Some functionality previously only accessible by deriving from QWebEnginePage are now accessible using synchronous signals.
  • Favicon API added to QWebEngineProfile to look up icons for specific URLs.
  • The new QWebEngineLoadingInfo class provides more detail about loading success or failure.
• Qt WebSockets
• Qt WebView

New Features in Qt 6.2

Qt Core Module

• Added functionality:
  • Added QByteArrayView::compare().
  • Added methods QFlags::test(Any)Flag(s).
  • Added QHashSeed to control hashing (seeds are now size_t); this shall replace qGlobalQHashSeed and qSetGlobalQHashSeed.
  • Added PRIxQTDATATYPE macros to facilitate printf()-style formatting without casts or warnings.
• Made many properties bindable.
• Grapheme clusters can now handle emojis.
• UNC paths and network shares on Windows are now handled consistently.
• The handling of the start-offset parameter, called from, in various indexOf() and lastIndexOf() methods of containers (principally QString, QByteArray and their views) is now more coherent.
• Like QString::number() has since the release of Qt 6.0, QByteArray::number()'s overloads for signed integral types now return a text with a minus sign followed by the number's absolute value instead of coercing to an unsigned type for all bases except ten, when passed a negative integer and any supported base.
• QCalendar now supports construction from the ID of a custom backend.
• QChar, QPoint, and QPointF are now primitive rather than merely relocatable.
• QCoreApplication::exit() is now, like quit(), a slot (as the documentation long claimed); same for QEventLoop and QThread.
• QDateTime now takes account of time-zones throughout time_t's range (in so far as the platform supplies such information), rather than artificially limiting the range to 1970 - 2037.
• Fleshed out the value-type behavior of QFlags, and it is now used more systematically.
• When building for C++20, QList (hence also QVector) is now a contiguous_iterator, satisfying contiguous_range.
• QLocalSocket::waitFor*() methods were made to support duplex operations on Windows (as they already did on Unix).
• Added std::chrono overloads to QLockFile methods, avoiding needless conversions between UTC and local time.
• QString can now be built from char8_t (when available).
• Made QThreadPool's thread priority configurable; the threads share the pool's name if it has one.
• Lots of Bug-fixing, clean up, and documentation improvements.

Qt GUI Module

• Added floating point image formats to QImage for both 16-bit and 32-bit floats.
• Converting RGB images to, or painting RGB colors onto, gray-scale images is now gamma corrected and produces the luminance values of the input color space.
• The CSS text-decoration-color attribute is now supported in rich text spans with underlines, overlines, and strikethrough.

Qt Quick Module

• Added support for selecting cells in a TableView by assigning it a ItemSelectionModel.

Qt Quick Controls Module

• Added a new control; SelectionRectangle. This control can be used to select cells in a TableView by using a styled selection rectangle.

Qt Widgets Module

• Added PM_LineEditIconSize, a new QStyle::PixelMetric enum value that allows styles to define a default size for icons in a QLineEdit.
• The new QGraphicsSceneEvent::timestamp method returns the timestamp of the original event, if applicable.
• QGraphicsSceneWheelEvent::phase, QGraphicsSceneWheelEvent::pixelDelta, and QGraphicsSceneWheelEvent::isInverted return the respective attributes of the original QWheelEvent.

Qt Network Module

• QSslSocket
  • TLS backends that were previously (in Qt 6.1) converted into plugin-like classes, were moved out of QtNetwork and implemented as real plugins.
  • Several TLS backends may now co-exist at runtime, for example, OpenSSL and Schannel, or OpenSSL and SecureTransport.
• QNetworkInformation
  • Introduced isBehindCaptivePortal, a new property that can be used to determine whether the user is connected to a network with a captive portal.

Qt QML Module

• Core language
  • Added support for optional chaining.
  • Added as casts: these mostly help tooling but can also be used to replace code such as return (obj instanceof Item) ? obj.width : 42 with (obj as Item)?.width ?? 42.
• Added a public CMake API for QML modules: qt_add_qml_module().
  • Takes care of generating qmldir and qmltypes.
  • Can automatically create a plugin if a plugin only registers types.
  • Has built-in support for a linting target.
• QML tooling
  • qmllint
    • Added a granular setting for the warning severity; warnings can be disabled entirely, make them informational only, or make them lead to a non-zero exit code.
    • Added a settings file (.qmllint.ini) for configuring warning levels on a directory-by-directory basis. A default settings file can be generated using qmllint --write-defaults.
    • Warnings can now be disabled in blocks via comments; //qmllint enable/disable <warning-type1> <warning-type2...>
    • Greatly improved performance when linting files, especially when linting multiple files with lots of imports.
    • Added support for JSON output for use in tooling.
  • qmlformat
    • qmlformat now utilizes our new qmldom library and should generally produce better output.

Qt Quick 3D Module

• Added support for instanced rendering, an optimized way of drawing multiple instances of the same objects with different transformations.
• Added 3D Particles, an API for adding particle effects to 3D scenes. This includes a technology preview of model blend particles.
• Added Qt Quick Input events for 2D items in 3D, both in scene and in textures.
• Added an API for ray-based picking from arbitrary points in the scene.
• Added RuntimeLoader, making it possible to load glTF2 files at runtime.
• Implemented parallax occlusion mapping: Enables the use of height maps without the cost of adding geometry.
• Implemented depth draw mode on materials: Enables fine control over depth rendering for a material.

Qt Data Visualization Module

• Fixed background rendering mode.
• RenderDirectToBackground_NoClear was deprecated as opting to not clear the window is no longer an option in Qt 6.
• Lots of minor bug fixes.

Qt Charts Module

• Added more marker shapes to pick from in QScatterSeries and QLegend.
• Added a light marker feature to QXYSeries and QLegend. This is a lighter weight rendering of points.
• Added an ability to select points in a series via method calls to QXYSeries and QBarSet.
• Added an ability to set a color or use a custom light marker to be used for selected points in QXYSeries.
• Added an ability to set a color to be used for selected bars in QBarSet.
• Added a feature to display a best fit line in a QXYSeries.
• Added an ability to customize the look of individual points in a QXYSeries. This feature allows setting the visibility, label visibility, and the size of each point.
• Added a method sizeBy() to QXYSeries that adjusts the size of the points in a series according to passed values.
• Added a method colorBy() to QXYSeries that adjusts color of the points in a series according to passed values and a gradient.
• Added a new axis class QColorAxis to support the colorBy() feature, displaying a color scale.
• Added an ability to disable label truncation in axes.
• Improved performance by caching recently used text bounds.
• Added interactive support to QLegend via a setInteractive() method. Once enabled, allows the legend to be detached with a double-click. Once detached, the legend can be dragged and resized, and reattached to a side of the chart by dragging it off the edge.
• Added attachedToChartChanged() signal to QLegend.
• Updated the legend example.

Qt for Python

• New examples, tutorials, and videos added to the Qt for Python documentation.
• Compatible with Python 3.10rc2.
• Added the QtDBus, QtNetworkAuth, and QtBluetooth modules.
• Added a new Shiboken feature, Opaque Containers, to avoid copying C++ containers into Python to use them.
• You can now use qtpaths instead of qmake when building PySide from source.
• Added support for std::function for some of QThreadPool's methods.
• Added new QML functions as well as support for qmlRegisterSingletonInstance.

Platform Changes

Technology Preview Platforms

Windows on ARM

• Added Windows on ARM64 as a technology preview platform.
• Supported as a build target; no host support yet.
• Known limitations:
  • No support for Qt WebEngine yet; missing official support for Chromium.
  • No support for SSL yet; missing official OpenSSL support.

Desktop Platforms

macOS on Apple Silicon

• Added official support as both a target and a host platform.
• Libraries in the Qt SDK are built as universal binaries.
• Known limitations:
  • SSL support is missing.
  • postgresql and odbc database plugins are missing (QTBUG-93204).
  • JIT support is missing (QTBUG-93206).

Wayland Client on Linux

• A touchpad pinch gesture now generates Zoom and Rotate QNativeGestureEvents if the compositor sends them via the pointer-gestures-unstable-v1 protocol. This allows a Qt Quick PinchHandler to operate via touchpad pinch gestures. Two, three, or four-finger gestures are recognized. A gesture of type Qt::PanNativeGesture can be generated by swiping with three or four fingers. Two-finger flicking still generates QWheelEvents as before.

Mobile Platforms

Android

• Some of the methods previously under the QtAndroid namespace in QtAndroidExtras (for example, sdkVersion() and context()), were moved to QNativeInterface::QAndroidApplication.
• Implemented a new permissions API in QCoreApplication.
• The remaining QtAndroidExtras APIs were left as private APIs in qtbase until cross-platform alternatives (for Intents, Services, etc.) are in place.
• Removed obsolete Ministro code as it's now unsupported by Android.
• Simplified AndroidManifest.xml to only contain tags relevant to the user, helping maintainability and reducing clutter.
• QCDebug() and friends now use the category as a tag in Android logcat.
• Updated Android Gradle plugin to 4.1.3.
• Fixed a non-SDK API bug with style (QTBUG-71590), though Android Style for widgets on Android 9+ is still affected (QTBUG-96149).
• The default targetSdkVersion is set to 30 in accordance with Google Play Store requirements.
• The build-tools version and platform version used is bumped to 30.
• QDesktopServices custom handlers are now enabled, and allow you to work with Android App Links, for example.
• Added information that allow applications to determine the source of an intent without creating an own extension of QtActivity.
• Fixed imports for QML modules and added the possibility of multiple QML root paths.
• Fixed Vulkan builds on Android.

iOS

• Improved CMake support.
• Known issues:
  • Missing default launch screen storyboard.
  • Custom libraries fail to install (QTBUG-95381).

Embedded Platforms

Available under the Qt for Device Creation license.

Boot to Qt

• The Boot to Qt stack was updated to use Yocto 3.3 (Hardknott).
• Added Intel NUC10 (64bit i5 x86) as a reference target.
• Added NVidia Jetson Tegra X2 as a target.

QNX

• Added QNX version 7.1 and Ubuntu 20.04 as a host.
• Added NXP iMX8QM as a reference target.

INTEGRITY

• Added INTEGRITY version 19.0.13 and Ubuntu 20.04 as a host.
• Added Qualcomm Snapdragon 8155P as a reference target.

WebOS

Qt 6.2 has been verified to work with LG webOS OSE 2.13.1 using Ubuntu 20.04 as development host and Raspberry Pi4 hardware.

List of API Changes

These pages contain an overview of API changes in Qt 6.2:

• New Classes and Functions in Qt 6.2
• Obsolete Classes