Qt Platform Abstraction

Integrating Qt with the native platform.

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The Qt Company Ltd.

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Publié le 27 décembre 2024 - Mis à jour le 27 décembre 2024

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Qt Platform Abstraction▲

The Qt Platform Abstraction (QPA) is the main platform abstraction layer in Qt.

The API can be identified by the QPlatform* class prefix, and is used for implementing higher level classes typically found in Qt GUI, e.g. QPlatformWindow for window system integration exposed through QWindow, or QPlatformTheme for deeper platform theming and integration, exposed through QStyleHint and QStyle.

There are no source or binary compatibility guarantees for the QPA classes, meaning that the API is only guaranteed to work with the Qt version it was developed against. API changes will however only be made in minor releases. (5.1, 5.2, and so on.)

API Overview▲

Window system integration
- QPlatformIntegration
- QPlatformAccessibility
- QPlatformBackingStore
- QPlatformClipboard
- QPlatformCursor
- QPlatformDrag
- QPlatformFontDatabase
- QPlatformGraphicsBuffer
- QPlatformInputContext
- QPlatformOffscreenSurface
- QPlatformOpenGLContext
- QPlatformScreen
- QPlatformServices
- QPlatformSharedGraphicsCache
- QPlatformSurface
- QPlatformWindow
Style/theming
- QPlatformTheme
- platform palettes
- platform fonts
- theme hints
Native dialogs and menus
- QPlatformDialogHelper
- QPlatformMenu
- QPlatformMenuBar
- QPlatformMenuItem

In addition to the QPA APIs, there are many other platform abstractions in Qt, for example the event dispatcher abstractions in Qt Core and the rendering hardware abstractions in RHI. The QPA APIs are mostly focused on window system integration and related support.

QPA Plugins▲

Concrete implementations of the interfaces listed above live in QPA plugins, or platform plugins, adding support for the various platforms Qt runs on. QPA plugins are implemented by subclassing the QPlatform* classes.

The following table summarizes the platform plugins available:

Plugin Name	Plugin Class Name	Description
qandroid	QAndroidPlatformIntegration	Android support
qbsdfb	QBsdFbIntegration	BsdFb support
qcocoa	QCocoaIntegrationPlugin	macOS support
qdirect2d	QWindowsDirect2DIntegrationPlugin	Similar to the qwindows plugin, but replaces the raster paint engine with a Direct2D-based paint engine for QPixmap and QBackingStore.
qdirectfb	QDirectFbIntegrationPlugin	DirectFB is centered around surfaces, which are the equivalent of a QPaintDevice.
qeglfs	QEglFSIntegrationPlugin	EGLFS support for embedded Linux devices.
qhaiku	QHaikuIntegration	Haiku support
qios	QIOSIntegrationPlugin	iOS support
qlinuxfb	QLinuxFbIntegrationPlugin	LinuxFB support for embedded Linux devices.
qmirclient	QMirClientIntegration	Mir client support
qopenwf	QOpenWFDIntegrationPlugin	OpenWF Display support for managing display control hardware.
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