QQuickFramebufferObject — PyQt Documentation v6.9.0 (original) (raw)

PyQt6.QtQuick.QQuickFramebufferObject

Inherits from QQuickItem.

Description¶

The QQuickFramebufferObject class is a convenience class for integrating OpenGL rendering using a framebuffer object (FBO) with Qt Quick.

Warning: This class is only functional when Qt Quick is rendering via OpenGL. It is not compatible with other graphics APIs, such as Vulkan or Metal. It should be treated as a legacy class that is only present in order to enable Qt 5 applications to function without source compatibility breaks as long as they tie themselves to OpenGL.

On most platforms, the rendering will occur on a dedicated thread. For this reason, the QQuickFramebufferObject class enforces a strict separation between the item implementation and the FBO rendering. All item logic, such as properties and UI-related helper functions needed by QML should be located in a QQuickFramebufferObject class subclass. Everything that relates to rendering must be located in the Renderer class.

To avoid race conditions and read/write issues from two threads it is important that the renderer and the item never read or write shared variables. Communication between the item and the renderer should primarily happen via the synchronize() function. This function will be called on the render thread while the GUI thread is blocked.

Using queued connections or events for communication between item and renderer is also possible.

Both the Renderer and the FBO are memory managed internally.

To render into the FBO, the user should subclass the Renderer class and reimplement its render() function. The Renderer subclass is returned from createRenderer().

The size of the FBO will by default adapt to the size of the item. If a fixed size is preferred, set textureFollowsItemSize() to false and return a texture of your choosing from createFramebufferObject().

Starting Qt 5.4, the QQuickFramebufferObject class is a QSGTextureProvider and can be used directly in ShaderEffects and other classes that consume texture providers.

Classes¶

Methods¶

__init__(parent: QQuickItem = None)

Constructs a new QQuickFramebufferObject with parent parent.

createRenderer() → Renderer

TODO

geometryChange(QRectF, QRectF)

TODO

isTextureProvider() → bool

TODO

mirrorVertically() → bool

releaseResources()

TODO

setMirrorVertically(bool)

Signals¶

mirrorVerticallyChanged(bool)

TODO

textureFollowsItemSizeChanged(bool)

TODO