The following is a part of an QtWayland example:
WaylandOutput {
sizeFollowsWindow: true
window: Window {
width: 1024
height: 768
visible: true
Repeater {
model: shellSurfaces
ShellSurfaceItem {
shellSurface: modelData
onSurfaceDestroyed: shellSurfaces.remove(index)
}
}
}
}
If I have two displays, and a part of a ShellSurfaceItem is in the first
display, and the other part of the ShellSurfaceItem in the second display. In
this case, I need to ensure the user can see this ShellSurfaceItem
on both first and second displays, on QtWayland, I can using two WaylandOutput
with two Window for this case, and create ShellSurfaceItem for which
WaylandOutput.
But, If I using two ShellSurfaceItem for one wl_surface, I can't sync the
window animation in different WaylandOutput, this is a hard job, because the
QQuickItem must bind to single Window, it's can't render to multi Windows.
The better way is redesign QtQuick scene graphics, like as:
1. Add QQuickScene class to instead of a part of functions of QQuickWindow.
a QQuickItem must be added to a QQuickScene, a QQuickScene is a coordinate
system.
2. Add QQuickViewport class, and allow attach multi QQuickViewport to one
QQuickScene. the QQuickViewport be responsible for render QQuickItem to target
output. And allow the QQuickViewport can render in a new thread(be different
than the other QQuickViewport in same QQuickScene).
3. Add QQuickRenderTarget::fromSurface(EGLSurface/VkSurface) functions, and
using QQuickRenderTarget to QQuickViewport::render(QQuickRenderTarget target).
4. The QQuickWindow don't depends on QSG* class, it can wapper
QQuickViewport and QQuickRenderTarget to render QQuickItem.
5. Add QQuickSceneHelper abstract class, The QQuickWindow event dispense to
QQuickSceneHelper, and QQuickSceneHelper dispense event to QuickItem. Provide
like as "virtual QQuickSceneHelper::setCursor" functions to instead of
QQuickWindow::setCursor in QQuickItem::setCursor.
6. The QQuickItem without QQuickWindow, using QQuickItem::pixelRatio to
instead of QQuickWindow::effectiveDevicePixelRatio(), the
QQuickItem::pixelRatio is only using for load resources(like as
QQuickImage::load), for the render matrix, using the
QQuickViewport::devicePixelRatio when rendeing.
The above changes may not change the abi.
If I misunderstand QtWayalnd and QtQuick Scene Graphics, please tell me, thanks.
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