Phosphor::Screens::IPanelSource Class Reference

Pluggable producer of panel-reservation offsets per screen. More...

#include <phosphor-screens/include/PhosphorScreens/IPanelSource.h>

Inheritance diagram for Phosphor::Screens::IPanelSource:

Classes
struct	Offsets
	Per-edge reserved geometry, in physical pixels relative to the screen's top-left. More...

Signals
void	panelOffsetsChanged (QScreen *screen)
	Offsets for screen changed.
void	requeryCompleted ()
	A requestRequery cycle completed.

Public Member Functions
	IPanelSource (QObject *parent=nullptr)
	~IPanelSource () override=default
virtual void	start ()=0
	Begin watching.
virtual void	stop ()=0
	Stop watching.
virtual Offsets	currentOffsets (QScreen *screen) const =0
	Snapshot for a given screen.
virtual bool	ready () const =0
	Has any successful query landed? Drives ScreenManager's panelGeometryReady one-shot signal — consumers that compute initial zone geometry at daemon startup gate on this so they don't lay out windows against the unreserved screen rect.
virtual void	requestRequery (int delayMs=0)=0
	Best-effort: ask the backend to re-query immediately, optionally after a short delay (e.g.

Detailed Description

Pluggable producer of panel-reservation offsets per screen.

Panels (taskbars, docks, status bars) reserve part of each screen's geometry. Different desktops report this differently: KDE Plasma exposes it via org.kde.plasmashell D-Bus, GNOME via org.gnome.Mutter, sway / Hyprland via wlr-foreign-toplevel, and so on. PhosphorScreens delegates the source-specific details to an IPanelSource so the manager core stays compositor-agnostic.

Implementations are owned by the consumer (typically the daemon). Lifetime: must outlive the ScreenManager that holds the pointer.

Threading: ScreenManager calls currentOffsets, ready, and requestRequery from the GUI thread; signals must be emitted on the GUI thread (use QMetaObject::invokeMethod(this, ..., Qt::QueuedConnection) if the implementation queries from a worker).

Constructor & Destructor Documentation

IPanelSource()

Phosphor::Screens::IPanelSource::IPanelSource ( QObject *  parent = nullptr )

inlineexplicit

~IPanelSource()

Phosphor::Screens::IPanelSource::~IPanelSource ( )

overridedefault

Member Function Documentation

currentOffsets()

virtual Offsets Phosphor::Screens::IPanelSource::currentOffsets ( QScreen *  screen ) const

pure virtual

Snapshot for a given screen.

Returns zero offsets if the source has no information for this screen yet.

Implemented in Phosphor::Screens::NoOpPanelSource, and Phosphor::Screens::PlasmaPanelSource.

panelOffsetsChanged

void Phosphor::Screens::IPanelSource::panelOffsetsChanged ( QScreen *  screen )

signal

Offsets for screen changed.

Emit only when the new values differ from the last known values (no spam on repeat queries).

ready()

virtual bool Phosphor::Screens::IPanelSource::ready ( ) const

pure virtual

Has any successful query landed? Drives ScreenManager's panelGeometryReady one-shot signal — consumers that compute initial zone geometry at daemon startup gate on this so they don't lay out windows against the unreserved screen rect.

Latch semantics: implementations MAY keep ready() returning true across stop / start cycles — the contract is "panels have been queried successfully at least once", not "a fresh query has completed since the last start". Consumers that need a liveness indicator should listen for requeryCompleted after their own requestRequery, rather than polling ready().

Implemented in Phosphor::Screens::NoOpPanelSource, and Phosphor::Screens::PlasmaPanelSource.

requeryCompleted

void Phosphor::Screens::IPanelSource::requeryCompleted ( )

signal

A requestRequery cycle completed.

Forwarded by ScreenManager as delayedPanelRequeryCompleted. Always fires at most once per requestRequery call, even if the underlying query coalesces with one already in flight.

requestRequery()

virtual void Phosphor::Screens::IPanelSource::requestRequery ( int  delayMs = 0 )

pure virtual

Best-effort: ask the backend to re-query immediately, optionally after a short delay (e.g.

to let a panel-editor UI close fully before settling). Implementations that don't support push-style refresh can no-op; requeryCompleted is still expected to fire at most once per call so callers can chain UI updates.

Implemented in Phosphor::Screens::NoOpPanelSource, and Phosphor::Screens::PlasmaPanelSource.

start()

virtual void Phosphor::Screens::IPanelSource::start ( )

pure virtual

Begin watching.

Implementations may emit panelOffsetsChanged any time after this returns; ScreenManager reads currentOffsets on each emission to refresh its cache.

Implemented in Phosphor::Screens::NoOpPanelSource, and Phosphor::Screens::PlasmaPanelSource.

stop()

virtual void Phosphor::Screens::IPanelSource::stop ( )

pure virtual

Stop watching.

Subsequent currentOffsets queries should still return the last-known values; only the change channel is closed.

Implemented in Phosphor::Screens::NoOpPanelSource, and Phosphor::Screens::PlasmaPanelSource.

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The documentation for this class was generated from the following file:

• phosphor-screens/include/PhosphorScreens/IPanelSource.h