LSubsurfaceRole Class Reference

Subsurface role for surfaces. More...

Inheritance diagram for LSubsurfaceRole:

Public Member Functions
	LSubsurfaceRole (const void *params) noexcept
	Constructor of the LSubsurfaceRole class. More...
	~LSubsurfaceRole ()=default
	Destructor of the LSubsurfaceRole class. More...
bool	isSynced () const noexcept
	Current mode. More...
const LPoint &	localPos () const noexcept
	Offset in surface coordinates. More...
Public Member Functions inherited from LBaseSurfaceRole
	LBaseSurfaceRole (LFactoryObject::Type type, LResource *resource, LSurface *surface, UInt32 roleId) noexcept
	Constructor of LBaseSurfaceRole class. More...
	~LBaseSurfaceRole ()
	The LBaseSurfaceRole class destructor. More...
virtual LOutput *	exclusiveOutput () const
	The output to which the surface should be constrained. More...
UInt32	roleId () const noexcept
	Role ID. More...
LSurface *	surface () const noexcept
	Returns the surface that has acquired the role provided in the constructor. More...
LResource *	resource () const
	Returns the Wayland resource for this role given in the constructor. More...
LClient *	client () const noexcept
	Client owner of the surface role. More...
Public Member Functions inherited from LFactoryObject
Type	factoryObjectType () const noexcept
	Gets the base factory object type. More...
Public Member Functions inherited from LObject
	LObject (const LObject &) noexcept
	Copy constructor. More...
LObject &	operator= (const LObject &) noexcept
	Assignment operator (each object has its own individual LWeak reference count). More...
void	setUserData (UIntPtr data) const noexcept
	Store an unsigned integer value/pointer. More...
UIntPtr	userData () const noexcept
	Retrieves the stored unsigned integer value/pointer. More...

Virtual Methods
virtual const LPoint &	rolePos () const override
	Position of the subsurface according to the role. More...
virtual void	localPosChanged ()
	Change of offset. More...
virtual void	syncModeChanged ()
	Change of mode. More...
virtual void	placedAbove (LSurface *sibling)
	Place above. More...
virtual void	placedBelow (LSurface *sibling)
	Place below. More...

Additional Inherited Members
Public Types inherited from LBaseSurfaceRole
enum	CommitOrigin
	Commit origin. More...
Public Types inherited from LFactoryObject
enum class	Type : Int32
	Base factory object types. More...
Protected Member Functions inherited from LBaseSurfaceRole
virtual void	handleSurfaceBufferAttach (wl_resource *buffer, Int32 x, Int32 y)
	Notifies a new surface buffer attachment. More...
virtual void	handleSurfaceOffset (Int32 x, Int32 y)
	Notifies a surface buffer offset change. More...
Protected Member Functions inherited from LObject
	LObject () noexcept=default
	Constructor of the LObject class. More...
virtual	~LObject () noexcept
	Destructor of the LObject class. More...
void	notifyDestruction () noexcept
	Notifies the object destruction. More...
Protected Attributes inherited from LBaseSurfaceRole
LPoint	m_rolePos
	Variable that stores the surface position given the role. More...

Detailed Description

Subsurface role for surfaces.

LSubsurfaceRole surfaces are always children of other surfaces and are positioned relative to their parent surface. They are meant to be treated and composited as if they were part of their parent surface, for example, for displaying a video frame within a web browser window.

The Subsurface role is part of the Wayland protocol.

Ordering

Clients can request to modify the order in which they are stacked relative to their parent surface or other sibling surfaces. See placedAbove() and placedBelow(). Louvre automatically updates the LCompositor::surfaces() list, keeping the order and also triggering the LSurface::orderChanged() event.

Modes

Subsurfaces can operate in two modes:

Synchronous Mode

In this mode, changes to the subsurface, such as its position, are applied exclusively when its parent performs a commit. This mode is used by clients to synchronize the animation or movement of multiple subsurfaces. The library keeps track of changes and applies them when the parent performs a commit.

Asynchronous Mode

In this mode, subsurface changes are applied independently of the commits of its parent.

Note

This documentation is for educational purposes only. Louvre handles all of this internally for you.

Constructor & Destructor Documentation

LSubsurfaceRole()

LSubsurfaceRole ( const void *  params )

noexcept

Constructor of the LSubsurfaceRole class.

Parameters

params

Internal parameters provided in LCompositor::createObjectRequest().

~LSubsurfaceRole()

~LSubsurfaceRole ( )

default

Destructor of the LSubsurfaceRole class.

Invoked after LCompositor::onAnticipatedObjectDestruction().

Member Function Documentation

isSynced()

bool isSynced ( ) const

inlinenoexcept

Current mode.

Returns

true if in synchronous mode, false otherwise.

localPos()

const LPoint& localPos ( ) const

inlinenoexcept

Offset in surface coordinates.

The offset relative to the top-left corner of the parent surface in surface coordinates.

rolePos()

virtual const LPoint& rolePos ( ) const

overridevirtual

Position of the subsurface according to the role.

The default implementation of rolePos() positions the subsurface relative to its parent rolePos() by adding the offset given by localPos().

Default implementation

const LPoint &LSubsurfaceRole::rolePos() const
{
    if (surface()->parent())
        m_rolePos = localPos() + surface()->parent()->rolePos();
 
    return m_rolePos;
}

Implements LBaseSurfaceRole.

localPosChanged()

virtual void localPosChanged ( )

virtual

Change of offset.

Default implementation

void LSubsurfaceRole::localPosChanged()
{
    surface()->repaintOutputs();
}

syncModeChanged()

virtual void syncModeChanged ( )

virtual

Change of mode.

Default implementation

void LSubsurfaceRole::syncModeChanged()
{
    /* No default implementation */
}

placedAbove()

virtual void placedAbove ( LSurface *  sibling )

virtual

Place above.

Note

Louvre automatically maintains the hierarchical order of LCompositor::surfaces().

Default Implementation

void LSubsurfaceRole::placedAbove(LSurface *sibling)
{
    L_UNUSED(sibling);
}

placedBelow()

virtual void placedBelow ( LSurface *  sibling )

virtual

Place below.

Note

Louvre automatically maintains the hierarchical order of LCompositor::surfaces().

Default Implementation

void LSubsurfaceRole::placedAbove(LSurface *sibling)
{
    L_UNUSED(sibling);
}