LToplevelMoveSession Class Reference

Toplevel move session utility. More...

Public Types
using	OnBeforeUpdateCallback = std::function< void(LToplevelMoveSession *)>
	Callback function type used in setOnBeforeUpdateCallback() More...

Public Member Functions
bool	start (const LEvent &triggeringEvent, const LPoint &initDragPoint)
	Start the move session. More...
void	updateDragPoint (const LPoint &pos)
	Updates the drag point, causing the toplevel to move. More...
const std::vector< LToplevelMoveSession * >::const_iterator	stop ()
	Stops the move session. More...
void	setConstraints (const LMargins &constraints={LEdgeDisabled, LEdgeDisabled, LEdgeDisabled, LEdgeDisabled}) noexcept
	Sets the constraints for each side in compositor-global coordinates. More...
const LMargins &	constraints () const noexcept
	Retrieves the constraints set with setConstraints(). More...
void	setOnBeforeUpdateCallback (const OnBeforeUpdateCallback &callback) noexcept
	Sets a custom callback function to be triggered each time before updating the toplevel position. More...
LToplevelRole *	toplevel () const noexcept
	Retrieves the LToplevelRole associated with this session. More...
const LEvent &	triggeringEvent () const noexcept
	Retrieves the triggering event provided during the start of the session. More...
bool	isActive () const noexcept
	Checks if the session is currently active. More...

Detailed Description

Toplevel move session utility.

This class serves as a utility for handling interactive move sessions for LToplevelRole surfaces.
Each LToplevelRole has an associated move session instance LToplevelRole::moveSession().

When a client triggers LToplevelRole::startMoveRequest(), the start() method should be invoked, providing the triggering event of the request and an initial drag point, which could be the current position of the pointer (typically obtained via LCursor::pos()) or a touch point if triggered by a touch event. This also adds the session to the LSeat::toplevelMoveSessions() vector.

Subsequently, whenever the drag point changes, such as within an LPointer::pointerMoveEvent() or LTouch::touchMoveEvent(), updateDragPoint() should be called. The LSeat::toplevelMoveSessions() provides access to all active move sessions, and the triggeringEvent() can be used to distinguish between pointer, touch or other kinds of sessions.

To dynamically modify constraints, a callback function can be specified with setOnBeforeUpdateCallback(), which is triggered each time before the toplevel position is updated. Within the callback function, setConstraints() can be used to update the constraints().

Finally, when the pointer button or touch point is released, the stop() method should be invoked to end the session and remove it from the LSeat::toplevelMoveSessions() vector. The stop() method also returns an iterator pointing to the next session in the vector which can be used in cases where the session is stopped while iterating through the vector.

Member Typedef Documentation

OnBeforeUpdateCallback

using OnBeforeUpdateCallback = std::function<void(LToplevelMoveSession*)>

Callback function type used in setOnBeforeUpdateCallback()

Member Function Documentation

start()

bool start	(	const LEvent &	triggeringEvent,
		const LPoint &	initDragPoint
	)

Start the move session.

Note

The session will automatically cease if the toplevel is destroyed.

Parameters

triggeringEvent	The triggering event provided in LToplevelRole::startMoveRequest().
initDragPoint	The initial pointer, touch, or other position at the start of the move operation.

Returns

true if the session successfully started, false if the toplevel is already in a session.

updateDragPoint()

void updateDragPoint

(

const LPoint &

pos

)

Updates the drag point, causing the toplevel to move.

Parameters

pos	The new position of the pointer or touch point.

stop()

const std::vector< LToplevelMoveSession * >::const_iterator stop

(

)

Stops the move session.

This method ends the current move session and removes it from the vector of active sessions.

Returns

An iterator pointing to the next session within the LSeat::toplevelMoveSessions() vector.

setConstraints()

void setConstraints ( const LMargins &  constraints = {LEdgeDisabled, LEdgeDisabled, LEdgeDisabled ,LEdgeDisabled} )

inlinenoexcept

Sets the constraints for each side in compositor-global coordinates.

Parameters

constraints

The margins specifying the constraints for each side. Use LEdgeDisable to disable constraints on specific sides.

constraints()

const LMargins& constraints ( ) const

inlinenoexcept

Retrieves the constraints set with setConstraints().

setOnBeforeUpdateCallback()

void setOnBeforeUpdateCallback ( const OnBeforeUpdateCallback &  callback )

inlinenoexcept

Sets a custom callback function to be triggered each time before updating the toplevel position.

Parameters

callback

The callback function to be executed before updating the toplevel window or nullptr to disable.

Default Implementation

setOnBeforeUpdateCallback([](LToplevelMoveSession *session)
{
    LMargins constraints { session->toplevel()->calculateConstraintsFromOutput(cursor()->output()) };
    constraints.bottom = LEdgeDisabled;
    session->setConstraints(constraints);
});

toplevel()

LToplevelRole* toplevel ( ) const

inlinenoexcept

Retrieves the LToplevelRole associated with this session.

triggeringEvent()

const LEvent& triggeringEvent ( ) const

inlinenoexcept

Retrieves the triggering event provided during the start of the session.

isActive()

bool isActive ( ) const

inlinenoexcept

Checks if the session is currently active.

Returns

true if the session is active, false otherwise.