IlvLayerVisibilityFilter Class Reference

Manager layer visibility filter class. More...

#include <ilviews/manager/layer.h>

List of all members.

Public Member Functions
virtual IlBoolean	isVisible (const IlvManagerLayer *mgrlayer, const IlvMgrView *mgrview) const =0
	Indicates if a visible layer must be displayed in a manager view.

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Detailed Description

Manager layer visibility filter class.

Library: ilvmgr

This abstract class provides a way to hide manager layers depending on conditions defined by the implementer of the IlvLayerVisibilityFilter subclass. The visibility of a layer in a manager view is determined by the value returned by the pure virtual member function isVisible. To be displayed, a layer must be visible for the manager view (see member functions isVisible() of IlvManager and IlvManagerLayer classes) and for the visibility filters set on the manager layer.
Note that a visibility filter cannot force a hidden layer to be displayed, it can only hide a layer that would be visible otherwise.
A typical use of visibility filters is to hide specific layers depending of the zoom level in a given manager view; for example to remove detailed information in a cartographic application when a large map is fully displayed and only show it when zooming on a small portion of the map.

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Member Function Documentation

virtual IlBoolean IlvLayerVisibilityFilter::isVisible	(	const IlvManagerLayer *	mgrlayer,
		const IlvMgrView *	mgrview
	)			const [pure virtual]

Indicates if a visible layer must be displayed in a manager view.

Must be implemented by subclasses. The returned value is used by by the manager to determine whether the specified layer can be displayed in the specified manager view. The method is only called if the layer is visible for the manager and for the manager view.

Returns:

IlTrue if the filter allows the layer to be visible in the manager view.

Parameters:

	mgrlayer	Specifies the manager layer.
	mgrview	Specifies the manager view.