PassiveCachingDD.h

A "passive" DisplayData is one which can only be used in conjunction with another non-passive DisplayData. As such, it will not negotiate coordinates on a WorldCanvas, nor will it provide coordinate conversion capabilities.

Member Description

PassiveCachingDD()

Constructor.

virtual ~PassiveCachingDD()

Destructor.

virtual Bool linToWorld(Vector<Double> &world, const Vector<Double> &lin)
virtual Bool worldToLin(Vector<Double> &lin, const Vector<Double> &world)

Coordinate transformation handlers, called by WorldCanvasHolder. These functions simply return False because this DisplayData is passive.

virtual String showPosition(const Vector<Double> &world, const Bool &displayAxesOnly = False)
virtual String showValue(const Vector<Double> &world)

Format a string containing coordinate or value information at the given world coordinate. They simply return empty Strings because this DisplayData is passive.

virtual Vector<String> worldAxisNames()
virtual Vector<String> worldAxisUnits()
virtual const Unit dataUnit()

World axis information suppliers.

virtual const uInt nelements(const WorldCanvasHolder &wcHolder) const
virtual const uInt nelements() const

Return the number of display elements (ie. drawable images) in this DisplayData.

virtual void setDefaultOptions()

Install the default options for this DisplayData.

virtual Bool setOptions(Record &rec, Record &recOut)

Apply options stored in rec to the DisplayData. A return value of True means a refresh is needed. recOut contains any fields which were implicitly changed as a result of the call to this function.

virtual Record getOptions()

Retrieve the current and default options and parameter types.

virtual void refreshEH(const WCRefreshEvent &ev)

Negotiatiate WorldCanvas linear coordinate system when asked to do so by the WorldCanvasHolder. In this implementation, simply return False to indicate that this DisplayData will not negotiate coordinates: it is a passive DisplayData.

virtual Bool sizeControl(WorldCanvasHolder &wcHolder, AttributeBuffer &holderBuf)

virtual void cleanup()

Tidy up the elements of this DisplayData.

virtual AttributeBuffer optionsAsAttributes()

Return the current options of this DisplayData as an AttributeBuffer. The caller must delete the returned buffer.

PassiveCachingDD(const PassiveCachingDD &other)

(Required) copy constructor.

void operator=(const PassiveCachingDD &other)

(Required) copy assignment.