IlvRadialGridDisplayer Class Reference

Grid displayer subclass for the abscissa scale of polar charts. More...

#include <ilviews/charts/grid.h>

Inheritance diagram for IlvRadialGridDisplayer:

List of all members.

Public Member Functions
	IlvRadialGridDisplayer (IlvPalette *major=0, IlvPalette *minor=0)
	Constructor.
virtual IlvRectangularGridDisplayer *	createRectangularGrid () const
	Creates and returns a rectangular grid instantiated with the current grid parameters.
virtual void	drawTick (IlUInt tickIdx, const IlvPoint &tickPoint, IlDouble tickAngle, IlBoolean major, IlvPort *dst, const IlvRegion *givenClip) const
	Draws the grid line for a given tick of the scale with which the grid is associated.

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Detailed Description

Grid displayer subclass for the abscissa scale of polar charts.

Library: ilvcharts

This class is a subclass of IlvAbstractGridDisplayer that allows you to define a radial grid composed of radial straight lines. This kind of grid is used only for polar charts. A polar chart displays data expressed in polar coordinates with an abscissa scale that is circular and ordinate scales that are radial. In a polar chart, the radial grid is used to draw the grid lines for the ticks of the circular scale, which means that it is used for the abscissa scale. If you want to set a grid on an ordinate scale of a polar chart, you must use a circular grid which is represented by an instance of the IlvCircularGridDisplayer class.

In a polar chart, the abscissa scale is drawn by using an instance of the IlvCircularScaleDisplayer class and the ordinate scales by using instances of the IlvRectangularScaleDisplayer class. Therefore, the radial grid can only be used with an IlvCircularScaleDisplayer object and when the projector used to project the data is an IlvPolarProjector object.

You can see an example of a radial grid on the figure below where a grid is set for the abscissa scale of the displayed chart.

See also:

IlvAbstractGridDisplayer, IlvCircularGridDisplayer.

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Constructor & Destructor Documentation

IlvRadialGridDisplayer::IlvRadialGridDisplayer	(	IlvPalette *	major = 0,
		IlvPalette *	minor = 0
	)

Constructor.

Initializes a new IlvRadialGridDisplayer object. To do this, the constructor calls the corresponding constructor IlvAbstractGridDisplayer::IlvAbstractGridDisplayer(IlvPalette*, IlvPalette*) of its parent class.

Parameters:

	major	The new palette that will be used to draw the major lines of the current grid.
	minor	The new palette that will be used to draw the minor lines of the current grid.

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Member Function Documentation

virtual IlvRectangularGridDisplayer* IlvRadialGridDisplayer::createRectangularGrid

(

)

const [virtual]

Creates and returns a rectangular grid instantiated with the current grid parameters.

Returns:

The rectangular grid that is created.

virtual void IlvRadialGridDisplayer::drawTick	(	IlUInt	tickIdx,
		const IlvPoint &	tickPoint,
		IlDouble	tickAngle,
		IlBoolean	major,
		IlvPort *	dst,
		const IlvRegion *	clip
	)			const [virtual]

Draws the grid line for a given tick of the scale with which the grid is associated.

Draws the grid line for the scale tick of index tickIdx, defined by the point tickPoint, which is its position in pixels, and by its angle tickAngle.

The grid line is drawn in the given port named dst using the clipping region clip.

Parameters:

	tickIdx	The index of the tick on the scale to which the grid is attached.
	tickPoint	The position in pixels of the scale tick for which the grid line is drawn. This point is already transformed.
	tickAngle	The angle of the scale tick for which the grid line is drawn.
	major	A Boolean value indicating whether the tick is a major step or a substep.
	dst	The port where the grid line is drawn.
	clip	The clipping region.

Warning:

[note] This method is called inside the IlvSingleScaleDisplayer::drawTick method. Therefore, the grid line is drawn when the scale tick is drawn.

[note] The data display area is automatically set by the scale with the IlvAbstractGridDisplayer::setDataDisplayArea method before the grid lines are drawn. This area can therefore be fetched with the IlvAbstractGridDisplayer::getDataDisplayArea method.

Implements IlvAbstractGridDisplayer.