A class representing a matrix of values as raster data. More...

#include <qwt_matrix_raster_data.h>

Inheritance diagram for QwtMatrixRasterData:

Classes
class	PrivateData

Public Types
enum	ResampleMode { NearestNeighbour , BilinearInterpolation , BicubicInterpolation }
	Resampling algorithm. More...

Public Types inherited from QwtRasterData
enum	Attribute { WithoutGaps = 0x01 }
	Raster data attributes. More...

enum	ConrecFlag { IgnoreAllVerticesOnLevel = 0x01 , IgnoreOutOfRange = 0x02 }
	Flags to modify the contour algorithm. More...

using	ContourLines = QMap< double, QPolygonF >
	Contour lines.

Public Member Functions
	QwtMatrixRasterData ()
	Constructor.

void	setResampleMode (ResampleMode mode)
	Set the resampling algorithm.

ResampleMode	resampleMode () const
	Return the resampling algorithm.

void	setInterval (Qt::Axis, const QwtInterval &)
	Assign the bounding interval for an axis.

virtual QwtInterval	interval (Qt::Axis axis) const override final
	Return bounding interval for an axis.

void	setValueMatrix (const QVector< double > &values, int numColumns)
	Assign a value matrix.

const QVector< double >	valueMatrix () const
	Return value matrix.

void	setValue (int row, int col, double value)
	Change a single value in the matrix.

int	numColumns () const
	Return number of columns of the value matrix.

int	numRows () const
	Return number of rows of the value matrix.

virtual QRectF	pixelHint (const QRectF &) const override
	Calculate the pixel hint.

virtual double	value (double x, double y) const override
	Return the value at a raster position.

Public Member Functions inherited from QwtRasterData
	QwtRasterData ()
	Constructor.

virtual	~QwtRasterData ()
	Destructor.

void	setAttribute (Attribute, bool on=true)
	Set an attribute.

bool	testAttribute (Attribute) const
	Test an attribute.

virtual void	initRaster (const QRectF &, const QSize &raster)
	Initialize the raster.

virtual void	discardRaster ()
	Discard the raster.

virtual ContourLines	contourLines (const QRectF &rect, const QSize &raster, const QList< double > &levels, ConrecFlags) const
	Calculate contour lines.

Detailed Description

A class representing a matrix of values as raster data.

QwtMatrixRasterData implements an interface for a matrix of equidistant values, that can be used by a QwtPlotRasterItem. It implements a couple of resampling algorithms, to provide values for positions, that or not on the value matrix.

Member Enumeration Documentation

◆ ResampleMode

enum QwtMatrixRasterData::ResampleMode

Resampling algorithm.

The default setting is NearestNeighbour.

Enumerator
NearestNeighbour	Return the value from the matrix that is nearest to the requested position.
BilinearInterpolation	Interpolate the value from the distances and values of the 4 surrounding values in the matrix.
BicubicInterpolation	Interpolate the value from the 16 surrounding values in the matrix using hermite bicubic interpolation.

Constructor & Destructor Documentation

◆ QwtMatrixRasterData()

QwtMatrixRasterData::QwtMatrixRasterData ( )

Constructor.

Destructor

Member Function Documentation

◆ interval()

QwtInterval QwtMatrixRasterData::interval ( Qt::Axis axis ) const

finaloverridevirtual

Return bounding interval for an axis.

Parameters

[in] axis Axis to query.

Returns: Bounding interval for the axis.

See also: setInterval()

Implements QwtRasterData.

◆ numColumns()

int QwtMatrixRasterData::numColumns ( ) const

Return number of columns of the value matrix.

Returns: Number of columns.

See also: valueMatrix(), numRows(), setValueMatrix()

◆ numRows()

int QwtMatrixRasterData::numRows ( ) const

Return number of rows of the value matrix.

Returns: Number of rows.

See also: valueMatrix(), numColumns(), setValueMatrix()

◆ pixelHint()

QRectF QwtMatrixRasterData::pixelHint ( const QRectF & area ) const

overridevirtual

Calculate the pixel hint.

pixelHint() returns the geometry of a pixel, that can be used to calculate the resolution and alignment of the plot item, that is representing the data.

NearestNeighbour: pixelHint() returns the surrounding pixel of the top left value in the matrix.
BilinearInterpolation: Returns an empty rectangle recommending to render in target device resolution.
Parameters

[in] area Requested area, ignored.

Returns
Calculated hint.

See also
ResampleMode, setMatrix(), setInterval()

Reimplemented from QwtRasterData.

◆ resampleMode()

QwtMatrixRasterData::ResampleMode QwtMatrixRasterData::resampleMode ( ) const

Return the resampling algorithm.

Returns: Resampling algorithm.

See also: setResampleMode(), value()

◆ setInterval()

void QwtMatrixRasterData::setInterval	(	Qt::Axis	axis,
		const QwtInterval &	interval
	)

Assign the bounding interval for an axis.

Setting the bounding intervals for the X/Y axis is mandatory to define the positions for the values of the value matrix. The interval in Z direction defines the possible range for the values in the matrix, what is f.e used by QwtPlotSpectrogram to map values to colors. The Z-interval might be the bounding interval of the values in the matrix, but usually it isn't. (f.e a interval of 0.0-100.0 for values in percentage).

Parameters

[in]	axis	X, Y or Z axis.
[in]	interval	Interval.

See also: QwtRasterData::interval(), setValueMatrix()

◆ setResampleMode()

void QwtMatrixRasterData::setResampleMode ( ResampleMode mode )

Set the resampling algorithm.

Parameters

[in] mode Resampling mode.

See also: resampleMode(), value()

◆ setValue()

void QwtMatrixRasterData::setValue	(	int	row,
		int	col,
		double	value
	)

Change a single value in the matrix.

Parameters

[in]	row	Row index.
[in]	col	Column index.
[in]	value	New value.

See also: value(), setValueMatrix()

◆ setValueMatrix()

void QwtMatrixRasterData::setValueMatrix	(	const QVector< double > &	values,
		int	numColumns
	)

Assign a value matrix.

The positions of the values are calculated by dividing the bounding rectangle of the X/Y intervals into equidistant rectangles (pixels). Each value corresponds to the center of a pixel.

Parameters

[in]	values	Vector of values.
[in]	numColumns	Number of columns.

See also: valueMatrix(), numColumns(), numRows(), setInterval()

◆ value()

double QwtMatrixRasterData::value	(	double	x,
		double	y
	)		const

overridevirtual

Return the value at a raster position.

Parameters

[in]	x	X value in plot coordinates.
[in]	y	Y value in plot coordinates.

Returns: Value at the position.

See also: ResampleMode

Implements QwtRasterData.

◆ valueMatrix()

const QVector< double > QwtMatrixRasterData::valueMatrix ( ) const

Return value matrix.

Returns: Value matrix.

See also: setValueMatrix(), numColumns(), numRows(), setInterval()

The documentation for this class was generated from the following files:

/home/runner/work/QWT/QWT/src/core/qwt_matrix_raster_data.h
/home/runner/work/QWT/QWT/src/core/qwt_matrix_raster_data.cpp

Classes

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ ResampleMode

Constructor & Destructor Documentation

◆ QwtMatrixRasterData()

Member Function Documentation

◆ interval()

◆ numColumns()

◆ numRows()

◆ pixelHint()

◆ resampleMode()

◆ setInterval()

◆ setResampleMode()

◆ setValue()

◆ setValueMatrix()

◆ value()

◆ valueMatrix()