QwtMatrixRasterData (3)

#include <qwt_matrix_raster_data.h>

Inherits QwtRasterData.

Public Types

enum ResampleMode { NearestNeighbour, BilinearInterpolation }

Public Member Functions

QwtMatrixRasterData ()

virtual ~QwtMatrixRasterData ()

void setResampleMode (ResampleMode mode)

ResampleMode resampleMode () const

virtual void setInterval (Qt::Axis, const QwtInterval &)

void setValueMatrix (const QVector< double > &values, size_t numColumns)

const QVector< double > valueMatrix () const

size_t numColumns () const

size_t numRows () const

virtual QRectF pixelHint (const QRectF &) const

virtual double value (double x, double y) const

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.

enum \fBQwtMatrixRasterData::ResampleMode\fP

Resampling algorithm The default setting is NearestNeighbour;.

Enumerator:

NearestNeighbour

Return the value from the matrix, that is nearest to the the requested position.

BilinearInterpolation

Interpolate the value from the distances and values of the 4 surrounding values in the matrix,

QwtMatrixRasterData::QwtMatrixRasterData ()

Constructor.

QwtMatrixRasterData::~QwtMatrixRasterData ()\fC [virtual]\fP

Destructor.

size_t QwtMatrixRasterData::numColumns () const \fBReturns:\fP

Number of columns of the value matrix

See also:

valueMatrix(), numRows(), setValueMatrix()

size_t QwtMatrixRasterData::numRows () const \fBReturns:\fP

Number of rows of the value matrix

See also:

valueMatrix(), numColumns(), setValueMatrix()

QRectF QwtMatrixRasterData::pixelHint (const QRectF &) const\fC [virtual]\fP

Pixel hint. .IP "•" 2 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 ( f.e. screen ) resolution.

See also:

ResampleMode, setMatrix(), setInterval()

Reimplemented from QwtRasterData.

\fBQwtMatrixRasterData::ResampleMode\fP QwtMatrixRasterData::resampleMode () const \fBReturns:\fP

resampling algorithm

See also:

setResampleMode(), value()

void QwtMatrixRasterData::setInterval (Qt::Axisaxis, const \fBQwtInterval\fP &interval)\fC [virtual]\fP

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:

axis X, Y or Z axis

interval Interval

See also:

QwtRasterData::interval(), setValueMatrix()

Reimplemented from QwtRasterData.

void QwtMatrixRasterData::setResampleMode (\fBResampleMode\fPmode)

Set the resampling algorithm. Parameters:

mode Resampling mode

See also:

resampleMode(), value()

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

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:

values Vector of values

numColumns Number of columns

See also:

valueMatrix(), numColumns(), numRows(), setInterval()()

double QwtMatrixRasterData::value (doublex, doubley) const\fC [virtual]\fP \fBReturns:\fP

the value at a raster position

Parameters:

x X value in plot coordinates

y Y value in plot coordinates

See also:

ResampleMode

Implements QwtRasterData.

const QVector< double > QwtMatrixRasterData::valueMatrix () const \fBReturns:\fP

Value matrix

See also:

setValueMatrix(), numColumns(), numRows(), setInterval()

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