QwtMatrixRasterData Class Reference

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

#include <qwt_matrix_raster_data.h>

Inheritance diagram for QwtMatrixRasterData:
Inheritance graph
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List of all members.

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

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

Resampling algorithm

  • 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 in the matrix,

The default setting is NearestNeighbour;


Constructor & Destructor Documentation

QwtMatrixRasterData::QwtMatrixRasterData (  ) 

Constructor.

QwtMatrixRasterData::~QwtMatrixRasterData (  )  [virtual]

Destructor.


Member Function Documentation

size_t QwtMatrixRasterData::numColumns (  )  const
Returns:
Number of columns of the value matrix
See also:
valueMatrix(), numRows(), setValueMatrix()
size_t QwtMatrixRasterData::numRows (  )  const
Returns:
Number of rows of the value matrix
See also:
valueMatrix(), numColumns(), setValueMatrix()
QRectF QwtMatrixRasterData::pixelHint ( const QRectF &   )  const [virtual]

Pixel hint.

  • 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.

QwtMatrixRasterData::ResampleMode QwtMatrixRasterData::resampleMode (  )  const
Returns:
resampling algorithm
See also:
setResampleMode(), value()
void QwtMatrixRasterData::setInterval ( Qt::Axis  axis,
const QwtInterval interval 
) [virtual]

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 ( ResampleMode  mode  ) 

Set the resampling algorithm.

Parameters:
mode Resampling mode
See also:
resampleMode(), value()
void QwtMatrixRasterData::setValueMatrix ( const QVector< double > &  values,
size_t  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:
values Vector of values
numColumns Number of columns
See also:
valueMatrix(), numColumns(), numRows(), setInterval()()
double QwtMatrixRasterData::value ( double  x,
double  y 
) const [virtual]
Returns:
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
Returns:
Value matrix
See also:
setValueMatrix(), numColumns(), numRows(), setInterval()
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