QwtMatrixRasterData(3) Qwt User's Guide QwtMatrixRasterData(3) NAME QwtMatrixRasterData - A class representing a matrix of values as raster data. SYNOPSIS #include Inherits QwtRasterData. Public Types enum ResampleMode { NearestNeighbour, BilinearInterpolation, BicubicInterpolation } Resampling algorithm The default setting is NearestNeighbour;. Public Member Functions QwtMatrixRasterData () Constructor. virtual ~QwtMatrixRasterData () Destructor. void setResampleMode (ResampleMode mode) Set the resampling algorithm. ResampleMode resampleMode () const void setInterval (Qt::Axis, const QwtInterval &) Assign the bounding interval for an axis. virtual QwtInterval interval (Qt::Axis axis) const override final void setValueMatrix (const QVector< double > &values, int numColumns) Assign a value matrix. const QVector< double > valueMatrix () const void setValue (int row, int col, double value) Change a single value in the matrix. int numColumns () const int numRows () const virtual QRectF pixelHint (const QRectF &) const override Calculate the pixel hint. virtual double value (double x, double y) const override 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. Definition at line 28 of file qwt_matrix_raster_data.h. Member Enumeration Documentation enum QwtMatrixRasterData::ResampleMode 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, BicubicInterpolation Interpolate the value from the 16 surrounding values in the matrix using hermite bicubic interpolation Definition at line 35 of file qwt_matrix_raster_data.h. Member Function Documentation QwtInterval QwtMatrixRasterData::interval (Qt::Axis axis) const [final], [override], [virtual] Returns Bounding interval for an axis See also setInterval Implements QwtRasterData. Definition at line 134 of file qwt_matrix_raster_data.cpp. int QwtMatrixRasterData::numColumns () const Returns Number of columns of the value matrix See also valueMatrix(), numRows(), setValueMatrix() Definition at line 195 of file qwt_matrix_raster_data.cpp. int QwtMatrixRasterData::numRows () const Returns Number of rows of the value matrix See also valueMatrix(), numColumns(), setValueMatrix() Definition at line 204 of file qwt_matrix_raster_data.cpp. QRectF QwtMatrixRasterData::pixelHint (const QRectF & area) const [override], [virtual] 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. o NearestNeighbour pixelHint() returns the surrounding pixel of the top left value in the matrix. o BilinearInterpolation Returns an empty rectangle recommending to render in target device ( f.e. screen ) resolution. Parameters area Requested area, ignored Returns Calculated hint See also ResampleMode, setMatrix(), setInterval() Reimplemented from QwtRasterData. Definition at line 229 of file qwt_matrix_raster_data.cpp. QwtMatrixRasterData::ResampleMode QwtMatrixRasterData::resampleMode () const Returns resampling algorithm See also setResampleMode(), value() Definition at line 99 of file qwt_matrix_raster_data.cpp. 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 axis X, Y or Z axis interval Interval See also QwtRasterData::interval(), setValueMatrix() Definition at line 120 of file qwt_matrix_raster_data.cpp. void QwtMatrixRasterData::setResampleMode (ResampleMode mode) Set the resampling algorithm. Parameters mode Resampling mode See also resampleMode(), value() Definition at line 90 of file qwt_matrix_raster_data.cpp. void QwtMatrixRasterData::setValue (int row, int col, double value) Change a single value in the matrix. Parameters row Row index col Column index value New value See also value(), setValueMatrix() Definition at line 181 of file qwt_matrix_raster_data.cpp. 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 values Vector of values numColumns Number of columns See also valueMatrix(), numColumns(), numRows(), setInterval()() Definition at line 155 of file qwt_matrix_raster_data.cpp. double QwtMatrixRasterData::value (double x, double y) const [override], [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. Definition at line 256 of file qwt_matrix_raster_data.cpp. const QVector< double > QwtMatrixRasterData::valueMatrix () const Returns Value matrix See also setValueMatrix(), numColumns(), numRows(), setInterval() Definition at line 167 of file qwt_matrix_raster_data.cpp. Author Generated automatically by Doxygen for Qwt User's Guide from the source code. Version 6.2.0 Sun Jul 18 2021 QwtMatrixRasterData(3)