QwtMatrixRasterData(3)

📦
version 6.3.0 · 4 versions
, in alpine 3.24

🌸 NAME 🌸

Bestie, welcome to QwtMatrixRasterData(3) from the Library Functions Manual 💖 — this whole page is about the class QwtMatrixRasterData, which is a class representing a matrix of values as raster data. Slay.

✨ SYNOPSIS ✨

#include <qwt_matrix_raster_data.h>

Inherits QwtRasterData.

👑 Public Types

  • enum ResampleMode { NearestNeighbour, BilinearInterpolation, BicubicInterpolation } — Resampling algorithm. The default setting is NearestNeighbour;.

🎀 Public Types inherited from QwtRasterData

  • enum Attribute { WithoutGaps = 0x01 } — Raster data attributes.
  • enum ConrecFlag { IgnoreAllVerticesOnLevel = 0x01, IgnoreOutOfRange = 0x02 } — Flags to modify the contour algorithm.
  • typedef QMap< double, QPolygonF > ContourLines — Contour lines.
  • typedef QFlags< Attribute > Attributes
  • typedef QFlags< ConrecFlag > ConrecFlags

🦋 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

🌈 Public Member Functions inherited from QwtRasterData

  • QwtRasterData () — Constructor.
  • virtual ~QwtRasterData () — Destructor.
  • void setAttribute (Attribute, bool on=true)
  • bool testAttribute (Attribute) const
  • virtual void initRaster (const QRectF &, const QSize &raster) — Initialize a raster.
  • virtual void discardRaster () — Discard a raster.
  • virtual ContourLines contourLines (const QRectF &rect, const QSize &raster, const QList< double > &levels, ConrecFlags) 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 aren't on the value matrix. Main character energy for a raster class, honestly.

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 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.

🧚 Constructor & Destructor Documentation 🧚

QwtMatrixRasterData::QwtMatrixRasterData ()

Constructor.

Definition at line 72 of file qwt_matrix_raster_data.cpp.

QwtMatrixRasterData::~QwtMatrixRasterData () [virtual]

Destructor.

Definition at line 79 of file qwt_matrix_raster_data.cpp.

🌈 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.

  • 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.

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 )

🚨 Mandatory bestie alert: setting the bounding intervals for the X/Y axis is mandatory to define the positions for the values of the value matrix. No cap.

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 👑

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