QwtGridRasterData Class Reference

A class that encapsulates grid data and provides interpolation methods. More...

#include <qwt_grid_raster_data.h>

Inheritance diagram for QwtGridRasterData:

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
	QwtGridRasterData ()
	Constructor.
void	setResampleMode (ResampleMode mode)
	Set the resample method.
ResampleMode	resampleMode () const
	Get the current resample method.
virtual QwtInterval	interval (Qt::Axis axis) const override final
	Return bounding interval for an axis.
void	setValue (const QVector< double > &x, const QVector< double > &y, const QVector< QVector< double > > &v)
	Set new x-axis, y-axis, and data matrix.
virtual double	value (double x, double y) const override
	Return the value at a raster position.
virtual QRectF	pixelHint (const QRectF &) const override
	Calculate the pixel hint.
int	xSize () const
	Return the size of x-axis.
int	ySize () const
	Return the size of y-axis.
std::pair< int, int >	valueSize () const
	Return the size of the value matrix.
double	atValue (int xIndex, int yIndex) const
	Return the value at specified position in the value matrix.
double	atX (int xIndex) const
	Return the x-axis value at specified index.
double	atY (int yIndex) const
	Return the y-axis value at specified index.
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 that encapsulates grid data and provides interpolation methods.

This class inherits from QwtRasterData and is used to represent 2D grid data. It supports various interpolation methods such as nearest neighbor and bilinear interpolation.

Member Enumeration Documentation

ResampleMode

enum QwtGridRasterData::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

QwtGridRasterData()

QwtGridRasterData::QwtGridRasterData

(

)

Constructor.

Destructor

Member Function Documentation

atValue()

double QwtGridRasterData::atValue	(	int	xIndex,
		int	yIndex
	)		const

Return the value at specified position in the value matrix.

Parameters

[in]	xIndex	X index.
[in]	yIndex	Y index.

Returns

Value at the position.

atX()

double QwtGridRasterData::atX

(

int

xIndex

)

const

Return the x-axis value at specified index.

Parameters

[in]

xIndex

X index.

Returns

X-axis value.

atY()

double QwtGridRasterData::atY

(

int

yIndex

)

const

Return the y-axis value at specified index.

Parameters

[in]

yIndex

Y index.

Returns

Y-axis value.

interval()

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

finaloverridevirtual

Return bounding interval for an axis.

Parameters

[in]

axis

Axis to query (X, Y, or Z)

Returns

Bounding interval for the axis

Implements QwtRasterData.

pixelHint()

QRectF QwtGridRasterData::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 representing the data. For NearestNeighbour mode, returns the surrounding pixel. For other modes, returns an empty rectangle.

Parameters

[in]

area

Requested area (ignored)

Returns

Calculated hint rectangle

Reimplemented from QwtRasterData.

resampleMode()

QwtGridRasterData::ResampleMode QwtGridRasterData::resampleMode

(

)

const

Get the current resample method.

Returns

The current resample method.

See also

setResampleMode(), value()

setResampleMode()

void QwtGridRasterData::setResampleMode

(

QwtGridRasterData::ResampleMode

mode

)

Set the resample method.

Sets the resample method to be used when querying values.

Parameters

[in]

mode

The resample method to use.

See also

resampleMode(), value()

setValue()

void QwtGridRasterData::setValue	(	const QVector< double > &	x,
		const QVector< double > &	y,
		const QVector< QVector< double > > &	v
	)

Set new x-axis, y-axis, and data matrix.

The data matrix layout:

• data matrix.size = xAxis.size
• data matrix.at(n).size = yAxis.size

  Parameters

  [in]	x	The x-axis values
  [in]	y	The y-axis values
  [in]	v	The 2D data matrix

value()

double QwtGridRasterData::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, or NaN if outside bounds

Implements QwtRasterData.

valueSize()

std::pair< int, int > QwtGridRasterData::valueSize

(

)

const

Return the size of the value matrix.

Returns

Pair of (xSize, ySize).

xSize()

int QwtGridRasterData::xSize

(

)

const

Return the size of x-axis.

Returns

Size of x-axis.

ySize()

int QwtGridRasterData::ySize

(

)

const

Return the size of y-axis.

Returns

Size of y-axis.

---

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

• /home/runner/work/QWT/QWT/src/core/qwt_grid_raster_data.h
• /home/runner/work/QWT/QWT/src/core/qwt_grid_raster_data.cpp