A generic container class for storing 2D grid data and providing resampling methods. More...

#include <qwt_grid_data.hpp>

Public Types
enum	ResampleMode { NearestNeighbour , BilinearInterpolation , BicubicInterpolation }
	Enumeration for resampling methods. More...

using	value_type = T
	Type of the stored values.

using	x_container_type = XContainer
	Type of the x-axis container.

using	y_container_type = YContainer
	Type of the y-axis container.

using	data_column_type = DataColumn
	Type of a single column in the data matrix.

using	data_container_type = DataContainer
	Type of the data matrix.

using	size_type = typename DataColumn::size_type

Public Member Functions
	QwtGridData ()
	Default constructor.

	QwtGridData (const x_container_type &xAxis, const y_container_type &yAxis, const data_container_type &data, ResampleMode mode=NearestNeighbour)
	Constructor with initial data.

void	setValue (const x_container_type &xAxis, const y_container_type &yAxis, const data_container_type &data)
	Set new x-axis, y-axis, and data matrix.

T	operator() (T x, T y) const
	Operator to query value at (x, y).

T	operator[] (const std::pair< T, T > &xy) const
	operator []

T	value (T x, T y) const
	Query value at (x, y).

void	setResampleMode (ResampleMode mode)
	Set the resampling mode.

ResampleMode	resampleMode () const
	Get the current resampling mode.

size_type	xSize () const
	Size of x-axis.

size_type	ySize () const
	Size of y-axis.

std::pair< size_type, size_type >	valueSize () const
	Size of the value matrix.

T	atX (size_type ix) const
	Value at x-axis index.

T	atY (size_type iy) const
	Value at y-axis index.

T	atValue (size_type ix, size_type iy) const
	Value at matrix index.

const x_container_type &	xAxis () const
	Get the x-axis values.

const y_container_type &	yAxis () const
	Get the y-axis values.

const data_container_type &	data () const
	Get the data matrix.

bool	valid () const
	Check if the object is valid.

void	validate ()
	Validate the data.

T	xMin () const

T	xMax () const

T	yMin () const

T	yMax () const

T	dataMin () const

T	dataMax () const

Static Public Member Functions
template<typename Container >
static size_type	findClosestIndex (const Container &arr, T val)
	Find the closest index in a sorted array.

template<typename Container >
static size_type	findLowerIndex (const Container &arr, T val)
	Find the lower bound index in a sorted array.

template<typename V >
static const V &	clamp (const V &value, const V &lo, const V &hi)

Protected Member Functions
void	findValueRange ()
	Get the minimum & maximum value in the data matrix.

T	nearestNeighbour (T x, T y) const
	Nearest neighbor interpolation.

T	bilinearInterpolation (T x, T y) const
	Bilinear interpolation.

T	bicubicInterpolation (T x, T y) const
	Perform bicubic interpolation.

Detailed Description

template<typename T, typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>
class QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >

A generic container class for storing 2D grid data and providing resampling methods.

This template class encapsulates a 2D table with x-axis and y-axis data. It supports three resampling methods: Nearest Neighbor, Bilinear Interpolation, and Bicubic Interpolation. The container types for the axes and data are templated to allow flexibility.

Y-axis direction (down), X-axis direction (right): n rows, m columns

|column[0]|column[1]| ... |column[m]| +------—+------—+--—+------—+ | [x0,yn] | [x1,yn] | ... | [xm,yn] | -> yAxis[n] corresponding row +------—+------—+--—+------—+ | ... | ... | ... | ... | +------—+------—+--—+------—+ | [x0,y1] | [x1,y1] | ... | [xm,y1] | -> yAxis[1] corresponding row +------—+------—+--—+------—+ | [x0,y0] | [x1,y0] | ... | [xm,y0] | -> yAxis[0] corresponding row +------—+------—+--—+------—+ ↑ ↑ ↑ ↑ xAxis[0] xAxis[1] ... xAxis[m]

Example Usage:

Example using std::vector:

std::vector<double> xAxis = {0, 1, 2, 3};
std::vector<double> yAxis = {0, 1, 2};
std::vector<std::vector<double>> data = {
    {1, 2, 3},
    {4, 5, 6},
    {7, 8, 9},
    {10, 11, 12}
};
 
// Create an instance with bilinear interpolation
QwtGridData<double> gridData(xAxis, yAxis, data, QwtGridData<double>::BilinearInterpolation);
 
// Query the value at (1.5, 1.5)
double value = gridData(1.5, 1.5);
std::cout << "Value at (1.5, 1.5): " << value << std::endl;

Example using QVector:

QVector<double> xAxis = {0, 1, 2, 3};
QVector<double> yAxis = {0, 1, 2};
QVector<QVector<double>> data = {
    {1, 2, 3},
    {4, 5, 6},
    {7, 8, 9},
    {10, 11, 12}
};
 
// Create an instance with bicubic interpolation
using QwtQVectorGridData = QwtGridData< double, QVector< double >, QVector< double >, QVector< double >, QVector<
QVector< double > > >; QwtQVectorGridData gridData(xAxis, yAxis, data, QwtQVectorGridData::BicubicInterpolation);
 
// Query the value at (1.5, 1.5)
double value = gridData(1.5, 1.5);
qDebug() << "Value at (1.5, 1.5):" << value;

Template Parameters

T	The type of the values stored in the grid.
XContainer	The container type for the x-axis values (default: std::vector).
YContainer	The container type for the y-axis values (default: same as XContainer).
DataColumn	The container type for a single column in the data matrix (default: same as XContainer).
DataContainer	The container type for the entire data matrix (default: same as XContainer).

Member Enumeration Documentation

◆ ResampleMode

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

enum QwtGridData::ResampleMode

Enumeration for resampling methods.

Defines the available resampling methods:

NearestNeighbour: Nearest neighbor interpolation.
BilinearInterpolation: Bilinear interpolation.
BicubicInterpolation: Hermite bicubic interpolation.

Constructor & Destructor Documentation

◆ QwtGridData() [1/2]

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::QwtGridData ( )

inline

Default constructor.

Initializes an empty QwtGridData object.

◆ QwtGridData() [2/2]

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::QwtGridData	(	const x_container_type &	xAxis,
		const y_container_type &	yAxis,
		const data_container_type &	data,
		ResampleMode	mode = `NearestNeighbour`
	)

inline

Constructor with initial data.

Initializes the object with x-axis, y-axis, and data matrix.

Parameters

xAxis	The x-axis values.
yAxis	The y-axis values.
data	The 2D data matrix.
mode	The resampling mode to use.

Member Function Documentation

◆ atValue()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::atValue	(	size_type	ix,
		size_type	iy
	)		const

inline

Value at matrix index.

Parameters

ix

Returns

◆ atX()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::atX ( size_type ix ) const

inline

Value at x-axis index.

Parameters

ix

Returns

◆ atY()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::atY ( size_type iy ) const

inline

Value at y-axis index.

Parameters

ix

Returns

◆ bicubicInterpolation()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::bicubicInterpolation	(	T	x,
		T	y
	)		const

inlineprotected

Perform bicubic interpolation.

Returns the bicubically interpolated value at the specified (x, y) position. This implementation uses the Hermite bicubic interpolation method.

Parameters

x	The x-coordinate.
y	The y-coordinate.

Returns: The bicubically interpolated value.

◆ bilinearInterpolation()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::bilinearInterpolation	(	T	x,
		T	y
	)		const

inlineprotected

Bilinear interpolation.

Parameters

x	The x-coordinate.
y	The y-coordinate.

Returns: The interpolated value.

◆ data()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

const data_container_type & QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::data ( ) const

inline

Get the data matrix.

Returns: The data matrix.

◆ findClosestIndex()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

template<typename Container >

static size_type QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::findClosestIndex	(	const Container &	arr,
		T	val
	)

inlinestatic

Find the closest index in a sorted array.

Parameters

arr	The sorted array.
val	The target value.

Returns: The index of the closest value.

◆ findLowerIndex()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

template<typename Container >

static size_type QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::findLowerIndex	(	const Container &	arr,
		T	val
	)

inlinestatic

Find the lower bound index in a sorted array.

Parameters

arr	The sorted array.
val	The target value.

Returns: The lower bound index.

◆ findValueRange()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

void QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::findValueRange ( )

inlineprotected

Get the minimum & maximum value in the data matrix.

Returns: std::pair<The minimum value, The maximum value> in the data matrix.

◆ nearestNeighbour()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::nearestNeighbour	(	T	x,
		T	y
	)		const

inlineprotected

Nearest neighbor interpolation.

Parameters

x	The x-coordinate.
y	The y-coordinate.

Returns: The nearest value.

◆ operator()()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::operator()	(	T	x,
		T	y
	)		const

inline

Operator to query value at (x, y).

Parameters

x	The x-coordinate.
y	The y-coordinate.

Returns: The interpolated or nearest value.

◆ operator[]()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::operator[] ( const std::pair< T, T > & xy ) const

inline

operator []

Queries value at the given (x, y) coordinates.

Parameters

xy,std::pair<x,y>

Returns: The interpolated or nearest value.

◆ resampleMode()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

ResampleMode QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::resampleMode ( ) const

inline

Get the current resampling mode.

Returns: The current resampling mode.

◆ setResampleMode()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

void QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::setResampleMode ( ResampleMode mode )

inline

Set the resampling mode.

Parameters

mode	The resampling mode to use.

◆ setValue()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

void QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::setValue	(	const x_container_type &	xAxis,
		const y_container_type &	yAxis,
		const data_container_type &	data
	)

inline

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

data matrix is look like that:

|column[0]|column[1]| ... |column[m]| +------—+------—+--—+------—+ | [x0,yn] | [x1,yn] | ... | [xm,yn] | -> yAxis[n] corresponding row +------—+------—+--—+------—+ | ... | ... | ... | ... | +------—+------—+--—+------—+ | [x0,y1] | [x1,y1] | ... | [xm,y1] | -> yAxis[1] corresponding row +------—+------—+--—+------—+ | [x0,y0] | [x1,y0] | ... | [xm,y0] | -> yAxis[0] corresponding row +------—+------—+--—+------—+ ↑ ↑ ↑ ↑ xAxis[0] xAxis[1] ... xAxis[m]

so (data matrix).size = xAxis.size,(data matrix).at(n).size = yAxis.size

Parameters

xAxis	The x-axis values.
yAxis	The y-axis values.
data	The 2D data matrix.

◆ valid()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

bool QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::valid ( ) const

inline

Check if the object is valid.

Returns: True if valid, false otherwise.

◆ value()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

T QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::value	(	T	x,
		T	y
	)		const

inline

Query value at (x, y).

Parameters

x	The x-coordinate.
y	The y-coordinate.

Returns: The interpolated or nearest value.

◆ valueSize()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

std::pair< size_type, size_type > QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::valueSize ( ) const

inline

Size of the value matrix.

Returns: <xsize,ysize>

◆ xAxis()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

const x_container_type & QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::xAxis ( ) const

inline

Get the x-axis values.

Returns: The x-axis values.

◆ xSize()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

size_type QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::xSize ( ) const

inline

Size of x-axis.

Returns

◆ yAxis()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

const y_container_type & QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::yAxis ( ) const

inline

Get the y-axis values.

Returns: The y-axis values.

◆ ySize()

template<typename T , typename XContainer = std::vector< T >, typename YContainer = std::vector< T >, typename DataColumn = std::vector< T >, typename DataContainer = std::vector< DataColumn >>

size_type QwtGridData< T, XContainer, YContainer, DataColumn, DataContainer >::ySize ( ) const

inline

Size of y-axis.

Returns

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

/home/runner/work/QWT/QWT/src/core/qwt_grid_data.hpp

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ ResampleMode

Constructor & Destructor Documentation

◆ QwtGridData() [1/2]

◆ QwtGridData() [2/2]

Member Function Documentation

◆ atValue()

◆ atX()

◆ atY()

◆ bicubicInterpolation()

◆ bilinearInterpolation()

◆ data()

◆ findClosestIndex()

◆ findLowerIndex()

◆ findValueRange()

◆ nearestNeighbour()

◆ operator()()

◆ operator[]()

◆ resampleMode()

◆ setResampleMode()

◆ setValue()

◆ valid()

◆ value()

◆ valueSize()

◆ xAxis()

◆ xSize()

◆ yAxis()

◆ ySize()