QgsContrastEnhancement Class Reference

Manipulates raster pixel values so that they enhanceContrast or clip into a specified numerical range according to the specified ContrastEnhancementAlgorithm. More...

#include <qgscontrastenhancement.h>

Public Types
enum	ContrastEnhancementAlgorithm {   NoEnhancement, StretchToMinimumMaximum, StretchAndClipToMinimumMaximum, ClipToMinimumMaximum,   UserDefinedEnhancement }
	This enumerator describes the types of contrast enhancement algorithms that can be used. More...

Public Member Functions
	QgsContrastEnhancement (Qgis::DataType datatype=Qgis::Byte)
	QgsContrastEnhancement (const QgsContrastEnhancement &ce)
	~QgsContrastEnhancement ()
ContrastEnhancementAlgorithm	contrastEnhancementAlgorithm () const
int	enhanceContrast (double value)
	Applies the contrast enhancement to a value. More...
bool	isValueInDisplayableRange (double value)
	Returns true if a pixel value is in displayable range, false if pixel is outside of range (i.e. More...
double	maximumValue () const
	Returns the maximum value for the contrast enhancement range. More...
double	minimumValue () const
	Returns the minimum value for the contrast enhancement range. More...
const QgsContrastEnhancement &	operator= (const QgsContrastEnhancement &)=delete
void	readXml (const QDomElement &elem)
void	setContrastEnhancementAlgorithm (ContrastEnhancementAlgorithm algorithm, bool generateTable=true)
	Sets the contrast enhancement algorithm. More...
void	setContrastEnhancementFunction (QgsContrastEnhancementFunction *function)
	Allows the user to set their own custom contrast enhancement function. More...
void	setMaximumValue (double value, bool generateTable=true)
	Sets the maximum value for the contrast enhancement range. More...
void	setMinimumValue (double value, bool generateTable=true)
	Sets the minimum value for the contrast enhancement range. More...
void	writeXml (QDomDocument &doc, QDomElement &parentElem) const

Static Public Member Functions
static ContrastEnhancementAlgorithm	contrastEnhancementAlgorithmFromString (const QString &contrastEnhancementString)
	Deserialize ContrastEnhancementAlgorithm. More...
static QString	contrastEnhancementAlgorithmString (ContrastEnhancementAlgorithm algorithm)
	Returns a string to serialize ContrastEnhancementAlgorithm. More...
static double	maximumValuePossible (Qgis::DataType)
	Helper function that returns the maximum possible value for a GDAL data type. More...
static double	minimumValuePossible (Qgis::DataType)
	Helper function that returns the minimum possible value for a GDAL data type. More...

Detailed Description

Manipulates raster pixel values so that they enhanceContrast or clip into a specified numerical range according to the specified ContrastEnhancementAlgorithm.

Definition at line 42 of file qgscontrastenhancement.h.

Member Enumeration Documentation

ContrastEnhancementAlgorithm

enum QgsContrastEnhancement::ContrastEnhancementAlgorithm

This enumerator describes the types of contrast enhancement algorithms that can be used.

Enumerator
NoEnhancement
StretchToMinimumMaximum
StretchAndClipToMinimumMaximum
ClipToMinimumMaximum
UserDefinedEnhancement

Definition at line 48 of file qgscontrastenhancement.h.

Constructor & Destructor Documentation

QgsContrastEnhancement() [1/2]

QgsContrastEnhancement::QgsContrastEnhancement

(

Qgis::DataType

datatype = Qgis::Byte

)

Definition at line 32 of file qgscontrastenhancement.cpp.

QgsContrastEnhancement() [2/2]

QgsContrastEnhancement::QgsContrastEnhancement

(

const QgsContrastEnhancement &

ce

)

Definition at line 51 of file qgscontrastenhancement.cpp.

~QgsContrastEnhancement()

QgsContrastEnhancement::~QgsContrastEnhancement

(

)

Definition at line 70 of file qgscontrastenhancement.cpp.

Member Function Documentation

contrastEnhancementAlgorithm()

ContrastEnhancementAlgorithm QgsContrastEnhancement::contrastEnhancementAlgorithm ( ) const

inline

Definition at line 100 of file qgscontrastenhancement.h.

contrastEnhancementAlgorithmFromString()

QgsContrastEnhancement::ContrastEnhancementAlgorithm QgsContrastEnhancement::contrastEnhancementAlgorithmFromString ( const QString &  contrastEnhancementString )

static

Deserialize ContrastEnhancementAlgorithm.

Definition at line 398 of file qgscontrastenhancement.cpp.

contrastEnhancementAlgorithmString()

QString QgsContrastEnhancement::contrastEnhancementAlgorithmString ( ContrastEnhancementAlgorithm  algorithm )

static

Returns a string to serialize ContrastEnhancementAlgorithm.

Definition at line 380 of file qgscontrastenhancement.cpp.

enhanceContrast()

int QgsContrastEnhancement::enhanceContrast

(

double

value

)

Applies the contrast enhancement to a value.

Return values are 0 - 254, -1 means the pixel was clipped and should not be displayed.

Definition at line 158 of file qgscontrastenhancement.cpp.

isValueInDisplayableRange()

bool QgsContrastEnhancement::isValueInDisplayableRange

(

double

value

)

Returns true if a pixel value is in displayable range, false if pixel is outside of range (i.e.

clipped).

Definition at line 208 of file qgscontrastenhancement.cpp.

maximumValue()

double QgsContrastEnhancement::maximumValue ( ) const

inline

Returns the maximum value for the contrast enhancement range.

Definition at line 95 of file qgscontrastenhancement.h.

maximumValuePossible()

double QgsContrastEnhancement::maximumValuePossible ( Qgis::DataType  dataType )

static

Helper function that returns the maximum possible value for a GDAL data type.

Definition at line 80 of file qgscontrastenhancement.cpp.

minimumValue()

double QgsContrastEnhancement::minimumValue ( ) const

inline

Returns the minimum value for the contrast enhancement range.

Definition at line 98 of file qgscontrastenhancement.h.

minimumValuePossible()

double QgsContrastEnhancement::minimumValuePossible ( Qgis::DataType  dataType )

static

Helper function that returns the minimum possible value for a GDAL data type.

Definition at line 116 of file qgscontrastenhancement.cpp.

operator=()

const QgsContrastEnhancement& QgsContrastEnhancement::operator= ( const QgsContrastEnhancement &  )

delete

readXml()

void QgsContrastEnhancement::readXml

(

const QDomElement &

elem

)

Definition at line 333 of file qgscontrastenhancement.cpp.

setContrastEnhancementAlgorithm()

void QgsContrastEnhancement::setContrastEnhancementAlgorithm	(	ContrastEnhancementAlgorithm	algorithm,
		bool	generateTable = true
	)

Sets the contrast enhancement algorithm.

The generateTable parameter is optional and is for performance improvements. If you know you are immediately going to set the Minimum or Maximum value, you can elect to not generate the lookup tale. By default it will be generated.

Definition at line 218 of file qgscontrastenhancement.cpp.

setContrastEnhancementFunction()

void QgsContrastEnhancement::setContrastEnhancementFunction

(

QgsContrastEnhancementFunction *

function

)

Allows the user to set their own custom contrast enhancement function.

Ownership of function is transferred.

Definition at line 248 of file qgscontrastenhancement.cpp.

setMaximumValue()

void QgsContrastEnhancement::setMaximumValue	(	double	value,
		bool	generateTable = true
	)

Sets the maximum value for the contrast enhancement range.

The generateTable parameter is optional and is for performance improvements. If you know you are immediately going to set the minimum value or the contrast enhancement algorithm, you can elect to not generate the lookup table. By default it will be generated.

See also

setMinimumValue()

Definition at line 260 of file qgscontrastenhancement.cpp.

setMinimumValue()

void QgsContrastEnhancement::setMinimumValue	(	double	value,
		bool	generateTable = true
	)

Sets the minimum value for the contrast enhancement range.

The generateTable parameter is optional and is for performance improvements. If you know you are immediately going to set the maximum value or the contrast enhancement algorithm, you can elect to not generate the lookup table. By default it will be generated.

See also

setMaximumValue()

Definition at line 286 of file qgscontrastenhancement.cpp.

writeXml()

void QgsContrastEnhancement::writeXml	(	QDomDocument &	doc,
		QDomElement &	parentElem
	)		const

Definition at line 312 of file qgscontrastenhancement.cpp.

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

• /tmp/buildd/qgis-3.2.0+99unstable/src/core/raster/qgscontrastenhancement.h
• /tmp/buildd/qgis-3.2.0+99unstable/src/core/raster/qgscontrastenhancement.cpp