QgsPropertyTransformer subclass for scaling an input numeric value into an output numeric value. More...

#include <qgspropertytransformer.h>

Inheritance diagram for QgsGenericNumericTransformer:

Public Member Functions
	QgsGenericNumericTransformer (double minValue=0.0, double maxValue=1.0, double minOutput=0.0, double maxOutput=1.0, double nullOutput=0.0, double exponent=1.0)
	Constructor for QgsGenericNumericTransformer.

QgsGenericNumericTransformer *	clone () const override
	Returns a clone of the transformer.

double	exponent () const
	Returns the exponent for an exponential expression.

bool	loadVariant (const QVariant &definition) override
	Loads this transformer from a QVariantMap, wrapped in a QVariant.

double	maxOutputValue () const
	Returns the maximum calculated size.

double	minOutputValue () const
	Returns the minimum calculated size.

double	nullOutputValue () const
	Returns the size value when an expression evaluates to NULL.

void	setExponent (double exponent)
	Sets the exponent for an exponential expression.

void	setMaxOutputValue (double size)
	Sets the maximum calculated size.

void	setMinOutputValue (double size)
	Sets the minimum calculated size.

void	setNullOutputValue (double size)
	Sets the size value for when an expression evaluates to NULL.

QString	toExpression (const QString &baseExpression) const override
	Converts the transformer to a QGIS expression string.

QVariant	toVariant () const override
	Saves this transformer to a QVariantMap, wrapped in a QVariant.

QVariant	transform (const QgsExpressionContext &context, const QVariant &value) const override
	Calculates the transform of a value.

Type	transformerType () const override
	Returns the transformer type.

double	value (double input) const
	Calculates the size corresponding to a specific input value.

Public Member Functions inherited from QgsPropertyTransformer
	QgsPropertyTransformer (const QgsPropertyTransformer &other)
	Copy constructor.

	QgsPropertyTransformer (double minValue=0.0, double maxValue=1.0)
	Constructor for QgsPropertyTransformer.

virtual	~QgsPropertyTransformer ()

QgsCurveTransform *	curveTransform () const
	Returns the curve transform applied to input values before they are transformed by the individual transform subclasses.

double	maxValue () const
	Returns the maximum value expected by the transformer.

double	minValue () const
	Returns the minimum value expected by the transformer.

QgsPropertyTransformer &	operator= (const QgsPropertyTransformer &other)

void	setCurveTransform (QgsCurveTransform *transform)
	Sets a curve transform to apply to input values before they are transformed by the individual transform subclasses.

void	setMaxValue (double max)
	Sets the maximum value expected by the transformer.

void	setMinValue (double min)
	Sets the minimum value expected by the transformer.

Static Public Member Functions
static QgsGenericNumericTransformer *	fromExpression (const QString &expression, QString &baseExpression, QString &fieldName)
	Attempts to parse an expression into a corresponding QgsSizeScaleTransformer.

Static Public Member Functions inherited from QgsPropertyTransformer
static QgsPropertyTransformer *	create (Type type)
	Factory method for creating a new property transformer of the specified type.

static QgsPropertyTransformer *	fromExpression (const QString &expression, QString &baseExpression, QString &fieldName)
	Attempts to parse an expression into a corresponding property transformer.

Additional Inherited Members
Public Types inherited from QgsPropertyTransformer
enum	Type { GenericNumericTransformer , SizeScaleTransformer , ColorRampTransformer }
	Transformer types. More...

Protected Member Functions inherited from QgsPropertyTransformer
double	transformNumeric (double input) const
	Applies base class numeric transformations.

Protected Attributes inherited from QgsPropertyTransformer
std::unique_ptr< QgsCurveTransform >	mCurveTransform
	Optional curve transform.

double	mMaxValue
	Maximum value expected by the transformer.

double	mMinValue
	Minimum value expected by the transformer.

Detailed Description

QgsPropertyTransformer subclass for scaling an input numeric value into an output numeric value.

Definition at line 340 of file qgspropertytransformer.h.

Constructor & Destructor Documentation

◆ QgsGenericNumericTransformer()

QgsGenericNumericTransformer::QgsGenericNumericTransformer	(	double	minValue = `0.0`,
		double	maxValue = `1.0`,
		double	minOutput = `0.0`,
		double	maxOutput = `1.0`,
		double	nullOutput = `0.0`,
		double	exponent = `1.0`
	)

Constructor for QgsGenericNumericTransformer.

Parameters

minValue	minimum expected input value
maxValue	maximum expected input value
minOutput	minimum value to return
maxOutput	maximum value to return
nullOutput	value to return for null inputs
exponent	optional exponential for non-linear scaling

Definition at line 133 of file qgspropertytransformer.cpp.

Member Function Documentation

◆ clone()

QgsGenericNumericTransformer * QgsGenericNumericTransformer::clone ( ) const

overridevirtual

Returns a clone of the transformer.

Implements QgsPropertyTransformer.

Definition at line 141 of file qgspropertytransformer.cpp.

◆ exponent()

double QgsGenericNumericTransformer::exponent ( ) const

inline

Returns the exponent for an exponential expression.

See also: setExponent()

Definition at line 433 of file qgspropertytransformer.h.

◆ fromExpression()

QgsGenericNumericTransformer * QgsGenericNumericTransformer::fromExpression	(	const QString &	expression,
		QString &	baseExpression,
		QString &	fieldName
	)

static

Attempts to parse an expression into a corresponding QgsSizeScaleTransformer.

Parameters

expression	expression to parse
baseExpression	will be set to the component of the source expression which is used to calculate the input to the property transformer. This will be set to an empty string if a field reference is the transformer input.
fieldName	will be set to a field name which is used to calculate the input to the property transformer. This will be set to an empty string if an expression is the transformer input.