Subgroup: other

Class: QgsGenericNumericTransformer¶

class qgis.core.QgsGenericNumericTransformer¶

Bases: qgis._core.QgsPropertyTransformer

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

New in version 3.0: Methods

`clone`
`create`	Factory method for creating a new property transformer of the specified type.
`curveTransform`	Returns the curve transform applied to input values before they are transformed by the individual transform subclasses.
`exponent`	Returns the exponent for an exponential expression.
`fromExpression`	Attempts to parse an expression into a corresponding `QgsSizeScaleTransformer`.
`loadVariant`
`maxOutputValue`	Returns the maximum calculated size.
`maxValue`	Returns the maximum value expected by the transformer.
`minOutputValue`	Returns the minimum calculated size.
`minValue`	Returns the minimum value expected by the transformer.
`nullOutputValue`	Returns the size value when an expression evaluates to NULL.
`setCurveTransform`	Sets a curve transform to apply to input values before they are transformed by the individual transform subclasses.
`setExponent`	Sets the exponent for an exponential expression.
`setMaxOutputValue`	Sets the maximum calculated size.
`setMaxValue`	Sets the maximum value expected by the transformer.
`setMinOutputValue`	Sets the minimum calculated size.
`setMinValue`	Sets the minimum value expected by the transformer.
`setNullOutputValue`	Sets the size value for when an expression evaluates to NULL.
`toExpression`
`toVariant`
`transform`
`transformNumeric`
`transformerType`
`value`	Calculates the size corresponding to a specific `input` value.

Attributes

`ColorRampTransformer`
`GenericNumericTransformer`
`SizeScaleTransformer`

clone(self) → QgsGenericNumericTransformer¶

exponent(self) → float¶: Returns the exponent for an exponential expression.

See also

setExponent()

See also

type()

fromExpression(expression: str) → Tuple[QgsGenericNumericTransformer, str, str]¶

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. :param 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.

Returns:	corresponding `QgsSizeScaleTransformer`, or None if expression could not

be parsed to a size scale transformer.

loadVariant(self, definition: Any) → bool¶

maxOutputValue(self) → float¶: Returns the maximum calculated size.

See also

minSize()

minOutputValue(self) → float¶: Returns the minimum calculated size.

See also

setMinSize()

See also

maxSize()

nullOutputValue(self) → float¶: Returns the size value when an expression evaluates to NULL.

See also

setNullSize()

setExponent(self, exponent: float)¶

Sets the exponent for an exponential expression.

Parameters:	exponent – exponent

See also

exponent()

setMaxOutputValue(self, size: float)¶

Sets the maximum calculated size.

Parameters:	size – maximum size

See also

maxSize()

See also

setMinSize()

setMinOutputValue(self, size: float)¶

Sets the minimum calculated size.

Parameters:	size – minimum size

See also

minSize()

See also

setMaxSize()

setNullOutputValue(self, size: float)¶

Sets the size value for when an expression evaluates to NULL.

Parameters:	size – null size

See also

nullSize()

toExpression(self, baseExpression: str) → str¶

toVariant(self) → Any¶

transform(self, context: QgsExpressionContext, value: Any) → Any¶

transformNumeric()¶

transformerType(self) → QgsPropertyTransformer.Type¶

value(self, input: float) → float¶

Calculates the size corresponding to a specific input value.

Returns:	calculated size using size scale transformer’s parameters and type