Class: QgsGenericNumericTransformer¶

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

List of all members, including inherited members

Class Hierarchy¶

Base classes¶

QgsPropertyTransformer

Abstract base class for objects which transform the calculated value of a property.

Methods

`exponent`	Returns the exponent for an exponential expression.
`maxOutputValue`	Returns the maximum calculated size.
`minOutputValue`	Returns the minimum calculated size.
`nullOutputValue`	Returns the size value when an expression evaluates to NULL.
`setExponent`	Sets the exponent for an exponential expression.
`setMaxOutputValue`	Sets the maximum calculated size.
`setMinOutputValue`	Sets the minimum calculated size.
`setNullOutputValue`	Sets the size value for when an expression evaluates to NULL.
`value`	Calculates the size corresponding to a specific input value.

Static Methods

fromExpression

Attempts to parse an expression into a corresponding QgsSizeScaleTransformer.

class qgis.core.QgsGenericNumericTransformer[source]¶

Bases: QgsPropertyTransformer

__init__(minValue: float = 0, maxValue: float = 1, minOutput: float = 0, maxOutput: float = 1, nullOutput: float = 0, exponent: float = 1)

Constructor for QgsGenericNumericTransformer.

Parameters:

minValue (float = 0) – minimum expected input value
maxValue (float = 1) – maximum expected input value
minOutput (float = 0) – minimum value to return
maxOutput (float = 1) – maximum value to return
nullOutput (float = 0) – value to return for null inputs
exponent (float = 1) – optional exponential for non-linear scaling

__init__(a0: QgsGenericNumericTransformer)

Parameters:: a0 (QgsGenericNumericTransformer)

exponent(self) → float[source]¶

Returns the exponent for an exponential expression.

See also

setExponent()

Return type:: float

static fromExpression(expression: str | None)[source]¶

Attempts to parse an expression into a corresponding QgsSizeScaleTransformer.

Parameters:

expression (Optional[str]) – expression to parse

Return type:

(Optional[QgsGenericNumericTransformer], str, str)

Returns:

corresponding QgsSizeScaleTransformer, or None if expression could not be parsed to a size scale transformer.
baseExpression: 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: 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.

maxOutputValue(self) → float[source]¶

Returns the maximum calculated size.

See also

minOutputValue()