Class: QgsGenericNumericTransformer¶
QgsPropertyTransformer
subclass for scaling an input numeric
value into an output numeric value.
Class Hierarchy¶
Base classes¶
Abstract base class for objects which transform the calculated value of a property. |
Methods
Returns the exponent for an exponential expression. |
|
Returns the maximum calculated size. |
|
Returns the minimum calculated size. |
|
Returns the size value when an expression evaluates to NULL. |
|
Sets the exponent for an exponential expression. |
|
Sets the maximum calculated size. |
|
Sets the minimum calculated size. |
|
Sets the size value for when an expression evaluates to NULL. |
|
Calculates the size corresponding to a specific input value. |
Static Methods
Attempts to parse an expression into a corresponding |
- 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:
- exponent(self) float [source]¶
Returns the exponent for an exponential expression.
See also
- Return type:
float
- static fromExpression(expression: str | None)[source]¶
Attempts to parse an expression into a corresponding
QgsSizeScaleTransformer
.- Parameters:
expression (Optional[str]) -> (Optional[QgsGenericNumericTransformer]) – expression to parse
- Returns:
corresponding
QgsSizeScaleTransformer
, orNone
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
- Return type:
float
- minOutputValue(self) float [source]¶
Returns the minimum calculated size.
See also
See also
- Return type:
float
- nullOutputValue(self) float [source]¶
Returns the size value when an expression evaluates to NULL.
See also
- Return type:
float
- setExponent(self, exponent: float)[source]¶
Sets the exponent for an exponential expression.
- Parameters:
exponent (float) – exponent
See also
- setMaxOutputValue(self, size: float)[source]¶
Sets the maximum calculated size.
- Parameters:
size (float) – maximum size
See also
See also
- setMinOutputValue(self, size: float)[source]¶
Sets the minimum calculated size.
- Parameters:
size (float) – minimum size
See also
See also