Class: QgsSizeScaleTransformer¶
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class
qgis.core.
QgsSizeScaleTransformer
(type: QgsSizeScaleTransformer.ScaleType = QgsSizeScaleTransformer.Linear, minValue: float = 0, maxValue: float = 1, minSize: float = 0, maxSize: float = 1, nullSize: float = 0, exponent: float = 1)¶ Bases:
qgis._core.QgsPropertyTransformer
Constructor for QgsSizeScaleTransformer.
- Parameters
type – scaling type
minValue – minimum expected value
maxValue – maximum expected value
minSize – minimum size to return
maxSize – maximum size to return
nullSize – size to return for null values
exponent – exponent for Exponential scaling method
QgsSizeScaleTransformer(QgsSizeScaleTransformer)
QgsPropertyTransformer subclass for scaling a value into a size according to various scaling methods.
New in version 3.0: Enums
Methods
Returns the exponent for an exponential expression.
Attempts to parse an expression into a corresponding QgsSizeScaleTransformer.
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.
Sets the size transformer’s scaling type (the method used to calculate the size from a value).
Calculates the size corresponding to a specific value.
Returns the size transformer’s scaling type (the method used to calculate the size from a value).
Signals
Attributes
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Area
= 1¶
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Exponential
= 3¶
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Flannery
= 2¶
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Linear
= 0¶
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class
ScaleType
¶ Bases:
int
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clone
(self) → QgsSizeScaleTransformer¶
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exponent
(self) → float¶ Returns the exponent for an exponential expression.
See also
See also
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fromExpression
(expression: str) → Tuple[QgsSizeScaleTransformer, str, str]¶ Attempts to parse an expression into a corresponding QgsSizeScaleTransformer.
- Parameters
expression – expression to parse
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 notbaseExpression: 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.
be parsed to a size scale transformer.
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loadVariant
(self, definition: Any) → bool¶
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minSize
(self) → float¶ Returns the minimum calculated size.
See also
See also
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nullSize
(self) → float¶ Returns the size value when an expression evaluates to NULL.
See also
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setExponent
(self, exponent: float)¶ Sets the exponent for an exponential expression.
- Parameters
exponent – exponent
See also
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setMaxSize
(self, size: float)¶ Sets the maximum calculated size.
- Parameters
size – maximum size
See also
See also
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setMinSize
(self, size: float)¶ Sets the minimum calculated size.
- Parameters
size – minimum size
See also
See also
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setNullSize
(self, size: float)¶ Sets the size value for when an expression evaluates to NULL.
- Parameters
size – null size
See also
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setType
(self, type: QgsSizeScaleTransformer.ScaleType)¶ Sets the size transformer’s scaling type (the method used to calculate the size from a value).
- Parameters
type – scale type
See also
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size
(self, value: float) → float¶ Calculates the size corresponding to a specific value.
- Parameters
value – value to calculate size for
- Returns
calculated size using size scale transformer’s parameters and type
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toExpression
(self, baseExpression: str) → str¶
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toVariant
(self) → Any¶
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transform
(self, context: QgsExpressionContext, value: Any) → Any¶
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transformNumeric
()¶
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transformerType
(self) → QgsPropertyTransformer.Type¶