Class: QgsColorRampTransformer

class qgis.core.QgsColorRampTransformer(minValue: float = 0, maxValue: float = 1, ramp: QgsColorRamp = None, nullColor: Union[QColor, Qt.GlobalColor, QGradient] = QColor(0, 0, 0, 0))

Bases: QgsPropertyTransformer

Constructor for QgsColorRampTransformer.

Parameters
  • minValue (float = 0) – minimum expected value

  • maxValue (float = 1) – maximum expected value

  • ramp (QgsColorRamp = None) – source color ramp. Ownership is transferred to the transformer.

  • nullColor (Union[QColor) – color to return for null values

QgsColorRampTransformer(other: QgsColorRampTransformer) Copy constructor

QgsPropertyTransformer subclass for transforming a numeric value into a color from a color ramp.

Methods

clone

rtype

QgsColorRampTransformer

color

Calculates the color corresponding to a specific value.

colorRamp

Returns the color ramp used for calculating property colors.

loadVariant

param definition

nullColor

Returns the color corresponding to a null value.

rampName

Returns the color ramp’s name.

setColorRamp

Sets the color ramp to use for calculating property colors.

setNullColor

Sets the color corresponding to a null value.

setRampName

Sets the color ramp’s name.

toExpression

param baseExpression

toVariant

rtype

Any

transform

param context

transformNumeric

transformerType

rtype

QgsPropertyTransformer.Type

clone(self) → QgsColorRampTransformer
Return type

QgsColorRampTransformer

color(self, value: float) → QColor

Calculates the color corresponding to a specific value.

Parameters

value (float) – value to calculate color for

Return type

QColor

Returns

calculated color using transformer’s parameters and type

colorRamp(self) → QgsColorRamp

Returns the color ramp used for calculating property colors.

Return type

QgsColorRamp

Returns

color ramp

See also

setColorRamp()

loadVariant(self, definition: Any) → bool
Parameters

definition (Any) –

Return type

bool

nullColor(self) → QColor

Returns the color corresponding to a null value.

See also

setNullColor()

Return type

QColor

rampName(self) → str

Returns the color ramp’s name.

See also

setRampName()

Return type

str

setColorRamp(self, ramp: QgsColorRamp)

Sets the color ramp to use for calculating property colors.

Parameters

ramp (QgsColorRamp) – color ramp, ownership of ramp is transferred to the transformer.

See also

colorRamp()

setNullColor(self, color: Union[QColor, Qt.GlobalColor, QGradient])

Sets the color corresponding to a null value.

Parameters

color (Union[QColor) – null color

See also

nullColor()

setRampName(self, name: str)

Sets the color ramp’s name. The ramp name must be set to match a color ramp available in the style database for conversion to expression to work correctly.

See also

rampName()

Parameters

name (str) –

toExpression(self, baseExpression: str) → str
Parameters

baseExpression (str) –

Return type

str

toVariant(self) → Any
Return type

Any

transform(self, context: QgsExpressionContext, value: Any) → Any
Parameters
Return type

Any

transformNumeric()
transformerType(self) → QgsPropertyTransformer.Type
Return type

QgsPropertyTransformer.Type