double valueAsDouble(int key, const QgsExpressionContext &context, double defaultValue=0.0, bool *ok=nullptr) const
Calculates the current value of the property with the specified key and interprets it as a double.
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
void setOriginalValueVariable(const QVariant &value)
Sets the original value variable value for the context.