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# compositionParameterView(_:didChangeParameterWithKey:)

Called after an input parameter in the composition parameter view has been edited.

```
func compositionParameterView(_ parameterView: QCCompositionParameterView!, didChangeParameterWithKey portKey: String!)
```

## Parameters

`parameterView`

The composition parameter view in which the parameter changed.

`portKey`

A key for one of the composition parameters, which is provided to you by the Quartz Composer engine.

## Discussion

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