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# FxOnScreenControlAPI_v2

The `FxOnScreenControlAPI_v2` protocol specifies additions to the `FxOnScreenControlAPI` protocol which defines the methods the host application provides to manage conversions between various on-screen coordinate spaces.

```
protocol FxOnScreenControlAPI_v2 : FxOnScreenControlAPI
```

## Overview

This protocol inherits from, and expands on, the `FxOnScreenControlAPI` protocol It can retrieve information about the canvas, such as its pixel aspect ratio or its zoom level so that a plug-in can draw its controls at the appropriate scale. As with the `FxOnScreenControlAPI` protocol, this aids in allowing the user to directly manipulate a plug-in’s parameters.

## Topics

### Canvas Information

[`canvasZoom()`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/canvasZoom())

Returns the zoom factor the user has set the canvas

[`canvasPixelAspectRatio()`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/canvasPixelAspectRatio())

Returns the pixel aspect ratio of the canvas.

[`pixelAspectRatio()`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/pixelAspectRatio())

Returns the pixel aspect ratio for which the on-screen control applies.

[`objectBounds()`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/objectBounds())

Returns the bounds of the object that the on-screen control applies to.

[`objectToScreenTransform()`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/objectToScreenTransform())

Returns a 4x4 matrix describing the transformation from object normalized space

### Input and Output Item Geometry

[`objectWidth(_:height:pixelAspectRatio:)`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/objectWidth(_:height:pixelAspectRatio:))

Returns the width, height, and pixel aspect ratio of the object for which the on-screen control is applied.

[`inputWidth(_:height:pixelAspectRatio:)`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/inputWidth(_:height:pixelAspectRatio:))

Returns the width, height, and pixel aspect ratio of the input to the filter or transition for which the on-screen control is applied.

[`inputBounds()`](/documentation/professional_video_applications/FxOnScreenControlAPI_v2/inputBounds())

Returns the bounds of the input to the filter or transition.


---

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