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# PKCanvasViewDelegate

Methods for monitoring drawing related changes in a canvas view.

```
@MainActor protocol PKCanvasViewDelegate : UIScrollViewDelegate
```

## Overview

Implement the methods of the [`PKCanvasViewDelegate`](/documentation/PencilKit/PKCanvasViewDelegate) protocol to monitor drawing events in a [`PKCanvasView`](/documentation/PencilKit/PKCanvasView) object. Specifically, determine the start- and end-of-event sequences using the currently selected tool, and determine when those events affect the drawn content.

## Topics

### Responding to drawing-related changes

[`canvasViewDrawingDidChange(_:)`](/documentation/PencilKit/PKCanvasViewDelegate/canvasViewDrawingDidChange(_:))

Tells the delegate that the contents of the current drawing changed.

[`canvasViewDidFinishRendering(_:)`](/documentation/PencilKit/PKCanvasViewDelegate/canvasViewDidFinishRendering(_:))

Tells the delegate that the previously drawn content is ready to display.

### Responding to selection changes

[`canvasViewSelectionDidChange(_:)`](/documentation/PencilKit/PKCanvasViewDelegate/canvasViewSelectionDidChange(_:))

Tells the delegate that the selection changes.

### Responding to new event sequences

[`canvasViewDidBeginUsingTool(_:)`](/documentation/PencilKit/PKCanvasViewDelegate/canvasViewDidBeginUsingTool(_:))

Tells the delegate that the user started a new drawing sequence with the currently selected tool.

[`canvasViewDidEndUsingTool(_:)`](/documentation/PencilKit/PKCanvasViewDelegate/canvasViewDidEndUsingTool(_:))

Tells the delegate that the user ended a drawing sequence with the tool they were using.


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