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# NSViewLayerContentScaleDelegate

An optional layer delegate method for handling resolution changes.

```
protocol NSViewLayerContentScaleDelegate : NSObjectProtocol
```

## Overview

Use this protocol to manage scale and contents for a layer hosted in a view. When a window changes its backing resolution, AppKit attempts to automatically update the `contentsScale` and `contents` of all `CALayer` objects in the window to match the new resolution. Layers backed by a view are updated automatically. Any layer whose `contents` property is set to an `NSImage` object is also updated automatically. Based on the `NSImage` object’s available representations, AppKit selects an appropriate bitmapped representation, or rasterizes a resolution-independent representation at the appropriate scale factor.

For all other layers, AppKit checks whether the layer has a delegate that implements this protocol.  If so, AppKit asks the layer’s delegate whether it should automatically update the `contentsScale` for that layer to match the new scale factor of the window.

## Topics

### Responding to Resolution Changes

[`layer(_:shouldInheritContentsScale:from:)`](/documentation/AppKit/NSViewLayerContentScaleDelegate/layer(_:shouldInheritContentsScale:from:))

Notifies you when a resolution changes occurs for the window that hosts the layer.

## See Also

  [View Programming Guide](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CocoaViewsGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40002978)


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