Returns the recommended layer contents scale for this image.
- macOS 10.7+
The preferred layer contents scale. Don't use a higher scale factor if the image can't provide it. If the image is resolution independent the return value will be the same as the input. If you specify
0for this parameter, the method uses the scale factor for the default screen.
The recommended layer contents scale. This scale factor may be different than the one in the
Use this method to obtain the scale factor value that you pass to the
layer method. This method uses the image data to determine the scale factor that is best suited for creating an image that looks good in the layer.