UIScreenExtension

This is an extension to UIScreen that provides information about the pixel density (or point density) of iPhones and iPads. For example this can be used to:

compute the dimension of the screen
draw a ruler; or

to show a proper ECG graph on the iPhone's screen.

public extension UIScreen {

  /// The number of pixels per inch for this device
  public static let pixelsPerInch: CGFloat?
  
  /// The number of pixels per centimeter for this device
  public static let pixelsPerCentimeter: CGFloat?
  
  /// The number of points per inch for this device
  public static let pointsPerInch: CGFloat?
  
  /// The number of points per centimeter for this device
  public static let pointsPerCentimeter: CGFloat?
  
  /// The screen dimension in inches
  public static let dimensionInInches: CGSize?
  
  /// The screen dimension in centimeters
  public static let dimensionInCentimeters: CGSize?
}

The constants will be set to .none if the device is unknown. This can happen if Apple releases a new iPhone, so please remember to deal with this in your code.

Installation and use

The extension can be installed using Swift Package Manager or Cocoapods by adding below line to your Podfile:

pod 'UIScreenExtension', :git => 'https://github.com/marchv/UIScreenExtension'

To use the extension in your code first import it by adding:

import UIScreenExtension

And then use it for example:

if let pointsPerCentimeter = UIScreen.pointsPerCentimeter {
   // code
}

Or to compute the diagonal screen dimension:

if let dimensionInInches = UIScreen.dimensionInInches {
    print(sqrt(pow(dimensionInInches.width, 2) + pow(dimensionInInches.height, 2))) // for example ~5.5 inches for iPhone 7 Plus
}

Support

The extension supports all iPhones, iPods and iPads that are supported by iOS 9-14.

Limitations

Please note that iPhone only apps upscaled on iPads will not work properly!

Improvements

Apple Watch support
Objective C support
Fetch information about new iPhone models from internet

Author