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.

The extension can be installed using 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
}

The extension supports all iPhones, iPods and iPads that are supported by iOS 9-12.

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

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

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:)