O'Reilly logo

Swift Essentials - Second Edition by Dr. Alex Blewitt

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Displaying objects with Quick Look

The playground timeline can display objects as well as numbers and simple strings. It is possible to load and view images in a playground using classes, such as UIImage (or NSImage on OS X). These are known as Quick Look supported objects, and by default include:

  • String (attributed and unattributed)
  • Views
  • Class and struct types (members are shown)
  • Colors

Tip

It is possible to build support for custom-based types into Swift by implementing a debugQuickLookObject method that returns a graphical view of the data.

Showing colored labels

To show a colored label, a color needs to be obtained first. When building against iOS, this will be UIColor; but when building against OS X, it will be NSColor. The methods and types are ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required