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 QuickLook supported objects, and by default include:
Strings (attributed and unattributed)
Views
Class and struct types (members are shown)
Colors
Tip
It is possible to build support for custom types in Swift, by implementing a debugQuickLookObject method that returns a graphical view of the data.
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 largely equivalent between the two, but this chapter will focus on the iOS types.
A color can be acquired with an initializer or by using one of the predefined colors that are exposed in Swift using methods:
import UIKit // AppKit for OS X let blue = UIColor...