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
NSImage on OS X). These are known as Quick Look supported objects, and by default include:
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.
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 ...