Before starting with code, let's have a look at some of the tools provided by UIKit to simplify the drawing process with core graphics. All the functionalities that we will list in this section produce results that can be achieved with core graphics in its "pure" form. You can view these UIKit helpers as shortcuts to some more complex core graphics functions. UIKit and core graphics elements can be easily distinguished by the prefixes of the classes and function names—UI for UIKit and CG for core graphics. You can find all the following code examples in the source code of the chapter.
The UIKit helpers can be used to alter the current graphic state by defining the current color for fill and stroke drawing actions. These functionalities are part of the UIColor class with its setFill(), setStroke(), and set() functions (the last sets both the stroke and fill colors). Execute the following code:
override func drawRect(rect: CGRect) {
drawRedRect...