Core Graphics gradient drawing with Swift? No problem.

cggradient.swift

let colorSpace = CGColorSpaceCreateDeviceRGB()
let componentCount : UInt = 4

let components : [CGFloat] = [
      0,   0,   0,   0,
    1.0, 1.0, 1.0, 1.0,
    1.0, 1.0, 1.0, 1.0,
      0,   0,   0,   0
]

let locations : [CGFloat] = [0, 0.25, 0.75, 1.0]

let gradient = CGGradientCreateWithColorComponents(colorSpace, components, locations, componentCount)

let startPoint = CGPoint(x: 0, y: 0)
let endPoint = CGPoint(x: CGRectGetWidth(bounds), y: 0)

CGContextDrawLinearGradient(ctx, gradient, startPoint, endPoint, 0)

// Swift 2 update:
let context = UIGraphicsGetCurrentContext() // <-- and you missed the context
CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, CGGradientDrawingOptions(rawValue: 0))

/*
Have been struggling with this for too long. Going to buy Paintcode instead!
*/