To expand on Banto's answer, the issue is that your view is 250x85 points, which, on retina devices is really 500x170 pixels.  When your x1 image is turned into a pattern it is applied at the point level.  The problem can be easily changed by setting the scale on the image to match the scale on the device:

let view = UIView(frame: CGRect(x: 0, y: 0, width: 250, height: 85))

let image = UIImage(named: "myfilepath.png")!
let scaled = UIImage(CGImage: image.CGImage, scale: UIScreen.mainScreen().scale, orientation: image.imageOrientation)

view.backgroundColor = UIColor(patternImage: scaled!)


How do I make image-based tiled background for UIView so that it doesn't scale?
More specifically above r=6 and below r=4+4cos(θ)

graph of the two curves

PolarPlot[{6, 4 + 4 Cos[t]}, {t, 0, 2 Pi}]

