CoreTextImage.swift

    func drawText(s: String, w: CGFloat, h: CGFloat, colour:CGColor) -> CGImageRef {
        let bounds = CGRectMake(0, 0, w, h)
        
        // Create the bitmap-backed CoreGraphics contexts
        let context = CGBitmapContextCreate(nil, Int(w), Int(h), 8, 0,
            CGColorSpaceCreateDeviceRGB(),
            CGImageAlphaInfo.PremultipliedFirst.rawValue | CGBitmapInfo.ByteOrder32Little.rawValue)
        
        CGContextSetFillColorWithColor(context, colour)
        CGContextFillRect(context, bounds)
        
        // Paragraph styles for the attributed string
        var alignment = CTTextAlignment.Center
        var settings = [
            CTParagraphStyleSetting(spec: .Alignment, valueSize: sizeofValue(alignment), value: &alignment)
        ]
        let style = CTParagraphStyleCreate(&settings, 1);

        // Font for the attributed string
        let font = UIFont(name: "DIN Condensed", size: h)
        
        let attr:CFDictionaryRef = [
            NSFontAttributeName:font!,
            NSForegroundColorAttributeName:UIColor.whiteColor(),
            NSParagraphStyleAttributeName:style]
        
        let attrString = CFAttributedStringCreate(kCFAllocatorDefault, s, attr)

        let framesetter = CTFramesetterCreateWithAttributedString(attrString)
        
        // To align vertically, we need to work out the height of the text
        let size = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, CFRangeMake(0, 0), nil, bounds.size, nil)
        
        // We need to translate the path 'downwards' to adjust for the difference between
        // the bounds height and the text height
        let top = (bounds.height / 2) - (size.height / 2) - ((font?.descender)! / 2)
        var transform = CGAffineTransformMakeTranslation(0, -top)
        let path = CGPathCreateWithRect(bounds, &transform)
        
        let frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, nil)
        CTFrameDraw(frame, context!)
        
        let cgImage = CGBitmapContextCreateImage(context)
        return cgImage!
    }