Swift - Playground - Core Graphics / Core Text / Custom View

Question

Question

I\'m attempting to make a custom UIView component in swift playground. I\'ve been able to figure out how to do everything except for render text correctly. I

Answer 1

I wrote a utility function for my app to draw text using CoreText. It returns the text size for further processing:

func drawText(context: CGContextRef, text: NSString, attributes: [String: AnyObject], x: CGFloat, y: CGFloat) -> CGSize {
    let font = attributes[NSFontAttributeName] as UIFont
    let attributedString = NSAttributedString(string: text, attributes: attributes)

    let textSize = text.sizeWithAttributes(attributes)

    // y: Add font.descender (its a negative value) to align the text at the baseline
    let textPath    = CGPathCreateWithRect(CGRect(x: x, y: y + font.descender, width: ceil(textSize.width), height: ceil(textSize.height)), nil)
    let frameSetter = CTFramesetterCreateWithAttributedString(attributedString)
    let frame       = CTFramesetterCreateFrame(frameSetter, CFRange(location: 0, length: attributedString.length), textPath, nil)

    CTFrameDraw(frame, context)

    return textSize
}

Call it like so:

var textAttributes: [String: AnyObject] = [
    NSForegroundColorAttributeName : UIColor(white: 1.0, alpha: 1.0).CGColor,
    NSFontAttributeName : UIFont.systemFontOfSize(17)
]

drawText(ctx, text: "Hello, World!", attributes: textAttributes, x: 50, y: 50)

Hope that helps you.