How to write this code in swift?

Question

I have this code written in Objective c :

NSRect textRect = NSMakeRect(42, 35, 117, 55);
{
    NSString* textContent = @"Hello, World!";
    NSMutableParagraphStyle* textStyle = NSMutableParagraphStyle.defaultParagraphStyle.mutableCopy;
    textStyle.alignment = NSCenterTextAlignment;

    NSDictionary* textFontAttributes = @{NSFontAttributeName: [NSFont fontWithName: @"Helvetica" size: 12], NSForegroundColorAttributeName: NSColor.blackColor, NSParagraphStyleAttributeName: textStyle};

    [textContent drawInRect: NSOffsetRect(textRect, 0, 1 - (NSHeight(textRect) - NSHeight([textContent boundingRectWithSize: textRect.size options: NSStringDrawingUsesLineFragmentOrigin attributes: textFontAttributes])) / 2) withAttributes: textFontAttributes];
}

now, i want to write this code in swift . This is what i've got until now :

let textRect = NSMakeRect(42, 35, 117, 55)
let textTextContent = NSString(string: "Hello, World!")
let textStyle = NSMutableParagraphStyle.defaultParagraphStyle().mutableCopy() as NSMutableParagraphStyle
textStyle.alignment = NSTextAlignment.CenterTextAlignment

let textFontAttributes = [NSFontAttributeName: NSFont(name: "Helvetica", size: 12), NSForegroundColorAttributeName: NSColor.blackColor(), NSParagraphStyleAttributeName: textStyle]

textTextContent.drawInRect(NSOffsetRect(textRect, 0, 1 - (NSHeight(textRect) - NSHeight(textTextContent.boundingRectWithSize(textRect.size, options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: textFontAttributes))) / 2), withAttributes: textFontAttributes)

this line is wrong :

   let textFontAttributes = [NSFontAttributeName: NSFont(name: "Helvetica", size: 12), NSForegroundColorAttributeName: NSColor.blackColor(), NSParagraphStyleAttributeName: textStyle]

What is wrong with that line ?

This is the error from the compiler :

"Could not find an overload for “init” that accepts the supplied arguments".

Answer 1

Swift's type inference is failing you because the font you're adding to the dictionary is an optional. NSFont(name:size:) returns an optional NSFont?, and you need an unwrapped version. To code defensively, you'll want something like this:

// get the font you want, or the label font if that's not available
let font = NSFont(name: "Helvetica", size: 12) ?? NSFont.labelFontOfSize(12)

// now this should work
let textFontAttributes = [NSFontAttributeName: font, NSForegroundColorAttributeName: NSColor.blackColor(), NSParagraphStyleAttributeName: textStyle]