How do I create a 1px line in Interface Builder?

Question

Note, I'm looking to make a 1px line, not a 1pt line. Meaning it should be 1px regardless of screen scale (so 0.5pt on Retina devices).

I can do this programmatically, but can I do it in the Interface Builder? For example I cannot set a UIView to have a height of less than 1.

If I can do it in IB then I don't have to declare an outlet and manually set the frame in awakeFromNib.

Answer 1

With xCode 6 and introduction of @IBInspectable and @IBDesignable keywords it is definitely possible and rather simple. No need to subclass/outlet anything.

You can do an extension (category) for NSLayoutConstraint with following code (swift):

extension NSLayoutConstraint {

    @IBInspectable var preciseConstant: Int {
        get {
            return Int(constant * UIScreen.mainScreen().scale)
        }
        set {
            constant = CGFloat(newValue) / UIScreen.mainScreen().scale
        }
    }
}

Then you can choose needed constraint in your IB.

Go to it's properties and set the value.

In above case it will render a view with 1 px height on 1x, 2x and 3x devices.

Answer 2

You can do it in .xib file. Just edit it as text and set constant="0.5" instead of "1" in your view height constraint

<constraints>
<constraint firstAttribute="height" constant="0.5" id="xUN-dm-ggj"/>
</constraints>

In Interface Builder

Answer 3

Seems that it is not possible, one must do it programmatically or build a custom view.

Answer 4

Based on @Nevs12 's answer and it's comments, I think it makes more sense to use such thing:

extension NSLayoutConstraint {
    @IBInspectable var usePixels: Bool {
        get {
            return false // default Value
        }
        set {
            if newValue {
                constant = constant / UIScreen.mainScreen().scale
            }
        }
    }
}