[swift-evolution] Proposal: Extend CG(Rect)Geometry with center methods

[Jacob Bandes-Storch]

Would it make sense to achieve the same thing by giving midX and midY
setters (they currently only have getters)?

I'm don't think I like the idea of tying down any CGRect extensions to a
"parent" rect, but saying "rect.midX = parent.midX" is pretty simple &
clear.

Jacob

On Thu, Dec 10, 2015 at 6:17 AM, D. Felipe Torres via swift-evolution <
swift-evolution at swift.org> wrote:

> One of the task that is performed often is center a frame with respect to
> it's parent.
> The code for this is short and simple:
>
> rect.origin.x = (rect.width-parent.width)/2 // or...
> rect.origin.y = (rect.height-parent.height)/2
>
> ## Current Problems
>
> - It is very easy to get it wrong and confuse X or Y and their length
> associations.
> - Because this code is often found in a layout method, several other rect
> variables may be defined in the scope which makes it easier to mistake one
> variable with another if their names are close (and you are used to
> autocomplete)
> - And finally but most importantly, while the equation here is simple, one
> must parse it and understand it and is not a very swifty approach.
>
> ##Proposed Additions
>
> 2 (actually 4) extensions in CGGeometry to CGRect:
>
> extension CGRect {
>       public func centerX(parentRect: CGRect) -> CGRect
>       public mutating func centerXInPlace(parentRect: CGRect)
>       public fun centerY(parentRect: CGRect) -> CGRect
>       public mutating func centerYInPlace(parentRect: CGRect)
> }
>
> This extension allows very easily (and verbally) center a rect in respect
> to a parent.
>
> I'm pretty sure there are other pretty useful extensions that can be added
> to CGGeometry as well but this one I think is basic and pretty important.
>
> --
> ++++++++++++++++++++++++++
> Diego Torres.
> Web: dtorres.me
>
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>
>
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