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

[Jacob Bandes-Storch]

I still think it might be valuable to pursue setters for all of the
currently-read-only convenience properties (minX, midX, maxX, minY, midY,
maxY).

Jacob

On Fri, Dec 11, 2015 at 1:17 PM, D. Felipe Torres <warorface at gmail.com>
wrote:

> Using the mid properties wouldn't help much as they are the middle of the
> bounds (origin + length/2) and because it's a derived value from two
> different structures, its not clear which structure you want to modify.
>
> Either way, after thinking more about it, there is too much ambiguity to
> the details of this. The intent is not always clear and looking into the
> other functions, they all stand on their own. A CGRect doesn't have any
> sense of hierarchy.
>
> It only appears when you have layers/views (and those do have a way of
> setting the center because the relationship/hierarchy is well defined).
>
> I don't see any more reason to pursue this proposal.
>
>
> On Fri, Dec 11, 2015 at 7:29 AM, Jacob Bandes-Storch <jtbandes at gmail.com>
> wrote:
>
>> 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
>>>
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>
>>>
>>
>
>
> --
> ++++++++++++++++++++++++++
> Diego Torres.
> Phone (Mobile Germany): +49 157 30070985
> Phone (Landline Chile): +56 2 29790978
> Web: dtorres.me
>
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