Re: UIStackView: Variable Spacing

[Fritz Anderson]

Confirming that your concern is now Auto Layout overhead?

---

Long, long ago, when there were no iPads or Auto Layout (2009?), the 
scrolling-performance session at WWDC said if your cells had nontrivial subview 
trees, and the table was stuttering, bite the bullet and start aggregating 
subview nodes into monoliths that you lay out and draw yourself.

iOS devices are an order of magnitude faster now, but that doesn’t solve the 
problem in principle, just puts it off.

---

Obviously it’s a lot of work to code (and maybe to execute — you’ll have to use 
trial-and-error to find an ad-hoc solution); ad-hoc makes refactoring harder; 
you’ll be spending your vacations in Caching Inferno; etc. You’d sacrifice Make 
it Right for Make it Fast. That’s supposed to be a smell, but in this case Make 
it Fast _is_ Make it Work.

I don’t know nearly enough about your application to say whether it’s an 
option. I’ve had reasonable success with splitting the difference and replacing 
leaf views with layers to relieve the combinatorial explosion AL risks.

---

If Auto Layout has no combinatorial risks, or surprisingly few, I’d be 
fascinated to know why.

— F

> On 6 Jul 2016, at 6:56 PM, Daniel Stenmark  wrote:
> 
> It’s not so much that adding a single dummy view wrecks us.  Our cell layout 
> has a lot going on, with a fair amount of variable spacing and multiple views 
> often being hidden and swapped out.  The UIStackView scrolling performance 
> slog I’m seeing is just sum of all that.
> 
> Sigh, oh well.  I guess that’s just another refactoring branch I’ll have to 
> shelve for now.
> 
> Dan
> 
>> On Jul 6, 2016, at 4:45 PM, Roland King  wrote:
>> 
>> 
>>> On 7 Jul 2016, at 04:37, Daniel Stenmark  wrote:
>>> 
>>> What’s the best way to achieve variable spacing between children of a 
>>> UIStackView?  I know that a popular approach is to add an empty dummy view 
>>> to act as padding, but this is being used in a UITableView cell, so 
>>> scrolling performance is critical and the implicit constraints created by 
>>> adding a ‘padding’ view are a death knell for us.  
>>> 
>>> Dan
>> 
>> 
>> There’s no trick way to do it, you need some extra view one way or another. 
>> 
>> It’s a bit surprising that adding extra, fixed sized children to the stack 
>> really adds that much overhead, that’s a few very simple constraints, all 
>> constant, and shouldn’t really make that much difference. Perhaps the 
>> stackview is being inefficient with the number of constraints it adds when 
>> you add an extra child. You could take a look at the view hierarchy and see 
>> if that’s the case or not. 
>> 
>> You could try going the other way around and making your real elements 
>> children of dummy views so you get to add the simplest top/bottom-padding 
>> constraints possible to those views, that may minimise the number of extra 
>> constraints added and you get to control it somewhat. But if your hierarchy 
>> is such that it’s straining the constraint system performance wise, whatever 
>> way you try to do this is going to have similar performance.
> 
> 
> ___
> 
> Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
> 
> Please do not post admin requests or moderator comments to the list.
> Contact the moderators at cocoa-dev-admins(at)lists.apple.com
> 
> Help/Unsubscribe/Update your Subscription:
> https://lists.apple.com/mailman/options/cocoa-dev/fritza%40manoverboard.org
> 
> This email sent to fri...@manoverboard.org


___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Re: UIStackView: Variable Spacing

[Daniel Stenmark]

It’s not so much that adding a single dummy view wrecks us.  Our cell layout 
has a lot going on, with a fair amount of variable spacing and multiple views 
often being hidden and swapped out.  The UIStackView scrolling performance slog 
I’m seeing is just sum of all that.

Sigh, oh well.  I guess that’s just another refactoring branch I’ll have to 
shelve for now.

Dan

> On Jul 6, 2016, at 4:45 PM, Roland King  wrote:
> 
> 
>> On 7 Jul 2016, at 04:37, Daniel Stenmark  wrote:
>> 
>> What’s the best way to achieve variable spacing between children of a 
>> UIStackView?  I know that a popular approach is to add an empty dummy view 
>> to act as padding, but this is being used in a UITableView cell, so 
>> scrolling performance is critical and the implicit constraints created by 
>> adding a ‘padding’ view are a death knell for us.  
>> 
>> Dan
> 
> 
> There’s no trick way to do it, you need some extra view one way or another. 
> 
> It’s a bit surprising that adding extra, fixed sized children to the stack 
> really adds that much overhead, that’s a few very simple constraints, all 
> constant, and shouldn’t really make that much difference. Perhaps the 
> stackview is being inefficient with the number of constraints it adds when 
> you add an extra child. You could take a look at the view hierarchy and see 
> if that’s the case or not. 
> 
> You could try going the other way around and making your real elements 
> children of dummy views so you get to add the simplest top/bottom-padding 
> constraints possible to those views, that may minimise the number of extra 
> constraints added and you get to control it somewhat. But if your hierarchy 
> is such that it’s straining the constraint system performance wise, whatever 
> way you try to do this is going to have similar performance.


___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Re: UIStackView: Variable Spacing

[Roland King]

> On 7 Jul 2016, at 04:37, Daniel Stenmark  wrote:
> 
> What’s the best way to achieve variable spacing between children of a 
> UIStackView?  I know that a popular approach is to add an empty dummy view to 
> act as padding, but this is being used in a UITableView cell, so scrolling 
> performance is critical and the implicit constraints created by adding a 
> ‘padding’ view are a death knell for us.  
> 
> Dan


There’s no trick way to do it, you need some extra view one way or another. 

It’s a bit surprising that adding extra, fixed sized children to the stack 
really adds that much overhead, that’s a few very simple constraints, all 
constant, and shouldn’t really make that much difference. Perhaps the stackview 
is being inefficient with the number of constraints it adds when you add an 
extra child. You could take a look at the view hierarchy and see if that’s the 
case or not. 

You could try going the other way around and making your real elements children 
of dummy views so you get to add the simplest top/bottom-padding constraints 
possible to those views, that may minimise the number of extra constraints 
added and you get to control it somewhat. But if your hierarchy is such that 
it’s straining the constraint system performance wise, whatever way you try to 
do this is going to have similar performance. 
___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Re: UIStackView: Variable Spacing

[Daniel Stenmark]

No, adding additional horizontal or vertical spacing constraints to the 
UIStackView’s arranged subviews results in conflicts with UIStackView's 
implicit constraints.

Dan

On Jul 6, 2016, at 3:52 PM, Quincey Morris 
>
 wrote:

On Jul 6, 2016, at 15:41 , Daniel Stenmark 
> wrote:

This would require my UIStackView’s children to have children of their own, 
which just means even more layout constraints to resolve at scroll-time.

Can’t you set constraints between the stack view children and/or the parent? I 
thought I had done that.



___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Re: UIStackView: Variable Spacing

[Quincey Morris]

On Jul 6, 2016, at 15:41 , Daniel Stenmark  wrote:
> 
> This would require my UIStackView’s children to have children of their own, 
> which just means even more layout constraints to resolve at scroll-time.  

Can’t you set constraints between the stack view children and/or the parent? I 
thought I had done that.


___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Re: UIStackView: Variable Spacing

[Daniel Stenmark]

This would require my UIStackView’s children to have children of their own, 
which just means even more layout constraints to resolve at scroll-time.

Dan

On Jul 6, 2016, at 3:34 PM, Quincey Morris 
>
 wrote:

On Jul 6, 2016, at 13:37 , Daniel Stenmark 
> wrote:

What’s the best way to achieve variable spacing between children of a 
UIStackView?

I’ve had success placing leading/trailing/top/bottom constraints on the child 
view, or on components within the child view, to siblings or parent as 
appropriate.


___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Re: UIStackView: Variable Spacing

[Quincey Morris]

On Jul 6, 2016, at 13:37 , Daniel Stenmark  wrote:
> 
> What’s the best way to achieve variable spacing between children of a 
> UIStackView?

I’ve had success placing leading/trailing/top/bottom constraints on the child 
view, or on components within the child view, to siblings or parent as 
appropriate.

___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

UIStackView: Variable Spacing

[Daniel Stenmark]

What’s the best way to achieve variable spacing between children of a 
UIStackView?  I know that a popular approach is to add an empty dummy view to 
act as padding, but this is being used in a UITableView cell, so scrolling 
performance is critical and the implicit constraints created by adding a 
‘padding’ view are a death knell for us.  

Dan

___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com