Open Radar

 
Summary:
I'm building a UI framework to drive the semi-formulaic layout of our forms and informational pages. Some screens necessitate changing the layout margins of a cell, but otherwise showing the same content. Thus, I am driven to desire the toggle "Follow Readable Width" in IB, which changes the effective application of layoutMargins. This checkbox persists at runtime, i.e., if I manually use the layoutMargins property during layout.

Turns out, you folks already have this! You're so good to me.

Except it's SPI. Sad panda.

Steps to Reproduce:
1. Attempt to bind constraints to the readableContentGuide without editing the constraints, like you can in IB.
2. Feel distraught.
3. Open an IB document as XML.
4. Use class-dump.
5. Feel even more distraught.

Expected Results:
I can use the layoutMarginsFollowReadableWidth attribute (like IB sets!).

Actual Results:
No such property is available in the header.

I'm forced to setValueForKey(_:) to achieve the desired API without rearchitecting, which makes me want to take a shower.

Version:
iOS 10.0 (14A5261v)

Notes:
IB sets this value via its encoded properties, so the requested property is already a matter of ABI. You'd make me really happy if you gave it a retconned availability attribute to iOS 9, too.

Configuration:
iPhone 6s Plus 64GB T-Mobile, using Wi-Fi

Attachments: