Fix problems with map view UI layout constraints

[friedbunny]

This addresses two problems with the map view’s UI elements (compass, attribution button, logo):

Fixes ambiguous constraints

Fixes #5549.

By declaring that the vertical constraint relationships were NSLayoutRelationGreaterThanOrEqual, this meant that there were many positions that could potentially satisfy these constraints. This is not what we want (and not what was being shown) — the vertical placement of these views should be NSLayoutRelationEqual to the exact values we calculate.

Fixes iOS 10 giving us incorrect topLayoutGuide values

Fixes #6755, where the vertical offset of the compass would be incorrect after device rotation.

Compared to iOS 9, iOS 10 is giving incorrect values for topLayoutGuide when the device is rotated. For reasons I don’t understand, re-adding a direct constraint against topLayoutGuide fixes the issue. This walks back a small part of #5671, where our accounting for layout guides moved entirely to -adjustContentInset.

This fix isn’t great, but it’s backwards compatible and it works.

Notes

• I do not believe that this addresses Wrong attribution positioning after resizing MGLMapView via constraints #6568.
• po [[UIWindow keyWindow] _autolayoutTrace] is great.

/cc @frederoni @1ec5

[mention-bot]

@friedbunny, thanks for your PR! By analyzing the history of the files in this pull request, we identified @1ec5, @frederoni and @incanus to be potential reviewers.

[frederoni]

Assumed the Swift equivalent would be something like po UIApplication.shared.delegate?.window._autotraceLayout but apparently not. 😕

[friedbunny]

As a private method, I think it’s not exposed in Swift (which is what lldb expects when you’re in a Swift app). Looks like expr -l objc++ -O -- [[UIWindow keyWindow] _autolayoutTrace] is how you’d do it. 😉

[1ec5]

The inequality constraints were originally added in #1328. Can you verify that these changes don’t regress #1327?

[friedbunny]

The bottom elements continue to move with the map view, but the compass has gone MIA:

[frederoni]

If you're using a map view that is not full size, you should set automaticallyAdjustsScrollViewInsets to false. I rebased this PR and added a forced re-layout after the device has been rotated which takes care of the layout bug in iOS 10.

The following cases has been tested in iOS 8, 9 and 10:

• ✅ Full size map view, w/ navbar and tabbar w/ automaticallyAdjustsScrollViewInsets=YES.
• ✅ Half size map view w/ automaticallyAdjustsScrollViewInsets=NO.

[ketz]

Sorry if I'm being thick, but I'm having the same problem when resizing the map view to show an info panel with a POI's details.

Where exactly should I set automaticallyAdjustsScrollViewInsets:NO? I'm not using auto layout, and all my views are created programatically.

thanks

[1ec5]

Where exactly should I set automaticallyAdjustsScrollViewInsets:NO?

automaticallyAdjustsScrollViewInsets is a property on the view controller that contains MGLMapView.

[1ec5]

If you're using a map view that is not full size, you should set automaticallyAdjustsScrollViewInsets to false.

@frederoni, just to be clear, though, we haven’t regressed #1327, have we? The compass should never float outside of the map view, even if you have a non-full-screen map view and automaticallyAdjustsScrollViewInsets set to YES.

[1ec5]

I reopened #6954 to track the regression exacerbated by this PR.