Fix the background view origin when presenting (#183)

* Fix the background view origin when presenting

When presenting over a ViewController (the “from” VC), if that ViewController is not at the screen’s origin, the background view will not appear at the correct position above it.

This fixes the problem by setting the background view’s frame to the “from” VC’s view’s frame **converted into the coordinate system of the container view.**

* add PR to CHANGELOG

CHANGELOG.md

@@ -1,5 +1,8 @@
 # _BulletinBoard_ Changelog
 ## Unreleased
+### Fixes
+- Fix the background view origin when presenting
+[#183](https://github.com/alexaubry/BulletinBoard/pull/183)
 
 ## 🔖 v4.1.2
 ### Fixes

Sources/Support/Animations/BulletinPresentationAnimationController.swift

@@ -31,15 +31,18 @@ class BulletinPresentationAnimationController: NSObject, UIViewControllerAnimate
             return
         }
 
+        let containerView = transitionContext.containerView
+
         // Fix the frame (Needed for iPad app running in split view)
-        if let fromFrame = transitionContext.viewController(forKey: .from)?.view.frame {
+        // (Convert the "from" view's frame coordinates to the container view's coordinate system)
+        if let fromView = transitionContext.viewController(forKey: .from)?.view {
+            let fromFrame = containerView.convert(fromView.frame, from: fromView)
             toVC.view.frame = fromFrame
         }
 
         let rootView = toVC.view!
         let contentView = toVC.contentView
         let backgroundView = toVC.backgroundView!
-        let containerView = transitionContext.containerView
 
         // Add root view