Added blur background support for iPhone and iPad. Slight API changes to avoid race conditions while sharing a presenter.

Riot/Modules/SlidingModal/SlidingModalContainerView.swift

@@ -39,6 +39,23 @@ class SlidingModalContainerView: UIView, Themable, NibLoadable {
     
     // MARK: - Properties
     
+    private weak var blurView: UIVisualEffectView?
+    var blurBackground: Bool = false {
+        didSet {
+            if blurBackground {
+                let blurView = UIVisualEffectView(effect: UIBlurEffect(style: .dark))
+                blurView.frame = self.dimmingView.bounds
+                blurView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+                self.dimmingView.addSubview(blurView)
+                self.blurView = blurView
+                self.dimmingView.backgroundColor = .clear
+            } else {
+                self.blurView?.removeFromSuperview()
+                self.dimmingView.backgroundColor = UIColor.black.withAlphaComponent(Constants.dimmingColorAlpha)
+            }
+        }
+    }
+    
     // MARK: Outlets
     
     @IBOutlet private weak var dimmingView: UIView!
@@ -61,6 +78,9 @@ class SlidingModalContainerView: UIView, Themable, NibLoadable {
         return -(self.contentViewHeightConstraint.constant + bottomSafeAreaHeight)
     }
     
+    // used to avoid changing constraint during animations
+    private var lastBounds: CGRect?
+    
     // MARK: Public
     
     var contentViewFrame: CGRect {
@@ -92,12 +112,26 @@ class SlidingModalContainerView: UIView, Themable, NibLoadable {
         super.layoutSubviews()
         
         self.contentView.layer.cornerRadius = Constants.cornerRadius
+        
+        guard lastBounds != nil else {
+            lastBounds = bounds
+            return
+        }
+        
+        if UIDevice.current.userInterfaceIdiom == .pad && lastBounds != bounds {
+            lastBounds = bounds
+            self.contentViewBottomConstraint.constant = (UIScreen.main.bounds.height + self.dismissContentViewBottomConstant) / 2
+        }
     }
     
     // MARK: - Public
     
     func preparePresentAnimation() {
-        self.contentViewBottomConstraint.constant = 0
+        if UIDevice.current.userInterfaceIdiom == .pad {
+            self.contentViewBottomConstraint.constant = (UIScreen.main.bounds.height + self.dismissContentViewBottomConstant) / 2
+        } else {
+            self.contentViewBottomConstraint.constant = 0
+        }
     }
     
     func prepareDismissAnimation() {