⭐️ Impl: RNIContentPositioningMode

ios/Temp/RNIContentPositioningMode.swift

@@ -0,0 +1,114 @@
+//
+//  RNIContentPositioningMode.swift
+//  react-native-ios-modal
+//
+//  Created by Dominic Go on 10/6/24.
+//
+
+import Foundation
+
+
+/// * `.stretch` is better for: `UIScrollView`
+/// * `.centered` is better for regular views when sizing fast
+///
+/// Notes:
+/// * In some cases, fabric/paper + yoga might not be able to keep up with
+///   layout, so it will appear to stutter/lag behind if it's parent resizes
+///   a lot.
+///
+/// * This is most noticeable when things are anchored to right and
+///   bottom edges (e.g. views that are floating via absolute positioning), or
+///   when certain views or subviews are centered.
+///
+/// * However `.centered` needs some extra logic, namely there needs to be
+///   2 constant constraints that need to be updated whenever react resizes
+///
+/// * as such, when creating the constraints via ,
+///   `RNIContentPositioningMode.createConstraints` these argument must be
+///   provided: `sizingLayoutGuide`
+///
+/// * If `sizingLayoutGuide` is not provided in `createConstraints`, then it'll
+///   fallback to: `.stretch`
+///
+/// * set the constraints of `sizingLayoutGuide` such that it's height and
+///   width is not ambiguous (e.g. via `heightConstraint`, and
+///   `widthConstraint` + some constant value, etc)
+///
+/// * when react layouts, update `sizingLayoutGuide`.
+///
+public enum RNIContentPositioningMode: String {
+  case stretch;
+  case centered;
+
+  // MARK: - Functions
+  // -----------------
+
+  public func createConstraints(
+    forView childView: UIView,
+    attachingTo parentView: UIView,
+    withContentSizingMode contentSizingMode: RNIContentSizingMode? = nil,
+    usingSizingLayoutGuide sizingLayoutGuide: UILayoutGuide? = nil,
+    shouldConstrainParentSizeToSizingLayoutGuide: Bool = false
+  ) -> [NSLayoutConstraint] {
+
+    switch (self, sizingLayoutGuide) {
+      case (.stretch, _),
+           (.centered, .none):
+
+        return [
+          childView.leadingAnchor.constraint(
+            equalTo: parentView.leadingAnchor
+          ),
+          childView.trailingAnchor.constraint(
+            equalTo: parentView.trailingAnchor
+          ),
+          childView.topAnchor.constraint(
+            equalTo: parentView.topAnchor
+          ),
+          childView.bottomAnchor.constraint(
+            equalTo: parentView.bottomAnchor
+          ),
+        ];
+
+      case (.centered, let .some(sizingLayoutGuide)):
+        var constraints = [
+          childView.centerXAnchor.constraint(
+            equalTo: parentView.centerXAnchor
+          ),
+          childView.centerYAnchor.constraint(
+            equalTo: parentView.centerYAnchor
+          ),
+          childView.widthAnchor.constraint(
+            equalTo: sizingLayoutGuide.widthAnchor
+          ),
+          childView.heightAnchor.constraint(
+            equalTo: sizingLayoutGuide.heightAnchor
+          ),
+        ];
+
+      guard shouldConstrainParentSizeToSizingLayoutGuide,
+            let contentSizingMode = contentSizingMode
+      else {
+        return constraints;
+      };
+
+      if contentSizingMode.isSizingHeightFromNative {
+        constraints.append(
+          parentView.heightAnchor.constraint(
+            equalTo: sizingLayoutGuide.heightAnchor
+          )
+        );
+      };
+
+      if contentSizingMode.isSizingWidthFromNative {
+        constraints.append(
+          parentView.widthAnchor.constraint(
+            equalTo: sizingLayoutGuide.widthAnchor
+          )
+        );
+      };
+
+      return constraints;
+    };
+  };
+};