Update ViewGeomery documentation (#298)

* Update ViewGeomery documentation

* Optimize RootGeometry

Author: Kyle-Ye

Sources/OpenSwiftUICore/Layout/View/ViewGeometry.swift

@@ -8,54 +8,133 @@
 package import Foundation
 package import OpenGraphShims
 
+/// A type that represents the position and dimensions of a view in its parent's coordinate space.
+///
+/// `ViewGeometry` encapsulates both the origin (position) and dimensions (size and alignment guides)
+/// of a view. It provides methods to access alignment guides and convert to other geometric types.
 package struct ViewGeometry: Equatable {
+    /// The position of the view in its parent's coordinate space.
     package var origin: ViewOrigin
+
+    /// The size and alignment information of the view.
     package var dimensions: ViewDimensions
-    
+
+    /// Creates a view geometry with the specified origin and dimensions.
+    ///
+    /// - Parameters:
+    ///   - origin: The position of the view.
+    ///   - dimensions: The size and alignment information of the view.
     package init(origin: ViewOrigin, dimensions: ViewDimensions) {
         self.origin = origin
         self.dimensions = dimensions
     }
-    
+
+    /// Creates a view geometry at the default origin with the specified dimensions.
+    ///
+    /// - Parameter dimensions: The size and alignment information of the view.
     package init(dimensions: ViewDimensions) {
         self.init(origin: ViewOrigin(), dimensions: dimensions)
     }
-    
+
+    /// Creates a view geometry with the specified CGPoint origin and dimensions.
+    ///
+    /// - Parameters:
+    ///   - origin: The position of the view as a CGPoint.
+    ///   - dimensions: The size and alignment information of the view.
     package init(origin: CGPoint, dimensions: ViewDimensions) {
         self.init(origin: ViewOrigin(origin), dimensions: dimensions)
     }
-    
+
+    /// Creates a view geometry using placement and dimensions information.
+    ///
+    /// - Parameters:
+    ///   - p: The placement that determines the origin of the view.
+    ///   - d: The size and alignment information of the view.
     package init(placement p: _Placement, dimensions d: ViewDimensions) {
         self.origin = ViewOrigin(p.frameOrigin(childSize: d.size.value))
         self.dimensions = d
     }
-    
+
+    /// Returns the position of the specified horizontal alignment guide.
+    ///
+    /// - Parameter guide: The horizontal alignment guide to measure.
+    /// - Returns: The x-coordinate of the alignment guide in the parent's coordinate space.
     package subscript(guide: HorizontalAlignment) -> CGFloat { dimensions[guide] }
+
+    /// Returns the position of the specified vertical alignment guide.
+    ///
+    /// - Parameter guide: The vertical alignment guide to measure.
+    /// - Returns: The y-coordinate of the alignment guide in the parent's coordinate space.
     package subscript(guide: VerticalAlignment) -> CGFloat { dimensions[guide] }
+
+    /// Returns the explicit position of the specified horizontal alignment guide if available.
+    ///
+    /// - Parameter guide: The horizontal alignment guide to measure.
+    /// - Returns: The x-coordinate of the alignment guide, or nil if not explicitly defined.
     package subscript(explicit guide: HorizontalAlignment) -> CGFloat? { dimensions[explicit: guide] }
+
+    /// Returns the explicit position of the specified vertical alignment guide if available.
+    ///
+    /// - Parameter guide: The vertical alignment guide to measure.
+    /// - Returns: The y-coordinate of the alignment guide, or nil if not explicitly defined.
     package subscript(explicit guide: VerticalAlignment) -> CGFloat? { dimensions[explicit: guide] }
 }
 
+/// Extension to provide convenient accessors for `Attribute<ViewGeometry>`.
 extension Attribute where Value == ViewGeometry {
+    /// Returns an attribute representing the origin of the view geometry.
+    ///
+    /// - Returns: An attribute containing the view's origin.
     package func origin() -> Attribute<ViewOrigin> { self[keyPath: \.origin] }
+    
+    /// Returns an attribute representing the size of the view geometry.
+    ///
+    /// - Returns: An attribute containing the view's size.
     package func size() -> Attribute<ViewSize> { self[keyPath: \.dimensions.size] }
 }
 
 extension ViewGeometry {
+    /// The frame of the view as a CGRect.
+    ///
+    /// This property combines the origin and size information into a CGRect.
     package var frame: CGRect {
         CGRect(origin: origin.value, size: dimensions.size.value)
     }
-    
+
+    /// A view geometry value representing an invalid state.
+    ///
+    /// This value is used to indicate errors or uninitialized states.
     package static let invalidValue = ViewGeometry(origin: ViewOrigin(invalid: ()), dimensions: .invalidValue)
-    
+
+    /// Indicates whether this view geometry is in an invalid state.
     package var isInvalid: Bool { origin.x.isNaN }
-    
+
+    /// A view geometry with zero origin and zero dimensions.
+    ///
+    /// This property provides a convenient way to create a view geometry at the origin
+    /// with zero size.
     package static let zero = ViewGeometry(origin: CGPoint.zero, dimensions: .zero)
-    
+
+    /// Returns the position of the specified alignment key.
+    ///
+    /// - Parameter key: The alignment key to measure.
+    /// - Returns: The coordinate of the alignment guide in the parent's coordinate space.
     package subscript(key: AlignmentKey) -> CGFloat { dimensions[key] }
-    
+
+    /// Returns the explicit position of the specified alignment key if available.
+    ///
+    /// - Parameter key: The alignment key to measure.
+    /// - Returns: The coordinate of the alignment guide, or nil if not explicitly defined.
     package subscript(explicit key: AlignmentKey) -> CGFloat? { dimensions[explicit: key] }
-    
+
+    /// Adjusts the origin to account for right-to-left layout direction.
+    ///
+    /// This method flips the x-coordinate when in right-to-left layout mode to maintain
+    /// proper visual alignment from the right edge of the parent.
+    ///
+    /// - Parameters:
+    ///   - layoutDirection: The layout direction to apply.
+    ///   - parentSize: The size of the parent container.
     package mutating func finalizeLayoutDirection(_ layoutDirection: LayoutDirection, parentSize: CGSize) {
         guard layoutDirection == .rightToLeft else { return }
         origin.x = parentSize.width - frame.maxX

Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift

@@ -634,20 +634,18 @@ package struct RootGeometry: Rule, AsyncAttribute {
             origin += (proposal-fittingSize) * 0.5
         }
 
-        // For RTL layout, adjust the x position to maintain proper visual alignment
-        if let layoutDirection, layoutDirection == .rightToLeft {
-            // This flips the x-coordinate to maintain proper visual layout in RTL mode
-            origin.x = proposedSize.width - CGRect(origin: origin, size: fittingSize).maxX
-        }
-
-        return ViewGeometry(
+        var geometry = ViewGeometry(
             origin: ViewOrigin(origin),
             dimensions: ViewDimensions(
                 guideComputer: layoutComputer,
                 size: fittingSize,
                 proposal: .init(proposal)
             )
         )
+        if let layoutDirection {
+            geometry.finalizeLayoutDirection(layoutDirection, parentSize: proposedSize.value)
+        }
+        return geometry
     }
 }