CoreGraphics: add some additional Rect methods

This adds a default constructor and the special value of `infinite` to
`Rect`.

Author: compnerd

Sources/SwiftWin32/CG/Rect.swift

@@ -30,6 +30,12 @@ public struct Rect {
 
   // MARK - Special Values
 
+  /// A rectangle that has infinite extent.
+  public static var infinite: Rect {
+    Rect(x: -.leastNormalMagnitude, y: -.leastNormalMagnitude,
+         width: .greatestFiniteMagnitude, height:.greatestFiniteMagnitude)
+  }
+
   /// The null rectangle, representing an invalid value.
   public static var null: Rect {
     Rect(x: .greatestFiniteMagnitude, y: .greatestFiniteMagnitude,
@@ -41,6 +47,11 @@ public struct Rect {
     Rect(x: 0, y: 0, width: 0, height: 0)
   }
 
+  /// Creates a rectangle with origin (0,0) and size (0,0).
+  public init() {
+    self = .zero
+  }
+
   // MARK - Basic Geometric Properties
 
   /// A point that specifies the coordinates of the rectangle’s origin.
@@ -171,6 +182,11 @@ public struct Rect {
     return self.size.height == 0 || self.size.width == 0 || self.isNull
   }
 
+  /// Returns whether a rectangle is infinite.
+  public var isInfinite: Bool {
+    return self == .infinite
+  }
+
   /// Returns whether the rectangle is equal to the null rectangle.
   public var isNull: Bool {
     return self == .null