update readme

Package.swift

@@ -7,6 +7,9 @@ let package = Package(
     name: "FortuneSwift",
     platforms: [
       .iOS(.v12),
+      .macOS(.v10_12),
+      .tvOS(.v10),
+      .watchOS(.v3)
     ],
     products: [
         // Products define the executables and libraries produced by a package, and make them visible to other packages.

README.md

@@ -1,4 +1,88 @@
-# Fortune
+# FortuneSwift
 
-A description of this package.
+FortuneSwift is a swift framework that uses Fortune's Algorithm to generate Voronoi diagrams and Delaunay triangulations from a set of points on a 2D plane. Fortune's Algorithm has a time complexity of `O(n log n)`, and a space complexity of `O(n)`. This framework is compatible with iOS 8+, macOS 10.13+.
+
+
+## Installation
+
+The FortuneSwift framework can be installed using the Swift Package Manager. In Xcode: `File > Swift Packages > Add Package Dependency..` with URL: `https://github.com/TateLiang/FortuneSwift.git`
+
+Or alternatively:
+- Add `.package(url: "https://github.com/TateLiang/FortuneSwift.git", from: "1.1.5")` to your `Package.swift` file's `dependencies`.
+- Update your packages using `$ swift package update`.
+
+
+## Usage
+
+### Setup
+
+1. Add package dependancy
+2. Import `import FortuneSwift`
+3. Create a `Voronoi` object, specifying an array of `Coordinate`s and the rectangular area.
+```
+let points: [Coordinate] = [ ... ]
+let rect = (x: 25, y: 25, width: 500, height: 500)
+
+let voronoi = Voronoi(sites: points, numPoints: points.count, rect: rect)
+```
+
+Alternatively, if the array is not given, `numPoints` of random points are generated within the rectangular area.
+```
+let voronoi = Voronoi(numPoints: 150, rect: rect)
+```
+
+### Processing Graph
+
+FortuneSwift outputs a doubly connected edge list (DCEL) stored as arrays of sites, voronoi vertices and half-edges. This framework provides four classes for accessing the diagram: `Coordinate`, `Site`, `Vertex` and `HalfEdge`. This information can be used to draw a Voronoi diagram or Delaunay triangulation.
+
+Once the voronoi object has been created, the resulting arrays can be obtained via the properties:
+```
+var voronoiVertices: [Vertex]
+var voronoiEdges: [HalfEdge]
+var voronoiSites: [Site]
+```
+
+The main properties of each class are detailed below. 
+
+##### Site
+```
+var x: Double
+var y: Double
+var firstEdge: HalfEdge?
+var surroundingEdges: [HalfEdge]?
+```
+
+##### Vertex
+```
+var x: Double
+var y: Double
+var incidentEdges: [HalfEdge]
+```
+
+##### HalfEdge
+```
+var origin: Vertex?
+var destination: Vertex?
+
+var twin: HalfEdge?
+var next: HalfEdge?
+var prev: HalfEdge?
+
+var incidentSite: Site?
+
+func walk() -> [HalfEdge]? 
+```
+
+### Notes
+
+- `firstEdge` is an arbitrary edge defining the voronoi cell of a site. `surroundingEdges` can be used for a list of all edges defining the cell.
+- The `HalfEdge`s trace out a voronoi cell counter-clockwise with the incidentSite to its left, assuming a coordinate system where y increases upward and x increases rightward.
+- `incidentSite` is `nil` if it is an edge on the exterior border of the bounding rectangle.
+- `walk()` outputs an ring of the `HalfEdges` defining the cell, or `nil` if the edges don't form a ring (should not happen)
+
+## Issues
+
+- Points outside of the bounding box will still effect the voronoi diagram, as the box simply bounds all of the infinite edges.
+- The algorithm does not work with the edge case where all points are collinear.
+- The algorithm does not work with the edge case where there are multiple sites at the same location.
 

Sources/FortuneSwift/Voronoi.swift

@@ -13,7 +13,7 @@ public struct Voronoi {
 
     var fortune = Fortune()
 
-    public var sites: [Coordinate] = []
+    private var sites: [Coordinate] = []
     public var voronoiVertices: [Vertex]?
     public var voronoiEdges: [HalfEdge]?
     public var voronoiSites: [Site]?