Update README.md

README.md

@@ -1 +1,58 @@
-# libfdgraph
+# Graphoon
+
+A force directed algorithm written in Lua.
+
+
+## Basic Usage
+
+The basic idea is that you create a new graph object, to which you can then add nodes and edges.
+
+```
+local GraphLibrary = require('Graphoon').Graph
+
+graph = GraphLibrary.new()
+graph:addNode( "Ash Williams" )
+graph:addNode( "Necronomicon" )
+graph:connectIDs( "Ash Williams", "Necronomicon" )
+```
+
+By itself Graphoon only provides functionality for creating the graph and calculating the layout based on physical attraction and repulsion forces.
+
+It provides a ```draw``` and ```update``` function, which can be used to easily write your own rendering code.
+
+The ```draw``` function should be called with two callback functions. The first callback will be used for all nodes and the second one for all the edges. 
+
+```
+graph:draw( function( node )
+				local x, y = node:getPosition()
+				drawCircle( 'fill', x, y, 10 )
+			end,
+			function( edge )
+				local ox, oy = edge.origin:getPosition()
+				local tx, ty = edge.target:getPosition()
+				drawLine( ox, oy, tx, ty )
+			end)
+```
+
+At its simplest the force calculations can be updated via ```graph:update( dt )```, but the ```update``` function also can receive optional callbacks for both nodes and edges.
+
+## Advanced usage
+
+### Using anchors
+
+Anchors can be used to attach a node to a certain position on the screen. This can be useful if you want to center a certain node for example.
+
+This can either be done directly via the constructor of the node:
+
+```
+-- Anchor the node to the center of the screen.
+graph:addNode( "Ash Williams", screenX * 0.5, screenY * 0.5, true )
+```
+
+Or by using the ```setAnchor``` function:
+
+```
+-- Invert anchor status
+node:setAnchor( not node:isAnchor() )
+```
+