private void OnEnable()
{
nodeIdPool = new IdentityPool();
nodes = new List <Node>();
connections = new List <Connection>();
SelectedNodes = new HashSet <Node>();
// initialize node style
nodeStyle = CommonStyle.BlueNode;
// initialize selected node style
selectedNodeStyle = CommonStyle.SelectedBlueNode;
// initialize input point style
inPointStyle = new GUIStyle();
inPointStyle.normal.background = EditorGUIUtility.Load("builtin skins/darkskin/images/btn left.png") as Texture2D;
inPointStyle.active.background = EditorGUIUtility.Load("builtin skins/darkskin/images/btn left on.png") as Texture2D;
inPointStyle.border = new RectOffset(4, 4, 12, 12);
// initialize output point style
outPointStyle = new GUIStyle();
outPointStyle.normal.background = EditorGUIUtility.Load("builtin skins/darkskin/images/btn right.png") as Texture2D;
outPointStyle.active.background = EditorGUIUtility.Load("builtin skins/darkskin/images/btn right on.png") as Texture2D;
outPointStyle.border = new RectOffset(4, 4, 12, 12);
// zoom
Zoom = 1;
ZoomRate = 0.01f;
MaxZoom = 1f;
MinZoom = 1f;
// initialize subwindow
SubwindowRect = new Rect(0, ToolBarHeight, LeftColWidth, position.height - ToolBarHeight);
OnInitialized();
}