Graph with Black background and white edges

Hello,

I am generating a graph using YifanHuLayout by reading .gexf file and wanted to have graph as a black background and white edges. I am generating graph exactly opposite of this as of now. Does anyone know what should I do to get black background and white edges.

Also, I want to change the thickness of edges with weight of edges. Does anyone know how to go about it?

Here is a code that I am using.

public class Headless {

 public void getGraph(){
  //Init a project - and therefore a workspace
  ProjectController pc = Lookup.getDefault().lookup(ProjectController.class);
  pc.newProject();
  Workspace workspace = pc.getCurrentWorkspace();

  //Get models and controllers for this new workspace - will be useful later
  AttributeModel attributeModel = Lookup.getDefault().lookup(AttributeController.class).getModel();
  GraphModel graphModel = Lookup.getDefault().lookup(GraphController.class).getModel();
  PreviewModel model = Lookup.getDefault().lookup(PreviewController.class).getModel();
  ImportController importController = Lookup.getDefault().lookup(ImportController.class);
  FilterController filterController = Lookup.getDefault().lookup(FilterController.class);
  RankingController rankingController = Lookup.getDefault().lookup(RankingController.class);

  //Import file
  Container container;
  try {
   URL url = getClass().getResource("test1.gexf");
   System.out.println(url);
      File file = new File(getClass().getResource("test1.gexf").toURI());
      container = importController.importFile(file);
      container.getLoader().setEdgeDefault(EdgeDefault.DIRECTED); //Force DIRECTED
  } catch (Exception ex) {
      ex.printStackTrace();
      return;
  }

  //Append imported data to GraphAPI
  importController.process(container, new DefaultProcessor(), workspace);

  //See if graph is well imported
  DirectedGraph graph = graphModel.getDirectedGraph();
  System.out.println("Nodes: " + graph.getNodeCount());
  System.out.println("Edges: " + graph.getEdgeCount());

  //See visible graph stats
  UndirectedGraph graphVisible = graphModel.getUndirectedGraphVisible();
  System.out.println("Nodes: " + graphVisible.getNodeCount());
  System.out.println("Edges: " + graphVisible.getEdgeCount());

  //Run YifanHuLayout for 100 passes - The layout always takes the current visible view
  YifanHuLayout layout = new YifanHuLayout(null, new StepDisplacement(1f));
  layout.setGraphModel(graphModel);
  layout.resetPropertiesValues();
  layout.setOptimalDistance(200f);

  for (int i = 0; i < 1000 && layout.canAlgo(); i++) {
   layout.goAlgo();
  }

  //Get Centrality
  GraphDistance distance = new GraphDistance();
  distance.setDirected(true);
  distance.execute(graphModel, attributeModel);

  //Rank color by Degree
  NodeRanking degreeRanking = rankingController.getRankingModel().getDegreeRanking();
  ColorTransformer colorTransformer = rankingController.getObjectColorTransformer(degreeRanking);
  colorTransformer.setColors(new Color[]{new Color(0xFEF0D9), new Color(0xB30000)});
  rankingController.transform(colorTransformer);

  //Rank size by centrality
  AttributeColumn centralityColumn = attributeModel.getNodeTable().getColumn(GraphDistance.BETWEENNESS);
  NodeRanking centralityRanking = rankingController.getRankingModel().getNodeAttributeRanking(centralityColumn);
  SizeTransformer sizeTransformer = rankingController.getObjectSizeTransformer(centralityRanking);
  sizeTransformer.setMinSize(3);
  sizeTransformer.setMaxSize(10);
  rankingController.transform(sizeTransformer);

  //Preview
  model.getNodeSupervisor().setShowNodeLabels(Boolean.TRUE);
  ColorizerFactory colorizerFactory = Lookup.getDefault().lookup(ColorizerFactory.class);
  model.getUniEdgeSupervisor().setColorizer((EdgeColorizer) colorizerFactory.createCustomColorMode(Color.BLACK)); //Set edges black
  model.getBiEdgeSupervisor().setColorizer((EdgeColorizer) colorizerFactory.createCustomColorMode(Color.BLACK)); //Set mutual edges black
  model.getNodeSupervisor().setBaseNodeLabelFont(model.getNodeSupervisor().getBaseNodeLabelFont().deriveFont(8));
  model.getUndirectedEdgeSupervisor().setCurvedFlag(false);
  model.getUniEdgeSupervisor().setCurvedFlag(false);
  model.getUniEdgeSupervisor().setArrowSize(0.0f);
  //Export
  ExportController ec = Lookup.getDefault().lookup(ExportController.class);
  try {
      ec.exportFile(new File("test4.pdf"));
  } catch (IOException ex) {
      ex.printStackTrace();
      return;
  }
 }
 public static void main(String[] args){
  Headless headLess = new Headless();
  headLess.getGraph();
 }

}

I appreciate your help!

Thanks!