java - 如何在 JAVAFX 2 中使用 AreaChart 绘制实时流数据图表 - 并发、动画、图表

Question

要求 - 使用实时流数据构建动画 AreaChart。也许每 1 秒绘制 300 个数据点。

详情-因此，我需要从医疗设备读取患者呼吸模式的实时流数据，并使用 JavaFX 中的 AreaChart 以波形方式显示它。我是 JavaFX 的新手，所以我构建了一个小型 POC，以了解并发性和动画在 JavaFX 中的工作原理。

这个概念可行，就实现功能而言，我对基本测试很满意。但是我对从下面的代码中获得的性能不满意。

在下面的工作代码中，我创建了一个单独的线程来模拟从医疗设备中获取数据。该线程只是生成一个随机数并将其添加到 ConcurrentLinkedQueue。

JavaFX 应用程序线程通过时间线从队列中拉出该数据，并将其添加到 AreaChart 系列。

这为我提供了所需的动画，并在运行时添加了数据。您可以复制粘贴此代码并对其进行测试。它应该可以工作。

但性能并不令人印象深刻 - CPU 使用率达到 56% - 我的笔记本电脑上有 Intel Core 2 Duo @ 2.53 GHZ 和 4GB 内存。我的显卡是带有最新驱动程序的 Mobile Intel 4 Series express。

如何改进实时数据的动画或绘图，以获得更好的性能？

注意:如果是瓶颈，我愿意在动画上妥协。我对此处所示的实现持开放态度 http://smoothiecharts.org/其中波形只是预构建的，只是从右到左流式传输。

  import java.util.concurrent.ConcurrentLinkedQueue;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  import javafx.animation.Animation;
  import javafx.animation.KeyFrame;
  import javafx.animation.SequentialTransition;
  import javafx.animation.Timeline;
  import javafx.application.Application;
  import javafx.event.ActionEvent;
  import javafx.event.EventHandler;
  import javafx.scene.Group;
  import javafx.scene.Scene;
  import javafx.scene.chart.AreaChart;
  import javafx.scene.chart.NumberAxis;
  import javafx.scene.chart.XYChart.Series;
  import javafx.stage.Stage;
  import javafx.util.Duration;

  /**
   * A chart that fills in the area between a line of data points and the axes.
   * Good for comparing accumulated totals over time.
   *
   * @see javafx.scene.chart.Chart
   * @see javafx.scene.chart.Axis
   * @see javafx.scene.chart.NumberAxis
   * @related charts/line/LineChart
   * @related charts/scatter/ScatterChart
   */
  public class AreaChartSample extends Application {
      private Series series;
      private int xSeriesData=0;
      private ConcurrentLinkedQueue<Number> dataQ = new ConcurrentLinkedQueue<Number>();
      private ExecutorService executor;
      private AddToQueue addToQueue;
      private Timeline timeline2;
      private SequentialTransition animation;

      private void init(Stage primaryStage) {
          Group root = new Group();
          primaryStage.setScene(new Scene(root));

          NumberAxis xAxis = new NumberAxis();
          xAxis.setAutoRanging(true);

          NumberAxis yAxis = new NumberAxis();
          yAxis.setAutoRanging(true);

          //-- Chart
          final AreaChart<Number,Number> sc = new AreaChart<Number,Number>(xAxis,yAxis);
          sc.setId("liveAreaChart");
          sc.setTitle("Animated Area Chart");

          //-- Chart Series
          series=new AreaChart.Series<Number,Number>();
          series.setName("Area Chart Series");
          series.getData().add(new AreaChart.Data<Number, Number>(5d, 5d));
          sc.getData().add(series);


          root.getChildren().add(sc);



      }

      @Override public void start(Stage primaryStage) throws Exception {
          init(primaryStage);
          primaryStage.show();

          //-- Prepare Executor Services
          executor = Executors.newCachedThreadPool();
          addToQueue=new AddToQueue();
          executor.execute(addToQueue);


          //-- Prepare Timeline
          prepareTimeline();


      }

      public static void main(String[] args) { launch(args); }

      private class AddToQueue extends Thread {

          public void run(){

          try {
              Thread.currentThread().setName(Thread.currentThread().getId()+"-DataAdder");
              //-- Add Random numbers to Q
              dataQ.add(Math.random());
              Thread.sleep(50);

              executor.execute(addToQueue);

          } catch (InterruptedException ex) {
              Logger.getLogger(AreaChartSample.class.getName()).log(Level.SEVERE, null, ex);
          }

          }
      }

      //-- Timeline gets called in the JavaFX Main thread
      private void prepareTimeline(){
          //-- Second slower timeline
          timeline2 = new Timeline();
          //-- This timeline is indefinite.  
          timeline2.setCycleCount(Animation.INDEFINITE);

          timeline2.getKeyFrames().add(
                  new KeyFrame(Duration.millis(100), new EventHandler<ActionEvent>() {
                      @Override public void handle(ActionEvent actionEvent) {
                          addDataToSeries();

                      }
                  })
          );

          //-- Set Animation- Timeline is created now.
          animation = new SequentialTransition();
          animation.getChildren().addAll(timeline2);
          animation.play();        

      }

      private void addDataToSeries(){

          for(int i=0;i<20;i++){ //-- add 20 numbers to the plot
              if(dataQ.isEmpty()==false)   {
                  series.getData().add(new AreaChart.Data(xSeriesData++,dataQ.remove()));

                  //-- Get rid of a bunch from the chart
                  if (series.getData().size() > 1000) {
                      series.getData().remove(0,999);
                  }

              }
              else{
                  return;
              }
          }
      }


  }

Answer 1

作为jewelsea在他/她的评论中说:

This question was cross posted (and answered well) on an Oracle JavaFX forum thread.

总而言之，解决方案包括:

• Turning animation off as it is designed for slower changing data so that it is animated on arrival;
• Changing the Timeline to a AnimationTimer as it is desired to update the chart every frame in order to keep in sync with incoming data and move as smoothly as possible;
• Fixing threading as OP did not need to extend Thread when using a Executor. Changing the creation of the executor service.