JavaFX中的高刷新率

Question

我正在尝试编写一个带有均衡器、频率分析仪和声级计的程序。模型部分似乎工作得很好，但我正在用 IHM 试验一些错误。

我的最后一个错误是水平仪。一段时间后（从几毫秒到几秒），它会冻结并且不再更新。因此，这是它的（简化）版本。我添加了可运行部分来测试和重现错误。当然，当我添加其他也需要频繁刷新的图形组件时，这个错误会更快出现。例如，频率分析由大约 1000 个点的折线图表示。

public class LevelMeter2 extends Parent implements Runnable {

    private IntegerProperty levelMeterHeight = new SimpleIntegerProperty();

    private Rectangle led;

    private IntegerProperty height = new SimpleIntegerProperty();
    private IntegerProperty width = new SimpleIntegerProperty();
    private DoubleProperty linearValue = new SimpleDoubleProperty();
    private Color backgroundColor=Color.BLACK;
    private double minLinearValue, maxLinearValue;

    public LevelMeter2 (int height2, int width2) {
        this.height.set(height2);
        this.levelMeterHeight.bind(height.multiply(0.9));
        this.width.set(width2);

        linearValue.set(1.0);
        minLinearValue = Math.pow(10, -60.0/100);
        maxLinearValue = Math.pow(10, 3.0/100)-minLinearValue;

        Rectangle levelMeterShape = new Rectangle();
        levelMeterShape.widthProperty().bind(width);
        levelMeterShape.heightProperty().bind(height);
        levelMeterShape.setStroke(backgroundColor);

        this.getChildren().add(levelMeterShape);

        led = new Rectangle();
        led.widthProperty().bind(width.multiply(0.8));
        led.translateXProperty().bind(width.multiply(0.1));
        led.heightProperty().bind(levelMeterHeight.multiply(linearValue));
        led.setFill(Color.AQUA);
        Rotate rotate = new Rotate();
        rotate.pivotXProperty().bind(width.multiply(0.8).divide(2));
        rotate.pivotYProperty().bind(height.divide(2));
        rotate.setAngle(180);
        led.getTransforms().add(rotate);
        this.getChildren().add(led);
        }

    public double convertdBToLinearValue (double dB) {
        return ((double)Math.round(100 * ((Math.pow(10, dB/100)-minLinearValue)/maxLinearValue)) ) /100   ;
        //return (Math.pow(10, dB/100)-minLinearValue)/maxLinearValue;
    }

    public double convertLinearValueTodB (double linearValue) {
        return 100*Math.log10(linearValue*maxLinearValue+minLinearValue);
    }

    public void setValue (double dB) {
        if (dB>3) {
            dB=3;
        }   
        linearValue.setValue(convertdBToLinearValue(dB));
    }

    @Override
    public void run() {
        int i = 0;
        double value=-20;
        while (i<1000) {
            setValue(value);
            value = (Math.random()-0.5)*10+value;
            if (value>3) {
                value=3;
            }
            if (value<-60) {
                value=-60;
            }
            i++;
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("END OF WHILE");
    }
}

还有一个“主要”来测试它：

public class MainGraph extends Application {

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

    @Override
    public void start(Stage primaryStage) throws Exception {
        HBox pane = new HBox();
        LevelMeter2 levelMeter = new LevelMeter2(300,30);
        Thread t = new Thread(levelMeter);
        pane.getChildren().add(levelMeter);

        t.start();
        Scene scene = new Scene(pane, 300, 300);
        primaryStage.setScene(scene);
        primaryStage.setTitle("Test IHM");
        primaryStage.setOnCloseRequest( event -> {
            System.out.println("FIN");
            System.exit(0);     
        });
        primaryStage.show();
    }    
}

我的代码有什么问题？如何编写更强大的代码，让我的 IHM 具有高刷新率？或者我怎样才能防止冻结？

感谢您的帮助。

Answer 1

我建议你离开 Threads 并使用 JavaFX Animation 包中的东西。在此示例中使用 Timeline。此代码设置为以大约 60 fps 的速率运行。您可以使用Duration.millis() 进行调整。

>Main

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

/**
 *
 * @author blj0011
 */
public class JavaFXApplication342 extends Application
{

    @Override
    public void start(Stage primaryStage)
    {

        LevelMeter2 levelMeter = new LevelMeter2(300, 30);

        Button button = new Button("Start");
        button.setOnAction((event) -> {
            switch (button.getText()) {
                case "Start":
                    levelMeter.startAnimation();
                    button.setText("Stop");
                    break;
                case "Stop":
                    levelMeter.stopAnimation();
                    button.setText("Start");
                    break;
            }
        });

        HBox pane = new HBox(levelMeter, button);
        Scene scene = new Scene(pane, 300, 300);
        primaryStage.setScene(scene);
        primaryStage.setTitle("Test IHM");
        primaryStage.setOnCloseRequest(event -> {
            System.out.println("FIN");
            System.exit(0);
        });
        primaryStage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {
        launch(args);
    }

}

LevelMeter2

import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.scene.Parent;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.transform.Rotate;
import javafx.util.Duration;

public final class LevelMeter2 extends Parent
{

    private final IntegerProperty levelMeterHeight = new SimpleIntegerProperty();

    Timeline timeline;
    double value = -20;

    private final Rectangle led;

    private final IntegerProperty height = new SimpleIntegerProperty();
    private final IntegerProperty width = new SimpleIntegerProperty();
    private final DoubleProperty linearValue = new SimpleDoubleProperty();
    private final Color backgroundColor = Color.BLACK;
    private final double minLinearValue;
    private final double maxLinearValue;

    public LevelMeter2(int height2, int width2)
    {
        this.height.set(height2);
        this.levelMeterHeight.bind(height.multiply(0.9));
        this.width.set(width2);

        linearValue.set(1.0);
        minLinearValue = Math.pow(10, -60.0 / 100);
        maxLinearValue = Math.pow(10, 3.0 / 100) - minLinearValue;

        Rectangle levelMeterShape = new Rectangle();
        levelMeterShape.widthProperty().bind(width);
        levelMeterShape.heightProperty().bind(height);
        levelMeterShape.setStroke(backgroundColor);

        this.getChildren().add(levelMeterShape);

        led = new Rectangle();
        led.widthProperty().bind(width.multiply(0.8));
        led.translateXProperty().bind(width.multiply(0.1));
        led.heightProperty().bind(levelMeterHeight.multiply(linearValue));
        led.setFill(Color.AQUA);
        Rotate rotate = new Rotate();
        rotate.pivotXProperty().bind(width.multiply(0.8).divide(2));
        rotate.pivotYProperty().bind(height.divide(2));
        rotate.setAngle(180);
        led.getTransforms().add(rotate);
        getChildren().add(led);

        timeline = new Timeline(new KeyFrame(Duration.millis(16), (event) -> {
            setValue(value);

            value = (Math.random() - 0.5) * 10 + value;
            if (value > 3) {
                value = 3;
            }
            if (value < -60) {
                value = -60;
            }

        }));
        timeline.setCycleCount(Timeline.INDEFINITE);
    }

    public double convertdBToLinearValue(double dB)
    {
        return ((double) Math.round(100 * ((Math.pow(10, dB / 100) - minLinearValue) / maxLinearValue))) / 100;
    }

    public double convertLinearValueTodB(double linearValue)
    {
        return 100 * Math.log10(linearValue * maxLinearValue + minLinearValue);
    }

    public void setValue(double dB)
    {
        if (dB > 3) {
            dB = 3;
        }
        linearValue.setValue(convertdBToLinearValue(dB));
    }

    public void startAnimation()
    {
        timeline.play();
    }

    public void stopAnimation()
    {
        timeline.stop();
    }
}

多个 LevelMeters 示例：

主要

import java.util.ArrayList;
import java.util.List;
import javafx.animation.ParallelTransition;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.HBox;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

/**
 *
 * @author blj0011
 */
public class JavaFXApplication342 extends Application
{

    @Override
    public void start(Stage primaryStage)
    {
        List<LevelMeter2> levelMeter2s = new ArrayList();
        List<Timeline> metersTimelines = new ArrayList();
        for (int i = 0; i < 9; i++) {
            LevelMeter2 levelMeter2 = new LevelMeter2(300, 30);
            levelMeter2s.add(levelMeter2);
            metersTimelines.add(levelMeter2.getTimeline());
        }

        ParallelTransition parallelTransition = new ParallelTransition();
        parallelTransition.getChildren().addAll(metersTimelines);

        Button button = new Button("Start");
        button.setOnAction((event) -> {
            switch (button.getText()) {
                case "Start":
                    parallelTransition.play();
                    button.setText("Stop");
                    break;
                case "Stop":
                    parallelTransition.stop();
                    button.setText("Start");
                    break;
            }
        });

        HBox hBox = new HBox();
        hBox.getChildren().addAll(levelMeter2s);

        VBox vBox = new VBox(hBox, new StackPane(button));
        Scene scene = new Scene(vBox, 300, 350);
        primaryStage.setScene(scene);
        primaryStage.setTitle("Test IHM");
        primaryStage.setOnCloseRequest(event -> {
            System.out.println("FIN");
            System.exit(0);
        });
        primaryStage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {
        launch(args);
    }

}

LevelMeter2

import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.scene.Parent;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.transform.Rotate;
import javafx.util.Duration;

public final class LevelMeter2 extends Parent
{

    private final IntegerProperty levelMeterHeight = new SimpleIntegerProperty();

    Timeline timeline;
    double value = -20;

    private final Rectangle led;

    private final IntegerProperty height = new SimpleIntegerProperty();
    private final IntegerProperty width = new SimpleIntegerProperty();
    private final DoubleProperty linearValue = new SimpleDoubleProperty();
    private final Color backgroundColor = Color.BLACK;
    private final double minLinearValue;
    private final double maxLinearValue;

    public LevelMeter2(int height2, int width2)
    {
        this.height.set(height2);
        this.levelMeterHeight.bind(height.multiply(0.9));
        this.width.set(width2);

        linearValue.set(1.0);
        minLinearValue = Math.pow(10, -60.0 / 100);
        maxLinearValue = Math.pow(10, 3.0 / 100) - minLinearValue;

        Rectangle levelMeterShape = new Rectangle();
        levelMeterShape.widthProperty().bind(width);
        levelMeterShape.heightProperty().bind(height);
        levelMeterShape.setStroke(backgroundColor);

        this.getChildren().add(levelMeterShape);

        led = new Rectangle();
        led.widthProperty().bind(width.multiply(0.8));
        led.translateXProperty().bind(width.multiply(0.1));
        led.heightProperty().bind(levelMeterHeight.multiply(linearValue));
        led.setFill(Color.AQUA);
        Rotate rotate = new Rotate();
        rotate.pivotXProperty().bind(width.multiply(0.8).divide(2));
        rotate.pivotYProperty().bind(height.divide(2));
        rotate.setAngle(180);
        led.getTransforms().add(rotate);
        getChildren().add(led);

        timeline = new Timeline(new KeyFrame(Duration.millis(25), (event) -> {
            setValue(value);

            value = (Math.random() - 0.5) * 10 + value;
            if (value > 3) {
                value = 3;
            }
            if (value < -60) {
                value = -60;
            }

        }));
        timeline.setCycleCount(Timeline.INDEFINITE);
    }

    public double convertdBToLinearValue(double dB)
    {
        return ((double) Math.round(100 * ((Math.pow(10, dB / 100) - minLinearValue) / maxLinearValue))) / 100;
    }

    public double convertLinearValueTodB(double linearValue)
    {
        return 100 * Math.log10(linearValue * maxLinearValue + minLinearValue);
    }

    public void setValue(double dB)
    {
        if (dB > 3) {
            dB = 3;
        }
        linearValue.setValue(convertdBToLinearValue(dB));
    }

    public void startAnimation()
    {
        timeline.play();
    }

    public void stopAnimation()
    {
        timeline.stop();
    }

    public Timeline getTimeline()
    {
        return timeline;
    }
}

Answer 2

您的run() 实现似乎正在从后台线程更新场景图。如Concurrency in JavaFX 中所述：

JavaFX 场景图……不是线程安全的，只能从 UI 线程（也称为 JavaFX 应用程序线程）访问和修改。在 JavaFX 应用程序线程上实现长时间运行的任务不可避免地会使应用程序 UI 无响应。”

改为使用Task，图示here 和here。您的call() 实现可以异步收集数据并通过updateValue() 通知GUI 当前状态。然后您的valueProperty() 侦听器可以安全地调用setValue()。因为“合并更新以防止 FX 事件队列饱和”，您的应用程序即使在较旧的硬件上也能令人满意地执行。

或者，如果您的音频源是supported Media 类型之一，则此AudioBarChartApp 会更新AudioSpectrumListener 中的BarChart 的数据模型，该AudioSpectrumListener 已使用相应的MediaPlayer 注册。下图显示pink noise。

private XYChart.Data<String, Number>[] series1Data;
…
audioSpectrumListener = (double timestamp, double duration,
                         float[] magnitudes, float[] phases) -> {
    for (int i = 0; i < series1Data.length; i++) {
        series1Data[i].setYValue(magnitudes[i] + 60);
    }
};