构建描述的LineChart需要花费15分钟
JavaFX,这对我的任务不起作用.
使用好的旧Swing和jFreeChart的类似实现需要1.5秒来构建图表.
但我还是想实现一个JavaFX.
这是我的代码：
public class FXMLController implements Initializable {
@FXML
private Label statusbar;
@FXML
public LineChart lineChart;
@FXML
public Button connect;
@FXML
public MenuItem options;
@FXML
public NumberAxis xAxis;
@FXML
NumberAxis yAxis;
@FXML
private void connect(ActionEvent event) {
}
public static FileChooser fileChooser = new FileChooser();
public static String path;
public static XYChart.Series<Integer,Integer> dataSeries = new XYChart.Series<Integer,Integer>();
public static int y = 0;
public static XYChart.Data<Integer,Integer> data;
@FXML
private void open(ActionEvent event) {
fileChooser.setTitle("Open Resource File");
fileChooser.getExtensionFilters().addAll(
new ExtensionFilter("Text Files","*.txt"),new ExtensionFilter("Image Files","*.png","*.jpg","*.gif"),new ExtensionFilter("Audio Files","*.wav","*.mp3","*.aac"),new ExtensionFilter("All Files","*.*"));
File selectedFile = fileChooser.showOpenDialog(new Stage());
if (selectedFile != null) {
path = selectedFile.getAbsolutePath();
System.out.println(path);
try {
ReadingFromFile.readFile(path);
} catch (IOException ex) {
Logger.getLogger(FXMLController.class.getName()).log(Level.SEVERE,null,ex);
}
}
}
@FXML
private void close(ActionEvent event) {
}
@FXML
private void getconnect(ActionEvent event) {
}
@Override
public void initialize(URL url,ResourceBundle rb) {
xAxis.setLabel("Tick");
xAxis.setTickUnit(100);
yAxis.setLabel("Signal");
xAxis.setForceZeroInRange(false);
lineChart.setLegendVisible(false);
lineChart.setCreateSymbols(false);
lineChart.setAnimated(false);
lineChart.getData().add(dataSeries);
}
}
并从文件中读取：
public class ReadingFromFile extends FXMLController {
public static String s = null;
public static String[] str;
public static int parseInt;
public static void readFile(String filename)
throws IOException {
BufferedReader br = new BufferedReader(new FileReader(filename));
try {
StringBuilder sb = new StringBuilder();
String line = br.readLine();
while (line != null) {
sb.append(line);
sb.append(System.lineSeparator());
line = br.readLine();
System.out.println(line);
try {
str = line.split(" ");
for (int i = 0; i < str.length; i = i + 2) {
s = str[i + 1] + str[i];
parseInt = Integer.parseInt(s,16);
javafx.application.Platform.runLater(new Runnable() {
@Override
public void run() {
data = new XYChart.Data<Integer,Integer>(y,parseInt);
//data.setNode(new HoveredThresholdNode(0,second,""));
dataSeries.getData().add(data);
y++;
}
});
}
} catch (java.lang.NullPointerException ex) {
System.out.println("тут ноль!!!");
}
}
} finally {
br.close();
}
}
}
解决方法
我遇到了类似的问题,每隔几秒就会给一次LineChart增加100,000点.我们使用
Ramer–Douglas–Peucker algorithm解决了它,这减少了线路中的点数而没有用户注意到.我在
JTS topology suite根据LGPL许可证找到了现成的实施方案.
这是我的测试代码.
public class ChartUpdate extends Application {
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage stage) {
NumberAxis xAxis = new NumberAxis(0,50_000,5000);
xAxis.setAutoRanging(false);
NumberAxis yAxis = new NumberAxis(-1,1,25);
yAxis.setAutoRanging(false);
LineChart<Number,Number> graph = new LineChart<>(xAxis,yAxis);
graph.setAnimated(false);
graph.setCreateSymbols(false);
graph.setLegendVisible(false);
Series<Number,Number> series = new Series<>();
stage.setScene(new Scene(graph));
GeometryFactory gf = new GeometryFactory();
long t0 = System.nanoTime();
Coordinate[] coordinates = new Coordinate[100_000];
for (int i = 0; i < coordinates.length; i++) {
coordinates[i] = new Coordinate(i,Math.sin(Math.toRadians(i / 100)));
}
Geometry geom = new LineString(new CoordinateArraySequence(coordinates),gf);
Geometry simplified = DouglasPeuckerSimplifier.simplify(geom,0.00001);
List<Data<Number,Number>> update = new ArrayList<Data<Number,Number>>();
for (Coordinate each : simplified.getCoordinates()) {
update.add(new Data<>(each.x,each.y));
}
long t1 = System.nanoTime();
System.out.println(String.format("Reduces points from %d to %d in %.1f ms",coordinates.length,update.size(),(t1 - t0) / 1e6));
ObservableList<Data<Number,Number>> list = FXCollections.observableArrayList(update);
series.setData(list);
graph.getData().add(series);
stage.show();
}
}
