Question

我写了两个简单的程序，两个都绘制了相同的Sierpinski三角形：
一个程序使用swing实现，一个使用javafx。存在非常显着的性能差异，摆动实施持续快得多：

（在这个测试案例中：在1秒内摆动.Javafx超过12秒）
是否可以预期或者我的javafx实现有什么问题？

Swing实施

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class SimpleSrpnskTriSw {

    private Triangles triPanel;

    SimpleSrpnskTriSw(int numberOfLevels){

        JFrame frame = new JFrame("Sierpinski Triangles (swing)");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        triPanel = new Triangles();
        frame.add(triPanel, BorderLayout.CENTER);
        frame.pack();

        frame.setResizable(false);
        frame.setVisible(true);

        triPanel.draw(numberOfLevels);
    }

    class Triangles extends JPanel{

        private static final int PANEL_WIDTH =600, PANEL_HEIGHT = 600;
        private static final int TRI_WIDTH= 500, TRI_HEIGHT= 500;
        private static final int SIDE_GAP = (PANEL_WIDTH - TRI_WIDTH)/2;
        private static final int TOP_GAP = (PANEL_HEIGHT - TRI_HEIGHT)/2;

        private int countTriangles;
        private long startTime;
        boolean working;
        private int numberOfLevels = 0;

        Triangles() {

            setPreferredSize(new Dimension(PANEL_WIDTH, PANEL_HEIGHT));
            startTime = System.currentTimeMillis();
            countTriangles = 0;
            working = true;
            draw();
        }

        void draw(int numLevels) {

            numberOfLevels = numLevels;
            working = true;
            draw();
        }

        void draw() {

            startTime = System.currentTimeMillis();
            countTriangles = 0;

            SwingUtilities.invokeLater(new Runnable() {
                @Override
                public void run() {

                    repaint();
                }
            });
        }

        @Override
        public void paintComponent(Graphics g) {

            super.paintComponent(g);
            g.setFont(new Font("Ariel", Font.PLAIN, 14));

            if(working) {

                g.setColor(getBackground());
                g.fillRect(0,0,PANEL_WIDTH,PANEL_HEIGHT);
                g.setColor(getForeground());

                g.drawString("Working.........", 15, 15);
                working = false;
                return;
            }

            if(numberOfLevels <= 0 ) {
                return;
            }
            Point top = new Point(PANEL_WIDTH/2, TOP_GAP);
            Point left = new Point(SIDE_GAP, TOP_GAP+ TRI_HEIGHT);
            Point right = new Point(SIDE_GAP + TRI_WIDTH, TOP_GAP+ TRI_HEIGHT);

            BufferedImage bi = getBufferedImage(top, left, right);
            Graphics2D g2d = (Graphics2D) g;
            g2d.drawImage(bi,0,0, this);

            g.drawString("Number of triangles: "+ countTriangles, 15, 15);
            g.drawString("Time : "+ (System.currentTimeMillis()- startTime)+ " mili seconds", 15, 35);
            g.drawString("Levels: "+ numberOfLevels, 15, 50);
        }

        private BufferedImage getBufferedImage(Point top, Point left, Point right) {

            BufferedImage bi = new BufferedImage(PANEL_WIDTH,PANEL_HEIGHT,
                                                            BufferedImage.TYPE_INT_ARGB);
            drawTriangle(bi, numberOfLevels, top, left, right);
            return bi;
        }

        private void drawTriangle(BufferedImage bi, int levels, Point top, Point left, Point right) {

            if(levels < 0) {
                return ;
            }

            countTriangles++;
            Graphics g = bi.getGraphics();
            g.setColor(Color.RED);

            Polygon tri = new Polygon();
            tri.addPoint(top.x, top.y);  //use top,left right rather than fixed points
            tri.addPoint(left.x, left.y);
            tri.addPoint(right.x, right.y);
            g.drawPolygon(tri);

            // Get the midpoint on each edge in the triangle
            Point p12 = midpoint(top, left);
            Point p23 = midpoint(left, right);
            Point p31 = midpoint(right, top);

            // recurse on 3 triangular areas
            drawTriangle(bi, levels - 1, top, p12, p31);
            drawTriangle(bi, levels - 1, p12, left, p23);
            drawTriangle(bi, levels - 1, p31, p23, right);
        }

        private Point midpoint(Point p1, Point p2) {

            return new Point((p1.x + p2.x) / 2, (p1.y + p2.y) / 2);
        }
    }

    public static void main(String[] args) {

        new SimpleSrpnskTriSw(13);
    }
}

JavaFx实施

import javafx.application.Application;
import javafx.application.Platform;
import javafx.concurrent.Task;
import javafx.geometry.Insets;
import javafx.geometry.Point2D;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.image.WritableImage;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class SimpleSrpnskTriFx extends Application {

    private final int PADDING = 5;
    private static int numberOfLevels;

    public static void launch(String... args){

        numberOfLevels = 8;

        if((args != null) && (args.length > 0)) {

            try {
                int num = Integer.parseInt(args[0]);
                numberOfLevels =  num ;
            } catch (NumberFormatException ex) {
                ex.printStackTrace();
                return;
            }
        }

        Application.launch(args);
    }

    @Override
    public void start(Stage stage) {

        stage.setOnCloseRequest((ae) -> {
            Platform.exit();
            System.exit(0);
        });

        stage.setTitle("Sierpinski Triangles (fx)");

        BorderPane mainPane = new BorderPane();
        mainPane.setPadding(new Insets(PADDING));

        Pane triPanel = new Triangles();

        BorderPane.setAlignment(triPanel, Pos.CENTER);
        mainPane.setCenter(triPanel);

        Scene scene = new Scene(mainPane);

        stage.setScene(scene);
        stage.centerOnScreen();

        stage.setResizable(false);
        stage.show();
    }

    class Triangles extends AnchorPane{

        private static final int PANEL_WIDTH =600, PANEL_HEIGHT = 600;
        private static final int TRI_WIDTH= 500, TRI_HEIGHT= 500;
        private static final int SIDE_GAP = (PANEL_WIDTH - TRI_WIDTH)/2;
        private static final int TOP_GAP = (PANEL_HEIGHT - TRI_HEIGHT)/2;
        private int countTriangles;
        private long startTime;
        private Point2D top, left, right;

        private Canvas canvas;
        private Canvas backgroundCanvas;
        private GraphicsContext gc;

        Triangles(){

            setPrefSize(PANEL_WIDTH, PANEL_HEIGHT);

            canvas = getCanvas();
            backgroundCanvas = getCanvas();
            gc = backgroundCanvas.getGraphicsContext2D();
            getChildren().add(canvas);
            draw(numberOfLevels);
        }

        void draw(int numberLevels) {

            Platform.runLater(new Runnable() {

                @Override
                public void run() {

                    canvas.getGraphicsContext2D().fillText("Working....",5,15);
                    setStartPoints();

                    startTime = System.currentTimeMillis();
                    countTriangles = 0;

                    RunTask task = new RunTask(numberLevels, top, left, right);
                    Thread thread = new Thread(task);
                    thread.setDaemon(true);
                    thread.start();
                }
            });
        }

        private void drawTriangle( int levels, Point2D top, Point2D left, Point2D right) {

            if(levels < 0) {//add stop criteria
                return ;
            }

            gc.strokePolygon( //implementing with strokeLine did not make much difference
                    new double[]{
                            top.getX(),left.getX(),right.getX()
                    },
                    new double[]{
                            top.getY(),left.getY(), right.getY()
                    },
                    3);

            countTriangles++;

            //Get the midpoint on each edge in the triangle
            Point2D p12 = midpoint(top, left);
            Point2D p23 = midpoint(left, right);
            Point2D p31 = midpoint(right, top);

            // recurse on 3 triangular areas
            drawTriangle(levels - 1, top, p12, p31);
            drawTriangle(levels - 1, p12, left, p23);
            drawTriangle(levels - 1, p31, p23, right);
        }

        private void setStartPoints() {

            top = new Point2D(getPrefWidth()/2, TOP_GAP);
            left = new Point2D(SIDE_GAP, TOP_GAP + TRI_HEIGHT);
            right = new Point2D(SIDE_GAP + TRI_WIDTH, TOP_GAP + TRI_WIDTH);
        }

        private Point2D midpoint(Point2D p1, Point2D p2) {

            return new Point2D((p1.getX() + p2.getX()) /
                    2, (p1.getY() + p2.getY()) / 2);
        }

        private void updateGraphics(boolean success){

            if(success) {

                copyCanvas();

                GraphicsContext gc = canvas.getGraphicsContext2D();
                gc.fillText("Number of triangles: "+ countTriangles,5,15);
                gc.fillText("Time : "+ (System.currentTimeMillis()- startTime )+ " mili seconds", 5,35);
                gc.fillText("Levels: "+ numberOfLevels,5,55);
            }

        }

        private Canvas getCanvas() {

            Canvas canvas = new Canvas();
            canvas.widthProperty().bind(widthProperty());
            canvas.heightProperty().bind(heightProperty());
            canvas.getGraphicsContext2D().setStroke(Color.RED);
            canvas.getGraphicsContext2D().setLineWidth(0.3f);

            return canvas;
        }

        private void copyCanvas() {

            WritableImage image = backgroundCanvas.snapshot(null, null);
            canvas.getGraphicsContext2D().drawImage(image, 0, 0);
        }

        /**
         */
        class RunTask extends Task<Void>{

            private int levels;
            private Point2D top, left;
            private Point2D right;

            RunTask(int levels, Point2D top, Point2D left, Point2D right){

                this.levels = levels;
                this.top = top;
                this.left = left;
                this.right = right;

                startTime = System.currentTimeMillis();
                countTriangles = 0;
            }

            @Override public Void call() {

                drawTriangle(levels,top, left, right);
                return null;
            }

            @Override
            protected void succeeded() {

                updateGraphics(true);
                super.succeeded();
            }

            @Override
            protected void failed() {

                updateGraphics(false);
            }
        }
    }

    public static void main(String[] args) {
        launch("13");
    }
}

Answer 1

Swing示例将图像展平 600 ² = 360,000像素。相比之下，JavaFX示例在最终渲染时会触发近240万个重叠多边形。请注意，您的JavaFX示例测量两者组成分形的时间和在scene graph中呈现分形的时间。

如果要保留包含分形的笔画，请将结果组成Canvas，如图here所示。

如果广告Image已足够，请将结果复制到BufferedImage，将其转换为JavaFX Image，然后将其显示在ImageView中，如下所示。 JavaFX结果比我硬件上的Swing示例快更快。

由于SwingFXUtils.toFXImage制作副本，后台Task<Image>可以继续更新单个BufferedImage，同时通过{{发布临时Image结果1}}。

updateValue()

JavaFx Gui与Swing的表现

1 个答案: