java - JavaFX 中的图形可视化(如 yFiles)

Question

类似于 Graphviz，但更具体地说，是 yFiles。

我想要一个节点/边类型的图形可视化。

我正在考虑将节点设为Circle，将边设为Line。问题是在节点/边缘出现的区域使用什么。我应该使用 ScrollPane、常规 Pane、Canvas 等等...

我将添加滚动功能、缩放、选择节点和拖动节点。

感谢您的帮助。

Answer 1

我有 2 个小时的时间要杀，所以我想我会试一试。事实证明，想出一个原型(prototype)很容易。

这是你需要的:

• 使用您创建的图形库的主类
• 带有数据模型的图表
• 轻松添加和删除节点和边(事实证明，最好命名节点单元格，以避免在编程过程中与 JavaFX 节点混淆)
• 一个 zoomable scrollpane
• 图形的布局算法

关于 SO 的要求实在是太多了，所以我将添加一些注释的代码。

应用程序实例化图表，添加单元格并通过边连接它们。

应用程序/Main.java

package application;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

import com.fxgraph.graph.CellType;
import com.fxgraph.graph.Graph;
import com.fxgraph.graph.Model;
import com.fxgraph.layout.base.Layout;
import com.fxgraph.layout.random.RandomLayout;

public class Main extends Application {

    Graph graph = new Graph();

    @Override
    public void start(Stage primaryStage) {
        BorderPane root = new BorderPane();

        graph = new Graph();

        root.setCenter(graph.getScrollPane());

        Scene scene = new Scene(root, 1024, 768);
        scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());

        primaryStage.setScene(scene);
        primaryStage.show();

        addGraphComponents();

        Layout layout = new RandomLayout(graph);
        layout.execute();

    }

    private void addGraphComponents() {

        Model model = graph.getModel();

        graph.beginUpdate();

        model.addCell("Cell A", CellType.RECTANGLE);
        model.addCell("Cell B", CellType.RECTANGLE);
        model.addCell("Cell C", CellType.RECTANGLE);
        model.addCell("Cell D", CellType.TRIANGLE);
        model.addCell("Cell E", CellType.TRIANGLE);
        model.addCell("Cell F", CellType.RECTANGLE);
        model.addCell("Cell G", CellType.RECTANGLE);

        model.addEdge("Cell A", "Cell B");
        model.addEdge("Cell A", "Cell C");
        model.addEdge("Cell B", "Cell C");
        model.addEdge("Cell C", "Cell D");
        model.addEdge("Cell B", "Cell E");
        model.addEdge("Cell D", "Cell F");
        model.addEdge("Cell D", "Cell G");

        graph.endUpdate();

    }

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

滚动 Pane 应具有白色背景。

应用程序/application.css

.scroll-pane > .viewport {
   -fx-background-color: white;
}

可缩放的滚动 Pane ，我得到了 code base from pixel duke :

ZoomableScrollPane.java

package com.fxgraph.graph;

import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.control.ScrollPane;
import javafx.scene.input.ScrollEvent;
import javafx.scene.transform.Scale;

public class ZoomableScrollPane extends ScrollPane {
    Group zoomGroup;
    Scale scaleTransform;
    Node content;
    double scaleValue = 1.0;
    double delta = 0.1;

    public ZoomableScrollPane(Node content) {
        this.content = content;
        Group contentGroup = new Group();
        zoomGroup = new Group();
        contentGroup.getChildren().add(zoomGroup);
        zoomGroup.getChildren().add(content);
        setContent(contentGroup);
        scaleTransform = new Scale(scaleValue, scaleValue, 0, 0);
        zoomGroup.getTransforms().add(scaleTransform);

        zoomGroup.setOnScroll(new ZoomHandler());
    }

    public double getScaleValue() {
        return scaleValue;
    }

    public void zoomToActual() {
        zoomTo(1.0);
    }

    public void zoomTo(double scaleValue) {

        this.scaleValue = scaleValue;

        scaleTransform.setX(scaleValue);
        scaleTransform.setY(scaleValue);

    }

    public void zoomActual() {

        scaleValue = 1;
        zoomTo(scaleValue);

    }

    public void zoomOut() {
        scaleValue -= delta;

        if (Double.compare(scaleValue, 0.1) < 0) {
            scaleValue = 0.1;
        }

        zoomTo(scaleValue);
    }

    public void zoomIn() {

        scaleValue += delta;

        if (Double.compare(scaleValue, 10) > 0) {
            scaleValue = 10;
        }

        zoomTo(scaleValue);

    }

    /**
     * 
     * @param minimizeOnly
     *            If the content fits already into the viewport, then we don't
     *            zoom if this parameter is true.
     */
    public void zoomToFit(boolean minimizeOnly) {

        double scaleX = getViewportBounds().getWidth() / getContent().getBoundsInLocal().getWidth();
        double scaleY = getViewportBounds().getHeight() / getContent().getBoundsInLocal().getHeight();

        // consider current scale (in content calculation)
        scaleX *= scaleValue;
        scaleY *= scaleValue;

        // distorted zoom: we don't want it => we search the minimum scale
        // factor and apply it
        double scale = Math.min(scaleX, scaleY);

        // check precondition
        if (minimizeOnly) {

            // check if zoom factor would be an enlargement and if so, just set
            // it to 1
            if (Double.compare(scale, 1) > 0) {
                scale = 1;
            }
        }

        // apply zoom
        zoomTo(scale);

    }

    private class ZoomHandler implements EventHandler<ScrollEvent> {

        @Override
        public void handle(ScrollEvent scrollEvent) {
            // if (scrollEvent.isControlDown())
            {

                if (scrollEvent.getDeltaY() < 0) {
                    scaleValue -= delta;
                } else {
                    scaleValue += delta;
                }

                zoomTo(scaleValue);

                scrollEvent.consume();
            }
        }
    }
}

每个单元格都表示为 Pane ，您可以将任何节点作为 View (矩形、标签、 ImageView 等)放入其中

Cell.java

package com.fxgraph.graph;

import java.util.ArrayList;
import java.util.List;

import javafx.scene.Node;
import javafx.scene.layout.Pane;

public class Cell extends Pane {

    String cellId;

    List<Cell> children = new ArrayList<>();
    List<Cell> parents = new ArrayList<>();

    Node view;

    public Cell(String cellId) {
        this.cellId = cellId;
    }

    public void addCellChild(Cell cell) {
        children.add(cell);
    }

    public List<Cell> getCellChildren() {
        return children;
    }

    public void addCellParent(Cell cell) {
        parents.add(cell);
    }

    public List<Cell> getCellParents() {
        return parents;
    }

    public void removeCellChild(Cell cell) {
        children.remove(cell);
    }

    public void setView(Node view) {

        this.view = view;
        getChildren().add(view);

    }

    public Node getView() {
        return this.view;
    }

    public String getCellId() {
        return cellId;
    }
}

细胞应该是通过某种工厂创建的，所以它们是按类型分类的:

CellType.java

package com.fxgraph.graph;

public enum CellType {

    RECTANGLE,
    TRIANGLE
    ;

}

实例化它们非常容易:

矩形单元格.java

package com.fxgraph.cells;

import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;

import com.fxgraph.graph.Cell;

public class RectangleCell extends Cell {

    public RectangleCell( String id) {
        super( id);

        Rectangle view = new Rectangle( 50,50);

        view.setStroke(Color.DODGERBLUE);
        view.setFill(Color.DODGERBLUE);

        setView( view);

    }

}

TriangleCell.java

package com.fxgraph.cells;

import javafx.scene.paint.Color;
import javafx.scene.shape.Polygon;

import com.fxgraph.graph.Cell;

public class TriangleCell extends Cell {

    public TriangleCell( String id) {
        super( id);

        double width = 50;
        double height = 50;

        Polygon view = new Polygon( width / 2, 0, width, height, 0, height);

        view.setStroke(Color.RED);
        view.setFill(Color.RED);

        setView( view);

    }

}

那么你当然需要边缘。你可以使用任何你喜欢的连接，甚至三次曲线。为简单起见，我使用一行:

Edge.java

package com.fxgraph.graph;

import javafx.scene.Group;
import javafx.scene.shape.Line;

public class Edge extends Group {

    protected Cell source;
    protected Cell target;

    Line line;

    public Edge(Cell source, Cell target) {

        this.source = source;
        this.target = target;

        source.addCellChild(target);
        target.addCellParent(source);

        line = new Line();

        line.startXProperty().bind( source.layoutXProperty().add(source.getBoundsInParent().getWidth() / 2.0));
        line.startYProperty().bind( source.layoutYProperty().add(source.getBoundsInParent().getHeight() / 2.0));

        line.endXProperty().bind( target.layoutXProperty().add( target.getBoundsInParent().getWidth() / 2.0));
        line.endYProperty().bind( target.layoutYProperty().add( target.getBoundsInParent().getHeight() / 2.0));

        getChildren().add( line);

    }

    public Cell getSource() {
        return source;
    }

    public Cell getTarget() {
        return target;
    }

}

对此的扩展是将边缘绑定(bind)到单元的端口(北/南/东/西)。

然后你想拖动节点，所以你必须添加一些鼠标手势。重要的部分是考虑缩放系数，以防图形 Canvas 被缩放

MouseGestures.java

package com.fxgraph.graph;

import javafx.event.EventHandler;
import javafx.scene.Node;
import javafx.scene.input.MouseEvent;

public class MouseGestures {

    final DragContext dragContext = new DragContext();

    Graph graph;

    public MouseGestures( Graph graph) {
        this.graph = graph;
    }

    public void makeDraggable( final Node node) {


        node.setOnMousePressed(onMousePressedEventHandler);
        node.setOnMouseDragged(onMouseDraggedEventHandler);
        node.setOnMouseReleased(onMouseReleasedEventHandler);

    }

    EventHandler<MouseEvent> onMousePressedEventHandler = new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) {

            Node node = (Node) event.getSource();

            double scale = graph.getScale();

            dragContext.x = node.getBoundsInParent().getMinX() * scale - event.getScreenX();
            dragContext.y = node.getBoundsInParent().getMinY()  * scale - event.getScreenY();

        }
    };

    EventHandler<MouseEvent> onMouseDraggedEventHandler = new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) {

            Node node = (Node) event.getSource();

            double offsetX = event.getScreenX() + dragContext.x;
            double offsetY = event.getScreenY() + dragContext.y;

            // adjust the offset in case we are zoomed
            double scale = graph.getScale();

            offsetX /= scale;
            offsetY /= scale;

            node.relocate(offsetX, offsetY);

        }
    };

    EventHandler<MouseEvent> onMouseReleasedEventHandler = new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent event) {

        }
    };

    class DragContext {

        double x;
        double y;

    }
}

然后您需要一个模型来存储单元格和边缘。任何时候都可以添加新单元格并删除现有单元格。您需要处理它们与现有的区别(例如，添加鼠标手势，添加它们时为它们设置动画等)。当您实现布局算法时，您将面临根节点的确定。所以你应该创建一个不可见的根节点(graphParent)，它不会被添加到图本身，但所有没有父节点的节点都从该节点开始。

模型.java

package com.fxgraph.graph;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.fxgraph.cells.TriangleCell;
import com.fxgraph.cells.RectangleCell;

public class Model {

    Cell graphParent;

    List<Cell> allCells;
    List<Cell> addedCells;
    List<Cell> removedCells;

    List<Edge> allEdges;
    List<Edge> addedEdges;
    List<Edge> removedEdges;

    Map<String,Cell> cellMap; // <id,cell>

    public Model() {

         graphParent = new Cell( "_ROOT_");

         // clear model, create lists
         clear();
    }

    public void clear() {

        allCells = new ArrayList<>();
        addedCells = new ArrayList<>();
        removedCells = new ArrayList<>();

        allEdges = new ArrayList<>();
        addedEdges = new ArrayList<>();
        removedEdges = new ArrayList<>();

        cellMap = new HashMap<>(); // <id,cell>

    }

    public void clearAddedLists() {
        addedCells.clear();
        addedEdges.clear();
    }

    public List<Cell> getAddedCells() {
        return addedCells;
    }

    public List<Cell> getRemovedCells() {
        return removedCells;
    }

    public List<Cell> getAllCells() {
        return allCells;
    }

    public List<Edge> getAddedEdges() {
        return addedEdges;
    }

    public List<Edge> getRemovedEdges() {
        return removedEdges;
    }

    public List<Edge> getAllEdges() {
        return allEdges;
    }

    public void addCell(String id, CellType type) {

        switch (type) {

        case RECTANGLE:
            RectangleCell rectangleCell = new RectangleCell(id);
            addCell(rectangleCell);
            break;

        case TRIANGLE:
            TriangleCell circleCell = new TriangleCell(id);
            addCell(circleCell);
            break;

        default:
            throw new UnsupportedOperationException("Unsupported type: " + type);
        }
    }

    private void addCell( Cell cell) {

        addedCells.add(cell);

        cellMap.put( cell.getCellId(), cell);

    }

    public void addEdge( String sourceId, String targetId) {

        Cell sourceCell = cellMap.get( sourceId);
        Cell targetCell = cellMap.get( targetId);

        Edge edge = new Edge( sourceCell, targetCell);

        addedEdges.add( edge);

    }

    /**
     * Attach all cells which don't have a parent to graphParent 
     * @param cellList
     */
    public void attachOrphansToGraphParent( List<Cell> cellList) {

        for( Cell cell: cellList) {
            if( cell.getCellParents().size() == 0) {
                graphParent.addCellChild( cell);
            }
        }

    }

    /**
     * Remove the graphParent reference if it is set
     * @param cellList
     */
    public void disconnectFromGraphParent( List<Cell> cellList) {

        for( Cell cell: cellList) {
            graphParent.removeCellChild( cell);
        }
    }

    public void merge() {

        // cells
        allCells.addAll( addedCells);
        allCells.removeAll( removedCells);

        addedCells.clear();
        removedCells.clear();

        // edges
        allEdges.addAll( addedEdges);
        allEdges.removeAll( removedEdges);

        addedEdges.clear();
        removedEdges.clear();

    }
}

然后是图表本身，其中包含可缩放的滚动 Pane 、模型等。在图表中处理添加和删除的节点(鼠标手势、添加到滚动 Pane 的单元格和边缘等)。

Graph.java

package com.fxgraph.graph;

import javafx.scene.Group;
import javafx.scene.control.ScrollPane;
import javafx.scene.layout.Pane;

public class Graph {

    private Model model;

    private Group canvas;

    private ZoomableScrollPane scrollPane;

    MouseGestures mouseGestures;

    /**
     * the pane wrapper is necessary or else the scrollpane would always align
     * the top-most and left-most child to the top and left eg when you drag the
     * top child down, the entire scrollpane would move down
     */
    CellLayer cellLayer;

    public Graph() {

        this.model = new Model();

        canvas = new Group();
        cellLayer = new CellLayer();

        canvas.getChildren().add(cellLayer);

        mouseGestures = new MouseGestures(this);

        scrollPane = new ZoomableScrollPane(canvas);

        scrollPane.setFitToWidth(true);
        scrollPane.setFitToHeight(true);

    }

    public ScrollPane getScrollPane() {
        return this.scrollPane;
    }

    public Pane getCellLayer() {
        return this.cellLayer;
    }

    public Model getModel() {
        return model;
    }

    public void beginUpdate() {
    }

    public void endUpdate() {

        // add components to graph pane
        getCellLayer().getChildren().addAll(model.getAddedEdges());
        getCellLayer().getChildren().addAll(model.getAddedCells());

        // remove components from graph pane
        getCellLayer().getChildren().removeAll(model.getRemovedCells());
        getCellLayer().getChildren().removeAll(model.getRemovedEdges());

        // enable dragging of cells
        for (Cell cell : model.getAddedCells()) {
            mouseGestures.makeDraggable(cell);
        }

        // every cell must have a parent, if it doesn't, then the graphParent is
        // the parent
        getModel().attachOrphansToGraphParent(model.getAddedCells());

        // remove reference to graphParent
        getModel().disconnectFromGraphParent(model.getRemovedCells());

        // merge added & removed cells with all cells
        getModel().merge();

    }

    public double getScale() {
        return this.scrollPane.getScaleValue();
    }
}

单元层的包装器。您可能需要添加多个图层(例如，突出显示选定单元格的选择图层)

CellLayer.java

package com.fxgraph.graph;

import javafx.scene.layout.Pane;

public class CellLayer extends Pane {

}

现在您需要一个单元格布局。我建议创建一个简单的抽象类，它会随着您开发图形而得到扩展。

package com.fxgraph.layout.base;

public abstract class Layout {

    public abstract void execute();

}

为简单起见，这里有一个使用随机坐标的简单布局算法。当然，您必须做更复杂的事情，例如树形布局等。

RandomLayout.java

package com.fxgraph.layout.random;

import java.util.List;
import java.util.Random;

import com.fxgraph.graph.Cell;
import com.fxgraph.graph.Graph;
import com.fxgraph.layout.base.Layout;

public class RandomLayout extends Layout {

    Graph graph;

    Random rnd = new Random();

    public RandomLayout(Graph graph) {

        this.graph = graph;

    }

    public void execute() {

        List<Cell> cells = graph.getModel().getAllCells();

        for (Cell cell : cells) {

            double x = rnd.nextDouble() * 500;
            double y = rnd.nextDouble() * 500;

            cell.relocate(x, y);

        }

    }

}

示例如下所示:

您可以使用鼠标按钮拖动单元格并使用鼠标滚轮放大和缩小。

---

添加新的单元格类型就像创建 Cell 的子类一样简单:

package com.fxgraph.cells;

import javafx.scene.control.Button;

import com.fxgraph.graph.Cell;

public class ButtonCell extends Cell {

    public ButtonCell(String id) {
        super(id);

        Button view = new Button(id);

        setView(view);

    }

}

package com.fxgraph.cells;

import javafx.scene.image.ImageView;

import com.fxgraph.graph.Cell;

public class ImageCell extends Cell {

    public ImageCell(String id) {
        super(id);

        ImageView view = new ImageView("http://upload.wikimedia.org/wikipedia/commons/thumb/4/41/Siberischer_tiger_de_edit02.jpg/800px-Siberischer_tiger_de_edit02.jpg");
        view.setFitWidth(100);
        view.setFitHeight(80);

        setView(view);

    }

}


package com.fxgraph.cells;

import javafx.scene.control.Label;

import com.fxgraph.graph.Cell;

public class LabelCell extends Cell {

    public LabelCell(String id) {
        super(id);

        Label view = new Label(id);

        setView(view);

    }

}

package com.fxgraph.cells;

import javafx.scene.control.TitledPane;

import com.fxgraph.graph.Cell;

public class TitledPaneCell extends Cell {

    public TitledPaneCell(String id) {
        super(id);

        TitledPane view = new TitledPane();
        view.setPrefSize(100, 80);

        setView(view);

    }

}

并创建类型

package com.fxgraph.graph;

public enum CellType {

    RECTANGLE,
    TRIANGLE,
    LABEL,
    IMAGE,
    BUTTON,
    TITLEDPANE
    ;

}

并根据类型创建实例:

...
public void addCell(String id, CellType type) {

    switch (type) {

    case RECTANGLE:
        RectangleCell rectangleCell = new RectangleCell(id);
        addCell(rectangleCell);
        break;

    case TRIANGLE:
        TriangleCell circleCell = new TriangleCell(id);
        addCell(circleCell);
        break;

    case LABEL:
        LabelCell labelCell = new LabelCell(id);
        addCell(labelCell);
        break;

    case IMAGE:
        ImageCell imageCell = new ImageCell(id);
        addCell(imageCell);
        break;

    case BUTTON:
        ButtonCell buttonCell = new ButtonCell(id);
        addCell(buttonCell);
        break;

    case TITLEDPANE:
        TitledPaneCell titledPaneCell = new TitledPaneCell(id);
        addCell(titledPaneCell);
        break;

    default:
        throw new UnsupportedOperationException("Unsupported type: " + type);
    }
}
...

你会得到这个