CODEWITHSUNDEEP
javafx
StuYYY
StuYYY

Reputation: 107

Draw multiple lines betweens Node while keeping it clean with javafx

I have multiple vertices drawn as Circle on a Pane. I would like to draw a graph, so I need to draw edges between Circles. I need to be able to draw multiple edges between vertices while keeping it clear. Until now, I was using Line, but if i draw 2 Line between the same vertices, we wont see them anymore. I also need to be able to draw an edge between a vertex and itself. Is there something i could use that would make this easier ? I thought about using a Path between each vertex and when adding a new vertex, using something different each time like an ArcTo or CurveTo etc... but it doesn't seem like a good idea, and i would like to have always the same link between vertices ( a line or slightly curved line ).

Upvotes: 0

Views: 304

Answers (1)

fabian
fabian

Reputation: 82461

I don't see why using curves is an issue. Varying the parameters should yield distinct curves. For 2 different vertices quadratic curves should suffice, for connecting the vertex to itself you could use cubic curves.

// create connections between independent circles
private static Pane createPaths(double x1, double y1, double x2, double y2, int lineCount) {
    Circle circle1 = new Circle(x1, y1, 5, Color.DODGERBLUE);
    Circle circle2 = new Circle(x2, y2, 5, Color.DODGERBLUE);
    double mx = (x1 + x2) / 2;
    double my = (y1 + y2) / 2;
    double dnX = y2 - y1;
    double dnY = x1 - x2;

    // normalize ortogonal
    double length = Math.hypot(dnX, dnY);
    dnX /= length;
    dnY /= length;

    Pane pane = new Pane();

    for (int i = 0; i < lineCount; i++) {
        double factor = calculateControlPointDistance(i, lineCount, length);
        Path path = new Path(new MoveTo(x1, y1),
                new QuadCurveTo(mx + factor * dnX, my + factor * dnY, x2, y2));
        pane.getChildren().add(path);
    }

    pane.getChildren().addAll(circle1, circle2);
    return pane;
}

private static final double DISTANCE = 100;

// connect circle to itself
private Pane createCycle(double x, double y, int count) {
    Pane pane = new Pane();

    final double angleStep = (count == 1 ? Math.PI / 2 : Math.PI / count);

    for (int i = 0; i < count; i++) {
        double angle = 2 * i * angleStep;
        Path path = new Path(new MoveTo(x, y),
                new CubicCurveTo(
                        x + Math.sin(angle) * DISTANCE,
                        y + Math.cos(angle) * DISTANCE,
                        x + Math.sin(angle + angleStep) * DISTANCE,
                        y + Math.cos(angle + angleStep) * DISTANCE,
                        x,
                        y));
        pane.getChildren().add(path);
    }

    pane.getChildren().add(new Circle(x, y, 5, Color.DODGERBLUE));
    return pane;
}

You may want of modify the start/end coordinates of the curves to be at the edge of the circle to achieve orthogonal tangents.

Upvotes: 2

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