Is there a way to dynamically draw lines between points over a coordinate plane?

Question

I am completing a project in which I have implemented a brute force algorithm for solving the Convex Hull problem. I need to also create a visual for this algorithm. I am trying to create a coordinate plane ranging from (-100, 100) on both the x and y axis, plot all the points in the complete set, and dynamically draw lines between the points in order to create the convex hull. For example, assume I have 4 points: A(1, 1), B(3,2), C(2, 4), and D(1,3). I want to first plot all four of these points and then draw a line from A to B and then from B to C and then from C to D and then finally from D to A. So far I have been trying to do this using JavaFX LineChart.

//        creating axis
        NumberAxis xAxis = new NumberAxis(-100, 100, 1);
        NumberAxis yAxis = new NumberAxis(-100, 100, 1);
//        creating chart
        LineChart<Number, Number> lineChart = new LineChart<>(xAxis, yAxis);

and then drew lines using

   public static void populatePoints(List<Double []> points, LineChart lineChart) {
        XYChart.Series series = new XYChart.Series();
        series.setName("Points of set");
        for (Double[] point : points) {
            series.getData().add(new XYChart.Data<Double, Double>(point[0], point[1]));
        }
        lineChart.getData().add(series);
    }

However, this just draws the lines in a typical line chart fashion. I need it to be in a convex shape. I have attached the result of my current code with points (-51.6, 72.97), (33.58, 98.97), (-86.68, 9.77), and (-49.41, -46.26).

I don’t think a chart is going to work for this. Just use a regular `Pane` and add `Circle`s for the points, and `Line`s. You can draw the axes easily enough if you need. — James_D, Oct 06 '22 at 23:38
This exists and has fill stuff is this helpful? https://docs.oracle.com/javase/8/javafx/api/javafx/scene/shape/Shape.html — clwhisk, Oct 07 '22 at 02:37

trashgod · Answer 1 · 2022-10-07T12:24:20.127

You can use the approach shown here:

Add the points to the series in the desired order.

Specify SortingPolicy.NONE.

  series.getData().add(new XYChart.Data(-86.68,  9.77));
  series.getData().add(new XYChart.Data(-51.6,   72.97));
  series.getData().add(new XYChart.Data( 33.58,  98.97));
  series.getData().add(new XYChart.Data(-49.41, -46.26));
  series.getData().add(new XYChart.Data(-86.68,  9.77));
  …
  policy.getSelectionModel().select(LineChart.SortingPolicy.NONE);

Is there a way to dynamically draw lines between points over a coordinate plane?

1 Answers1

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