Java Community | Help. Code. Learn.•2d ago

Rendering too resource-intensive

I am using Swing to render a graph in a window; however rendering is taking too long and is too resource-intensive. What changes can I make to help with performance? Here is the class responsible for rendering my graph:

public class GraphPanel extends JPanel {
    private Graph graph;
    private PathfindAlgorithm algo;


    public GraphPanel(Graph graph, PathfindAlgorithm pathfindAlgorithm) {
        this.setBackground(Color.black);
        setGraph(graph);
        setPathAlgo(pathfindAlgorithm);
    }

    public void setPathAlgo(PathfindAlgorithm algo) {
        this.algo = algo;
    }

    public void setGraph(Graph graph) {
        this.graph = graph;
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        renderConnectedEdges(g);
        renderExploredEdges(g);
        renderPath(g);
        renderStartEndNodes(g);
    }

    private void renderStartEndNodes(Graphics g) {
        if (algo.getStartNode() != null && algo.getEndNode() != null) {
            int width = 10, height = 10;

            Point2D p1 = calculatePixelPos(new Point2D.Double(algo.getStartNode().latitude, algo.getStartNode().longitude));
            Point2D p2 = calculatePixelPos(new Point2D.Double(algo.getEndNode().latitude, algo.getEndNode().longitude));

            g.setColor(Color.GREEN);
            g.fillOval((int) p1.getX() - width / 2, (int) p1.getY() - height / 2, width, height);

            g.setColor(Color.BLUE);
            g.fillOval((int) p2.getX()- width / 2, (int) p2.getY() - height / 2, width, height);
        }
    }

    private void renderConnectedEdges(Graphics g) {
        g.setColor(Color.YELLOW);
        graph.nodes.values().forEach(node -> {
            node.adjacentEdges.forEach(edge -> {
                Point2D p1 = calculatePixelPos(new Point2D.Double(edge.nodeA.latitude, edge.nodeA.longitude));
                Point2D p2 = calculatePixelPos(new Point2D.Double(edge.nodeB.latitude, edge.nodeB.longitude));

                g.drawLine((int) p1.getX(), (int) p1.getY(), (int) p2.getX(), (int) p2.getY());
            });
        });
    }


    private void renderExploredEdges(Graphics g) {}
    private void renderPath(Graphics g) {}

    private Point2D calculatePixelPos(Point2D point) {
        int panelWidth = getWidth();
        int panelHeight = getHeight();

        double minLat = graph.nodes.values().stream().mapToDouble(n -> n.latitude).min().orElse(0);
        double maxLat = graph.nodes.values().stream().mapToDouble(n -> n.latitude).max().orElse(1);
        double minLon = graph.nodes.values().stream().mapToDouble(n -> n.longitude).min().orElse(0);
        double maxLon = graph.nodes.values().stream().mapToDouble(n -> n.longitude).max().orElse(1);

        double x = ((point.getY() - minLon) / (maxLon - minLon)) * (panelWidth - 40) + 20;
        double y = (1 - (point.getX() - minLat) / (maxLat - minLat)) * (panelHeight - 40) + 20;

        return new Point2D.Double(x, y);
    }

    public void updateGraphView() {
        repaint();
    }
}

public class GraphPanel extends JPanel {
    private Graph graph;
    private PathfindAlgorithm algo;


    public GraphPanel(Graph graph, PathfindAlgorithm pathfindAlgorithm) {
        this.setBackground(Color.black);
        setGraph(graph);
        setPathAlgo(pathfindAlgorithm);
    }

    public void setPathAlgo(PathfindAlgorithm algo) {
        this.algo = algo;
    }

    public void setGraph(Graph graph) {
        this.graph = graph;
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        renderConnectedEdges(g);
        renderExploredEdges(g);
        renderPath(g);
        renderStartEndNodes(g);
    }

    private void renderStartEndNodes(Graphics g) {
        if (algo.getStartNode() != null && algo.getEndNode() != null) {
            int width = 10, height = 10;

            Point2D p1 = calculatePixelPos(new Point2D.Double(algo.getStartNode().latitude, algo.getStartNode().longitude));
            Point2D p2 = calculatePixelPos(new Point2D.Double(algo.getEndNode().latitude, algo.getEndNode().longitude));

            g.setColor(Color.GREEN);
            g.fillOval((int) p1.getX() - width / 2, (int) p1.getY() - height / 2, width, height);

            g.setColor(Color.BLUE);
            g.fillOval((int) p2.getX()- width / 2, (int) p2.getY() - height / 2, width, height);
        }
    }

    private void renderConnectedEdges(Graphics g) {
        g.setColor(Color.YELLOW);
        graph.nodes.values().forEach(node -> {
            node.adjacentEdges.forEach(edge -> {
                Point2D p1 = calculatePixelPos(new Point2D.Double(edge.nodeA.latitude, edge.nodeA.longitude));
                Point2D p2 = calculatePixelPos(new Point2D.Double(edge.nodeB.latitude, edge.nodeB.longitude));

                g.drawLine((int) p1.getX(), (int) p1.getY(), (int) p2.getX(), (int) p2.getY());
            });
        });
    }


    private void renderExploredEdges(Graphics g) {}
    private void renderPath(Graphics g) {}

    private Point2D calculatePixelPos(Point2D point) {
        int panelWidth = getWidth();
        int panelHeight = getHeight();

        double minLat = graph.nodes.values().stream().mapToDouble(n -> n.latitude).min().orElse(0);
        double maxLat = graph.nodes.values().stream().mapToDouble(n -> n.latitude).max().orElse(1);
        double minLon = graph.nodes.values().stream().mapToDouble(n -> n.longitude).min().orElse(0);
        double maxLon = graph.nodes.values().stream().mapToDouble(n -> n.longitude).max().orElse(1);

        double x = ((point.getY() - minLon) / (maxLon - minLon)) * (panelWidth - 40) + 20;
        double y = (1 - (point.getX() - minLat) / (maxLat - minLat)) * (panelHeight - 40) + 20;

        return new Point2D.Double(x, y);
    }

    public void updateGraphView() {
        repaint();
    }
}

10 Replies

JavaBot•2d ago

⌛ This post has been reserved for your question.

Hey @Danish Pirate! Please use /close or the Close Post button above when your problem is solved. Please remember to follow the help guidelines. This post will be automatically marked as dormant after 300 minutes of inactivity.

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danishpirateOP•2d ago

updateGraphView() is called whenever the nodes in my graph are connected upon initalization and whenever a node is visited.

dan1st•2d ago

How exactly do you see it taking too long?

danishpirateOP•2d ago

I need to wait a couple of seconds for anything to be rendered at first. Then my window freezes I optimized it a bit by caching minLat, maxLat, minLon, maxLon instead of calculating them every view update.

dan1st•2d ago

so the rendercomponent takes too much time? I didn't know you'd need to iterate over all nodes there

danishpirateOP•this hour

I need to redraw all the edges between the nodes every view update.

dan1st•this hour

can you check what actually takes too long?

danishpirateOP•this hour

Seems to be the iterating over the nodes

dan1st•23h ago

So you are iterating over all nodes/edges and computing min/max for lat/lon fir each of them Why? just compute these once per rendering

JavaBot•21h ago

Post Closed

This post has been closed by <@173447330719072258>.

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Rendering too resource-intensive

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