force_graph 0.3.2

use force_graph::{ForceGraph, Node, NodeData};
use macroquad::prelude::*;

const NODE_RADIUS: f32 = 15.0;

#[macroquad::main("Demo")]
async fn main() {
    // create a force graph with default parameters
    let mut graph = <ForceGraph>::new(Default::default());

    // create nodes
    let n1_idx = graph.add_node(NodeData {
        x: screen_width() / 4.0,
        y: screen_height() / 4.0,
        ..Default::default()
    });
    let n2_idx = graph.add_node(NodeData {
        x: 3.0 * screen_width() / 4.0,
        y: screen_height() / 4.0,
        ..Default::default()
    });
    let n3_idx = graph.add_node(NodeData {
        x: screen_width() / 4.0,
        y: 3.0 * screen_height() / 4.0,
        ..Default::default()
    });
    let n4_idx = graph.add_node(NodeData {
        x: 3.0 * screen_width() / 4.0,
        y: 3.0 * screen_height() / 4.0,
        ..Default::default()
    });
    let n5_idx = graph.add_node(NodeData {
        x: screen_width() / 2.0,
        y: screen_height() / 2.0,
        is_anchor: true,
        ..Default::default()
    });

    // set up links between nodes
    graph.add_edge(n1_idx, n5_idx, Default::default());
    graph.add_edge(n2_idx, n5_idx, Default::default());
    graph.add_edge(n3_idx, n5_idx, Default::default());
    graph.add_edge(n4_idx, n5_idx, Default::default());

    let mut dragging_node_idx = None;
    loop {
        clear_background(BLACK);
        draw_text(
            "Drag nodes with the left mouse button",
            50.0,
            50.0,
            25.0,
            WHITE,
        );

        // draw edges
        graph.visit_edges(|node1, node2, _edge| {
            draw_line(node1.x(), node1.y(), node2.x(), node2.y(), 2.0, GRAY);
        });

        // draw nodes
        graph.visit_nodes(|node| {
            draw_circle(node.x(), node.y(), NODE_RADIUS, WHITE);

            // highlight hovered or dragged node
            if node_overlaps_mouse_position(node)
                || dragging_node_idx
                    .filter(|idx| *idx == node.index())
                    .is_some()
            {
                draw_circle_lines(node.x(), node.y(), NODE_RADIUS, 2.0, RED);
            }
        });

        // drag nodes with the mouse
        if is_mouse_button_down(MouseButton::Left) {
            graph.visit_nodes_mut(|node| {
                if let Some(idx) = dragging_node_idx {
                    if idx == node.index() {
                        let (mouse_x, mouse_y) = mouse_position();
                        node.data.x = mouse_x;
                        node.data.y = mouse_y;
                    }
                } else if node_overlaps_mouse_position(node) {
                    dragging_node_idx = Some(node.index());
                }
            });
        } else {
            dragging_node_idx = None;
        }

        graph.update(get_frame_time());

        next_frame().await
    }
}

fn node_overlaps_mouse_position(node: &Node) -> bool {
    let (mouse_x, mouse_y) = mouse_position();
    ((node.x() - mouse_x) * (node.x() - mouse_x) + (node.y() - mouse_y) * (node.y() - mouse_y))
        < NODE_RADIUS * NODE_RADIUS
}