visjs-network
Version:
A dynamic, browser-based network visualization library.
81 lines (71 loc) • 2.23 kB
JavaScript
/**
* Hierarchical Repulsion Solver
*/
class HierarchicalRepulsionSolver {
/**
* @param {Object} body
* @param {{physicsNodeIndices: Array, physicsEdgeIndices: Array, forces: {}, velocities: {}}} physicsBody
* @param {Object} options
*/
constructor(body, physicsBody, options) {
this.body = body
this.physicsBody = physicsBody
this.setOptions(options)
}
/**
*
* @param {Object} options
*/
setOptions(options) {
this.options = options
}
/**
* Calculate the forces the nodes apply on each other based on a repulsion field.
* This field is linearly approximated.
*
* @private
*/
solve() {
var dx, dy, distance, fx, fy, repulsingForce, node1, node2, i, j
var nodes = this.body.nodes
var nodeIndices = this.physicsBody.physicsNodeIndices
var forces = this.physicsBody.forces
// repulsing forces between nodes
var nodeDistance = this.options.nodeDistance
// we loop from i over all but the last entree in the array
// j loops from i+1 to the last. This way we do not double count any of the indices, nor i === j
for (i = 0; i < nodeIndices.length - 1; i++) {
node1 = nodes[nodeIndices[i]]
for (j = i + 1; j < nodeIndices.length; j++) {
node2 = nodes[nodeIndices[j]]
// nodes only affect nodes on their level
if (node1.level === node2.level) {
dx = node2.x - node1.x
dy = node2.y - node1.y
distance = Math.sqrt(dx * dx + dy * dy)
var steepness = 0.05
if (distance < nodeDistance) {
repulsingForce =
-Math.pow(steepness * distance, 2) +
Math.pow(steepness * nodeDistance, 2)
} else {
repulsingForce = 0
}
// normalize force with
if (distance === 0) {
distance = 0.01
} else {
repulsingForce = repulsingForce / distance
}
fx = dx * repulsingForce
fy = dy * repulsingForce
forces[node1.id].x -= fx
forces[node1.id].y -= fy
forces[node2.id].x += fx
forces[node2.id].y += fy
}
}
}
}
}
export default HierarchicalRepulsionSolver