highcharts
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JavaScript charting framework
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JavaScript
/* *
*
* Networkgraph series
*
* (c) 2010-2025 Paweł Fus
*
* License: www.highcharts.com/license
*
* !!!!!!! SOURCE GETS TRANSPILED BY TYPESCRIPT. EDIT TS FILE ONLY. !!!!!!!
*
* */
;
/* *
*
* Functions
*
* */
/**
* Attractive force.
*
* In Euler integration, force is stored in a node, not changing it's
* position. Later, in `integrate()` forces are applied on nodes.
*
* @private
* @param {Highcharts.Point} link
* Link that connects two nodes
* @param {number} force
* Force calculated in `repulsiveForceFunction`
* @param {Highcharts.PositionObject} distanceXY
* Distance between two nodes e.g. `{x, y}`
* @param {number} distanceR
*/
function attractive(link, force, distanceXY, distanceR) {
const massFactor = link.getMass(), translatedX = (distanceXY.x / distanceR) * force, translatedY = (distanceXY.y / distanceR) * force;
if (!link.fromNode.fixedPosition) {
link.fromNode.dispX -=
translatedX * massFactor.fromNode / link.fromNode.degree;
link.fromNode.dispY -=
translatedY * massFactor.fromNode / link.fromNode.degree;
}
if (!link.toNode.fixedPosition) {
link.toNode.dispX +=
translatedX * massFactor.toNode / link.toNode.degree;
link.toNode.dispY +=
translatedY * massFactor.toNode / link.toNode.degree;
}
}
/**
* Attractive force function. Can be replaced by API's
* `layoutAlgorithm.attractiveForce`
*
* Other forces that can be used:
*
* basic, not recommended:
* `function (d, k) { return d / k }`
*
* @private
* @param {number} d current distance between two nodes
* @param {number} k expected distance between two nodes
* @return {number} force
*/
function attractiveForceFunction(d, k) {
return d * d / k;
}
/**
* Barycenter force. Calculate and applys barycenter forces on the
* nodes. Making them closer to the center of their barycenter point.
*
* In Euler integration, force is stored in a node, not changing it's
* position. Later, in `integrate()` forces are applied on nodes.
*
* @private
*/
function barycenter() {
const gravitationalConstant = this.options.gravitationalConstant, xFactor = this.barycenter.xFactor, yFactor = this.barycenter.yFactor;
this.nodes.forEach(function (node) {
if (!node.fixedPosition) {
const degree = node.getDegree(), phi = degree * (1 + degree / 2);
node.dispX += ((xFactor - node.plotX) *
gravitationalConstant *
phi / node.degree);
node.dispY += ((yFactor - node.plotY) *
gravitationalConstant *
phi / node.degree);
}
});
}
/**
* Estimate the best possible distance between two nodes, making graph
* readable.
* @private
*/
function getK(layout) {
return Math.pow(layout.box.width * layout.box.height / layout.nodes.length, 0.3);
}
/**
* Integration method.
*
* In Euler integration, force were stored in a node, not changing it's
* position. Now, in the integrator method, we apply changes.
*
* Euler:
*
* Basic form: `x(n+1) = x(n) + v(n)`
*
* With Rengoild-Fruchterman we get:
* `x(n+1) = x(n) + v(n) / length(v(n)) * min(v(n), temperature(n))`
* where:
* - `x(n+1)`: next position
* - `x(n)`: current position
* - `v(n)`: velocity (comes from net force)
* - `temperature(n)`: current temperature
*
* Known issues:
* Oscillations when force vector has the same magnitude but opposite
* direction in the next step. Potentially solved by decreasing force by
* `v * (1 / node.degree)`
*
* Note:
* Actually `min(v(n), temperature(n))` replaces simulated annealing.
*
* @private
* @param {Highcharts.NetworkgraphLayout} layout
* Layout object
* @param {Highcharts.Point} node
* Node that should be translated
*/
function integrate(layout, node) {
node.dispX +=
node.dispX * layout.options.friction;
node.dispY +=
node.dispY * layout.options.friction;
const distanceR = node.temperature = layout.vectorLength({
x: node.dispX,
y: node.dispY
});
if (distanceR !== 0) {
node.plotX += (node.dispX / distanceR *
Math.min(Math.abs(node.dispX), layout.temperature));
node.plotY += (node.dispY / distanceR *
Math.min(Math.abs(node.dispY), layout.temperature));
}
}
/**
* Repulsive force.
*
* @private
* @param {Highcharts.Point} node
* Node that should be translated by force.
* @param {number} force
* Force calculated in `repulsiveForceFunction`
* @param {Highcharts.PositionObject} distanceXY
* Distance between two nodes e.g. `{x, y}`
*/
function repulsive(node, force, distanceXY, distanceR) {
node.dispX +=
(distanceXY.x / distanceR) * force / node.degree;
node.dispY +=
(distanceXY.y / distanceR) * force / node.degree;
}
/**
* Repulsive force function. Can be replaced by API's
* `layoutAlgorithm.repulsiveForce`.
*
* Other forces that can be used:
*
* basic, not recommended:
* `function (d, k) { return k / d }`
*
* standard:
* `function (d, k) { return k * k / d }`
*
* grid-variant:
* `function (d, k) { return k * k / d * (2 * k - d > 0 ? 1 : 0) }`
*
* @private
* @param {number} d current distance between two nodes
* @param {number} k expected distance between two nodes
* @return {number} force
*/
function repulsiveForceFunction(d, k) {
return k * k / d;
}
/* *
*
* Default Export
*
* */
const EulerIntegration = {
attractive,
attractiveForceFunction,
barycenter,
getK,
integrate,
repulsive,
repulsiveForceFunction
};
export default EulerIntegration;