vis.js is a dynamic, browser-based visualization library
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/**
* Created by Alex on 3/20/2015.
*/
import EdgeBase from './EdgeBase'
class BezierEdgeBase extends EdgeBase {
constructor(options, body, labelModule) {
super(options, body, labelModule);
}
/**
* This function uses binary search to look for the point where the bezier curve crosses the border of the node.
*
* @param nearNode
* @param ctx
* @param viaNode
* @param nearNode
* @param ctx
* @param viaNode
* @param nearNode
* @param ctx
* @param viaNode
*/
_findBorderPositionBezier(nearNode, ctx, viaNode = this._getViaCoordinates()) {
var maxIterations = 10;
var iteration = 0;
var low = 0;
var high = 1;
var pos, angle, distanceToBorder, distanceToPoint, difference;
var threshold = 0.2;
var node = this.to;
var from = false;
if (nearNode.id === this.from.id) {
node = this.from;
from = true;
}
while (low <= high && iteration < maxIterations) {
var middle = (low + high) * 0.5;
pos = this.getPoint(middle, viaNode);
angle = Math.atan2((node.y - pos.y), (node.x - pos.x));
distanceToBorder = node.distanceToBorder(ctx, angle);
distanceToPoint = Math.sqrt(Math.pow(pos.x - node.x, 2) + Math.pow(pos.y - node.y, 2));
difference = distanceToBorder - distanceToPoint;
if (Math.abs(difference) < threshold) {
break; // found
}
else if (difference < 0) { // distance to nodes is larger than distance to border --> t needs to be bigger if we're looking at the to node.
if (from == false) {
low = middle;
}
else {
high = middle;
}
}
else {
if (from == false) {
high = middle;
}
else {
low = middle;
}
}
iteration++;
}
pos.t = middle;
return pos;
}
/**
* Calculate the distance between a point (x3,y3) and a line segment from
* (x1,y1) to (x2,y2).
* http://stackoverflow.com/questions/849211/shortest-distancae-between-a-point-and-a-line-segment
* @param {number} x1
* @param {number} y1
* @param {number} x2
* @param {number} y2
* @param {number} x3
* @param {number} y3
* @private
*/
_getDistanceToBezierEdge(x1, y1, x2, y2, x3, y3, via) { // x3,y3 is the point
let xVia, yVia;
xVia = via.x;
yVia = via.y;
let minDistance = 1e9;
let distance;
let i, t, x, y;
let lastX = x1;
let lastY = y1;
for (i = 1; i < 10; i++) {
t = 0.1 * i;
x = Math.pow(1 - t, 2) * x1 + (2 * t * (1 - t)) * xVia + Math.pow(t, 2) * x2;
y = Math.pow(1 - t, 2) * y1 + (2 * t * (1 - t)) * yVia + Math.pow(t, 2) * y2;
if (i > 0) {
distance = this._getDistanceToLine(lastX, lastY, x, y, x3, y3);
minDistance = distance < minDistance ? distance : minDistance;
}
lastX = x;
lastY = y;
}
return minDistance;
}
}
export default BezierEdgeBase;