vis.js is a dynamic, browser-based visualization library
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 

161 lines
4.5 KiB

import EdgeBase from './EdgeBase'
/**
* The Base Class for all Bezier edges. Bezier curves are used to model smooth
* gradual curves in paths between nodes.
*
* @extends EdgeBase
*/
class BezierEdgeBase extends EdgeBase {
/**
* @param {Object} options
* @param {Object} body
* @param {Label} labelModule
*/
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 {Node} nearNode
* @param {CanvasRenderingContext2D} ctx
* @param {Node} viaNode
* @returns {*}
* @private
*/
_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 from x
* @param {number} y1 from y
* @param {number} x2 to x
* @param {number} y2 to y
* @param {number} x3 point to check x
* @param {number} y3 point to check y
* @param {Node} via
* @returns {number}
* @private
*/
_getDistanceToBezierEdge(x1, y1, x2, y2, x3, y3, via) { // x3,y3 is the point
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)) * via.x + Math.pow(t, 2) * x2;
y = Math.pow(1 - t, 2) * y1 + (2 * t * (1 - t)) * via.y + 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;
}
/**
* Draw a bezier curve between two nodes
*
* The method accepts zero, one or two control points.
* Passing zero control points just draws a straight line
*
* @param {CanvasRenderingContext2D} ctx
* @param {Object} values | options for shadow drawing
* @param {Object|undefined} viaNode1 | first control point for curve drawing
* @param {Object|undefined} viaNode2 | second control point for curve drawing
*
* @protected
*/
_bezierCurve(ctx, values, viaNode1, viaNode2) {
var hasNode1 = (viaNode1 !== undefined && viaNode1.x !== undefined);
var hasNode2 = (viaNode2 !== undefined && viaNode2.x !== undefined);
ctx.beginPath();
ctx.moveTo(this.fromPoint.x, this.fromPoint.y);
if (hasNode1 && hasNode2) {
ctx.bezierCurveTo(viaNode1.x, viaNode1.y, viaNode2.x, viaNode2.y, this.toPoint.x, this.toPoint.y);
} else if (hasNode1) {
ctx.quadraticCurveTo(viaNode1.x, viaNode1.y, this.toPoint.x, this.toPoint.y);
} else {
// fallback to normal straight edge
ctx.lineTo(this.toPoint.x, this.toPoint.y);
}
// draw a background
this.drawBackground(ctx, values);
// draw shadow if enabled
this.enableShadow(ctx, values);
ctx.stroke();
this.disableShadow(ctx, values);
}
/**
*
* @returns {*|{x, y}|{x: undefined, y: undefined}}
*/
getViaNode() {
return this._getViaCoordinates();
}
}
export default BezierEdgeBase;