Graph database Analysis of the Steam Network
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;(function() {
'use strict';
sigma.utils.pkg('sigma.canvas.edges');
/**
* This edge renderer will display edges as curves with arrow heading.
*
* @param {object} edge The edge object.
* @param {object} source node The edge source node.
* @param {object} target node The edge target node.
* @param {CanvasRenderingContext2D} context The canvas context.
* @param {configurable} settings The settings function.
*/
sigma.canvas.edges.dotCurvedArrow =
function(edge, source, target, context, settings) {
var color = edge.color,
prefix = settings('prefix') || '',
edgeColor = settings('edgeColor'),
defaultNodeColor = settings('defaultNodeColor'),
defaultEdgeColor = settings('defaultEdgeColor'),
cp = {},
size = edge[prefix + 'size'] || 1,
count = edge.count || 0,
tSize = target[prefix + 'size'],
sX = source[prefix + 'x'],
sY = source[prefix + 'y'],
tX = target[prefix + 'x'],
tY = target[prefix + 'y'],
aSize = Math.max(size * 2.5, settings('minArrowSize')),
d,
aX,
aY,
vX,
vY;
cp = (source.id === target.id) ?
sigma.utils.getSelfLoopControlPoints(sX, sY, tSize, count) :
sigma.utils.getQuadraticControlPoint(sX, sY, tX, tY, count);
if (source.id === target.id) {
d = Math.sqrt(Math.pow(tX - cp.x1, 2) + Math.pow(tY - cp.y1, 2));
aX = cp.x1 + (tX - cp.x1) * (d - aSize - tSize) / d;
aY = cp.y1 + (tY - cp.y1) * (d - aSize - tSize) / d;
vX = (tX - cp.x1) * aSize / d;
vY = (tY - cp.y1) * aSize / d;
}
else {
d = Math.sqrt(Math.pow(tX - cp.x, 2) + Math.pow(tY - cp.y, 2));
aX = cp.x + (tX - cp.x) * (d - aSize - tSize) / d;
aY = cp.y + (tY - cp.y) * (d - aSize - tSize) / d;
vX = (tX - cp.x) * aSize / d;
vY = (tY - cp.y) * aSize / d;
}
if (!color)
switch (edgeColor) {
case 'source':
color = source.color || defaultNodeColor;
break;
case 'target':
color = target.color || defaultNodeColor;
break;
default:
color = defaultEdgeColor;
break;
}
context.strokeStyle = color;
context.lineWidth = size;
context.beginPath();
context.moveTo(sX, sY);
if (source.id === target.id) {
context.bezierCurveTo(cp.x2, cp.y2, cp.x1, cp.y1, aX, aY);
} else {
context.quadraticCurveTo(cp.x, cp.y, aX, aY);
}
context.stroke();
context.fillStyle = color;
context.beginPath();
context.moveTo(aX + vX, aY + vY);
context.lineTo(aX + vY * 0.6, aY - vX * 0.6);
context.lineTo(aX - vY * 0.6, aY + vX * 0.6);
context.lineTo(aX + vX, aY + vY);
context.closePath();
context.fill();
if(edge.sourceDotColor != undefined || edge.targetDotColor != undefined) {
var dotOffset = edge.dotOffset || 3;
var dotSize = edge.dotSize || 1;
dotSize = size*dotSize;
dotOffset = dotOffset*tSize;
if(edge.sourceDotColor != undefined) {
createDot(context, sX, sY, cp, tX, tY, dotOffset, dotSize, edge.sourceDotColor);
}
if (edge.targetDotColor != undefined){
createDot(context, tX, tY, cp, sX, sY, dotOffset, dotSize, edge.targetDotColor);
}
}
};
function createDot(context, sX, sY, cp, tX, tY, offset, size, color) {
context.beginPath();
context.fillStyle = color;
var dot = getPointOnBezier(sX, sY, cp.x, cp.y, tX, tY,
offset);
context.arc(dot.x, dot.y, size * 3, 0, 2 * Math.PI,
false);
context.fill();
}
function getQBezierValue(t, p1, p2, p3) {
var iT = 1 - t;
return iT * iT * p1 + 2 * iT * t * p2 + t * t * p3;
}
function getQuadraticCurvePoint(startX, startY, cpX, cpY, endX, endY, position) {
return {
x:getQBezierValue(position, startX, cpX, endX),
y:getQBezierValue(position, startY, cpY, endY)
};
}
function getDistanceBetweenPoints(x1, y1, x2, y2){
return Math.sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));
}
/* Function to get a point on a bezier curve a certain distance away from
its source. Needed since the position on a beziercurve is given to the
formula as a percentage (t).*/
function getPointOnBezier(startX, startY, cpX, cpY, endX, endY, distance){
var bestT = 0;
var bestAccuracy = 1000;
var stepSize = 0.001;
for(var t = 0; t<1; t+=stepSize){
var currentPoint = getQuadraticCurvePoint(startX, startY, cpX, cpY,
endX, endY, t);
var currentDistance = getDistanceBetweenPoints(startX, startY,
currentPoint.x, currentPoint.y);
if(Math.abs(currentDistance-distance) < bestAccuracy){
bestAccuracy = Math.abs(currentDistance-distance);
bestT = t;
}
}
return getQuadraticCurvePoint(startX, startY, cpX, cpY, endX, endY, bestT);
}
})();