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