I'm working with the following code snippet and I'm trying to correct a few errors with the behaviour of the links.
The intended behaviour is as follows:
- By default, the links are coloured according to the 'type' of link (either 'A' or 'E')
- On mouseover of a node, the node and it's immediate neighbours remain at full opacity and colour, but the remaining nodes and links drop opacity and the link colour turns to white.
- On mouseout, the nodes and links return to their original opacity and colour
- On zoom, both the nodes and links zoom accordingly.
Unfortunately my code doesn't satisfy the last three bullet points, and somewhere along the way the links are now being rendered on top of the nodes rather than the other way around.
Can anyone help point out where I've gone wrong?
Codepen - https://codepen.io/quirkules/pen/BOKRjY
//create somewhere to put the force directed graph
var height = 650,
width = 950;
var svg = d3.select("body").append("svg")
.attr('width',width)
.attr('height',height);
var radius = 15;
var nodes_data = [
{"name": "Lillian", "sex": "F"},
{"name": "Gordon", "sex": "M"},
{"name": "Sylvester", "sex": "M"},
{"name": "Mary", "sex": "F"},
{"name": "Helen", "sex": "F"},
{"name": "Jamie", "sex": "M"},
{"name": "Jessie", "sex": "F"},
{"name": "Ashton", "sex": "M"},
{"name": "Duncan", "sex": "M"},
{"name": "Evette", "sex": "F"},
{"name": "Mauer", "sex": "M"},
{"name": "Fray", "sex": "F"},
{"name": "Duke", "sex": "M"},
{"name": "Baron", "sex": "M"},
{"name": "Infante", "sex": "M"},
{"name": "Percy", "sex": "M"},
{"name": "Cynthia", "sex": "F"},
{"name": "Feyton", "sex": "M"},
{"name": "Lesley", "sex": "F"},
{"name": "Yvette", "sex": "F"},
{"name": "Maria", "sex": "F"},
{"name": "Lexy", "sex": "F"},
{"name": "Peter", "sex": "M"},
{"name": "Ashley", "sex": "F"},
{"name": "Finkler", "sex": "M"},
{"name": "Damo", "sex": "M"},
{"name": "Imogen", "sex": "F"}
]
//Sample links data
//type: A for Ally, E for Enemy
var links_data = [
{"source": "Sylvester", "target": "Gordon", "type":"A" },
{"source": "Sylvester", "target": "Lillian", "type":"A" },
{"source": "Sylvester", "target": "Mary", "type":"A"},
{"source": "Sylvester", "target": "Jamie", "type":"A"},
{"source": "Sylvester", "target": "Jessie", "type":"A"},
{"source": "Sylvester", "target": "Helen", "type":"A"},
{"source": "Helen", "target": "Gordon", "type":"A"},
{"source": "Mary", "target": "Lillian", "type":"A"},
{"source": "Ashton", "target": "Mary", "type":"A"},
{"source": "Duncan", "target": "Jamie", "type":"A"},
{"source": "Gordon", "target": "Jessie", "type":"A"},
{"source": "Sylvester", "target": "Fray", "type":"E"},
{"source": "Fray", "target": "Mauer", "type":"A"},
{"source": "Fray", "target": "Cynthia", "type":"A"},
{"source": "Fray", "target": "Percy", "type":"A"},
{"source": "Percy", "target": "Cynthia", "type":"A"},
{"source": "Infante", "target": "Duke", "type":"A"},
{"source": "Duke", "target": "Gordon", "type":"A"},
{"source": "Duke", "target": "Sylvester", "type":"A"},
{"source": "Baron", "target": "Duke", "type":"A"},
{"source": "Baron", "target": "Sylvester", "type":"E"},
{"source": "Evette", "target": "Sylvester", "type":"E"},
{"source": "Cynthia", "target": "Sylvester", "type":"E"},
{"source": "Cynthia", "target": "Jamie", "type":"E"},
{"source": "Mauer", "target": "Jessie", "type":"E"},
{"source": "Duke", "target": "Lexy", "type":"A"},
{"source": "Feyton", "target": "Lexy", "type":"A"},
{"source": "Maria", "target": "Feyton", "type":"A"},
{"source": "Baron", "target": "Yvette", "type":"E"},
{"source": "Evette", "target": "Maria", "type":"E"},
{"source": "Cynthia", "target": "Yvette", "type":"E"},
{"source": "Maria", "target": "Jamie", "type":"E"},
{"source": "Maria", "target": "Lesley", "type":"E"},
{"source": "Ashley", "target": "Damo", "type":"A"},
{"source": "Damo", "target": "Lexy", "type":"A"},
{"source": "Maria", "target": "Feyton", "type":"A"},
{"source": "Finkler", "target": "Ashley", "type":"E"},
{"source": "Sylvester", "target": "Maria", "type":"E"},
{"source": "Peter", "target": "Finkler", "type":"E"},
{"source": "Ashley", "target": "Gordon", "type":"E"},
{"source": "Maria", "target": "Imogen", "type":"E"}
]
//set up the simulation and add forces
var simulation = d3.forceSimulation()
.nodes(nodes_data);
var link_force = d3.forceLink(links_data)
.id(function(d) { return d.name; });
var charge_force = d3.forceManyBody()
.strength(-100);
var center_force = d3.forceCenter(width / 2, height / 2);
simulation
.force("charge_force", charge_force)
.force("center_force", center_force)
.force("link",link_force)
;
//add tick instructions:
simulation.on("tick", tickActions );
//add encompassing group for the zoom
var g = svg.append("g")
.attr("class", "everything");
//draw circles for the nodes
var node = g.append("g")
.attr("class", "nodes")
.selectAll("circle")
.data(nodes_data)
.enter()
.append("circle")
.attr("r", radius)
.attr("fill", circleColour)
.on("mouseover", mouseOver(.1))
.on("mouseout", mouseOut);
// add the curved links to our graphic
var link = svg.selectAll(".link")
.data(links_data)
.enter()
.append("path")
.attr("class", "link")
.style('stroke', linkColour)
.attr('stroke-width', 2);
//add drag capabilities
var drag_handler = d3.drag()
.on("start", drag_start)
.on("drag", drag_drag)
.on("end", drag_end);
drag_handler(node);
//add zoom capabilities
var zoom_handler = d3.zoom()
.on("zoom", zoom_actions);
zoom_handler(svg);
/** Functions **/
//Function to choose what color circle we have
//Let's return blue for males and red for females
function circleColour(d){
if(d.sex =="M"){
return "blue";
} else {
return "pink";
}
}
//Function to choose the line colour and thickness
//If the link type is "A" return green
//If the link type is "E" return red
function linkColour(d){
if(d.type == "A"){
return "green";
} else {
return "red";
}
}
//Drag functions
//d is the node
function drag_start(d) {
if (!d3.event.active) simulation.alphaTarget(0.3).restart();
d.fx = d.x;
d.fy = d.y;
}
//make sure you can't drag the circle outside the box
function drag_drag(d) {
d.fx = d3.event.x;
d.fy = d3.event.y;
}
function drag_end(d) {
if (!d3.event.active) simulation.alphaTarget(0);
d.fx = null;
d.fy = null;
}
//Zoom functions
function zoom_actions(){
g.attr("transform", d3.event.transform)
}
function tickActions() {
//update circle positions each tick of the simulation
node
.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; });
//update link positions
link.attr("d", positionLink);
}
// links are drawn as curved paths between nodes,
// through the intermediate nodes
function positionLink(d) {
var offset = 30;
var midpoint_x = (d.source.x + d.target.x) / 2;
var midpoint_y = (d.source.y + d.target.y) / 2;
var dx = (d.target.x - d.source.x);
var dy = (d.target.y - d.source.y);
var normalise = Math.sqrt((dx * dx) + (dy * dy));
var offSetX = midpoint_x + offset * (dy / normalise);
var offSetY = midpoint_y - offset * (dx / normalise);
return "M" + d.source.x + "," + d.source.y +
"S" + offSetX + "," + offSetY +
" " + d.target.x + "," + d.target.y;
}
// links are drawn as curved paths between nodes,
// through the intermediate nodes
function positionLink(d) {
var offset = 30;
var midpoint_x = (d.source.x + d.target.x) / 2;
var midpoint_y = (d.source.y + d.target.y) / 2;
var dx = (d.target.x - d.source.x);
var dy = (d.target.y - d.source.y);
var normalise = Math.sqrt((dx * dx) + (dy * dy));
var offSetX = midpoint_x + offset * (dy / normalise);
var offSetY = midpoint_y - offset * (dx / normalise);
return "M" + d.source.x + "," + d.source.y +
"S" + offSetX + "," + offSetY +
" " + d.target.x + "," + d.target.y;
}
// build a dictionary of nodes that are linked
var linkedByIndex = {};
links_data.forEach(function(d) {
linkedByIndex[d.source.index + "," + d.target.index] = 1;
});
// check the dictionary to see if nodes are linked
function isConnected(a, b) {
return linkedByIndex[a.index + "," + b.index] || linkedByIndex[b.index + "," + a.index] || a.index == b.index;
}
// fade nodes on hover
function mouseOver(opacity) {
return function(d) {
// check all other nodes to see if they're connected
// to this one. if so, keep the opacity at 1, otherwise
// fade
node.style("stroke-opacity", function(o) {
thisOpacity = isConnected(d, o) ? 1 : opacity;
return thisOpacity;
});
node.style("fill-opacity", function(o) {
thisOpacity = isConnected(d, o) ? 1 : opacity;
return thisOpacity;
});
// also style link accordingly
link.style("stroke-opacity", function(o) {
return o.source === d || o.target === d ? 1 : opacity;
});
link.style("stroke", function(o) {
return o.source === d || o.target === d ? o.source.colour : "#ddd";
});
};
}
function mouseOut() {
node.style("stroke-opacity", 1);
node.style("fill-opacity", 1);
link.style("stroke-opacity", 1);
link.style("stroke", "#ddd");
}
