How to remove node in D3 force layout? - d3.js

I have a simple D3 simulation that looks like this
When I click the 'remove 1 and 4' button I want to remove nodes 1 and 4 from the simulation. The result, however, is the following:
Visually it seems to have removed 3 and 4 (not 1 and 4).
My code is below. Any ideas what I need to do to make this work correctly?
I'm assuming I've fundamentally misunderstood how updating nodes works in d3. Any help appreciated.
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<!DOCTYPE html>
<meta charset="utf-8">
<script type="text/javascript" src="http://d3js.org/d3.v3.js"></script>
<body>
<button>remove 1 and 4</button>
<script>
var width = 400,
height = 400;
var nodes = [1, 2, 3, 4].map(function(x) { return { name: x}});
var force = d3.layout.force()
.size([width, height])
.nodes(nodes)
.linkDistance(30)
.charge(-500)
.on("tick", tick);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var content = svg.append("g");
var nodesData = force.nodes(),
nodeElement = content.selectAll(".node");
function tick() {
nodeElement.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
}
d3.selectAll('button').on('click', function() {
//remove 1 and 4
nodesData = [
nodesData[1],
nodesData[2]
]
refresh();
});
var WIDTH = 100;
//
// this logic is slightly modified from http://bl.ocks.org/tgk/6068367
//
function refresh() {
force.nodes(nodesData)
nodeElement = nodeElement.data(nodesData);
var nodeGroup = nodeElement.enter()
.append('g')
.attr("class", "node");
// node text
nodeGroup.append("text")
.attr("class", "nodetext")
.attr("dx", WIDTH/2)
.attr("dy", "14px")
.text(function(n) { return 'node '+n.name })
nodeElement.exit().remove();
force.start();
}
refresh();
</script>

You can solve your problem by adding a "key" function to the .data call inside the refresh function: nodeElement = nodeElement.data(nodesData, function(d){ return d.name });.
The problem you saw is not specific to updating nodes. Ordinarily, selections work based off of index of the data array. So if first D3 had [a,b,c,d] and now it has [a,d], it's going to take the first two elements ([a,b]) unless you tell it the key that defines each item in the array. That's what the function above does.
For more see https://github.com/d3/d3-selection/blob/master/README.md#selection_data

Related

In D3.js I am confused by behavior of exit()

Today I am learning about D3.js
I started by studying this content:
https://bost.ocks.org/mike/circles/
Most of it seems easy to understand and follow.
But I have a problem getting exit() to work.
I do understand the idea that I can use exit() to force elements in my DOM to synch with values in a JS array.
So I wrote some code to demonstrate this idea and my code fails.
I want to know how I can rewrite my JS so that exit() will force elements in my DOM to synch with values in a JS array.
<html>
<body>
Ref:
<a href='https://bost.ocks.org/mike/circles/' target='x'>
https://bost.ocks.org/mike/circles/
</a>
<script src="https://d3js.org/d3.v3.min.js" charset="utf-8"></script>
<script>
// I should create 3 circles
var svg1 = d3.select('body')
.append('svg')
.attr('id','svg1')
.attr('width',800).selectAll("circle")
.data([0, 1, 2])
.enter()
.append("circle")
.attr("cy", 60)
.attr("cx", function(d, i) { return i * 100 + 30 })
.attr("r", function(d) { return 5+5*d })
// So far so good. I see 3 circles
// Now I should remove some.
var mycircles_a = svg1.selectAll("circle")
.data([99, 88])
// I should ask D3 to make the data-array sync with the circle-elements:
mycircles_a.exit().remove()
// Above call fails for some reason; I still see 3 circles!
// I should see 2 circles because mycircles_a is bound to an array with only 2 values.
'bye'
</script>
</body>
</html>
In your example svg1 is, itself, an "enter" selection.
Your code works just fine if you break the chain, making svg1 just a selection that creates the SVG:
var svg1 = d3.select('body')
.append('svg')
.attr('id','svg1')
.attr('width',800);
svg1.selectAll("circle")
.data([0, 1, 2])
.enter()
.append("circle")
.attr("cy", 60)
.attr("cx", function(d, i) { return i * 100 + 30 })
.attr("r", function(d) { return 5+5*d })
var mycircles_a = svg1.selectAll("circle")
.data([99, 88])
mycircles_a.exit().remove()
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
You're not saving a reference to svg1 correctly.
https://jsfiddle.net/y008c61L/
var svg1 = d3.select('body')
.append('svg')
.attr('id','svg1')
.attr('width',800);
svg1.selectAll("circle")
//...

Integrating with canvas drawings in nodes

I'm attempting to draw a graph/network in which node contents should be filled with a third party library. So far, I was able to draw the graph with d3 with a container () for each node to be filled later on. My problem is that the containers seem not to yet exist when there are referred for drawing. Adding an onload event doesn't work either, but using a onclick event shows that everything is in place to work and most probably drawing starts before the DOM elements are actually created.
What is the best practice to make sure d3 generated DOM elements are created before starting assigning them content? The third party JS library I use only requires the div id to draw content in.
From arrays of nodes and relationships return by Neo4j, I build a graph with d3 as follow. Images to be displayed in nodes are stored in the neo4j data base as Base64 strings.
var width = 500, height = 500;
var div = d3.select("body").append("div")
.attr("class", "tooltip")
.style("opacity", 0);
var col = obj.columns;
var data = obj.data;
var nodes = obj.data[0][0].nodes;
var nodeMap = {};
nodes.forEach(function(x) { nodeMap[x.label] = x; });
var edges = obj.data[0][0].edges;
var links = edges.map(function(x) {
return { source: nodeMap[x.source], target: nodeMap[x.target], value: x.value };
});
var svg = d3.select("#graph").append("svg")
.attr("width", width)
.attr("height", height)
.attr("pointer-events", "all")
.append('g')
.call(d3.behavior.zoom().on("zoom", redraw))
.append('g');
var force = d3.layout.force()
.gravity(.3)
.distance(150)
.charge(-4000)
.size([width, height]);
var drag = force.drag()
.on("dragstart", dragstart);
force
.nodes(nodes)
.links(links)
.friction(0.8)
.start();
var link = svg.selectAll(".link")
.data(links)
.enter().append("line")
.attr("class", "link");
var node = svg.selectAll(".node")
.data(nodes)
.enter().append("svg:g")
.attr("class", "node")
.on("dblclick", dblclick)
.call(force.drag);
node.append("circle")
.attr("r", 50);
node.append("image")
// display structure in nodes
.attr("xlink:href", function(d){
if (d.imgB64) {
return 'data:image/png;base64, ' + d.imgB64 ;
}
})
.attr("x", -40)
.attr("y", -40)
.attr("width", 80)
.attr("height", 80);
force.on("tick", function() {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
});
That code works fine. Hence, what I'm attempting to do is to replace the Base64 images with canvas drawings generated by a third party library.
This library works as follow:
var myCanvas = newCanvasViewer(id, data);
This function knows how to generate an image from the given data and puts the result in the DOM element, if the element already exists in the DOM, or generate a new canvas element in the DOM, directly in but unfortunately erasing any other existing DOM elements.
So, I changed the d3 above code, replacing the node.append('image') block with:
node.append("canvas")
.attr("id", function(d) {
var cnv = newCanvasViewer(d.name, d.data);
return d.name;
});
This obviously doesn't work, canvas objects are displayed but not in the nodes, probably because the DOM element doesn't exist yet when calling newCanvasViewer. Furthermore, the d3 graph is overwritten.
When setting an onclick function calling newCanvasViewer, the drawing shows up within the nodes on click.
node.append("circle")
.attr("r", 50)
.attr("onclick", function(d) {
return "newCanvasViewer('"+d.name+"', '"+d.data+"')";
});
node.append("canvas")
.attr("id", function(d) {
return d.name;
});
Since I would like each node to display its canvas drawing from start, I was wondering when to call the newCanvasViewer function? I guess an oncreate function at each node would make it, but doesn't exist.
Would a call back function work? Should I call it once d3 is finished with the whole network drawing?
In order to be more comprehensive, here is the HTML and javascript code with callback function to attempt drawing canvas content once d3 d3 is done drawing. I'm still stuck, the canvas sample is actually displayed but no canvas content show in nodes, probably due to timing between generating canvas containers and using them.
HTML:
<body onload="init(); cypherQuery()">
<div id="graph" align="left" valign="top"></div>
<div id="sample">
<canvas id="mol" style="width: 160px; height: 160px;"></canvas>
</div>
</body>
Javascript (in the HTML header):
var xmlhttp;
function init() {
xmlhttp = new XMLHttpRequest();
}
function cypherQuery() {
// perform neo4j query, extract JSON and call the network drawing (d3).
// ...
var obj = JSON.parse(xmlhttp.responseText);
drawGraph(obj, drawCanvas);
// this is just to show that canvasViewer does the
// job if the <canvas id='...'> element exists in DOM
var nodes = obj.data[0][0].nodes;
var cnv = newCanvasViewer("sample", nodes[0].data);
}
function drawGraph(obj, drawCanvas) {
// see code above from...
var width = 500, height = 500;
// ... to
force.on("tick", function() {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("transform", function(d) {
return "translate(" + d.x + "," + d.y + ")";
});
});
function redraw() {
svg.attr("transform", "translate(" + d3.event.translate + ")" + " scale(" + d3.event.scale + ")");
// node.attr("font-size", (nodeFontSize / d3.event.scale) + "px");
}
function dblclick(d) {
d3.select(this).classed("fixed", d.fixed = false);
}
if (callback && typeof(callback) === "function") {
callback(nodes);
}
}

how to zoom only map and smiley could stay at same place and size

I having problem of zoom over map. The actual problem is when i zoom map, the location showing on map using smiley could also zoom but i don't want to zoom smiley. It could stay at same size and place. Sometime smiley get overlap so to avoid this i am trying to solve the above problem but i don't have idea how to transform attribute contains many things like images and text on map of d3.js. Please have a look at jsfiddle link and you can see that at japan 3 smiley get overlap and keep overlapped even after zooming map.
My JSfiddle link
my code is following:
<!DOCTYPE html>
<meta charset="utf-8">
<style>
path {
stroke: white;
stroke-width: 0.25px;
fill: grey;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/topojson.v0.min.js"></script>
<script>
var width = 960,
height = 500;
var data = [
{
"code":"TYO",
"city":"TOKYO",
"country":"JAPAN",
"lat":"35.68",
"lon":"139.76"
},
{
"code":"OSK",
"city":"Osaka",
"country":"JAPAN",
"lat":" 34.40",
"lon":"135.37"
},
{
"code":"HISH",
"city":"Hiroshima",
"country":"JAPAN",
"lat":"34.3853",
"lon":"132.4553"
},
{
"code":"BKK",
"city":"BANGKOK",
"country":"THAILAND",
"lat":"13.75",
"lon":"100.48"
},
{
"code":"DEL",
"city":"DELHI",
"country":"INDIA",
"lat":"29.01",
"lon":"77.38"
},
{
"code":"SEA",
"city":"SEATTLE",
"country":"USA",
"lat":"38.680632",
"lon":"-96.5001"
}
];
var projection = d3.geo.mercator()
.center([0, 5 ])
.scale(200)
.rotate([-180,0]);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var path = d3.geo.path()
.projection(projection);
var g = svg.append("g");
// load and display the World
d3.json("world-110m2.json", function(error, topology) {
// load and display the cities
function drawMap(data){
var circle = g.selectAll("circle")
.data(data)
.enter()
.append("g")
circle.append("circle")
.attr("cx", function(d) {
return projection([d.lon, d.lat])[0];
})
.attr("cy", function(d) {
return projection([d.lon, d.lat])[1];
})
.attr("r", 5)
.style("fill", "red");
circle.append("image")
.attr("xlink:href", "http://fc08.deviantart.net/fs71/f/2013/354/8/7/blinking_smiley__animated__by_mondspeer-d6ylwn3.gif")//http://t2.gstatic.//com/images?q=tbn:ANd9GcT6fN48PEP2-z-JbutdhqfypsYdciYTAZEziHpBJZLAfM6rxqYX";})
.attr("class", "node")
.attr("x", function(d) {
return (projection([d.lon, d.lat])[0]) - 8;
})
.attr("y", function(d) {
return (projection([d.lon, d.lat])[1])-8;
})
.attr("width",20)
.attr("height",20)
//});
}
g.selectAll("path")
.data(topojson.object(topology, topology.objects.countries)
.geometries)
.enter()
.append("path")
.attr("d", path)
drawMap(data);
});
// zoom and pan
var zoom = d3.behavior.zoom()
.on("zoom",function() {
g.attr("transform","translate("+
d3.event.translate.join(",")+")scale("+d3.event.scale+")");
g.selectAll("circle")
.attr("d", path.projection(projection));
g.selectAll("path")
.attr("d", path.projection(projection));
});
svg.call(zoom)
</script>
</body>
</html>
Any body help me to zoom only map image not smiley
Implement semantic zooming :)
Try use this example to change your code :) :
Semantic zoom on map with circle showing capital
JSFIDDLE : http://jsfiddle.net/xf7222dg/2/
The code below shrinks the 'circles' depending on scale
var zoom = d3.behavior.zoom()
.on("zoom",function() {
g.attr("transform","translate("+
d3.event.translate.join(",")+")scale("+d3.event.scale+")");
g.selectAll("circle")
.attr("r", function(){
var self = d3.select(this);
var r = 8 / d3.event.scale; // set radius according to scale
self.style("stroke-width", r < 4 ? (r < 2 ? 0.5 : 1) : 2); // scale stroke-width
return r;
});
});
Here is it working with your smileys: http://jsfiddle.net/dmn0d11f/7/
You have to change the 'width' of the nodes (images) not the radius like with the circles. So select the nodes and instead of changing 'r' change 'width' :
g.selectAll(".node")
.attr("width", function(){
var self = d3.select(this);
var r = 28 / d3.event.scale; // set radius according to scale
self.style("stroke-width", r < 4 ? (r < 2 ? 0.5 : 1) : 2); // scale stroke-width
return r;
});

d3 problems. Circle image not appearing

I am following this tutorial:
I have this code so far:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>D3 Test</title>
<script type="text/javascript" src="d3/d3.v3.js"></script>
<link rel="stylesheet" href="custom.css">
</head>
<body>
<script type="text/javascript">
var w = 500;
var h = 100;
var svg = d3.select("body")
.append("svg")
.attr("width", w) // <-- Here
.attr("height", h); // <-- and here!
// var dataset = []; //Initialize empty array
// for (var i = 0; i < 25; i++) { //Loop 25 times
// var newNumber = Math.round(Math.random() * 30); //New random number (0-30)
// dataset.push(newNumber); //Add new number to array
// }
var dataset = [ 5, 10, 15, 20, 25 ];
svg.selectAll("circle")
.data(dataset)
.enter()
.append("circle");
var circles = svg.selectAll("circle")
.data(dataset)
.enter()
.append("circle");
circles.attr("cx", function(d, i) {
return (i * 50) + 25;
})
.attr("cy", h/2)
.attr("r", function(d) {
return d;
});
The SVG tag is showing up but there aren't any circles in the tag. What is going on? What am I missing? Currently it's just an empty SVG tag.
To get it working delete your first
svg.selectAll("circle")
.data(dataset)
.enter()
.append("circle");
var w = 500;
var h = 100;
var svg = d3.select("body")
.append("svg")
.attr("width", w) // <-- Here
.attr("height", h); // <-- and here!
// var dataset = []; //Initialize empty array
// for (var i = 0; i < 25; i++) { //Loop 25 times
// var newNumber = Math.round(Math.random() * 30); //New random number (0-30)
// dataset.push(newNumber); //Add new number to array
// }
var dataset = [5, 10, 15, 20, 25];
//svg.selectAll("circle")
// .data(dataset)
// .enter()
// .append("circle");
var circles = svg.selectAll("circle")
.data(dataset)
.enter()
.append("circle");
circles.attr("cx", function (d, i) {
return (i * 50) + 25;
})
.attr("cy", h / 2)
.attr("r", function (d) {
return d;
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
This first statement does in fact insert/append your circles using the enter() selection. They are present in the svg, but are empty since no attributes have been set. Furthermore, you are not keeping the references to them as you haven't assigned them to any variable.
The second statement uses an assignment to var circles. But, binding the same data and again refering to the enter() selection will yield an empty selection because no new data actually entered. Using this empty selection your attempts to set attributes like cx, cy and r are fruitless. Having deleted the first one, though, this statement now does exactly the job you are looking for.
Check one of the following articles for a more detailed view on using data joins with d3:
General Update Pattern
Thinking with joins
How Selections Work

meteor add d3 grafics dynamically fails

I'm drawing a d3 donut. Now I want to add as many donuts as entries in database. If I add something to database, automatic updating fails. I have to reload My code in the Browser - then I see the new donut. Isnt Meteor.autorun updating automatically?
Code is:
Template.donuts.rendered = function (){
var self = this;
self.node = self.find("p");
// Data
var dataset = {
apples: [2, 2, 2, 2, 2]
};
//Width and height
var width = 100,
height = 100,
radius = Math.min(width, height) / 2;
// render
self.handle = Meteor.autorun(function () {
var color = d3.scale.category10();
var pie = d3.layout.pie()
.sort(null);
var arc = d3.svg.arc()
.innerRadius(radius - 20)
.outerRadius(radius - 5);
var svg = d3.select(self.node).append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
var path = svg.selectAll("path")
.data(pie(dataset.apples))
.enter().append("path")
.attr("fill", function(d, i) { return color(i); })
.attr("d", arc);
});
}; //Template.donuts
it is called via handlebars
<template name="donuts">
{{#each nodes}}
<p></p>
{{/each}}
</template>
What am I doing wrong. Thank you for your time.
Your rendered hook is on the wrong level. Right now you're connecting it to the template that contains the donuts, when it looks like you want to have each donut be rendered in a certain way. First, start by reorganising your templates:
<template name="donuts">
{{#each nodes}}
{{> node}}
{{/each}}
</template>
<template name="node"><p></p></template>
Now you can tell a node what to do when it's rendered:
Template.node.rendered = function() {
// d3 code
}
The rendered call will be automatically run whenever the node is re-rendered, which will happen if you change a dependency. If nodes is a reactive source like a mongodb cursor, this will work immediately. Otherwise, please add more code so we can figure out what else is going on.
Meteor.autorun() will run whenever its dependencies change. You need a reactive datasource inside the function.
Found a more elegant solution:
// Donuts //
function donutinit() {
var dataset = {
apples: [2, 2, 2, 2, 2]
};
//Width and height
var width = 100,
height = 100,
radius = Math.min(width, height) / 2;
// render
var color = d3.scale.category10();
var pie = d3.layout.pie()
.sort(null);
var arc = d3.svg.arc()
.innerRadius(radius - 20)
.outerRadius(radius - 5);
var svg = d3.select("#donut_canvas").append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
var path = svg.selectAll("path")
.data(pie(dataset.apples))
.enter().append("path")
.attr("fill", function(d, i) { return color(i); })
.attr("d", arc);
};
Template.donut.rendered = function() {
donutinit();
};
After that iterate with handlebars over #donut_canvas. The Meteor.autorun or Meteor.rendered gave me unpredictable amounts of donuts - it rendered additional donuts. I had to reload it then.
Answer is inspired from here: Google map contained in meteor Template is rendered twice
Thank you for your time.

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