Skip to content

Instantly share code, notes, and snippets.

@trinary

trinary/README.md

Created March 28, 2014 01:16
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save trinary/9823006 to your computer and use it in GitHub Desktop.
Save trinary/9823006 to your computer and use it in GitHub Desktop.
Download ZIP
Raw
README.md

This example demonstrates how to prevent D3’s force layout from moving nodes that have been repositioned by the user. When the force layout’s drag behavior dispatches a dragstart event, the fixed property of the dragged node is set to true. This prevents the force layout from subsequently changing the position of the node (due to forces). Double-click to release a node.

Internally, the force layout uses three bits to control whether a node is fixed. The first bit can be set externally, as in this example. The second and third bits are set on mouseover and mousedown, respectively, so that nodes are fixed temporarily during dragging. Although the second and third bits are automatically cleared when dragging ends, the first bit stays true in this example, and thus nodes remain fixed after dragging.

Also note that the force layout resumes automatically on dragmove. This ensures that other nodes in the graph respond naturally to the dragged node’s movement.

Raw
graph.json
{
"nodes": [
{"x": 469, "y": 410},
{"x": 493, "y": 364},
{"x": 442, "y": 365},
{"x": 467, "y": 314},
{"x": 477, "y": 248},
{"x": 425, "y": 207},
{"x": 402, "y": 155},
{"x": 369, "y": 196},
{"x": 350, "y": 148},
{"x": 539, "y": 222},
{"x": 594, "y": 235},
{"x": 582, "y": 185},
{"x": 633, "y": 200}
],
"links": [
{"source": 0, "target": 1},
{"source": 1, "target": 2},
{"source": 2, "target": 0},
{"source": 1, "target": 3},
{"source": 3, "target": 2},
{"source": 3, "target": 4},
{"source": 4, "target": 5},
{"source": 5, "target": 6},
{"source": 5, "target": 7},
{"source": 6, "target": 7},
{"source": 6, "target": 8},
{"source": 7, "target": 8},
{"source": 9, "target": 4},
{"source": 9, "target": 11},
{"source": 9, "target": 10},
{"source": 10, "target": 11},
{"source": 11, "target": 12},
{"source": 12, "target": 10}
]
}
Raw
index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style>
.link {
stroke: #000;
stroke-width: 1.5px;
}
.node {
cursor: move;
fill: #ccc;
stroke: #000;
stroke-width: 1.5px;
}
.node.fixed {
fill: #f00;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
var width = 960,
height = 500;
var force = d3.layout.force()
.size([width, height])
.charge(-400)
.linkDistance(40)
.on("tick", tick);
var drag = force.drag()
.on("dragstart", dragstart);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var link = svg.selectAll(".link"),
node = svg.selectAll(".node");
d3.json("graph.json", function(error, graph) {
force
.nodes(graph.nodes)
.links(graph.links)
.start();
link = link.data(graph.links)
.enter().append("line")
.attr("class", "link");
node = node.data(graph.nodes)
node.enter().append("g")
node.append("circle")
.attr("class", "node")
.attr("r", 12)
.on("dblclick", dblclick)
.call(drag);
node.on("mouseover", function(d,i) {
var group = d3.select(this)
var mouseover = group.append("g").classed("mouseover", true);
mouseover.append("text").text(i);
});
node.on("mouseout", function(d,i) {
d3.selectAll(".mouseover").remove();
});
});
function tick() {
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 dblclick(d) {
d3.select(this).classed("fixed", d.fixed = false);
}
function dragstart(d) {
d3.select(this).classed("fixed", d.fixed = true);
}
</script>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment