Draggable Network II

This brushable and draggable network supports multiple selections via the SHIFT key. Click and drag the background area to make a rectangular selection (brushing). Once you’ve selected some nodes, drag them around to reposition the network. You might use this technique to hand-tweak a force-directed layout for better appearance, saving the manually-adjusted node positions back to a file.

For greater control, you can hold down the SHIFT key to add to or remove from an existing selection, either by creating a new rectangular selection or clicking on an individual nodes. You can use the OPTION and SPACE keys to modify the rectangular selection while dragging. You can also use the arrow keys to nudge selected nodes.

A further improvement to this example would be to allow rigid-body transformations of selected nodes (scale and rotate, in addition to translate). You might do this by checking for the META key while dragging. If the META key is down, you’d rotate and scale the nodes around the selected node’s centroid, rather than just translating. You might also try running a few iterations of the force layout on selected nodes interactively. Fork this example to implement these ideas yourself!

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.node {
  stroke: #fff;
  stroke-width: 1.5px;
}

.node .selected {
  stroke: red;
}

.link {
  stroke: #999;
}

</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var width = 960,
    height = 500,
    shiftKey;

var svg = d3.select("body")
    .attr("tabindex", 1)
    .on("keydown.brush", keydowned)
    .on("keyup.brush", keyupped)
    .each(function() { this.focus(); })
  .append("svg")
    .attr("width", width)
    .attr("height", height);

var link = svg.append("g")
    .attr("class", "link")
  .selectAll("line");

var brush = svg.append("g")
    .attr("class", "brush");

var node = svg.append("g")
    .attr("class", "node")
  .selectAll("circle");

d3.json("graph.json", function(error, graph) {
  if (error) throw error;

graph.links.forEach(function(d) {
    d.source = graph.nodes[d.source];
    d.target = graph.nodes[d.target];
  });

graph.nodes.forEach(function(d) {
    d.selected = false;
    d.previouslySelected = false;
  });

link = link
    .data(graph.links)
    .enter().append("line")
      .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; });

brush.call(d3.brush()
        .extent([[0, 0], [width, height]])
        .on("start", brushstarted)
        .on("brush", brushed)
        .on("end", brushended));

node = node
    .data(graph.nodes)
    .enter().append("circle")
      .attr("r", 4)
      .attr("cx", function(d) { return d.x; })
      .attr("cy", function(d) { return d.y; })
      .on("mousedown", mousedowned)
      .call(d3.drag().on("drag", dragged));

function brushstarted() {
    if (d3.event.sourceEvent.type !== "end") {
      node.classed("selected", function(d) {
        return d.selected = d.previouslySelected = shiftKey && d.selected;
      });
    }
  }

function brushended() {
    if (d3.event.selection != null) {
      d3.select(this).call(d3.event.target.move, null);
    }
  }

function dragged(d) {
    nudge(d3.event.dx, d3.event.dy);
  }
});

function nudge(dx, dy) {
  node.filter(function(d) { return d.selected; })
      .attr("cx", function(d) { return d.x += dx; })
      .attr("cy", function(d) { return d.y += dy; })

link.filter(function(d) { return d.source.selected; })
      .attr("x1", function(d) { return d.source.x; })
      .attr("y1", function(d) { return d.source.y; });

link.filter(function(d) { return d.target.selected; })
      .attr("x2", function(d) { return d.target.x; })
      .attr("y2", function(d) { return d.target.y; });
}

function keyupped() {
  shiftKey = d3.event.shiftKey || d3.event.metaKey;
}

</script>

https://d3js.org/d3.v4.min.js