D3 Selectable Force-Directed Graph

SelectableForceDirectedGraph

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README.md

This is an extension of Mike Bostock's Draggable Network II example, allowing one to drag multiple nodes in a force-directed graph. Nodes can be selected by holding the shift key and either dragging on the canvas or clicking on specific nodes. The selection and dragging semantics aim to mirror those of most window managers:

1. Shift clicking on a node toggles whether it is selected
2. Clicking (without shift) on a node, selects it and deselects everything else.
3. Shift dragging on the canvas toggles the selection status of the nodes enclosed within it.
4. Dragging a set of selected nodes drags all of them.
5. Clicking on the canvas de-selects everything.

graph.json

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}

index.html

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

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

.node .selected {
  stroke: black;
}

.link {
  stroke: #999;
}

.brush .extent {
  fill-opacity: .1;
  stroke: #fff;
  shape-rendering: crispEdges;
}

</style>
<body>
    <div align='center' id="d3_selectable_force_directed_graph"></div>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="plot.js"></script>
<script>selectableForceDirectedGraph();</script>

plot.js

function selectableForceDirectedGraph() {
    var width = 960,

    height = 500,
    shiftKey, ctrlKey;

    var nodeGraph = null;
    var xScale = d3.scale.linear()
    .domain([0,width]).range([0,width]);
    var yScale = d3.scale.linear()
    .domain([0,height]).range([0, height]);

    var svg = d3.select("#d3_selectable_force_directed_graph")
    .attr("tabindex", 1)
    .on("keydown.brush", keydown)
    .on("keyup.brush", keyup)
    .each(function() { this.focus(); })
    .append("svg")
    .attr("width", width)
    .attr("height", height);

    var zoomer = d3.behavior.zoom().
        scaleExtent([0.1,10]).
        x(xScale).
        y(yScale).
        on("zoomstart", zoomstart).
        on("zoom", redraw);

    function zoomstart() {
        node.each(function(d) {
            d.selected = false;
            d.previouslySelected = false;
        });
        node.classed("selected", false);
    }

    function redraw() {
        vis.attr("transform",
                 "translate(" + d3.event.translate + ")" + " scale(" + d3.event.scale + ")");
    }

    var brusher = d3.svg.brush()
    //.x(d3.scale.identity().domain([0, width]))
    //.y(d3.scale.identity().domain([0, height]))
    .x(xScale)
    .y(yScale)
    .on("brushstart", function(d) {
        node.each(function(d) { 
            d.previouslySelected = shiftKey && d.selected; });
    })
    .on("brush", function() {
        var extent = d3.event.target.extent();

        node.classed("selected", function(d) {
            return d.selected = d.previouslySelected ^
            (extent[0][0] <= d.x && d.x < extent[1][0]
             && extent[0][1] <= d.y && d.y < extent[1][1]);
        });
    })
    .on("brushend", function() {
        d3.event.target.clear();
        d3.select(this).call(d3.event.target);
    });

    var svg_graph = svg.append('svg:g')
    .call(zoomer)
    //.call(brusher)

    var rect = svg_graph.append('svg:rect')
    .attr('width', width)
    .attr('height', height)
    .attr('fill', 'transparent')
    //.attr('opacity', 0.5)
    .attr('stroke', 'transparent')
    .attr('stroke-width', 1)
    //.attr("pointer-events", "all")
    .attr("id", "zrect")

    var brush = svg_graph.append("g")
    .datum(function() { return {selected: false, previouslySelected: false}; })
    .attr("class", "brush");

    var vis = svg_graph.append("svg:g");

    vis.attr('fill', 'red')
    .attr('stroke', 'black')
    .attr('stroke-width', 1)
    .attr('opacity', 0.5)
    .attr('id', 'vis')


    brush.call(brusher)
    .on("mousedown.brush", null)
    .on("touchstart.brush", null) 
    .on("touchmove.brush", null)
    .on("touchend.brush", null); 

    brush.select('.background').style('cursor', 'auto');

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

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

    center_view = function() {
        // Center the view on the molecule(s) and scale it so that everything
        // fits in the window

        if (nodeGraph === null)
            return;

        var nodes = nodeGraph.nodes;

        //no molecules, nothing to do
        if (nodes.length === 0)
            return;

        // Get the bounding box
        min_x = d3.min(nodes.map(function(d) {return d.x;}));
        min_y = d3.min(nodes.map(function(d) {return d.y;}));

        max_x = d3.max(nodes.map(function(d) {return d.x;}));
        max_y = d3.max(nodes.map(function(d) {return d.y;}));


        // The width and the height of the graph
        mol_width = max_x - min_x;
        mol_height = max_y - min_y;

        // how much larger the drawing area is than the width and the height
        width_ratio = width / mol_width;
        height_ratio = height / mol_height;

        // we need to fit it in both directions, so we scale according to
        // the direction in which we need to shrink the most
        min_ratio = Math.min(width_ratio, height_ratio) * 0.8;

        // the new dimensions of the molecule
        new_mol_width = mol_width * min_ratio;
        new_mol_height = mol_height * min_ratio;

        // translate so that it's in the center of the window
        x_trans = -(min_x) * min_ratio + (width - new_mol_width) / 2;
        y_trans = -(min_y) * min_ratio + (height - new_mol_height) / 2;


        // do the actual moving
        vis.attr("transform",
                 "translate(" + [x_trans, y_trans] + ")" + " scale(" + min_ratio + ")");

                 // tell the zoomer what we did so that next we zoom, it uses the
                 // transformation we entered here
                 zoomer.translate([x_trans, y_trans ]);
                 zoomer.scale(min_ratio);

    };

    function dragended(d) {
        //d3.select(self).classed("dragging", false);
        node.filter(function(d) { return d.selected; })
        .each(function(d) { d.fixed &= ~6; })

    }

    d3.json("graph.json", function(error, graph) {
        nodeGraph = graph;

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

        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; });


        var force = d3.layout.force()
        .charge(-120)
        .linkDistance(30)
        .nodes(graph.nodes)
        .links(graph.links)
        .size([width, height])
        .start();

        function dragstarted(d) {
            d3.event.sourceEvent.stopPropagation();
            if (!d.selected && !shiftKey) {
                // if this node isn't selected, then we have to unselect every other node
                node.classed("selected", function(p) { return p.selected =  p.previouslySelected = false; });
            }

            d3.select(this).classed("selected", function(p) { d.previouslySelected = d.selected; return d.selected = true; });

            node.filter(function(d) { return d.selected; })
            .each(function(d) { d.fixed |= 2; })
        }

        function dragged(d) {
            node.filter(function(d) { return d.selected; })
            .each(function(d) { 
                d.x += d3.event.dx;
                d.y += d3.event.dy;

                d.px += d3.event.dx;
                d.py += d3.event.dy;
            })

            force.resume();
        }
        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("dblclick", function(d) { d3.event.stopPropagation(); })
        .on("click", function(d) {
            if (d3.event.defaultPrevented) return;

            if (!shiftKey) {
                //if the shift key isn't down, unselect everything
                node.classed("selected", function(p) { return p.selected =  p.previouslySelected = false; })
            }

            // always select this node
            d3.select(this).classed("selected", d.selected = !d.previouslySelected);
        })

        .on("mouseup", function(d) {
            //if (d.selected && shiftKey) d3.select(this).classed("selected", d.selected = false);
        })
        .call(d3.behavior.drag()
              .on("dragstart", dragstarted)
              .on("drag", dragged)
              .on("dragend", dragended));

              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('cx', function(d) { return d.x; })
                  .attr('cy', function(d) { return d.y; });

              };

              force.on("tick", tick);

    });


    function keydown() {
        shiftKey = d3.event.shiftKey || d3.event.metaKey;
        ctrlKey = d3.event.ctrlKey;

        console.log('d3.event', d3.event)

        if (d3.event.keyCode == 67) {   //the 'c' key
            center_view();
        }

        if (shiftKey) {
            svg_graph.call(zoomer)
            .on("mousedown.zoom", null)
            .on("touchstart.zoom", null)                                                                      
            .on("touchmove.zoom", null)                                                                       
            .on("touchend.zoom", null);                                                                       

            //svg_graph.on('zoom', null);                                                                     
            vis.selectAll('g.gnode')
            .on('mousedown.drag', null);

            brush.select('.background').style('cursor', 'crosshair')
            brush.call(brusher);
        }
    }

    function keyup() {
        shiftKey = d3.event.shiftKey || d3.event.metaKey;
        ctrlKey = d3.event.ctrlKey;

        brush.call(brusher)
        .on("mousedown.brush", null)
        .on("touchstart.brush", null)                                                                      
        .on("touchmove.brush", null)                                                                       
        .on("touchend.brush", null);                                                                       

        brush.select('.background').style('cursor', 'auto')
        svg_graph.call(zoomer);
    }
}

thumbnail.png

Thanks for this. Learn a lot from it.

Thank you for the code. I followed your instruction but couldn't get what I expected:

I defined the transform function outside:

         var transform = d3.transform(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('cx', function(d) { return d.x; })
            .attr('cy', function(d) { return d.y; });

        })

and then:

        node = node.data(graph.nodes).enter()
        .append("g")
        .attr(transform) 
        .append("circle")
        .attr("r", 8)
        .append("text).text(function(d) { return d.label; })
        .on("dblclick", function(d) { d3.event.stopPropagation(); })
        ."rest of the code"