venn.js

A javascript library for laying out area proportional venn and euler diagrams.

Details of how this library works can be found on the blog post I wrote about this. There are also more examples on that page.

Usage

This library depends on d3.js to display the venn diagrams.

Simple layout

To lay out a simple diagram, just define the sets and their sizes along with the sizes of all the set intersection. Calling 'venn.venn' will position the sets such that the areas of each region are proportional to the sizes, and 'venn.drawD3Diagram' will display this diagram:

// define sets and set set intersections
var sets = [{label: "A", size: 10}, {label: "B", size: 10}],
    overlaps = [{sets: [0,1], size: 2}];

// get positions for each set
sets = venn.venn(sets, overlaps);

// draw the diagram in the 'simple_example' div
venn.drawD3Diagram(d3.select(".simple_example"), sets, 300, 300);

View this example

Dynamic layout

To have a layout that reacts to a change in input, you just need to recompute the areas and call updateD3Diagram to do the transition:

// draw the initial set
var sets = venn.venn(getSets(), getSetIntersections());
venn.drawD3Diagram(d3.select(".dynamic"), sets, w, h);

// redraw the sets on any change in input
d3.selectAll("input").on("change", function() {
    var sets = venn.venn(getSets(), getSetIntersections());
    venn.updateD3Diagram(d3.select(".dynamic"), sets);
});

View this example

Changing the Style

To change the style of the venn diagram, use D3 to set attributes on the 'text' and 'circle' objects that are returned from the drawD3Diagram call:

var diagram = venn.drawD3Diagram(d3.select(".lastfm"),
                                 venn.venn(sets, overlaps), 
                                 450, 450);

// add a border, darken up the circles, change text colour
diagram.circles.style("fill-opacity", .6)
               .style("stroke-width", 1);
diagram.text.style("stroke", "#444")
            .style("fill", "#444");

// add a tooltip showing the size of each set
var tooltip = d3.select("body").append("div")
    .attr("class", "venntooltip");

diagram.circles
    .on("mousemove", function() {
        tooltip.style("left", (d3.event.pageX) + "px")
               .style("top", (d3.event.pageY - 28) + "px");
    })
    .on("mouseover", function(d, i) {
        d3.select(this).style("fill-opacity", .8);
        d3.select(this).style("stroke-width", 2);
        tooltip.transition().style("opacity", .9);
        tooltip.text(d.size + " users");
    })
    .on("mouseout", function(d, i) {
        d3.select(this).style("fill-opacity", 0.6);
        tooltip.transition().style("opacity", 0);
        d3.select(this).style("stroke-width", 0);
    });

View this example

MDS Layout

In most cases the greedy initial layout does a good job of positioning the sets, but there are cases where it breaks down. One case is detailed in this blog post, and it can be better laid out using multidimensional scaling to generate the initial layout.

To enable this just include the mds.js and numeric.js libraries first, and then generate the venn positions by calling:

sets = venn.venn(sets, overlaps, {layoutFunction: venn.classicMDSLayout});

View this example

Released under the MIT License.