venn.js

This is a maintained fork of https://github.com/benfred/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 the original author wrote about this. A follow up post discusses testing strategy and algorithmic improvements.

Install

npm install --save @upsetjs/venn.js

Usage

There are two modes in which this library can be used. First, in a managed case by using the VennDiagram function that will render the data using D3. Second, in a manual case as a layout library that is just preparing the data for you.

In the following, these set data are used:

const sets = [
  { sets: ['A'], size: 12 },
  { sets: ['B'], size: 12 },
  { sets: ['A', 'B'], size: 2 },
];

Managed 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 intersections.

The VennDiagram object will calculate a layout that is proportional to the input sizes, and display it in the appropriate selection when called:

const chart = venn.VennDiagram();
d3.select('#venn').datum(sets).call(chart);

View this example

Changing the Style

The style of the Venn Diagram can be customized by using D3 after the diagram has been drawn. For instance to draw a Venn Diagram with white text and a darker fill:

const chart = venn.VennDiagram();
d3.select('#inverted').datum(sets).call(chart);

d3.selectAll('#inverted .venn-circle path').style('fill-opacity', 0.8);

d3.selectAll('#inverted text').style('fill', 'white');

View this example, along with other possible styles

The position of text within each circle of the diagram may also be modified via the symmetricalTextCentre property (defaults to false):

// draw a diagram with text symmetrically positioned in each circle's centre
const chart = venn.VennDiagram({ symmetricalTextCentre: true });

Dynamic layout

To have a layout that reacts to a change in input, all that you need to do is update the dataset and call the chart again:

// draw the initial diagram
const chart = venn.VennDiagram();
d3.select('#venn').datum(getSetIntersections()).call(chart);

// redraw the diagram on any change in input
d3.selectAll('input').on('change', function () {
  d3.select('#venn').datum(getSetIntersections()).call(chart);
});

View this example

Making the diagram interactive

Making the diagram interactive is basically the same idea as changing the style: just add event listeners to the elements in the venn diagram. To change the text size and circle colours on mouseenter:

d3.selectAll('#rings .venn-circle')
  .on('mouseenter', function () {
    const node = d3.select(this).transition();
    node.select('path').style('fill-opacity', 0.2);
    node.select('text').style('font-weight', '100').style('font-size', '36px');
  })
  .on('mouseleave', function () {
    const node = d3.select(this).transition();
    node.select('path').style('fill-opacity', 0);
    node.select('text').style('font-weight', '100').style('font-size', '24px');
  });

View this example

The colour scheme for the diagram's circles may also be modified via the colorScheme option, and the text within each circle can have its fill modified via the textFill option:

const chart = venn.VennDiagram({
  colorScheme: ['rgb(235, 237, 238)', '#F26250'],
  textFill: '#FFF',
});

Adding tooltips

Another common case is adding a tooltip when hovering over the elements in the diagram. The only tricky thing here is maintaining the correct Z-order so that the smallest intersection areas are on top, while still making the area that is being hovered over appear on top of the others:

// draw venn diagram
const div = d3.select('#venn');
div.datum(sets).call(venn.VennDiagram());

// add a tooltip
const tooltip = d3.select('body').append('div').attr('class', 'venntooltip');

// add listeners to all the groups to display tooltip on mouseenter
div
  .selectAll('g')
  .on('mouseenter', function (d) {
    // sort all the areas relative to the current item
    venn.sortAreas(div, d);

    // Display a tooltip with the current size
    tooltip.transition().duration(400).style('opacity', 0.9);
    tooltip.text(d.size + ' users');

    // highlight the current path
    const selection = d3.select(this).transition('tooltip').duration(400);
    selection
      .select('path')
      .style('stroke-width', 3)
      .style('fill-opacity', d.sets.length == 1 ? 0.4 : 0.1)
      .style('stroke-opacity', 1);
  })

  .on('mousemove', function () {
    tooltip.style('left', d3.event.pageX + 'px').style('top', d3.event.pageY - 28 + 'px');
  })

  .on('mouseleave', function (d) {
    tooltip.transition().duration(400).style('opacity', 0);
    const selection = d3.select(this).transition('tooltip').duration(400);
    selection
      .select('path')
      .style('stroke-width', 0)
      .style('fill-opacity', d.sets.length == 1 ? 0.25 : 0.0)
      .style('stroke-opacity', 0);
  });

View this example

Manual Usage

Besides the handy VennDiagram wrapper, the library can used as a pure layout function using the layout method. One can render the result manually in D3 or even in HTML Canvas.

The signature of the function can be found as part of the TypeScript typings at index.ds.ts

Custom D3 Rendering

// compute layout data
const data = venn.layout(sets);
// custom data binding and rendering
const g = d3
  .select('#venn')
  .selectAll('g')
  .data(data)
  .join((enter) => {
    const g = enter.append('g');
    g.append('title');
    g.append('path');
    g.append('text');
    return g;
  });
g.select('title').text((d) => d.data.sets.toString());
g.select('text')
  .text((d) => d.data.sets.toString())
  .attr('x', (d) => d.text.x)
  .attr('y', (d) => d.text.y);
g.select('path')
  .attr('d', (d) => d.path)
  .style('fill', (d, i) => (d.circles.length === 1 ? d3.schemeCategory10[i] : undefined));

Canvas Rendering

const data = venn.layout(sets, { width: 600, height: 350 });
const ctx = document.querySelector('canvas').getContext('2d');

data.forEach((d, i) => {
  ctx.fillStyle = `hsla(${(360 * i) / data.length},80%,50%,0.6)`;
  ctx.fill(new Path2D(d.path));
});

ctx.font = '16px Helvetica Neue, Helvetica, Arial, sans-serif';
ctx.textAlign = 'center';
ctx.textBaseline = 'central';
ctx.fillStyle = 'white';

data.forEach((d, i) => {
  ctx.fillText(d.data.sets.toString(), d.text.x, d.text.y);
});

License

Released under the MIT License.

Development Environment

npm i -g yarn
yarn install
yarn sdks vscode

Common commands

yarn test
yarn lint
yarn format
yarn build
yarn release
yarn release:pre