Graph2D documentation

Overview

Graph2D is an interactive visualization chart to draw data in a 2D graph. You can freely move and zoom in the graph by dragging and scrolling in the window.

Graph2d uses HTML DOM and SVG for rendering. This allows for flexible customization using css styling.

Contents

Example

The following code shows how to create a Graph2D and provide it with data. More examples can be found in the examples directory. 

<!DOCTYPE HTML>
<html>
<head>
  <title>Graph2D | Basic Example</title>

  <style type="text/css">
    body, html {
      font-family: sans-serif;
    }
  </style>

  <script src="../../dist/vis.js"></script>
  <link href="../../dist/vis.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div id="visualization"></div>

<script type="text/javascript">
  var container = document.getElementById('visualization');
  var items = [
      {x: '2014-06-11', y: 10},
      {x: '2014-06-12', y: 25},
      {x: '2014-06-13', y: 30},
      {x: '2014-06-14', y: 10},
      {x: '2014-06-15', y: 15},
      {x: '2014-06-16', y: 30}
  ];

  var dataset = new vis.DataSet(items);
  var options = {
      start: '2014-06-10',
      end: '2014-06-18'
  };
  var graph2d = new vis.Graph2D(container, dataset, options);
</script>
</body>
</html>

Loading

The class name of the Graph2D is vis.Graph2D. When constructing a Graph2D, an HTML DOM container must be provided to attach the graph to. Optionally, data an options can be provided. Data is a vis DataSet or an Array, described in section Data Format. Options is a name-value map in the JSON format. The available options are described in section Configuration Options. Groups is a vis DataSet containing groups. The available options and the method of construction are described in section Data Format. 

var graph = new vis.Graph2D(container [, data] [, options] [,groups]);

Data, options and groups can be set or changed later on using the functions Graph2D.setData(data), Graph2D.setOptions(options) and Graph2D.setGroups(groups).

Data Format

Graph2D can load data from an Array, a DataSet or a DataView. JSON objects are added to this DataSet by using the add() function. Data points must have properties x, y, and z, and can optionally have a property style and filter.

Graph2D can be provided with two types of data:

Items

var items = [
    {x: '2014-06-13', y: 30, group: 0},
    {x: '2014-06-14', y: 10, group: 0},
    {x: '2014-06-15', y: 15, group: 1},
    {x: '2014-06-16', y: 30, group: 1},
    {x: '2014-06-17', y: 10, group: 1},
    {x: '2014-06-18', y: 15, group: 1}
];
Name Type Required Description
x number yes Location on the x-axis.
y number yes Location on the y-axis.
group number | string no The ID of the group this point belongs to.

Groups

Like the items, groups are regular JavaScript Arrays and Objects. Using groups, items can be grouped together. Items are filtered per group, and displayed as individual graphs. Groups can contain the properties id, content, className (optional) and options (optional).

Groups can be applied to a timeline using the method setGroups. A table with groups can be created like: 

var groups = new vis.DataSet();
groups.add({
    id: 1,
    content: 'Group 1'
    // Optional: a field 'className'
    // Optional: options
  })
groups.add({
  // more groups...
});

Groups can have the following properties:

Name Type Required Description
id String | Number yes An id for the group. The group will display all items having a property group which matches the id of the group.
content String yes The contents of the group. This can be plain text or html code.
className String no This field is optional. A className can be used to give groups an individual css style.
options JSON object no This field is optional. The options can be used to give a group a specific draw style. Any options that are colored green in the Configuration Options can be used as options here.

Configuration Options

Graph2D Options

Options can be used to customize the Graph2D to your purposes. These options can be passed to the Graph2D object either in the constructor, or by the setOptions function. 
var options = {
    width:  '100%',
    height: '400px',
    style: 'surface'
};
The options colored in green can also be used as options for the groups. All options are optional.
Name Type Default Description
yAxisOrientation String 'left' This defines with which axis, left or right, the graph is coupled. Example 5 shows groups with different Y axis. If no groups are coupled with an axis, it will not be shown.
defaultGroup String 'default' This is the label for the default, ungrouped items when shown in a legend.
sort Boolean true This determines if the items are sorted automatically. They are sorted by the x value. If sort is enabled, more optimizations are possible, increasing the performance.
sampling Boolean true If sampling is enabled, graph2D will automatically determine the amount of points per pixel. If there are more than 1 point per pixel, not all points will be drawn. Disabling sampling will cause a decrease in performance.
graphHeight Number | String '400px' This is the height of the graph SVG canvas. If it is larger than the height of the outer frame, you can drag up and down the vertical direction as well as the usual horizontal direction.
shaded Boolean | Object false Toggle a shaded area with the default settings.
shaded.enabled Boolean false This toggles the shading.
shaded.orientation String 'bottom' This determines if the shaded area is at the bottom or at the top of the curve. The options are 'bottom' or 'top'.
style String 'line' This allows the user to define if this should be a linegraph or a barchart. The options are: 'line' or 'bar'.
barChart.width Number 50 The width of the bars.
barChart.align String 'center' The alignment of the bars with regards to the coordinate. The options are 'left', 'right' or 'center'.
catmullRom Boolean | Object true Toggle the interpolation with the default settings. For more customization use the JSON format.
catmullRom.enabled Boolean true Toggle the interpolation.
catmullRom.parametrization String 'centripetal' Define the type of parametrizaion. Example 7 shows the different methods. The options are 'centripetal' (best results), 'chordal' and 'uniform'. Uniform is the computationally cheapest variant. If catmullRom is disabled, linear interpolation is used.
drawPoints Boolean | Object true Toggle the drawing of the datapoints with the default settings.
drawPoints.enabled Boolean true Toggle the drawing of the datapoints.
drawPoints.size Number 6 Determine the size at which the data points are drawn.
drawPoints.style String 'square' Determine the shape of the data points. The options are 'square' or 'circle'.
dataAxis.showMinorLabels Boolean true Toggle the drawing of the minor labels on the Y axis.
dataAxis.showMajorLabels Boolean true Toggle the drawing of the major labels on the Y axis.
dataAxis.icons Boolean false Toggle the drawing of automatically generated icons the Y axis.
dataAxis.width Number | String '40px' Set the (minimal) width of the yAxis. The axis will resize to accomodate the labels of the Y values.
dataAxis.visible Boolean true Show or hide the data axis.
legend Boolean false Toggle the legend with the default settings.
legend.enabled Boolean false Toggle the legend.
legend.icons Boolean true Show automatically generated icons on the legend.
legend.left.visible Boolean true Both axis, left and right, have a corresponding legend. This toggles the visibility of the legend that is coupled with the left axis.
legend.left.position String 'top-left' Determine the position of the legend coupled to the left axis. Options are 'top-left', 'top-right', 'bottom-left' or 'bottom-right'.
legend.right.visible Boolean true This toggles the visibility of the legend that is coupled with the right axis.
legend.right.position String 'top-right' Determine the position of the legend coupled to the right axis. Options are 'top-left', 'top-right', 'bottom-left' or 'bottom-right'.

Timeline Options

Graph2D is built upon the framework of the timeline. These options from the timeline can be used with graph2D. All options are optional.

Name Type Default Description
autoResize boolean true If true, the Timeline will automatically detect when its container is resized, and redraw itself accordingly. If false, the Timeline can be forced to repaint after its container has been resized using the function redraw().
end Date | Number | String none The initial end date for the axis of the timeline. If not provided, the latest date present in the items set is taken as end date.
height Number | String none The height of the timeline in pixels or as a percentage. When height is undefined or null, the height of the timeline is automatically adjusted to fit the contents. It is possible to set a maximum height using option maxHeight to prevent the timeline from getting too high in case of automatically calculated height.
margin.axis Number 20 The minimal margin in pixels between items and the time axis.
margin.item Number 10 The minimal margin in pixels between items.
max Date | Number | String none Set a maximum Date for the visible range. It will not be possible to move beyond this maximum.
maxHeight Number | String none Specifies the maximum height for the Timeline. Can be a number in pixels or a string like "300px".
min Date | Number | String none Set a minimum Date for the visible range. It will not be possible to move beyond this minimum.
minHeight Number | String none Specifies the minimum height for the Timeline. Can be a number in pixels or a string like "300px".
orientation String 'bottom' Orientation of the timeline: 'top' or 'bottom' (default). If orientation is 'bottom', the time axis is drawn at the bottom, and if 'top', the axis is drawn on top.
showCurrentTime boolean true Show a vertical bar at the current time.
showCustomTime boolean false Show a vertical bar displaying a custom time. This line can be dragged by the user. The custom time can be utilized to show a state in the past or in the future. When the custom time bar is dragged by the user, the event timechange is fired repeatedly. After the bar is dragged, the event timechanged is fired once.
showMajorLabels boolean true By default, the timeline shows both minor and major date labels on the time axis. For example the minor labels show minutes and the major labels show hours. When showMajorLabels is false, no major labels are shown.
showMinorLabels boolean true By default, the timeline shows both minor and major date labels on the time axis. For example the minor labels show minutes and the major labels show hours. When showMinorLabels is false, no minor labels are shown. When both showMajorLabels and showMinorLabels are false, no horizontal axis will be visible.
start Date | Number | String none The initial start date for the axis of the timeline. If not provided, the earliest date present in the events is taken as start date.
width String '100%' The width of the timeline in pixels or as a percentage.
zoomMax Number 315360000000000 Set a maximum zoom interval for the visible range in milliseconds. It will not be possible to zoom out further than this maximum. Default value equals about 10000 years.
zoomMin Number 10 Set a minimum zoom interval for the visible range in milliseconds. It will not be possible to zoom in further than this minimum.

Methods

The Graph2D supports the following methods.

Method Return Type Description
clear([what]) none Clear the Graph2D. An object can be passed specifying which sections to clear: items, groups, and/or options. By Default, items, groups and options are cleared, i.e. what = {items: true, groups: true, options: true}. Example usage: 
Graph2D.clear();                // clear items, groups, and options
Graph2D.clear({options: true}); // clear options only
destroy() none Destroy the Graph2D. The Graph2D is removed from memory. all DOM elements and event listeners are cleaned up.
getCustomTime() Date Retrieve the custom time. Only applicable when the option showCustomTime is true.
setCustomTime(time) none Adjust the custom time bar. Only applicable when the option showCustomTime is true. time is a Date object.
getWindow() Object Get the current visible window. Returns an object with properties start: Date and end: Date.
on(event, callback) none Create an event listener. The callback function is invoked every time the event is triggered. Avialable events: rangechange, rangechanged, select. The callback function is invoked as callback(properties), where properties is an object containing event specific properties. See section Events for more information.
off(event, callback) none Remove an event listener created before via function on(event, callback). See section Events for more information.
redraw() none Force a redraw of the Graph2D. Can be useful to manually redraw when option autoResize=false.
setGroups(groups) none Set a data set with groups for the Graph2D. groups can be an Array with Objects, a DataSet, or a DataView. For each of the groups, the items of the Graph2D are filtered on the property group, which must correspond with the id of the group.
setItems(items) none Set a data set with items for the Graph2D. items can be an Array with Objects, a DataSet, or a DataView.
setOptions(options) none Set or update options. It is possible to change any option of the Graph2D at any time. You can for example switch orientation on the fly.
setWindow(start, end) none Set the current visible window. The parameters start and end can be a Date, Number, or String. If the parameter value of start or end is null, the parameter will be left unchanged.

Events

Graph2D fires events when changing the visible window by dragging, when selecting items, and when dragging the custom time bar.

Here an example on how to listen for a rangeChanged event. 

Graph2D.on('select', function (properties) {
  alert('selected items: ' + properties.nodes);
});

A listener can be removed via the function off: 

function onChange (properties) {
  alert('changed!');
}

// add event listener
Graph2D.on('rangechanged', onChange);

// do stuff...

// remove event listener
Graph2D.off('rangechanged', onChange);

The following events are available.

name Description Properties
rangechange Fired repeatedly when the user is dragging the Graph2D window.
  • start (Number): timestamp of the current start of the window.
  • end (Number): timestamp of the current end of the window.
rangechanged Fired once after the user has dragged the Graph2D window.
  • start (Number): timestamp of the current start of the window.
  • end (Number): timestamp of the current end of the window.
timechange Fired repeatedly when the user is dragging the custom time bar. Only available when the custom time bar is enabled.
  • time (Date): the current time.
timechanged Fired once after the user has dragged the custom time bar. Only available when the custom time bar is enabled.
  • time (Date): the current time.

Styles

All parts of the Graph2D have a class name and a default css style just like the Timeline. The styles can be overwritten, which enables full customization of the layout of the Graph2D.

Additionally, Graph2D has 10 preset styles for graphs, which are cycled through when loading groups. These styles can be overwritten as well, along with defining your own classes to style the graphs! Example 4 and example 5 show the usage of custom styles.

Data Policy

All code and data is processed and rendered in the browser. No data is sent to any server.