CrosshairCursor plugin for Chartist.js

A Chartist.js plugin to easily add a data crosshair to your charts!

Installation

bower install chartist-plugin-crosshaircursor

npm install chartist-plugin-crosshaircursor

yarn add chartist-plugin-crosshaircursor

Available options with their defaults

var noop = function() {};

var defaultOptions = {
  wrapChart: function(chart) {
    var chartWrapper = document.createElement('div');
    chartWrapper.className = "crosshairCursor-wrapper";
    chart.container.parentNode.insertBefore(chartWrapper, chart.container);
    chartWrapper.appendChild(chart.container);
    chartWrapper.style.cursor = 'pointer';
    chartWrapper.style.position = 'relative';

    return chartWrapper;
  },
  x: true,
  y: true,
  click: noop,
  hover: noop,
  freezeChange: noop,
  styles: {
    x: {
      backgroundColor: '#dedede',
      width: '1px',
      height: '95%'
    },
    y: {
      backgroundColor: '#dedede',
      width: '100%',
      height: '1px'
    }
  }
};

wrapChart

In order for the plugin to work, the chart must be wrapped in a parent element. The default function provided to the wrapChart option programmatically generates a parent element and wraps the chart for you, which by default is in a div element with the class name crosshairCursor-wrapper. If you want to change this behaviour, you can pass in your own chart wrapping function ensuring the parent element is returned.

x / y

The crosshair cursor type can be customized to an x-axis cursor, y-axis cursor or a full crosshair cursor spanning both axis. By default, both x and y are set to true, creating a full crosshair. To generate an x-axis cursor, set only x to true. To generate a y-axis curusor, set only y to true. x and y cannot both be set to false.

click

The click option allows you to pass in a custom click function which provides you with two arguments: the crosshairCursor object, which exposes a bunch of functions you can use within the function, and the current data points you are hovered over (if any) at the moment of click. As an example, you can easily write a function that locks the crosshair cursor in place on click if that is the desired behaviour:

click: function(crosshairCursor, chartData) {
  crosshairCursor.isFrozen() ? crosshairCursor.unfreeze() : crosshairCursor.freeze()
}

By default, the click option is an empty function.

hover

The hover option allows you to pass in a custom function which is executed on mousemove and allows you to receive any meta data on the data points you're hovered over. Like the click function, it provides you with two arguments: the crosshairCursor object and the data points you are currently hovered over.

hover: function(crosshairCursor, chartData) {
  // custom hover function
}

By default, the hover option is an empty function.

freezeChange

The freezeChange option allows you to pass in a custom function which is ran each time the crosshair cursor is frozen or unfrozen. The new frozen status is passed as the function argument and as demonstrated with the click option example above, the crosshair cursor can be frozen and unfrozen really easily, if that behaviour is required.

freezeChange: function(status) {
  // custom function
}

By default, the freezeChange option is an empty function.

styles

The styles option is an object that defines the crosshair cursor's styling. You can set the cursor colour using the backgroundColor attribute for each crosshair cursor type, as well as setting the width and height. If you don't define any styles, it will default to the following:

styles: {
  x: {
    backgroundColor: '#dedede',
    width: '1px',
    height: '95%'
  },
  y: {
    backgroundColor: '#dedede',
    width: '100%',
    height: '1px'
  }
}

Available methods

create

create is executed when the chart is first created on the page. It wraps the chart in a container element and generates the crosshair cursors. You can call this method yourself if you've used the destroy method below and need to recreate the crosshairCursor functionality.

destroy

destroy unwraps the chart and deletes the crosshair cursors generated on create. It restores your chart, as if the plugin wasn't in use. You can call create to re-initialize the plugin setup.

wrapChart

wrapChart is called within the create method. If you've passed in your own custom chart wrapping function, it will be called here. if you don't pass in your own custom chart wrapping function, the default function will be used (see wrapChart part in the Avilable options section above).

show

show makes the crosshair cursors visible by css, if they are hidden.

hide

hide makes the crosshair cursors invisible by css: display: none;, if they are visible.

reset

reset unfreezes the chart (if it's frozen) and hides the crosshair cursors.

freeze

freeze freezes the crosshair cursor in place on the chart and calls the freezeChange function (if the user has passed one into the options object).

unfreeze

unfreeze unfreezes the crosshair cursor and calls the freezeChange function (if the user has passed one into the options object).

isFrozen

isFrozen returns the current frozen status of the chart.

currentPoints

currentPoints returns a list of chart data points currently hovered over by the crosshair, if there are any.

element

element returns the chart parent container, generated by the wrapChart function. You can set your own event listeners to this element, if desired. For example, you could freeze the chart whenever the letter f gets pressed:

var freezeCursor = function(){
  chart.crosshairCursor.isFrozen() ? chart.crosshairCursor.unfreeze() : chart.crosshairCursor.freeze()
};
chart.crosshairCursor.element().addEventListener('onkeydown', freezeCursor)

Sample usage for a line chart

var chart = new Chartist.Line('.chart', {
  labels: ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'],
  series: [
    {
      name: 'line',
      data: [
        {value: 12, meta: {id: 1, title: "First point"}},
        {value: 9, meta: {id: 2, title: "Second point"}},
        {value: 7, meta: {id: 3, title: "Third point"}},
        {value: 9, meta: {id: 4, title: "Fourth point"}},
        {value:5, meta: {id: 5, title: "Fifth point"}}
      ]
    }
  ]
}, {
     width: '600px',
     height: '300px',
     fullWidth: true,
     chartPadding: { right: 40 },
     plugins: [
       Chartist.plugins.crosshairCursor({
         x: true,
         y: false,
         click: function(crosshairCursor, chartData) {
           crosshairCursor.isFrozen() ? crosshairCursor.unfreeze() : crosshairCursor.freeze()
         },
         hover: function(crosshairCursor, chartData) {
           // custom hover function
         }
       })
     ]});

Setting up the chart and data

The data array that gets passed into the series option must contain a meta object. The meta data contained in this object for each data point gets passed into the click and hover functions (defined in the options object) as the second argument.

Javascript events

The following events are available for use if needed:

chart.on('crosshairCursor:frozen', function (isFrozen) {
  console.log("Chart is frozen?", isFrozen)
}, false);

chart.on('crosshairCursor:hovered', function(highlightedPoints) {
  console.log("Highlighted points" highlightedPoints)
}, false);

chart.on('crosshairCursor:click', function(highlightedPoints) {
  console.log("Highlighted points" highlightedPoints)
}, false);

Available classes

.crosshairCursor-wrapper {} // the default chart wrapper class name, if a custom `wrapChart` function is not set
.crosshairCursor-x {} // the x-axis cursor (colour, width and height to be set in the "styles" option object)
.crosshairCursor-y {} // the y-axis cursor (colour, width and height to be set in the "styles" option object)
.ct-point.crosshairCursor-highlight {} // data point class name when the crosshair cursor highlights it

Sample CSS

.crosshairCursor-wrapper {
  height: 300px;
  width: 600px;
}
.crosshairCursor-highlight {
  stroke: #FFDA34 // the colour of any highlighted data points
}

duchuy/chartist-plugin-crosshairCursor

CrosshairCursor plugin for Chartist.js

Installation

Available options with their defaults

wrapChart

x / y

click

hover

freezeChange

styles

Available methods

create

destroy

wrapChart

show

hide

reset

freeze

unfreeze

isFrozen

currentPoints

element

Sample usage for a line chart

Setting up the chart and data

Javascript events

Available classes

Sample CSS