JavaScript Firefly Tools API

Firefly tools is an API that can be used from JavaScript. High-level API allows to render the main components of Firefly and make them share the same data model. Low-level API gives direct access to Firefly React components and application state. Firefly tools API also allows to dispatch or add a listener to virtually any action, available to Firefly internally. This makes it possible to extend Firefly by executing custom code on various UI events, like mouse move or region selection.

The main Firefly components are:

These components can be setup to share the same data model. Therefore you can do the following combinations:

Lower level API is built around the following modules:

  • firefly.ui - UI components
  • firefly.util - utilities
  • firefly.action - actions, changing application state

More information about lower level API can be found here:

Starting Firefly Tools in JavaScript

Getting started with firefly tools involves three basic steps.

  1. Load the javascript file firefly_loader.js
  2. Define some divs in the html document where you will load the viewer widgets.
  3. Define onFireflyLoaded() function. When firefly_loader.js loads it will call this function.

This is all best explained with a code example. This examples creates a div with id myID, loads firefly, and plots a FITS file in the onFireflyLoaded function.

<!doctype html>
    <head><title>Demo of Firefly Tools</title></head>
        <!-- need a div id to plot to -->
        <div id="myID" style="width: 350px; height: 350px;"></div>
        <script type="text/javascript">
            // this function must exist, called when firefly loads
            var onFireflyLoaded= function() {        
                firefly.showImage('myId', {
                    plotId: 'myImageId',
                    url: '',       
        <!-- script name is firefly_loader.js -->
        <script src='firefly_loader.js'></script>

Remote Firefly Tools Interface

The interface to remotely communicate to the firefly viewer:

firefly.getViewer() - gives a handle to launch the firefly tools in another browser window or tab

Parameter type Description
channel string the channel id string, if not specified then one will be generated
file string file the html of the viewer to launch. In time there will be several
return object viewer interface

Rendering UI components

Firefly React components can be found in firefly.ui module.

firefly.util.renderDOM(div, Component, props) - render React component into the DOM tree

Parameter Type Description
div string or Object a div element or a string id of the div element
Component Object a React component
props Object properties for the React component

firefly.util.unrenderDOM(div) - remove the rendered element

Parameter Type Description
div string or Object a div element or a string id of the div element


const props = {
    // data is an array of rows,
    // first col - nPoints or number of points in the bin, second col - binMin, third col - binMax
    // supports variable length bins
    data : [
    width: 400,
    height: 200,
    logs: 'xy',
    desc: 'Both X and Y are using log scale',
    binColor: '#336699'
// render Histogram component in the div with 'histogramHere' id
firefly.util.renderDOM('histogramHere', firefly.ui.Histogram, props);

Dispatching and watching actions

Firefly is built around React/Redux paradigm. The idea of React is that it will always render the state of your component. Redux manages that state of your application. The data in the state is immutable. It cannot change directly. When the program fires an action describing the change to the data, a new version of the state is created with the changes. Then React re-renders the parts that are different. Therefore, application goes from one state change to the next.


Being able to dispatch Firefly actions and listen to them makes it possible to write new code, which could control Firefly widgets or interact with them.

An external script would trigger UI change by calling an action dispatcher and react to UI action by adding a listener to this action.


firefly.action.type object is a handle to Firefly action types. Action types are its properties. firefly.actions object contains action dispatchers.

Each action has two properties: type and payload. Payload is different from action to action and is an object constructed from the parameters of the corresponding action dispatcher. Hence, action payload is documented in action dispatcher function. Most of action dispatcher functions are camel-cased dispatch[ActionType]. For example, action with type READOUT_DATA is dispatched with a function named dispatchReadoutData.

firefly.util.addActionListener(actionType,callBack) - add a listener to any action type

Parameter Type Description
actionType a string or and array of strings Each string is an action constant from firefly.action.type
callback function The callback will be called with two parameters: action object and state object. If it returns true the listener will be removed.
return function a function that will remove the listener

Other Utility Methods

The rest of Firefly utilities are split into the following modules by function:

  • firefly.util.image - image utilities
  • firefly.util.table - table utilities
  • firefly.util.chart - chart utilities

FITS Visualization

A FITS image viewer is created by calling the following method:

  • firefly.showImage() - shows FITS image viewer in a div
Parameter type Description
targetDiv string target div to put the image in
request object the request object literal with the plotting parameters
  • setGlobalImageDef() - set global fallback params for every image plotting call
Parameter Description
object params a object literal such as any image plot or showImage uses

The FITS viewer can take many, many possible parameters. Some parameters control how to get an image, a image can be retrieved from a service, a url, of a file on the server. Others control the zoom, stretch, and color, title, and default overlays. There are also parameters to pre-process an image, such as crop, rotate or flip. You can also specify three color parameters and the associated files.

For the details of FITS plotting parameters see:


    ZoomType  : 'TO_WIDTH'
} );
firefly.showImage('myDiv', {
    URL      : '',
    Title    : 'Some WISE image'


firefly.showImage('myDiv', {
    Type      : 'SERVICE',
    plotGroupId : 'myGroup',
    Service  : 'WISE',
    Title     : 'Wise',
    GridOn     : true,
    SurveyKey  : 'Atlas',
    SurveyKeyBand  : '2',
    WorldPt    : '10.68479;41.26906;EQ_J2000',
    SizeInDeg  : '.12',
    RangeValues : firefly.util.image.RangeValues.serializeSimple('Sigma',-2,8,'Linear'),
    AllowImageSelection : true 

Deprecated ImageViewer interface

The following ImageViewer interface is deprecated. Please use firefly.showImage() instead

  • firefly.makeImageViewer() - makes an inline image viewer for a html document
  • firefly.getExpandedViewer() - makes an image viewer to fill the screen in a browser tab or window, little used feature.
  • firefly.getExternalViewer() - makes an image viewer which will run in a browser tab or window. It is used to plot an image.

Deprecated ImageViewer methods:

Method Description
plot() plot a FITS image
plotURL() convenience method to plot an image referenced by url
plotFile() convenience method to plot an image file on the server
plotFileOrURL() convenience method to plot an image referenced by file or url
setDefaultParams() set parameters that will apply to plot calls

Utility methods for FITS visualization

firefly.util.image.getPrimePlot method

firefly.util.image.getPrimePlot(plotId) - get the plot object by its plot id

If plotId is omitted, active plot is returned.

Parameter Type Description
plotId string plot id

plotState property of the plot object gives access to the information about current state of the plot, such as zoom level, rotation information, working and original FITS file names, etc.


function getWorkingFitsFile(pt) {
    const activePlot = firefly.util.image.getPrimePlot();
    const plotState = activePlot.plotState;
    return plotState.getWorkingFitsFileStr();

firefly.util.image.CCUtil - coordinate conversion utilities

  • firefly.util.image.CCUtil.getImageCoords(plot,pt - get image coordinates of the point
  • firefly.util.image.CCUtil.getWorldCoords(plot,pt) - get world coordinates of the point
  • firefly.util.image.CCUtil.getViewPortCoords(plot,pt) - get viewport coordinates of the point
  • firefly.util.image.CCUtil.getScreenCoords(plot,pt) - get screen coordinates of the point
Parameter Type Description
plot Object Firefly plot object
pt Object Firefly point object


function getImagePt(pt) {
    const activePlot = firefly.util.image.getPrimePlot();
    return pt ? firefly.util.image.CCUtil.getImageCoords(activePlot, pt) : undefined;
firefly.util.image.serializeSimpleRangeValues method

firefly.util.image.serializeSimpleRangeValues(stretchType,lowerValue,upperValue,algorithm) - serialize a stretch request into a string, for use with the "RangeValues" parameter

Parameter Type Description
stretchType string the type of stretch may be 'Percent', 'Absolute', 'Sigma'
lowerValue number lower value of stretch, based on stretchType
upperValue number upper value of stretch, based on stretchType
algorithm string algorithm the stretch algorithm to use, may be 'Linear', 'Log', 'LogLog', 'Equal', 'Squared', 'Sqrt'
return string a serialized version of range values to be passed as a viewer parameter


firefly.showImage('imageDiv', {
    plotId: 'p1',
    Service: 'TWOMASS',
    Title  : '2MASS from service',
    SurveyKey  : 'k',
    WorldPt    : '10.68479;41.26906;EQ_J2000',
    RangeValues : firefly.util.image.serializeSimpleRangeValues("Sigma",-1,2,"Linear"),
    SizeInDeg  : '.12'

firefly.util.image.initAutoReadout(readoutComponent, props) - initialize the auto readout.

To use minimal readout, do the following:



Adding Context Extensions to FITS viewer

Context extensions make it possible to add user-defined actions on certain operations. When an extension is added, FITS viewer will present an extra menu item in the context menu of the operation, on which the extension is defined. These are the operations on which context extensions can be added:

  • Area Select (square)
  • Line Select
  • Point Select
  • Circle Select (coming soon)

The best way to describe how to add an extension, is to see the code.

  var extFunc= function(data) {
      // do something when the extension is selected called.
 var extension= {  // object literal to create extension definition
                id : 'MySpecialExt',       // extension id
                plotId : 'primaryID',      // plot to put extension on
                title : 'My Op',           // title use sees 
                toolTip : "a tool tip",    // tooltip
                extType: "POINT",          // type of extension
                callback: extFunc          // function (defined above) for callback
 // to remove the extension added above, use firefly.util.image.extensionRemove('MySpecialExt') 

To add an extension to a fits viewer create a object literal with the following fields:

name type description
id string any string id that you want to give the extension
plotId string the plot ID to put the extension on. (will be the same as the div name)
imageUrl string, url url of an image icon (icon should be 24x24) to show in the context menu
title string title that the user will see if not image icon is supplied
toolTip string tooltip the viewer will use for your extension
extType string extension type, must be 'AREA_SELECT', 'LINE_SELECT', 'POINT', or 'CIRCLE_SELECT' (details below)
callback function the function to call when the extension is selected (details below)

extType details:

  • 'AREA_SELECT' - When the user draws a square this menu will be activate
  • 'LINE_SELECT' - When the user draw a line this menu will be activated.
  • 'POINT' - When any point on the plot is clicked
  • 'CIRCLE_SELECT' - When the user draws a circle (not yet supported, coming soon)

callback function takes one parameter, an object literal, the fields vary depend on the extension type - todo - need to document callback object literal parameters

Region Support

firefly.action.dispatchCreateRegionLayer method

firefly.action.dispatchCreateRegionLayer(regionId, layerTitle, fileOnServer ='', regionAry=[], plotId = [], selectMode) - overlay region data on an image plots with the given ids

Parameter Type Description
regionId string region layer id
layerTitle string title for the layer, displaying regions
fileOnServer string region file on the server
regionAry array an array of strings, each describing a ds9 region
plotId string or array a plot id or an array of plot ids
selectMode object rendering features for the selected region

Note: if no plotId is given, the region layer is created on all plots.

firefly.action.dispatchDeleteRegionLayer method

firefly.action.dispatchDeleteRegionLayer(regionId, plotId) - remove region layer from the given plot

Parameter Type Description
regionId string region layer id
plotId string or array a plot id or an array of plot ids

Note: if no plotId is given, the region layer is removed from all plots.

firefly.action.dispatchAddRegionEntry method

firefly.action.dispatchAddRegionEntry(regionId, regionChanges, plotId=[], layerTitle='', selectMode = {}) - add region data to the given region layer

Parameter Type Description
regionId string region layer id
regionChanges array an array of strings, each describing a ds9 region

Other parameters are optional drawing layer creation parameters, similar to those of firefly.action.dispatchCreateRegionLayer. It is possible to create region layer by adding the first region to it.

firefly.action.dispatchRemoveRegionEntry method

firefly.action.dispatchRemoveRegionEntry(regionId, regionChanges) - remove region data from the given region layer

Parameter Type Description
regionId string region layer id
regionChanges array an array of strings, each describing a ds9 region

When the last region of the drawing layer is removed, the drawing layer is automatically deleted.

firefly.action.dispatchSelectRegion method

firefly.action.dispatchSelectRegion(drawLayerId, selectedRegion) - select region from a drawing layer

Parameter Type Description
drawLayerId string region layer id
selectedRegion string string describing ds9 region
firefly.util.image.getSelectedRegion method

firefly.util.image.getSelectedRegion(drawLayerId) - get ds9 string for the selected region in the given drawing layer. The returned string will always have coordinate system (image, physical, j2000, ...) in the front.

Parameter Type Description
drawLayerId string region layer id


function onRegionSelect(action) {
    if (action.payload.selectedRegion !== null) {
        const regionStr = firefly.util.image.getSelectedRegion(action.payload.drawLayerId);
        console.log('Selected region string: '+regionStr);
function onFireflyLoaded() {
    const req = {
        plotId: 'image1',
        URL: '',
        Title: 'WISE m51'
    firefly.showImage('image1_div', req);
    // parameters to dispatchCreateRegionLayer: regionId, layerTitle, fileOnServer ='', regionAry=[], plotId = []
    const regionAry = [
        'image; box 250 250 100 80 0 # color=red',
        'image; box 250 250 50 40 0 # color=red'
    firefly.action.dispatchCreateRegionLayer('region1', 'Region Layer 1', null, regionAry, ['image1', 'image2']);
    // add a listener to detect region selection changes
    firefly.util.addActionListener(firefly.action.type.REGION_SELECT, onRegionSelect);

Table Visualization

Creating table request

  • firefly.util.table.makeFileRequest(title, source, alt_source, options={}) - make a table request from a file
  • firefly.util.table.makeTblRequest(id, title, params={}, options={}
  • firefly.util.table.makeIrsaCatalogRequest(title, project, catalog, params={}, options={})

options - table request options, object with the following properties:

Property Type Description
startIdx number the starting index to fetch, defaults to zero
pageSize number the number of rows per page, defaults to 100
filters string list of conditions separted by comma(,). Format: `(col_name index) operator value. Operator is one of '> < = ! >= <= IN'`
sortInfo string sort information. Format: `(ASC DESC),col_name[,col_name]*`
inclCols string list of columns to select: column names separted by comma (,)
META_INFO object meta information passed as key/value pair to server then returned as tableMeta
use string optional, one of 'catalog_overlay', 'catalog_primary', 'data_primary'
tbl_id string a unique id of a table, auto-created if not given
  • firefly.showTable(targetDiv, request, options)

Parameters ia an object literal. div is the div to load the table into. Below is a list of all possible parameters.

Parameter Type Description
targetDiv string target div to put the table in
request object request object the table is created from
options number table options

options - table options, object with the following properties:

Property Type Description
tbl_group string the group this table belongs to, defaults to 'main'
removable boolean true if this table can be removed from view, defaults to true
showUnits boolean defaults to false
showFilters boolean defaults to false
selectable boolean defaults to true
expandable boolean defaults to true
showToolbar boolean defaults to true
border boolean defaults to true


tblReq = firefly.util.table.makeFileRequest(null, '',null,
                pageSize: 15,
                META_INFO: {CENTER_COLUMN: 'crval1;crval2;EQJ2000'}
firefly.showTable('table_div', tblReq);

The Table tools currently supports the following file formats:

  • IPAC Table file format
  • CSV - first row should be column headers
  • TSV - first row should be column header
  • FITS Tables


  • firefly.showChart(targetDiv, parameters)
Parameter Type Description
targetDiv string target div to put the XY Plot in
parameters object chart parameters

Chart parameters object literal can contain the following attributes.

Parameter Description
data An array of Plotly trace objects, see plotly.js reference
layout Optional. Plotly layout object, see plotly.js layout reference
chartId Optional. A unique identifier of the chart
groupId Optional. Chart group for grouping charts together
deletable Optional. If not set, single chart in a group is not deletable, multiple are deletable
tbl_group When set, all other chart parameters are ignored.
Show the default chart for an active table in the specified table group.

Firefly is using plotly.js library to display charts. Plotly charts are described declaratively as JSON objects. Every aspect of a plotly chart (the colors, the grids, the data, and so on) has a corresponding JSON attribute. plotly.js reference contains an extensive list of these attributes.

All chart attributes fall into two categories: traces (objects that describe a single series of data in a graph) and layout (attributes that apply to the rest of the chart, like the title, xaxis, or annotations). Traces are categorized by chart type (e.g. scatter, heatmap).

To use a table as a source of chart data, trace object needs to contain tbl_id attribute and references to the table columns in the form of tables::<columnNameOrExpression>. Firefly will substitute table column references with the arrays of column data. The length of each array will match the number of rows in the table.

Example of a scatter chart connected to a table:

    {data: [{tbl_id: 'myTblId', x: 'tables::col1', y: 'tables::col2', mode: 'markers'}]});

Example with tbl_group:

var tblReq1 =  firefly.util.table.makeIrsaCatalogRequest('allwise-500', 'WISE', 'allwise_p3as_psd',
    {   position: '10.68479;41.26906;EQ_J2000',
        SearchMethod: 'Cone',
        radius: 300
    {   tbl_id: 'tbl1',
        META_INFO: {defaultChartDef: JSON.stringify({data: [{x: 'tables::w1mpro', y: 'tables::w2mpro', mode: 'markers'}]})}
var tblReq2 =  firefly.util.table.makeIrsaCatalogRequest('allwise-10', 'WISE', 'allwise_p3as_psd',
    {   position: '202.48;47.23;EQ_J2000',
        SearchMethod: 'Cone',
        radius: 30
    {   tbl_id: 'tbl2',
        META_INFO: {defaultChartDef: JSON.stringify({data: [{x: 'tables::w1mpro', y: 'tables::w2mpro', mode: 'markers'}]})}
    firefly.showTable('table-div', tblReq1, {tbl_group: 'allwise'});
    firefly.showTable('table-div', tblReq2, {tbl_group: 'allwise'});
    firefly.showChart('chart-div', {tbl_group: 'allwise'});

Charts support the same table formats as Table:

  • IPAC Table file format
  • CSV - first row should be column headers
  • TSV - first row should be column headers
  • FITS Tables

Firefly Charts Extensions

Firefly has extended Plotly library by adding fireflyHistogram and fireflyHeatmap trace types.

Both fireflyHistogram and fireflyHeatmap aggregate data on the server, which is particularly beneficial for large tables.

Example of a heatmap:

var heatmapData = [
        type: 'fireflyHeatmap',
        tbl_id: 'myLargeTbl',
        x: 'tables::w1mpro',
        y: 'tables::w2mpro',
        name: 'w1-w2',
        colorscale: 'Blues',
        firefly: { nbins: {x: 100, y: 100} }
firefly.showChart('heatmap-div', {data: heatmapData});

Example of two histogram traces:

var fireflyHistogramData = [
    type: 'fireflyHistogram',
    firefly: {
        tbl_id: 'mytbl',
        options: {
            numBins: 30,
            algorithm: 'fixedSizeBins',
            fixedBinSizeSelection: 'numBins',
            columnOrExpr: 'col-0.02'
    name: 'col-0.02',
    marker: {color: 'rgba(153, 51, 153, 0.8)'}
    type: 'fireflyHistogram',
    firefly: {
        tbl_id: 'mytbl',
        options: {
            numBins: 40,
            algorithm: 'fixedSizeBins',
            fixedBinSizeSelection: 'numBins',
            columnOrExpr: 'col+0.02' // same column shifted
    name: 'col+0.02',
    marker: {color: 'rgba(102,153,0, 0.7)'}}
firefly.showChart('histogram-div', {data: fireflyHistogramData});

Histogram options object literal can contain the following attributes.

Parameter Description
columnOrExpr column or expression to use for histogram, can contain multiple column names ex. log(col) or (col1-col2)/col3
algorithm fixedSizeBins or bayesianBlocks
fixedBinSizeSelection option for fixedSizeBins algorithm: numBins or binWidth
numBins number of bins for fixed bins algorithm, numBins option
binWidth binWidth for fixed bins algorithm, binWidth option
falsePositiveRate false positive rate for bayesian blocks algorithm

Connecting Coverage image to table

firefly.showCoverage= (div,options) - add a coverage image to a div

Parameters Type
div string, the div to put the image viewer into
params object literal, plotting parameters for FITS Viewer

Coverage is a an image, which includes all points of a catalog. Coverage image size is computed by looking at columns in the tables. If you use the default column names you do not have to specify how to determine the center or the four corners.

  • ALL_CORNERS: Determines if the coverage will use the box style and what corners will be used.
                     Should be specified as a string with the values comma separated. For example-
                     "ra1,dec1,ra2,dec2,ra3,dec3,ra4,dec4". If this parameter is not specified then the example
                     is the default.
                     If you specify CORNER_COLUMNS then you must also specify CENTER_COLUMN.
  • CENTER_COLUMN: Determines if the coverage will use the x style (if CORNER_COLUMNS is not specified)
                     and what is the center point.
                     Should be specified as a string with the values comma separated. For example-
                     "ra,dec". If this parameter is not specified then the example is the default.
const tblReq = firefly.util.table.makeFileRequest(null, '',null,
                        META_INFO: {
                            CENTER_COLUMN: 'crval1;crval2;EQJ2000'
firefly.showTable('table_div', tblReq);
firefly.showCoverage('coverage_div', {gridOn:true})

You can show point sources on your coverage image by telling Firefly that the table should be used as a catalog overlay and which columns define RA and Dec. When CatalogCoordColumns attribute is present, CENTER_COLUMN is optional.

const tblReq = firefly.util.table.makeFileRequest(null, '',null,
                        META_INFO: {
                            CatalogOverlayType: 'WISE', 
                            CatalogCoordColumns: 'crval1;crval2;EQJ2000'
firefly.showTable('table_div', tblReq);
firefly.showCoverage('coverage_div', {gridOn:true})

Connecting Charts to table

firefly.showChart(targetDiv, parameters) - add a chart to a div

Please, see firefly.showChart for usage.


tblReq = firefly.util.table.makeIrsaCatalogRequest('wise catalog', 'WISE', 'allwise_p3as_psd',
        position: '10.68479;41.26906;EQ_J2000',
        SearchMethod: 'Cone',
        radius: 300
    {data: [{tbl_id: tblReq.tbl_id, x: 'tables::w1mpro+w4mpro', y: 'tables::w2mpro', mode: 'markers'}]});

More Code Examples