Scatter chart API reference

Documentation about the Scatter chart including information about all of the options that are available to you. The Scatter chart can show various points on X/Y scales as well as a time scale. The Scatter chart is quite versatile and can be used to show a variety of different types of data.

Example

<script>
    // The data sets as shown on the chart. Each point is an array, described below.
    data1 = [ [67,78],[67,40,'red'],[150,26],[164,35],[203,53]];
    data2 = [ [0,78,'green'],[67,40,'green'] ];

    new RGraph.Scatter({
        id: 'cvs',
        data: [ data1 , data2 ],            
        options: {
            backgroundBarsColor1: 'white',
            backgroundBarsColor2: 'white',
            backgroundGridColor: 'rgba(238,238,238,1)',
            marginLeft: 30,
            xaxisLabels: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
            xaxisScaleMax: 365
        }
    }).draw();
</script>

Each point on the Scatter chart is made by supplying an array of up to 4 elements:

If you wish to specify a tooltip, but not a colour (ie use the default colour instead), you can pass null instead of a colour.

Properties

You can use these properties to control how the chart appears. You can set them by including them in the options section of the configuration as above.

Background properties

PropertyDescriptionDefault
backgroundColorIf you want to have a single background colour for your chart you can use this. It doesn't cover the margins. If you want that then you can simply apply a CSS background colour to the canvas tag.null
backgroundBarsCountThe number of background bars.5
backgroundBarsColor1The colour of the background bars. (1 of 2).rgba(0,0,0,0)
backgroundBarsColor2The colour of the background bars. (2 of 2).rgba(0,0,0,0)
backgroundGridWhether to show the background grid or not.true
backgroundGridColorThe colour of the background grid.#eee
backgroundHbarsAn array of information stipulating horizontal coloured bars. You can use these to indicate limits. Eg:
myScatter.set('backgroundHbars', [[75, 10, 'yellow'], [85, 15, 'red']]);
This would give you two bars, one red and a lower yellow bar. The units correspond to your scale, and are the starting point and the height.
null
backgroundVbarsAn array of vertical bar information. They're specified like his:
myScatter.set('backgroundVbars', [[0, 181, 'rgba(0,255,0,0.5)']]);
Normally the values are:
  • The start value
  • The extent of the bar (the width in scale terms)
  • The colour
However when you're using a date/time chart that isn't very practical - so when you're using date/time values the two values that you specify should be the start and end date/times like this:
obj.set('backgroundVbars', [['2013/06/01','2013/07/01','pink']]);
null
backgroundGridBorderDetermines whether a border line is drawn around the grid.true
backgroundGridHlinesDetermines whether to draw the horizontal grid lines.true
backgroundGridVlinesDetermines whether to draw the vertical grid lines.true
backgroundGridHlinesCountWhen using autofit this allows you to specify how many horizontal grid lines you want.5
backgroundGridVlinesCountWhen using autofit this allows you to specify how many vertical grid lines you want.20
backgroundGridAlignIf you want to have your grid lines line up with the labels (both X and Y axes), you can set this to true and RGraph will attempt to make the grid lines line up.false
backgroundImageIf you want to specify a background image to use on your chart, specify it with this property. If you use effects with a background image on your chart it may make the effect flicker. Using a background image with the ondraw event may mean that the event fires twice. There is a property that you can check though that is set when the image has loaded: obj.__rgraph_background_image_loaded__ Simply check this flag in your ondraw event. If it's true then the background image has loaded.null
backgroundImageStretchBy default your background image is stretched (if necessary) to cover the whole chart area (margins not included). If this is not what you want then set this property to false.true
backgroundImageXThe X position of the image. The coordinates are the top left corner of the image.null
backgroundImageYThe Y position of the image. The coordinates are the top left corner of the image.null
backgroundImageWThe width of the image. If you have a large canvas with many charts - you may need to specify this.null
backgroundImageHThe height of the image. If you have a large canvas with many charts - you may need to specify this.null
backgroundImageAlignInstead of specifying the coordinates of the image, you can instead simply align it top, bottom, left or right. Examples are:
  • top left
  • bottom right
  • bottom
  • right
null
backgroundImageAlphaThe alpha value (the opacity) of the image.1

General axis properties

PropertyDescriptionDefault
axesIf this is set to true, no axes will be drawn.false
axesColorThe colour of the axes.black
axesLinewidthThe linewidth of the axes.1

X axis properties

PropertyDescriptionDefault
xaxisSet this to true if you don't want an X axis.true
xaxisLabelsAn array of the X labels for the chart.An empty array
xaxisLabelsBoldWhether the labels are bold or not.null
xaxisLabelsItalicWhether the X axis labels are italic or not.null
xaxisLabelsFontThe font used to show the X axis labels.null
xaxisLabelsSizeThe size of the X axis labels.null
xaxisLabelsColorThe colour of the labels.null (same as textColor)
xaxisLabelsOffsetxThis allows you finer grained control in the horizontal direction over the X label positioning if you need it.0
xaxisLabelsOffsetyThis allows you finer grained control in the vertical direction over the X label positioning if you need it.0
xaxisLabelsSpecificAlignIf you are using specific points for X labels, by default the labels are left aligned within its section. With this setting you can center the labels within its section.left
xaxisLabelsAngleThe angle of the horizontal labels (at the bottom of the chart). This can be from 90 to -90 degrees.0
xaxisTickmarksCountThe number of X tick marks.null (linked to number of labels)
xaxisTickmarksLastWhether to draw an end X tick. Usually used when combining Scatter charts.false
xaxisPositionWhere the X axis should be drawn. Can be either center or bottom.bottom
xaxisScaleIf true then an X scale is drawn instead of X labels.false
xaxisScaleUnitsPreThese are units that are prepended to the number.none
xaxisScaleUnitsPostThese are units that are appended to the number.none
xaxisScaleDecimalsThe number of decimals used for the X scale. If not specified the scaleDecimals property is used.null
xaxisScaleFormatterThis can be a function, which is passed the object and the number and should return a formatted number (formatted as you wish).
function myFormatter(obj, num)
{
    return num + 'F'; // An example of formatting
}
null
xaxisScaleLabelsCountThis is a number representing how many X labels there should be when you're using the X scale.10
xaxisScaleMinThe minimum X axis value you wish to set.0
xaxisScaleMaxThe maximum X axis value you wish to set. For example if you're displaying products sold in a year, you might use 365.none - must be supplied
xaxisTitleThis allows you to specify a title for the X axis.none
xaxisTitleSizeThis allows you to specify a size for the X axis title.null
xaxisTitleFontThis allows you to specify a font for the X axis title.null
xaxisTitleBoldThis controls whether the X axis title is bold or not.true
xaxisTitleColorThis controls the colour of the X axis title.black
xaxisTitleXBy giving this you can specifically set the X position of the X axis title.null
xaxisTitleYBy giving this you can specifically set the Y position of the X axis title.null
xaxisTitlePosThis is multiplied with the margin to give the position of the X axis title.0.25

Y axis properties

PropertyDescriptionDefault
yaxisSet this to true if you don't want a Y axis.false
yaxisLabelsA boolean (true or false) that controls whether the chart has Y labels.true
yaxisLabelsCountA value that controls how many Y labels there are. Formerly this could be 1/3/5/10 however now it can be any value.5
yaxisLabelsSpecificYou can use this option to give your own Y labels (eg ['Low', 'Medium', 'High']. Note: Since March 2013 you may now need to add an extra (optionally) empty element to the array of labels to achieve your desired result.null
yaxisLabelsOffsetxThis allows you finer grained control in the horizontal direction over the Y label positioning if you need it.0
yaxisLabelsOffsetyThis allows you finer grained control in the vertical direction over the Y label positioning if you need it.0
yaxisTickmarksCountThe number of Y tick marks.10
yaxisTickmarksLastWhether to draw an end Y tick. Usually used when combining Scatter charts.true
yaxisPositionWhere the Y axis should be drawn. Can be either left or right.left
yaxisTitleThis allows you to specify a title for the Y axis.none
yaxisTitleSizeThis allows you to specify a size for the Y axis title.null
yaxisTitleFontThis allows you to specify a font for the Y axis title.null
yaxisTitleBoldThis controls whether the Y axis title is bold or not.true
yaxisTitleColorThis controls what colour the Y axis is.black
yaxisTitlePosThis is multiplied with the margin to give the position of the Y axis title.0.25
yaxisTitlePositionInstead of using the option above you can instead use this option, specifying left or right.left
yaxisTitleXBy giving this you can specifically set the X position of the Y axis title.null
yaxisTitleYBy giving this you can specifically set the Y position of the Y axis title.null
yaxisScaleDecimalsThe number of decimal places to display for the Y scale.0
yaxisScalePointThe character used as the decimal point..
yaxisScaleThousandThe character used as the thousand separator.,
yaxisScaleRoundWhether to round the maximum scale value up or not. This will produce slightly better scales in some instances.null
yaxisScaleZerostartWhether the scale starts at zero or not.true
yaxisScaleUnitsPreThe units (if any) that the Y axis is measured in (these are prepended to the number).none
yaxisScaleUnitsPostThe units (if any) that the Y axis is measured in (these are appended to the number).none
yaxisScaleMinThe optional minimum Y scale value. If not specified it will be zero. By using the yaxisScaleMin and yaxisScaleMax properties and leaving the xaxisPosition option set at bottom you can show an offset X axis.null
yaxisScaleMaxThe optional maximum Y scale value. If not specified then it will be calculated.null (It's calculated)
yaxisScaleInvertReverses the Y axis so that 0 is at the top, instead of the bottom.false

Color properties

PropertyDescriptionDefault
colorsDefaultThis is the default colour of tick marks, which is used if a colour isn't given.#000
colorsBubbleGraduatedBy default the Bubble chart bubbles are graduated in colour. By setting this to false you can disable the gradients and use flat colours.true

Other label properties

PropertyDescriptionDefault
labelsAboveIf true this will show the values of the points above them.false
labelsAboveFontThe font used to render the text.null
labelsAboveSizeIf you're showing the labels above the points, this controls their size.null
labelsAboveColorThe colour of the text.null
labelsAboveBoldWhether the labels are bold or not.null
labelsAboveItalicWhether the labels are italic or not.null
labelsAboveDecimalsIf your points have lots of decimals, you use this option to curtail them.0
labelsAboveFormatterXIf you need to format the X value then you can use this function to do so. An example function to format a datetime value is:
labelsAboveFormatterX: function (obj, value)
{
    var d = new Date(value);
        date = d.getDate();
        month = d.getMonth();
        year  = d.getFullYear();
    
    return '{1}/{2}/{3}'.format(date, month, year);
},
null
labelsAboveFormatterYIf you need to format the X value then you can use this function to do so. An example function to format a datetime value is:
labelsAboveFormatterY: function (obj, value)
{
    return value;
},
null
textFontThe font used to render the text.Arial
textColorThe colour of the labels.black
textSizeThe size of the text (in points).10
textBoldWhether the text is bold or not.10
textItalicWhether the text is bold or not.10
textAccessibleA new feature in 2016 that allows you to use DOM text in place of canvas text. It makes for much higher quality text that you can also select if desired (for copy/paste operations). It won't fit all situations and you can read more about the DOM text feature here. A good way to control borders/margins/padding etc is not to set them on the canvas but to wrap the canvas in a div and set them on that like this:
<div style="margin-left: 50px; display: inline-block">
<canvas id="cvs" width="650" height="250"></canvas>
</div>
true
textAccessibleOverflowThis can be visible or hidden and it controls whether the text is clipped to the edges of the canvas. It defaults to be visible and means you can set small margins if you wish.visible
textAccessiblePointereventsThis controls whether the DOM text responds to mouse based events or not (it sets the pointer-events CSS property to none).true

Margin properties

PropertyDescriptionDefault
marginLeftThe left margin of the chart, (the margin is where the labels and title are)).25
marginRightThe right margin of the chart, (the margin is where the labels and title are).25
marginTopThe top margin of the chart, (the margin is where the labels and title are).25
marginBottomThe bottom margin of the chart, (the margin is where the labels and title are).25

Tick mark properties

PropertyDescriptionDefault
tickmarksStyleThe style of the tick marks. Can be: cross, plus, circle, diamond, square or null (no tick marks). As of August 2014 this can be a location of an image file to use as the tick marks or a data: URL. See below for details.cross
tickmarksSizeThe size of the tick marks.3
tickmarksImageHalignThis can be left, right or center and determines the horizontal alignment of the tick mark.center
tickmarksImageValignThis can be top, bottom or center and determines the vertical alignment of the tick mark.center
tickmarksImageOffsetxAfter the alignment has been applied, this is added to the X coordinate of the tick mark.0
tickmarksImageOffsetyAfter the alignment has been applied, this is added to the Y coordinate of the tick mark.0

Title properties

PropertyDescriptionDefault
titleThe title of the scatter chart.none
titleFontThe font that the title is rendered in. If not specified the textFont setting is used (usually Arial).null
titleSizeThe size of the title. If not specified the size is usually 2pt bigger than the textSize setting.null
titleBoldWhether the title is bold or not.true
titleItalicWhether the title is italic or not.false
titleBackgroundThe background colour (if any) for the title.null
titleXTo give the exact X coordinate for the title - use this. This can also be a string like this: "-5" -- in which case it's converted to a number and added to the calculated coordinate - allowing you to adjust the calculated coordinate.null
titleYTo give the exact Y coordinate for the title - use this. This can also be a string like this: "-5" -- in which case it's converted to a number and added to the calculated coordinate - allowing you to adjust the calculated coordinate.null
titleColorThe colour of the title.black

Interactive features properties

PropertyDescriptionDefault
tooltipsEffectThe effect used for showing tooltips. Can be either fade or none.fade
tooltipsHotspotThis controls the size of the hotspot on the chart for tooltips.3
tooltipsHighlightSet this to false if you don't want your charts to be highlighted.true
tooltipsCssClassThis is the name of the CSS class the chart uses.RGraph_tooltip
tooltipsOverrideIf you wish to handle showing tooltips yourself, this should be a function object which does just that. There's more information in the tooltips documentation page.null
tooltipsNohideonclearNot an option that you'll need particularly often if at all. Setting this to true means that when you call the RGraph.clear() API function tooltips DO NOT get hidden.false
crosshairsIf true, you will get a crosshair centring on the current mouse position.false
crosshairsLinewidthThis controls the linewidth of the crosshairs.1
crosshairsColorThe colour of the crosshairs.#333
crosshairsCoordsIf true, this will show the coordinates that the crosshairs are currently over.false
crosshairsCoordsFixedIf true, this makes the coordinates static (attached), instead of following the pointer around.false
crosshairsFadeoutIf true, when you move your mouse off of the canvas the coordinates will fade out.false
crosshairsCoordsLabelsXInstead of X and Y, you can specify more meaningful labels.X
crosshairsCoordsLabelsYInstead of X and Y, you can specify more meaningful labels.Y
crosshairsCoordsFormatterXThis can be a function with which you can format the value to appear just as you want. Simply return the value that you wish to be displayed. The single argument is an object that has two properties: object (which is the chart object) and value (which is the X value).null
crosshairsCoordsFormatterYThis can be a function with which you can format the value to appear just as you want. Simply return the value that you wish to be displayed. The single argument is an object that has two properties: object (which is the chart object) and value (which is the Y value).null
crosshairsLabelsYInstead of X and Y, you can specify more meaningful labels.Y
crosshairsHlineThis determines whether the horizontal crosshair line is shown.true
crosshairsHlineThis determines whether the vertical crosshair line is shown.true
contextmenuAn array of context menu items. More information about context menus is here.An empty array
annotatableWhether annotations are enabled for the chart (ie you can draw on the chart interactively.false
annotatableColorIf you do not allow the use of the palette, then this will be the only colour allowed for annotations.black
annotatableLinewidthThis is the line width of the annotations.1
resizableDefaulting to false, this determines whether your chart will be resizable. Because of the numerous event handlers this has to install code on, This feature is unlikely to work with other dynamic features (the context menu is fine however).false
resizableHandleBackgroundWith this you can specify the background colour for the resize handle. If you're adjusting the position of the handle then you may need this to make the handle stand out more.null
resizableMinwidthThis allows you to set a minimum width that the chart can be resized to.null
resizableMinheightThis allows you to set a minimum height that the chart can be resized to.null
resizableMaxwidthThis allows you to set a maximum width that the chart can be resized to.null
resizableMaxheightThis allows you to set a maximum height that the chart can be resized to.null

Line properties

PropertyDescriptionDefault
lineWhether to show a connecting line (like in the sixth example).false
lineColorsThe colours of the lines connecting the tick marks.['green', 'red']
lineShadowColorThe colour of the lines shadow (if any).rgba(0,0,0,0)
lineShadowOffsetxThe X offset of the lines shadow.3
lineShadowOffsetyThe Y offset of the lines shadow.3
lineShadowBlurThe severity of the line shadows blurring effect.2
lineSteppedLike the line chart, Scatter chart lines can be stepped by setting this to true.false
lineLinewidthThis can be either a number or an array of numbers (for multiple lines) and controls the linewidth that is used for the lines.1
lineDashWith this setting you can control the linedash setting so your lines can be dashed (or dotted).

Note: Browser support is limited (but growing) for dashed/dotted lines - so depending on your browser you may see just a solid line.
null

Key properties

The key properties are documented on the key documentation page.

Event properties

PropertyDescriptionDefault
eventsClickIf you want to add your own onclick function you can do so by assigning it to this property. See here for details.null
eventsMousemoveIf you want to add your own onmousemove function you can do so by assigning it to this property. See here for details.null
eventsMouseoverIf you want to add your own onmouseover function you can do so by assigning it to this property. See here for details.null
eventsMouseoutIf you want to add your own onmouseout function you can do so by assigning it to this property. See here for details.null

Miscellaneous properties

PropertyDescriptionDefault
highlightStyleBy default this is null but you can set it to a function if you wish so that function is called to do the chart highlighting. Its passed the shape object as an argument.null
boxplotWidthThis stipulates the default width of boxes. For more on boxplots, see here.10
boxplotCappedThis stipulates whether the boxplot will have caps on the end of the whiskers. This could be useful if you're creating a stock chart for example. For more on boxplots, see here.true
cleartoThis is used in animations and effects as the default colour to use when clearing the canvas.null

Methods

obj.get(name)

An accessor that you can use to retrieve the values of properties.

obj.set(name, value)

An accessor that you can use to set the values of properties.

obj.getShape(event)

This method makes it easier to get hold of which point on the Scatter chart has been clicked or hovered over. It returns an array of:

The shape also includes textual indices like this: shape['object'] And they are:

(If the return value is null, then no point is being hovered over). Example usage is:
<script src="RGraph.common.core.js"></script>
<script src="RGraph.line.js"></script>

<canvas id="cvs" width="600" height="250" style="border: 1px gray dashed">[No canvas support]</canvas>

<script>
    scatter = new RGraph.Scatter({
        id: 'cvs',
        data:[
            [[5,1, 'red', 'A'],[4,2,, 'B'],[3,9,,'C'],[10,12,,'D'],[300,2,,'E']],
            [[5,6, 'red', 'F'],[2,9,,'G'],[13,19,,'H'],[18,17,,'I'],[340,12,,'J']]
        ],
        options: {
            xaxisScaleMax: 365,
            line: true,
            xaxisLabels: ['Q1', 'Q2', 'Q3', 'Q4']
        }
    )).draw();

    scatter.canvas.onmousemove = function (e)
    {
        var canvas  = e.target;
        var context = canvas.getContext('2d');
        var obj     = canvas.__object__;
        var point   = obj.getShape(e);

        if (point) {
            p('\r\nX Coordinate: ' + point[0] + '\r\n' +
              'Y Coordinate: ' + point[1] + '\r\n' +
              'Dataset: ' + point[2] + '\r\n' +
              'Datapoint: ' + point[3] + '\r\n' +
              'Tooltip: ' + point[4] + '\r\n');
        }
    }
</script>

obj.getXValue(mixed)

This method can be used to get the X value at a particular point or at the mouse coordinates, based on the X maximum value that is being used. Not simply the coordinates of the mouse. The argument can either be an event object (for use in event listener functions) OR a two element array consisting of the X and Y coordinates (ie when you're not necessarily in an event listener). It returns null if the mouse or coordinates are in the margin areas. For an example of using this method see this HOWTO document.

obj.getYValue(mixed)

This method can be used to get the Y value at a particular point or at the mouse coordinates, based on the scale that is in use. Not simply the coordinates of the mouse. The argument can either be an event object (for use in event listener functions) OR a two element array consisting of the X and Y coordinates (ie when you're not necessarily in an event listener). It returns null if the mouse or coordinates are in the margin areas. For an example of using this method see this HOWTO document.

obj.getYCoord(value)

This method can be used to get an appropriate Y coordinate for a value when you're doing custom drawing on the chart. It returns the coordinate for the max/min value if the given number is out of range.

obj.getXCoord(value)

This method can be used to get an appropriate X coordinate for a value when you're doing custom drawing on the chart. It returns null if the given number is out of range. If you're using a date/time chart with the min and max set to date/time strings you can also pass this function a date/time string eg:

obj.getXCoord('2013-06-12T15:14:16');
obj.on(event, function)

This method can be used to set an event listener on an object. It operates in a similar way to the jQuery on() function. The first argument is the event that you wish to attach to and the second is the handler function. For example:

.on('draw', function (obj)
{
    // Put event code here
});

The function is useful if you use method chaining when creating your charts:

<script>
    new RGraph.Scatter({
        id: 'cvs',
        data: [ [12,35],[23,53],[35,35],[45,58],[56,55],[86,86] ],
        xaxisScaleMax: 100
    }).on('draw', function (e, shape)
    {
        // Put your ondraw code here
    }).on('click', function (e, shape)
    {
        // Handle the click event
    }).draw();
</script>
The exec option and method

The exec function is documented here.

Box/Whisker (candlestick) plots

Instead of a single Y value, you have the ability to specify an array of 5, 6, 7 or 8 values, which will be used to make a box plot (also known as a candlestick plot). These values are (in order):

<script>
    new RGraph.Scatter({
        id: 'scatter8',
        data: [
            [10,[1,1,16,24,24, 'red', 'green']],
            [105,[5,10,15,25,25, 'red', 'green']],
            [125,[10,15,25,35,45, 'red', 'green']],
            [325,[10,15,25,35,45, 'red', 'green', 30]]
        ],
        options: {
            title: 'An example of a boxplot',
            xaxisLabels: ['Q1', 'Q2', 'Q3', 'Q4'],
            xaxisScaleMax: 365,
            yaxisScaleMax: 50,
            boxplotWidth: 12 // the default width
        }
    }).draw();
</script>

Capped ends

For better compatibility with stock charts, you can now specify that the horizontal lines at the ends of the box plot are not shown with the boxplotCapped option.

Specific points for labels on the X axis

Instead of a simple string which is used as the label, each entry of the labels array can be a two element array consisting of the label and the X value that the label should be placed at. For example:

scatter.set({
    labels:[
        ['Quarter 1', 0],
        ['Quarter 2', 90],
        ['Quarter 3', 181],
        ['Quarter 4', 273]
    ]
});

Custom tick marks

If none of the available tick mark styles are suitable, you can specify a function that draws the tick mark, enabling you to draw the tick mark yourself. For example:

<script>
    line.set('tickmarksStyle', myTick);

    /**
    * The function that is called once per tick mark, to draw it
    * 
    * @param object obj           The chart object
    * @param object data          The chart data
    * @param number x             The X coordinate
    * @param number y             The Y coordinate
    * @param number xVal          The X value
    * @param number yVal          The Y value
    * @param number xMax          The maximum X scale value
    * @param number yMax          The maximum Y scale value
    * @param string colour        The colour of the tick mark
    * @param string dataset_index The index of the data (which starts at zero
    * @param string data_index    The index of the data in the dataset (which starts at zero)
    */
    function myTick (obj, data, x, y, xVal, yVal, xMax, yMax, color, dataset_index, data_index)
    {
        // Draw your custom tick here
    }
</script>

As of August 2014 you can also specify an image to use as a tick mark. Various styles of URL are supported:

obj.set({tickmarks: 'image:foo.png'});     // Starts with image: prefix
obj.set({tickmarks: '/images/foo.png'});   // Starts with a /
obj.set({tickmarks: '../images/foo.png'}); // Starts with ../
obj.set({tickmarks: 'data: ...'});         // Starts with data: (for inline images)
obj.set({tickmarks: 'images/foo.png'});    // Starts with images/

Note about colours and the key

If you're using a key you may need to set lineColors to allow it to use the correct colours. For example:

obj.set('lineColors', ['red','green','blue']);

Note about the oncrosshairs event

With the Scatter chart you can use the oncrosshairs custom event to pull out the crosshair coordinates like this (the coordinates are only available if you have them displayed):

function myFunc (obj)
{
    var xCoord = obj.canvas.__crosshairs_x__;
    var yCoord = obj.canvas.__crosshairs_y__;
}
RGraph.addCustomEventListener(obj, 'oncrosshairs', function ()
{
    // Handle the event here
});

Note about the data_arr array

Sometimes you may wish to view your data as one big array, instead of one array per dataset. In this case the obj.data_arr is available. This is one long array containing all of the individual data points. Remember that with the Scatter chart the data points themselves are arrays/objects of X/Y/color/tooltip etc information.

Date/time based charts

Instead of using a number as the X coordinate you can instead use a date/time value instead. Likewise you can use the same style date/time values as the xaxisScaleMin and xaxisScaleMax values. The underlying date/time parsing uses the Date.parse() function (via the RGraph.parseDate() function) so you can use values such as: 2012-01-01 00:00:00 There's an example of a date/time chart in the download archive (examples/scatter-date-time-values.html)

Animation effects

These effects are available and can be used instead of the draw() function. There are also generic effects available which you can see here: Generic effects and transitions
<script>
    // Optional callback function that's called when the effect is complete
    function myCallback (obj)
    {
        // ...
    }

    new RGraph.Scatter({
        id: 'cvs',
        data: [[5,5],[10,10],[15,15],[20,20]],
        options: {
            xaxisScaleMax: 90
        }
    }).trace({frames: 60}, myCallback)
</script>