RGraph: HTML5 Javascript charts library - Bar charts documentation

Bar charts, along with Line charts, are the most configurable of all the charts available, because they're the most common of chart types.

The example file is here.

Properties
Methods

 
<script>
    window.onload = function ()
    {
        var data = [280,45,133,166,84,259,266,960,219,311];
    
        var bar = new RGraph.Bar('myCanvas', data);
        bar.Set('chart.labels', ['Richard', 'Alex', 'Nick', 'Scott', 'Kjnell', 'Doug', 'Charles', 'Michelle', 'Mark', 'Alison']);
        bar.Set('chart.gutter.left', 45);
        bar.Set('chart.background.barcolor1', 'rgba(255,255,255,1)');
        bar.Set('chart.background.barcolor2', 'rgba(255,255,255,1)');
        bar.Set('chart.background.grid', true);
        bar.Set('chart.colors', ['rgba(255,0,0,1)']);
        bar.Draw();
    }
</script>

Properties

You can use these properties to control how the bar chart apears. You can set them by using the Set() method. Eg:

myBar.Set('name', 'value');

Background
Axes properties
Colors
Margins
Labels and text
Titles
Shadow
Scale
Key
Interactive features
Zoom
Miscellaneous

Background

chart.background.barcolor1
The color of the background bars, (1 of 2).
Default: white

chart.background.barcolor2
The color of the background bars, (2 of 2).
Default: white

chart.background.grid
Whether to show the background grid or not.
Default: true

chart.background.grid.color
The color of the background grid.
Default: #ddd

chart.background.grid.hsize
The horizontal background grid size.
Default: 40

chart.background.grid.vsize
The vertical background grid size.
Default: 18

chart.background.grid.width
The width that the background grid lines are. Decimals (eg 0.5) are permitted.
Default: 1

chart.background.grid.border
Determines whether a border line is drawn around the grid.
Default: true

chart.background.grid.hlines
Determines whether to draw the horizontal grid lines.
Default: true

chart.background.grid.vlines
Determines whether to draw the vertical grid lines.
Default: true

chart.background.grid.autofit
Instead of specifying a pixel width/height for the background grid, you can use autofit and specify how many horizontal and vertical lines you want.
Default: true

chart.background.grid.autofit.numhlines
When using autofit this allows you to specify how many horizontal grid lines you want.
Default: 5

chart.background.grid.autofit.numvlines
When using autofit this allows you to specify how many vertical grid lines you want.
Default: 20

chart.background.grid.autofit.align
If 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. If you have a chart.hmargin set then the alignment will be thrown out.
Default: false

chart.background.hbars
An array of information stipulating horizontal coloured bars. You can use these to indicate limits. Eg: myBar.Set('hbars', [[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.
Default: null

chart.background.image
If you want to specify a background image to use on your chart, specify it with this property.
Default: null

Axes properties

chart.noaxes
Whether the axes are drawn
Default: false (the axes ARE drawn)

chart.noxaxis
Whether the X axis is drawn
Default: false (the X axis IS drawn)

chart.noyaxis
Whether the Y axis is drawn
Default: false (the Y axis IS drawn)

chart.noendxtick
When you're combining the Bar and Line charts, you may want to use this property to stop the end X tick from being drawn.
Default: false (the end tick IS drawn)

Colors

chart.strokecolor
The color of the outline of the bars.
Default: #666

chart.colors
An array of the colors of the actual bars.
Default: An array - ['rgb(0,0,255)', '#0f0', '#00f', '#ff0', '#0ff', '#0f0']

chart.colors.sequential
If true, for regular bar charts, (not stacked or grouped), the colors that you specify will be used in a sequential fashion.
Default: false

chart.colors.reverse
If true, for stacked bar charts only, the colors that you specify will be used in a reverse order to what they are normally.
Default: false

Margins

chart.hmargin
The horizontal margin (in pixels) of the chart. The horizontal margin is on the inside of the axes.
Default: 5

chart.gutter.left
The left gutter of the chart, (the gutter is where the labels and title are)).
Default: 25

chart.gutter.right
The right gutter of the chart, (the gutter is where the labels and title are).
Default: 25

chart.gutter.top
The top gutter of the chart, (the gutter is where the labels and title are).
Default: 25

chart.gutter.bottom
The bottom gutter of the chart, (the gutter is where the labels and title are).
Default: 25

Labels and text

chart.text.color
The color of the labels.
Default: black

chart.text.size
The size (in points) of the labels.
Default: 10

chart.text.angle
The angle of the horizontal text labels (at the bottom of the chart). This can be one of three values - 0, 45 or 90.
Default: 0 (Horizontal)

chart.text.font
The font used to render the text.
Default: Verdana

chart.labels
An array of the labels to be used on the chart.
Default: An empty array

chart.labels.above
If true, values will be shown above the bars. For regular and stacked bar charts units are included, whereas for grouped bar charts they're not (usually there isn't enough space for them).
Default: false

chart.labels.above.decimals
This stipulates how many decimals are used in the above bar labels.
Default: 0

chart.labels.above.size
The font size of the above bar labels. Useful if you only have a few bars.
Default: false

chart.labels.above.angle
You can use this to angle the text shown above the bars. It can be anything from -90 to 90 (degrees).
Default: null

chart.labels.ingraph
An array of labels for the chart which are drawn "inside" the chart. If you have 5 data points then this should have a corresponding number of elements, though there is a shorthand available.
Default: null

chart.ylabels
Can be true or false and determines whether the chart has Y axis labels.
Default: true

chart.ylabels.count
A value that controls how many Y labels there are. Previously (prior to 8th August 2010) this could be 1,3,5. Now it can be any number, but keep in mind that if you use this it may result in decimals.
Default: 5

chart.ylabels.specific
You can use this option to give your own Y labels (eg ['Low', 'Medium', 'High'].
Default: null

chart.xlabels.offset
This allows you finer grained control over the X label positioning if you need it.
Default: 0

chart.numyticks
The number of Y tickmarks. If you have changed the number of Y labels, you may also want to change this to match.
Default: 10

Titles

chart.title
The title of the chart, if any.
Default: null

chart.title.font
The font that the title is rendered in. If not specified the chart.text.font setting is used (usually Verdana)
Default: null

chart.title.size
The size of the title. If not specified the size is usually 2pt bigger than the chart.text.size setting.
Default: null

chart.title.bold
Whather the title is bold or not.
Default: true

chart.title.background
The background color (if any) for the title.
Default: null

chart.title.color
The color of the title.
Default: black

chart.title.hpos
This allows you to completely override the horizontal positioning of the title. It should be a number between 0 and 1, and is multiplied with the whole width of the canvas and then used as the horizontal position.
Default: null

chart.title.vpos
This allows you to completely override the vertical positioning of the title. It should be a number between 0 and 1, and is multiplied with the gutter and then used as the vertical position. It can be useful if you need to have a large gutter.
Default: null

chart.title.xaxis
This allows to specify a title for the X axis.
Default: none

chart.title.xaxis.size
This allows you to specify a size for the X axis title.
Default: null

chart.title.xaxis.font
This allows to specify a font for the X axis title.
Default: null

chart.title.xaxis.bold
This controls whether the X axis title is bold or not.
Default: true

chart.title.yaxis
This allows to specify a title for the Y axis.
Default: none

chart.title.yaxis.size
This allows you to specify a size for the Y axis title.
Default: null

chart.title.yaxis.font
This allows to specify a font for the Y axis title.
Default: null

chart.title.yaxis.bold
This controls whether the Y axis title is bold or not.
Default: true

chart.title.xaxis.pos
This is multiplied with the gutter to give the position of the X axis title.
Default: 0.25

chart.title.yaxis.pos
This is multiplied with the gutter to give the position of the Y axis title.
Default: 0.25

Shadow

chart.shadow
Whether a drop shadow is applied.
Default: false

chart.shadow.color
The color of the shadow.
Default: #666

chart.shadow.offsetx
The X offset of the shadow.
Default: 3

chart.shadow.offsety
The Y offset of the shadow.
Default: 3

chart.shadow.blur
The severity of the shadow blurring effect.
Default: 3

Scale

chart.scale.formatter
To allow thoroughly custom formats of numbers in the scale, you can use this option to specify a function that is used by RGraph to format numbers. This function should handle ALL of the formatting. Eg:

function myFormatter(obj, num)
{
    return num + 'F'; // An example of formatting
}
myGraph.Set('chart.scale.formatter', myFormatter);

Default: null

chart.scale.decimals
The number of decimal places to display for the Y scale.
Default: 0

chart.scale.point
The character used as the decimal point.
Default: .

chart.units.pre
The units that the Y axis is measured in. This string is displayed BEFORE the actual number, allowing you to specify values such as "$50".
Default: none

chart.units.post
The units that the Y axis is measured in. This string is displayed AFTER the actual number, allowing you to specify values such as "50ms".
Default: none

chart.ymax
The optional maximum Y scale value. If not specified then it will be calculated.
Default: null (It's calculated)

chart.ymin
The optional minimum Y scale value. If not specified then it will be 0.
Default: 0

Key

chart.key
An array of key information.
Default: [] (An empty array)

chart.key.background
The color of the key background. Typically white, you could set this to something like rgba(255,255,255,0.7) to allow people to see things behind it.
Default: white

chart.key.halign
Instead of specifying the exact x/y coordinates, you can use this property to simply specify whether the key hould be aligned left or right.
Default: right

chart.key.position
Determines the position of the key.Either graph (default), or gutter.
Default: graph

chart.key.position.x
This allows you to specify a specific X coordinate for the key.
Default: null

chart.key.position.y
This allows you to specify a specific Y coordinate for the key.
Default: null

chart.key.position.gutter.boxed
If you have the key in gutter mode (ie horizontal), this allows you to give a background color.
Default: true

chart.key.shadow
Whether a small drop shadow is applied to the key.
Default: false

chart.key.shadow.color
The color of the shadow.
Default: #666

chart.key.shadow.blur
The extent of the blurring effect used on the shadow.
Default: 3

chart.key.shadow.offsetx
The X offset of the shadow.
Default: 2

chart.key.shadow.offsety
The Y offset of the shadow.
Default: 2

chart.key.rounded
This controls whether the corners of the key (in graph mode) are curved. If the key is gutter mode, this has no effect.
Default: false

chart.key.color.shape
This can be square, circle or line and controls how the color indicators in the key appear.
Default: square

chart.key.linewidth
The line width of the surrounding border on the key.
Default: 1

Interactive features

chart.contextmenu
An array of context menu items. More information on context menus is here.
Default: [] (An empty array)

chart.tooltips
A numerically indexed array of tooltips that are shown when a bar is clicked. These can contain HTML.
Default: null

chart.tooltips.effect
The animated effect used for showing tooltips. Can be either fade or expand.
Default: fade

chart.tooltips.event
This is the event that triggers the tooltips. It can be either onclick or onmousemove.
Default: onclick

chart.tooltips.css.class
This is the name of the CSS class the chart uses.
Default: RGraph_tooltip

chart.tooltips.override
If you wish to handle showing tooltips yourself, this should be a function object which does just that. There's more information on the tooltips documentation page
Default: null

chart.tooltips.highlight
When combining chartss you will need to set this option to fase.
Default: true

chart.crosshairs
If true, you will get a crosshair centering on the current mouse position.
Default: false

chart.crosshairs.linewidth
This controls the linewidth of the crosshairs.
Default: 1

chart.crosshairs.color
The color of the crosshairs.
Default: #333

chart.crosshairs.hlines
This determines whether the horizontal crosshair is shown.
Default: true

chart.crosshairs.vlines
This determines whether the vertical crosshair is shown.
Default: true

chart.annotatable
Whether annotations are enabled for the chart (ie you can draw on the chart interactively.
Default: false

chart.annotate.color
If you do not allow the use of the palette, then this will be the only colour allowed for annotations.
Default: black

chart.resizable
Defaulting 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).
Default: false

chart.resize.handle.background
With this you can specify the background color 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.
Default: null

chart.adjustable
Defaulting to false, this determines whether your bar chart will be adjustable.
Default: false

Zoom

chart.zoom.mode
Can be used to control whether the zoom is in thumbnail or canvas mode. Possible values are: thumbnail and canvas.
Default: canvas

chart.zoom.factor
This is the factor that the chart will be zoomed by (bigger values means more zoom)
Default: 1.5

chart.zoom.fade.in
Whether the zoomed canvas fades in or not. This also can be used to control the fade in for the zoom in thumbnail mode.
Default: true

chart.zoom.fade.out
Whether the zoomed canvas fades out or not. This also can be used to control the fade in for the zoom in thumbnail mode.
Default: true

chart.zoom.hdir
The horizontal direction of the zoom. Possible values are: left, center, right
Default: right

chart.zoom.vdir
The vertical direction of the zoom. Possible values are: up, center, down
Default: down

chart.zoom.delay
The delay (in milliseconds) between frames.
Default: 50

chart.zoom.frames
The number of frames in the zoom animation.
Default: 10

chart.zoom.shadow
Whether or not the zoomed canvas has a shadow or not.
Default: true

chart.zoom.thumbnail.width
When the zoom is in thumbnail mode, this is the width (in pixels) of the thumbnail.
Default: 75

chart.zoom.thumbnail.height
When the zoom is in thumbnail mode, this is the height (in pixels) of the thumbnail.
Default: 75

chart.zoom.background
Defaulting to true, this determines whether the zoom has a dark, semi-opaque background that covers the entire web page.
Default: true

Miscellaneous

chart.highlight.stroke
If you use tooltips, this controls the colour of the highlight stroke.
Default: black

chart.highlight.fill
If you use tooltips, this controls the colour of the highlight fill.
Default: rgba(255,255,255,0.5)

chart.line
Formerly a boolean, this now stipulates a line chart object which is to be drawn on top of the bar chart. You can see an example here.
Default: null

chart.variant
This simply stipulates whether you want a regular bar chart, a dot chart, a pyramid chart a 3D chart, a sketch or a glassy chart. Possible values are:

bar
dot
pyramid
arrow
3d
sketch
glass

The pyramid, dot, arrow, sketch and glass variants are only effective for regular bar charts - not grouped or stacked charts.
Default: bar

chart.xaxispos
The position of the X axis. This can be bottom, center or top.
Default: bottom

chart.axis.color
The color of the axes.
Default: black

chart.grouping
How the bars are grouped, and it should be one of: grouped or stacked
Default: grouped

Methods

obj.getBar()

This method makes it easier to get hold of which bar has been clicked on, or hovered over. It returns an array of:

The chart object
The X coordinate
The Y coordinate
The width of the bar
The height of the bar
The numerical index of the bar. This corresponds (for example) to the tooltips array, and the coordinates array

An example usage is:

<canvas id="cvs" width="600" height="250">[No canvas support]</canvas>

<script src="RGraph.common.core.js"></script>
<script src="RGraph.bar.js"></script>

<script>
    myGraph = new RGraph.Bar('myCanvas', [1.2, 1.3, 1.4, 1.5,6,1.9,2,2.1,2.5]);
    myGraph.Set('chart.labels', ['John', 'Barry', 'Rich', 'Craig', 'Tom', 'Frank', 'Helen', 'Joyce', 'Fred'])
    myGraph.Draw();

    RGraph.Register(myGraph);
    
    myGraph.canvas.onclick = function (e)
    {
        RGraph.Redraw();
    
        var canvas  = e.target;
        var context = canvas.getContext('2d');
        var obj     = canvas.__object__;
        var coords  = obj.getBar(e);
        
        if (coords) {
            var top    = coords[1];
            var left   = coords[2];
            var width  = coords[3];
            var height = coords[4];
            
            context.beginPath();
                context.strokeStyle = 'black';
                context.fillStyle = 'rgba(255,255,255,0.5)';
                context.strokeRect(top, left, width, height);
                context.fillRect(top, left, width, height);
            context.stroke();
            context.fill();
        }
    }
</script>