RGraph: HTML5 Javascript charts library - Pie charts documentation

The pie chart can be used, for example, to represent something that is akin to percentages. ie A set of data that should be taken as part of a whole.

The example file is here.

<script>
    window.onload = function ()
    {
        var data = [564,155,499,611,322];
    
        var pie = new RGraph.Pie('myPie', data);
        pie.Set('chart.labels', ['Abc', 'Def', 'Ghi', 'Jkl', 'Mno']);
        pie.Set('chart.linewidth', 5);
        pie.Set('chart.stroke', '#fff');
        pie.Draw();
    }
</script>

Properties
Methods

Properties

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

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

Margins
Colors
Labels and text
Titles
Shadows
Interactive features
Key
Zoom
Miscellaneous

Margins

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

Colors

chart.colors
Colors to be used for the pie segments.
Default: ['rgb(255,0,0)', '#ddd', 'rgb(0,255,0)', 'rgb(0,0,255)', 'rgb(255,255,0)', 'rgb(0,255,255)', 'red', 'pink', 'black', 'white']

chart.strokestyle
The color of the seperating lines. By setting this to your background color, and setting the linewidth to approx. 5, it will make the pie chart look "exploded".
Default: #999

Labels and text

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

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

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

chart.labels
An array of labels to be used for the chart.
Default: [] (an empty array)

chart.labels.sticks
Stipulates that sticks for the labels are shown.
Default: false

chart.labels.sticks.color
Sets the color of the label sticks.
Default: #aaa

chart.labels.sticks.length
Sets the length of the label sticks.
Default: 7

Titles

chart.title
The title of the pie chart.
Default: none

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

Shadows

chart.shadow
Whether a simple shadow effect is applied.
Default: false

chart.shadow.color
The color of the shadow.
Default: rgba(0,0,0,0.5)

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

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

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

Interactive features

chart.tooltips
An array of tooltips, starting from the middle right (ie east) axis, and going clockwise sequentially.
Default: [] (An empty array)

chart.tooltips.event
This can be onclick or onmousemove and determines which event is used for tooltips.
Default: onclick

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

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

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

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

chart.key.interactive
This option enables the facility to click on the pie chart to highlight (explode only) the relevant segment.
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.align
Whether to left, center or right align the pie chart.
Default: center

chart.linewidth
By setting this to roughly 5, and setting the strokestyle to the same colour as your background colour,you will get a segment separation effect.
Default: 1

chart.variant
This can be either pie (the default) or donut. Setting this to donut is how you get a donut chart.
Default: pie

chart.variant.donut.color
This is the color of the center of the Donut chart.
Default: white

chart.highlight.style
Can be either explode, 2d or 3d and determines which style of segment highlighting is used in conjunction with tooltips.
Default: 2d

chart.highlight.style.2d.fill
When 2D highlighting for tooltips is used, this controls the color of the highlighting. The former name for this property was chart.highlight.style.2d.color.
Default: rgba(255,255,255,0.5)

chart.highlight.style.2d.stroke
When 2D highlighting for tooltips is used, this controls the stroke color of the highlighting.
Default: rgba(255,255,255,0)

chart.explode
This can either be an array with the same number of elements as segments, or a single number, in which case every segment will be exploded that amount. If it's an array then only those segments will be exploded - eg [0,5,0,0]
Default: [] (an empty array)

Methods

obj.getSegment()

obj.getSegment() makes it easy to determine which segment of the Pie chart was clicked on. It provides:

Originating X coordinate
Originating Y coordinate
The radius of the segment
The starting angle (in degrees)
The ending angle (in degrees)
The zero-indexed segment number

<script>
    RGraph.Register(myGraph);
    
    myGraph.canvas.onclick = function (e)
    {
        RGraph.FixEventObject(e);
        RGraph.Redraw();

        var canvas  = e.target;
        var context = canvas.getContext('2d');
        var obj     = canvas.__object__;
        var segment = obj.getSegment(e);
        
        if (segment) {
            context.fillStyle = 'rgba(255,255,255,0.5)';
            context.beginPath();
                
                // Angles are provided in degrees, so convert them to radians
                segment[3] /= 57.29;
                segment[4] /= 57.29;
            
                context.moveTo(segment[0], segment[1]);
                context.arc(segment[0], segment[1], segment[2], segment[3], segment[4], 0);
            context.stroke();
            context.fill();
            
            e.stopPropagation();
        }
    }
    
    window.onclick = function (e)
    {
        RGraph.Redraw();
    }
</script>

obj.Explode()

The Explode() method allows you to programmatically trigger the exploding (ie the highlighting of) a particular segment. The Explode() method is used like so:

<script>
    myObj = new RGraph.Pie('cvs', [8,9,4,6]);
    myObj.Draw();

    myObj.Explode(index, size);
</script>

The index argument is the zero-index segment to operate on (counting from the north axis). An the size is measured in pixels.

Important Note

This method was formerly a common object method, called RGraph.getSegment(e), but has now (6th March 2011) been moved to be part of the Pie chart object.