# RGraph: HTML5 canvas graph library - Scatter graph documentation

A scatter graph. Used to represent many data points over a period of time. For example, events occurring in a given year.

The example file is here.

    <script>
        window.onload = function ()
        {
            var data = [
                        [67,78,'red', 'The winner!'], [67,40,'red'], [58,12], [78,56], [365,90], [360,300], [320,150], [15,45],
                        [16,43], [84,12], [67,89,'green'], [90,23,'green'], [23,80], [80,66], [55,66], [88,12], [43,45], [61,12],
                        [15,89], [13,16]
                       ];
            var sg = new RGraph.Scatter('myScatter', data);
            sg.Set('chart.background.barcolor1','rgba(255,255,255,1)');
            sg.Set('chart.background.barcolor2', 'rgba(255,255,255,1)');
            sg.Set('chart.grid.color', 'rgba(238,238,238,1)');
            sg.Set('chart.gutter', 30);
            sg.Set('chart.labels', ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']);
            sg.Set('chart.xmax', 365); // Important!
            sg.Draw();
        }
    </script>

As you can see each mark on the Scatter chart is made by supplying an array of up to 4 elements:

- The X value (required)
- The Y value (required)
- The color (optional)
- The tooltip for this mark (optional)

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

## Available properties

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

myScatter.Set('chart.xmax', 365);

- Background
- Labels and text
- Margins
- Axis properties
- Titles
- Scale
- Interactive features
- Line properties
- Zoom
- Miscellaneous

### Background

chart.background.barcolor1
The color of the background bars.
Default: rgba(0,0,0,0)
chart.background.barcolor2
The color of the background bars.
Default: rgba(0,0,0,0)
chart.background.grid
Whether to show the background grid or not.
Default: true
chart.background.grid.color
The color of the background grid.
Default: #eee
chart.background.hbars
An array of information stipulating horizontal coloured bars. You can use these to indicate limits. Eg: myScatter.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.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: false
chart.background.grid.autofit.numhlines
When using autofit this allows you to specify how many horizontal grid lines you want.
Default: 7
chart.background.grid.autofit.numvlines
When using autofit this allows you to specify how many vertical grid lines you want.
Default: 20

### Labels and text

chart.labels
An array of the X labels for the graph.
Default: [] (An empty array)
chart.ylabels
A boolean (true or false) that controls whether the graph has Y labels.
Default: true
chart.ylabels.count
A value (1, 3 or 5) that controls how many Y labels there are.
Default: 5
chart.text.font
The font used to render the text.
Default: Verdana
chart.text.color
The color of the labels.
Default: black
chart.text.size
The size of the text (in points).
Default: 10
chart.text.angle
The angle of the horizontal text labels (at the bottom of the graph). This can be one of three values - 0, 45 or 90.
Default: 0 (Horizontal)

### Margins

chart.gutter
The gutter on the graph (the area outside of the axes).
Default: 25

### Axis properties

chart.xmax
The maximum X axis value you wish to set. For example if you're displaying products sold in a year, you might use 365.
Default: none - must be supplied
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 it will be zero.
Default: null
chart.ticksize
The size of the tickmarks.
Default: 3
chart.tickmarks
The style of the tickmarks. Can be: cross, plus, circle, diamond, square or null (no tickmarks).
Default: cross
chart.xticks
This controls whether the X axis tickmarks are drawn.
Default: true
chart.xaxispos
Where the X axis should be drawn. Can be either center or bottom.
Default: bottom
chart.axis.color
The color of the axes.
Default: black
chart.noaxes
If this is set to true, no axes will be drawn.
Default: false

### Titles

chart.title
The title of the scatter graph.
Default: none
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.color
The color of the title.
Default: black
chart.title.xaxis
This allows to specify a title for the X axis.
Default: none
chart.title.yaxis
This allows to specify a title for the Y axis.
Default: none
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

### Scale

chart.scale.decimals
The number of decimal places to display for the Y scale.
Default: 0
chart.units.pre
The units (if any) that the Y axis is measured in (these are preppended to the number).
Default: none
chart.units.post
The units (if any) that the Y axis is measured in (these are appended to the number).
Default: none

### Interactive features

chart.tooltips.effect
The animated effect used for showing tooltips. Can be either fade or expand.
Default: fade
chart.tooltips.hotspot
This controls the size of the hotspot on the chart for tooltips.
Default: 3
chart.tooltips.css.class
This is the name of the CSS class the graph 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.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.contextmenu
An array of context menu items. More information on context menus is here.
Default: null
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: #000
chart.resizable
Defaulting to false, this determines whether your graph 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

### Line properties

chart.line
Whether to show a connecting line (like in the sixth example).
Default: false
chart.line.colors
The colors of the lines connecting the tick marks.
Default: ['green', 'red']
chart.line.shadow.color
The color of the lines shadow (if any).
Default: rgba(0,0,0,0) (invisible)
chart.line.shadow.offsetx
The X offset of the lines shadow.
Default: 3
chart.line.shadow.offsety
The Y offset of the lines shadow.
Default: 3
chart.line.shadow.blur
The severity of the line shadows blurring effect.
Default: 2
chart.line.stepped
Like the line chart, Scatter chart lines can be stepped by setting this to true
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 graph 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.defaultcolor
This is the default color of tick marks, which is used if a color isn't given.
Default: #000
chart.boxplot.width
This stipulates the default width of boxes. For more on boxplots, see here.
Default: 8

#### Box 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. The example page shows a box plot. These values are (in order):

- Lower whisker
- Bottom of box
- Middle value (which isn't necessarily in the center of the box - this depends on your data)
- Top of box
- Upper whisker
- Upper color (optional)
- Lower color (optional)
- Width (optional)

    <script>
        scatter8 = new RGraph.Scatter('scatter8', [
                                                   [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]]
                                                  ]);
        scatter8.Set('chart.title', 'An example of a boxplot');
        scatter8.Set('chart.labels', ['Q1', 'Q2', 'Q3', 'Q4']);
        scatter8.Set('chart.xmax', 365);
        scatter8.Set('chart.ymax', 50);
        scatter8.Set('chart.boxplot.width', 12); // The default width
        scatter8.Draw();
    </script>

#### Specific points for labels on the X axis

Instead of a simple string which is used as the label, each entry of the chart.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('chart.labels', [
                                 ['Quarter 1', 0],
                                 ['Quarter 2', 90],
                                 ['Quarter 3', 181],
                                 ['Quarter 4', 273]
                                ]);