Stacked area chart

Version: 4.2

Stacked Area chart

A stacked area chart is a way of plotting data points on a filled line. Often, it is used to show trend data, or the comparison of two data sets.

Programmatically, you could use a stacked area chart as following:

// creates the chart    
StackedAreaChart chart = new StackedAreaChart();
// adds to DOM
component.add(chart);
...
// example for Elemental2
// gets the chart instance as DOM element
Element element = chart.getChartElement().as();
// adds to DOM
DomGlobal.document.body.appendChild(element);

By UIBinder (ONLY for GWT), you could use a stacked area chart as following:

<ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder"
   xmlns:g="urn:import:com.google.gwt.user.client.ui"
   xmlns:c="urn:import:org.pepstock.charba.client.gwt.widgets">

   <g:HTMLPanel  width="100%">
      ....
      <c:StackedAreaChartWidget ui:field="chart"/>
      ...
   </g:HTMLPanel>
</ui:UiBinder> 

Dataset

The stacked area chart allows a number of properties to be specified for each stacked area dataset. These are used to set display properties for a specific dataset.

Every chart has got a method to create a typed dataset accordingly with the chart type. The dataset can be also created instantiating the constructor.

// creates the chart
StackedAreaChart chart = new StackedAreaChart();
// creates the dataset
StackedAreaDataset dataset = chart.newDataset();
// sets the option
dataset.setBackgroundColor(HtmlColor.RED);
...
// creates the dataset
StackedAreaDataset datasetNew = new StackedAreaDataset();
// sets the option
datasetNew.setBackgroundColor(HtmlColor.RED);
...
// sets the datasets to the chart
chart.getData().setDatasets(dataset, datasetNew);

The following are the attributes that you can set:

Name	Type	Scriptable	Description
backgroundColor	String - IsColor - Pattern - Gradient	Yes	The fill color/pattern under the line.
borderCapStyle	CapStyle	Yes	Cap style of the line. See MDN.
borderColor	String - IsColor - Gradient	Yes	The color of the line.
borderDash	int[]	Yes	Length and spacing of dashes. See MDN.
borderDashOffset	double	Yes	Offset for line dashes. See MDN.
borderJoinStyle	JoinStyle	Yes	Line joint style. See MDN.
borderWidth	int	Yes	The width of the line in pixels.
cubicInterpolationMode	CubicInterpolationMode	Yes	Algorithm used to interpolate a smooth curve from the discrete data points.
clip	boolean - double - Clip	-	How to clip relative to chart area. Positive value allows overflow, negative value clips that many pixels inside chart area.
fill	String - int - boolean - IsFill	Yes	How to fill the area under the line. See Filling modes.
hoverBackgroundColor	String - IsColor - Pattern - Gradient	Yes	The fill color/pattern under the line, when hovered.
hoverBorderCapStyle	CapStyle	Yes	Cap style of the line, when hovered. See MDN.
hoverBorderColor	String - IsColor - Gradient	Yes	The color of the line, when hovered.
hoverBorderDash	int[]	Yes	Length and spacing of dashes, when hovered. See MDN.
hoverBorderDashOffset	int	Yes	Offset for line dashes, when hovered. See MDN.
hoverBorderJoinStyle	JoinStyle	Yes	Line joint style, when hovered. See MDN.
hoverBorderWidth	int	Yes	The width of the line in pixels, when hovered.
indexAxis	IndexAxis	-	The base axis of the dataset. 'IndexAxis.X' for horizontal lines and 'IndexAxis.Y' for vertical lines.
label	String	-	The label for the dataset which appears in the legend and tooltips.
normalized	boolean	-	If `true`, you provide data with indices that are unique, sorted, and consistent across data sets and provide the normalized.
order	int	-	The drawing order of dataset. Also affects order for stacking, tooltip, and legend.
parsing	boolean	-	If `false`, the data set parsing is disable. If parsing is disabled, data must be sorted and in the formats the associated chart type and scales use internally.
pointBackgroundColor	String[] - IsColor[] - Gradient[]	Yes	The fill color for points.
pointBorderColor	String[] - IsColor[] - Gradient[]	Yes	The border color for points.
pointBorderWidth	int[]	Yes	The width of the point border in pixels.
pointHitRadius	double[]	Yes	The pixel size of the non-displayed point that reacts to mouse events.
pointHoverBackgroundColor	String[] - IsColor[] - Gradient[]	Yes	Point background color when hovered.
pointHoverBorderColor	String[] - IsColor[] - Gradient[]	Yes	Point border color when hovered.
pointHoverBorderWidth	int[]	Yes	Border width of point when hovered.
pointHoverRadius	double[]	Yes	The radius of the point when hovered.
pointRadius	double[]	Yes	The radius of the point shape. If set to 0, the point is not rendered.
pointRotation	double[]	Yes	The rotation of the point in degrees.
pointStyle	PointStyle[] - Img[] - Canvas[]	Yes	Style of the point.
showLine	boolean	-	If `false`, the line is not drawn for this dataset.
spanGaps	boolean - double	-	If `true`, lines will be drawn between points with no or null data. If `false`, points with `NaN` data will create a break in the line. Can also be a number specifying the maximum gap length to span. The unit of the value depends on the scale used.
stepped	Stepped	-	If the line is shown as a stepped line.
tension	double	-	Bezier curve tension of the line. Set to 0 to draw straight lines. This option is ignored if monotone cubic interpolation is used.
xAxisID	String	-	The ID of the x axis to plot this dataset on.
yAxisID	String	-	The ID of the y axis to plot this dataset on.

General

The general options for a stacked area dataset can control behaviors not related to styling or interactions and they are the following:

Name	Defaults	Description
clip	Undefined.DOUBLE	How to clip relative to chart area.
indexAxis	IndexAxis.X	The base axis of the dataset.
label	`null`	The label for the dataset which appears in the legend and tooltips.
normalized	`false`	If `true`, you provide data with indices that are unique, sorted, and consistent across data sets and provide the normalized.
order	0	The drawing order of dataset. Also affects order for stacking, tooltip, and legend.
parsing	`true`	If `false`, the data set parsing is disable. If parsing is disabled, data must be sorted and in the formats the associated chart type and scales use internally.
xAxisID	DefaultScaleId.X	The ID of the x axis to plot this dataset on.
yAxisID	DefaultScaleId.Y	The ID of the y axis to plot this dataset on.

Point styling

The style of each point of the dataset can be configured by the following properties:

Name	Description
pointBackgroundColor	The fill color for points.
pointBorderColor	The border color for points.
pointBorderWidth	The width of the point border in pixels.
pointHitRadius	The pixel size of the non-displayed point that reacts to mouse events.
pointRadius	The radius of the point shape.
pointRotation	The rotation of the point in degrees.
pointStyle	Style of the point.

All above options have got the fallback to the associated Point elements, retrievable by the following statements:

// from chart instance
Point point = chart.getOptions().getElements().getPoint();
// sets options for all line datasets of the chart
point.setRadius(6);
...
// from defaults
Point defaultPoint  = Defaults.get().getGlobal().getElements().getPoint();
// sets options for all line datasets of all charts
defaultPoint.setRadius(6);

Line styling

The style of each line of the dataset can be configured by the following properties:

Name	Description
backgroundColor	The fill color under the line.
borderCapStyle	Cap style of the line.
borderColor	The color of the line.
borderDash	Length and spacing of dashes.
borderDashOffset	Offset for line dashes.
borderJoinStyle	Line joint style
borderWidth	The width of the line in pixels.
cubicInterpolationMode	Algorithm used to interpolate a smooth curve from the discrete data points.
fill	How to fill the area under the line.
stepped	If the line is shown as a stepped line.
tension	Bezier curve tension of the line.

All above options have got the fallback to the associated Line elements, retrievable by the following statements:

// from chart instance
Line line = chart.getOptions().getElements().getLine();
// sets options for all line datasets of the chart
line.setBorderWidth(6);
...
// from defaults
Line defaultLine  = Defaults.get().getGlobal().getElements().getLine();
// sets options for all line datasets of all charts
defaultLine.setBorderWidth(6);

Point interactions

The interaction with each point can be controlled with the following properties:

Name	Description
pointHoverBackgroundColor	Point background color when hovered.
pointHoverBorderColor	Point border color when hovered.
pointHoverBorderWidth	Border width of point when hovered.
pointHoverRadius	The radius of the point when hovered.

All above options have got the fallback to the associated Point elements, retrievable by the following statements:

// from chart instance
Point point = chart.getOptions().getElements().getPoint();
// sets options for all line datasets of the chart
point.setRadius(6);
...
// from defaults
Point defaultPoint  = Defaults.get().getGlobal().getElements().getPoint();
// sets options for all line datasets of all charts
defaultPoint.setRadius(6);

Line interactions

The interaction with each line can be controlled with the following properties:

Name	Description
hoverBackgroundColor	The fill color under the line, when hovered.
hoverBorderCapStyle	Cap style of the line, when hovered.
hoverBorderColor	The color of the line, when hovered.
hoverBorderDash	Length and spacing of dashes, when hovered.
hoverBorderDashOffset	Offset for line dashes, when hovered.
hoverBorderJoinStyle	Line joint style, when hovered.
hoverBorderWidth	The width of the line in pixels, when hovered.

All above options have got the fallback to the associated Line elements, retrievable by the following statements:

// from chart instance
Line line = chart.getOptions().getElements().getLine();
// sets options for all line datasets of the chart
line.setBorderWidth(6);
...
// from defaults
Line defaultLine  = Defaults.get().getGlobal().getElements().getLine();
// sets options for all line datasets of all charts
defaultLine.setBorderWidth(6);

Scriptable

Scriptable options at dataset level accept a callback which is called for each of the underlying data values. See more details in Configuring charts section.

// creates chart
StackedAreaChart chart = new StackedAreaChart();
// creates dataset
StackedAreaDataset dataset = chart.newDataset();
// sets the option by a callback 
dataset.setBackgroundColor(new ColorCallback<DatasetContext>(){

   @Override
   public IsColor invoke(DatasetContext context){
      // logic
      return color;
   }
});

The following options can be set by a callback:

Name	Callback	Returned types
backgroundColor	ColorCallback<DatasetContext>	String - IsColor - Pattern - Gradient
borderCapStyle	CapStyleCallback<DatasetContext>	CapStyle
borderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
borderDash	BorderDashCallback<DatasetContext>	List<Integer>
borderDashOffset	BorderDashOffsetCallback<DatasetContext>	double
borderJoinStyle	JoinStyleCallback<DatasetContext>	JoinStyle
borderWidth	WidthCallback<DatasetContext>	int
cubicInterpolationMode	CubicInterpolationModeCallback	CubicInterpolationMode
fill	FillCallback	String - int - boolean - IsFill
hoverBackgroundColor	ColorCallback<DatasetContext>	String - IsColor - Pattern - Gradient
hoverBorderCapStyle	CapStyleCallback<DatasetContext>	CapStyle
hoverBorderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
hoverBorderDash	BorderDashCallback<DatasetContext>	List<Integer>
hoverBorderDashOffset	BorderDashOffsetCallback<DatasetContext>	int
hoverBorderJoinStyle	JoinStyleCallback<DatasetContext>	JoinStyle
hoverBorderWidth	WidthCallback<DatasetContext>	int
pointBackgroundColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointBorderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointBorderWidth	WidthCallback<DatasetContext>	int
pointHitRadius	RadiusCallback<DatasetContext>	double
pointHoverBackgroundColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointHoverBorderColor	ColorCallback<DatasetContext>	String - IsColor - Gradient
pointHoverBorderWidth	WidthCallback<DatasetContext>	int
pointHoverRadius	RadiusCallback<DatasetContext>	double
pointRadius	RadiusCallback<DatasetContext>	double
pointRotation	RotationCallback<DatasetContext>	double
pointStyle	PointStyleCallback	PointStyle - Img - Canvas

Data structure

The data of a dataset for a stacked area chart are passed by an array or list of doubles and the x axis is generally a category. When a stacked area chart is created with a category axis, the labels property of the data object must be specified.

// sets data as an array of doubles
dataset.setData(1,2,3,4,6);

// sets data as a list of double
List<Double> list = new LinkedList<>();
list.add(1);
list.add(2);
list.add(3);
dataset.setData(list);

Options

The stacked area chart specific options implementation to be configured. These options are merged with the global chart configuration options to form the options passed to the chart.

// creates chart
StackedAreaChart chart = new StackedAreaChart();
// gets the chart options
StackedOptions options = chart.getOptions();
// sets option
options.setResponsive(true);