Describes all the possible graphical representations available in the JViews Charts library and a presentation of their implementation.

The Polyline charts have the following characteristics:

 

IlvSinglePolylineRenderer Properties

A single polyline renderer can draw an additional marker for each data point. This marker is an instance of an implementation of the IlvMarker interface, and is set by means of the setMarker method. You can also specify the rendering style of the marker symbol with the setMarkerStyleBy default, the style of the marker is computed according to the style of the renderer.

IlvPolylineChartRenderer Properties

This renderer supports three representation modes: Superimposed, Stacked, and Stacked100.

Superimposed Mode

Polylines are drawn on top of each other.

Stacked Mode

Polylines are stacked, so that each one displays the contribution of a y-value in a set of several y-values.

Stacked100 Mode

The contribution of a y-value is computed as a percentage of all the y-values for a given x-value.

The representation mode can be set either at construction time specifying a corresponding IlvPolylineChartRenderer mode constant as parameter of the constructor, or by means of the setMode method.

The Area charts have the following characteristics:

 

IlvSingleAreaRenderer Properties

This class inherits from the IlvSinglePolylineRenderer properties previously listed, except for the graphical representation that represents a data set as an area instead of polylines.

IlvAreaChartRenderer Properties

This class inherits from the IlvPolylineChartRenderer representation modes listed in section IlvPolylineChartRenderer Properties.

The Bar charts have the following characteristics:

 

IlvBarChartRenderer properties

A bar chart renderer supports five representation modes: Superimposed, Clustered, Stacked, Stacked100, and Stacked Diverging.

Superimposed mode

Bars are drawn on top of each other.

Clustered mode

Bars are laid out in clusters, each cluster representing the set of y-values corresponding to a given x-value. The default cluster width can be modified by means of the setClusterWidth method.

Stacked mode

Bars are stacked, so that each one displays the contribution of a y-value in a set of several y-values.

Stacked100 mode

The contribution of a y-value is computed as a percentage of all the y-values for a given x-value.

Stacked Diverging mode

Bar are stacked, in a way that accommodate negative values. In this mode, negative values are stacked separately from positive values: positive y values will be stacked together in a bar towards positive values, and negative y values will be stacked together in a bar in the opposite direction.

This rendering mode makes it easy to visually understand negative values.

Customizing the bar width

The width of a bar is determined as a certain percentage of the normal distance of consecutive x values of the data set. By default, this normal distance is computed automatically; this is adequate for data sets for which the x values are all distributed in equal distance. For data sets with irregularities such as holes, this normal distance can be explicitly specified through the method setCategory. The percentage can be specified through the renderer method setWidthPercent.

The Bubble charts have the following characteristics:

 

IlvSingleBubbleRenderer Properties

A bubble chart represents a two-dimensional data model as bubbles of variable size. The data model should be described by two data sets, the first data set determining the location of the bubbles, and the second data set determining the size of the bubbles.

IlvBubbleChartRenderer Properties

An IlvBubbleChartRenderer creates one child renderer for every pair of data sets contained in its data source.

The High/Low charts have the following characteristics:

 

IlvSingleHiLoRenderer Properties

An IlvSingleHiLoRenderer instance renders two data sets that contain corresponding points at the same indices.

This class defines two rendering styles: a rise style and a fall style.

The rise style is used to draw the point pairs for which the first value is less than the second value.

The fall style is used to draw the point pairs for which the first value is greater than the second value.

The possible graphical representations supported by this class are Bar, Arrow, Marked, and Stick, and are illustrated in Graphical Representations: Bar, Arrow, Marked, and Stick:

IlvHiLoChartRenderer Properties

This renderer supports three representation modes: Clustered, OpenClose, and Candle.

Clustered Mode

This class creates an instance of IlvSingleHiLoRenderer for every pair of data sets contained in its data source, and the creation of the associated legend item is delegated to the child renderer createLegendItems method.

OpenClose Mode

This class handles two pairs of data sets: the first pair for the low/high values, the second pair for the open/close values, each pair being rendered by a child renderer, respectively of type Stick and Marked. In this mode, the legend item creation is directly handled by the composite renderer.

Candle Mode

This class handles two pairs of data sets as for the OpenClose mode, the low/high values being rendered with a Marked child renderer, the Open/Close values with a Bar child renderer. In this mode, the legend item creation is directly handled by the composite renderer.

The Pie charts have the following characteristics:

 

IlvSinglePieRenderer Properties

This class renders a data set as a pie chart. Each data point of a data set is rendered as a slice.

Specific slices of an IlvSinglePieRenderer can be exploded from the pie chart using the setExploded method. The explode ratio of a slice can be changed by means of the setExplodeRatio method.

This renderer defines one rendering style for each data point, so that each slice of the pie is drawn using its own rendering style.

IlvPieChartRenderer properties

A Pie chart can be drawn with a hole in its center. This type of chart is called a doughnut chart. The hole size is expressed as a percentage of the available space that the hole will occupy. Pie renderers are usually added to pie charts but can also be used with other chart type (Cartesian for example).

The Scatter charts have the following characteristics:

 

IlvSingleScatterRenderer Properties

This class renders a data set with scattered graphical markers. Markers are simple graphical objects implementing the IlvMarker interface, and markers of predefined type can be retrieved through the IlvMarkerFactory class.

A scatter renderer draws square markers by default. You can change this marker by means of the setMarker method, passing a new IlvMarker instance as parameter.

The marker size can be changed at any time by means of the setMarkerSize method, passing the half-size of the marker as parameter.

IlvScatterChartRenderer Properties

This renderer class displays data sets as several scatter charts. Each data set is drawn by its own child renderer using a specified marker type. The marker used to draw the graphical representations can either be common to all child renderers, specified at construction time, or specific to a child renderer, by changing its own marker. By default, each data set is drawn using square markers.

The Stair charts have the following characteristics:

 

IlvSingleStairRenderer Properties

This class inherits from the IlvSingleAreaRenderer properties, except that the graphical representation represents a transition between two values as a stair instead of straight lines.

IlvStairChartRenderer Properties

This class inherits from the IlvPolylineChartRenderer properties.

x_n is x with subscript n, that is, x_n in HTML.

In stair charts, unlike in other types of charts, the last point of a data set is not represented like the previous data points. Namely, the representation of the data set ends immediately after the last point. This is surprising, but it gives you complete flexibility on how to terminate the data set.

In stacked or summed charts, normally the first alternative is used.

A treemap chart displays objects as rectangles. The important objects are represented by large areas while the less important objects are represented by smaller areas, as illustrated in Treemap Chart.

In a treemap chart, rectangles relate each other in a containment structure, where each rectangle is part of another rectangle. As illustrated in Treemap Chart, Cost of manufacturing is part of the Cost of revenues, which itself is part of Expenses. Graphically, this relationship is displayed as follows: the rectangle associated with Cost of manufacturing occupies part of the area of the rectangle associated with Cost of revenues, and the latter is part of the area for Expenses.

Expenses is the root of the model: it is not a part of a bigger budget. This is why the Expenses rectangle occupies the entire treemap chart area.

The treemap chart can also be used to display structured data sets with 4 to 10 dimensions of data. (Other types of 2D charts can show data sets with usually up to 3 dimensions of data.) In other words, if you have a table with many rows and 4 to 10 columns, the treemap is the most appropriate chart to display your data.

The treemap chart is a generalization of the pie chart. They share the feature that important objects are represented by large areas and less important objects by smaller areas. But where a pie chart displays a linear list of objects, treemaps display a tree of objects.

The input data of a treemap chart is represented by an IlvTreeTableDataSource instance. See Structure of the extended data model for a description on how to connect to an IlvTreeTableDataSource.

IlvTreemapChartRenderer Properties

The Treemap charts have the following characteristics:

 

Setting the Area Column

The treemap chart can be applied to any entity that can be partitioned into disjointed parts.

In a treemap chart display, the most important setting is the object attribute (or model column) which is translated into the area representing the object.

The area value must meet the following requirements:

The area, and its notion of importance, depends on the application domain. Here are a few examples:

When the objects are indivisible and have the same importance, you can assign the same area to all objects.

The area values are normalized by the treemap renderer; therefore the scaling of the area values does not matter: the rendering will not change if all area values are multiplied by a fixed constant factor.

The area column is set by means of the methods setAreaColumn or setAreaColumnName.

Setting the Color Scheme

Besides the area, the color is the most visible attribute of an object in a treemap chart.

The expressiveness of the treemap depends on the color column and the color scheme. The color column depends on the type of application. The color scheme is used to distinguish the important properties of the objects.

The color is chosen according to what the user wants to see in the view. It is determined by a model column, called the color column, and a color scheme. The color column yields the numerical values that are represented through the color. The color scheme converts the numerical values into color; it has the ability to emphasize some types of value.

The color scheme is set by means of the method setColorScheme. The color column is set by means of the methods setColorColumn or setColorColumnName.

The color scheme is selected together with the color column. The values of this column are transformed into a color.

There are also color schemes that do not use a color column at all: