Perforce JViews Charts Sample: Parametric Charts

Description

This sample shows a parametric chart that displays a set of values against a set of other values.

How to Use the Sample

The main frame is split into two sub-panels:

The bottom panel contains two bar charts that display the price and performance of a set of products. Both charts are editable by clicking and dragging a point.
The top panel contains a scatter chart where:
- The performance is mapped on the y-axis.
- The price is mapped on the x-axis.

How to Run the Sample as an Application

This sample can be run as an application. The installation directory contains an executable JAR file, parametric.jar, that allows you to execute the sample with a double click from a file browser. Note that if you are using Internet Explorer, you can open the installation directory and execute the JAR file from the browser. This technique may not work in other Web browsers.

Alternatively, you can run the sample application from the command line. First check that the Ant utility is properly configured. If not, see the instructions on how to configure Ant for Perforce JViews.

Then, go to the installation directory of the sample and type:

ant run

Topics Covered

Using combined data sets to display parametric charts.
Subclassing IlvGradientRenderingHint and changing the values that are mapped into colors. In this sample, the color of a data point depends on the ratio between its y-value and its x-value.
Overridding the drawLegendSymbol() method of a chart renderer to display a legend symbol filled with a gradient.

Detailed Description

Parametric charts are perfect to see the correlation between two parameters. The parameters are assigned to the x axis and the y axis, respectively.

In this sample, we use a subclass of IlvCombinedDataSet to display a set of values against another set of values. Two charts are used to display the price and the performance of a set of products. A parametric data set is created from the price and performance data sets. This parametric data set is displayed by a scatter chart, where the color of each marker depends on the ratio between the performance and the price of the corresponding product (a green color indicates that the product has a good performance-price ratio, while a red color indicates that this ratio is poor).

The change of color is handled by a subclass ofIlvGradientRenderingHint. The transition values of the gradient are computed according to the best and worse ratio among the set of products. A listener is set on the parametric data set so that the transition values are updated if the best or the worse value changes. An editing interactor is set on the price and performance charts, which lets you change each product characteristic and witness the visual effect on the parametric chart.

Installation Directory

The Parametric Charts sample is installed here.