Pentaho offers many embeddable structures, not just the Pentaho Reporting engine engine. You can also embed or extend the Pentaho Analyzer engine (Mondrian), the Pentaho BI Platform, part or all of Pentaho Data Integration (Kettle), and the Weka data mining engine. This section is focused on reporting, however, so the below scenarios only involve the reporting components of Pentaho Business Analytics.
Build a custom reporting tool
Pentaho Report Designer is built on the Pentaho Reporting engine, as is the interactive reporting functionality built into the Pentaho User Console in the BI Platform. If you need a graphical report creation tool, it would be easier to modify Report Designer than it would be to rewrite it from scratch. For web-based interactive reporting, you will have an easier time embedding the entire BI Platform than trying to isolate and embed just the interactive component
Hack the Pentaho Report Designer
Report Designer is both modular and extensible, so you can remove or disable large portions of it, or create your own custom data sources, output formats, formulas, and functions. You can also customize Report Designer with your own background images, icons, language, and splash screen
Embed the Pentaho BI platform
The BI Platform is the heart of the larger Pentaho Server, which is a complete J2EE web application that provides engines for Pentaho Reporting, Data Integration, and Analyzer, as well as a fully customizable web-based user interface that offers interactive reporting, real-time Analyzer views, and interactive dashboard creation.
The Pentaho Server is fully customizable, so your options range from simple rebranding to removing entire components or developing your own plugins to add major user-facing functionality.