KParts

KParts is a component framework within the KDE platform that enables applications to embed external components, known as parts, inside their user interfaces. A part is a self-contained component that provides a user interface, typically a widget, and a defined set of capabilities exposed through a common host-controlled API. The host application acts as a container, loading parts at runtime and embedding the part’s widget into its window.

Parts are designed to maximize code reuse by allowing the same component to be used in multiple applications. For example, a file viewer or document editor part can be embedded in different hosts such as a file manager or a web browser. Parts are distributed as plugins and discovered through KDE’s service framework, using a service description that identifies how to create the part’s widget. The host uses the KParts framework to instantiate the part, connect signals and slots, and pass data to and from the part, such as a document to display or a URL to load.

Typical workflow involves the host requesting a part by type or mime type. The KParts loader finds a suitable part, creates it, and provides its widget for embedding. The host may then call methods on the part to initialize it and to exchange data, while the part emits events in response to user interaction. When the embedded experience is no longer needed, the host unloads the part.

Historically, KParts has been used in several KDE applications to provide pluggable views and editors, most notably in Konqueror. The framework emphasizes modularity, plugin-based distribution, and runtime composition of applications within the KDE ecosystem.