RmlUi has a simple, straightforward system for writing plugins. Plugins receive notification when contexts and elements are created and destroyed.
Creating a plugin
All plugins derive from the
Rml::Plugin class. The virtual functions that can be overridden are:
// Called when RmlUi is initialised. virtual void OnInitialise(); // Called when RmlUi shuts down. virtual void OnShutdown(); // Called when a document load request occurs, before the document's file is opened. virtual void OnDocumentOpen(Context* context, const Rml::String& document_path); // Called when a document is successfully loaded from file or instanced, initialised and added to its context. This is called before the document's 'load' event. virtual void OnDocumentLoad(ElementDocument* document); // Called when a document is unloaded from its context. This is called after the document's 'unload' event. virtual void OnDocumentUnload(ElementDocument* document); // Called when a new context is created. virtual void OnContextCreate(Rml::Context* context); // Called when a context is destroyed. virtual void OnContextDestroy(Rml::Context* context); // Called when a new element is created. virtual void OnElementCreate(Rml::Element* element); // Called when an element is destroyed. virtual void OnElementDestroy(Rml::Element* element);
RmlUi engine events
OnInitialise() function will be called on all registered plugins when RmlUi is successfully initialised. If RmlUi is already initialised when a plugin is registered,
OnInitialise() will be immediately called on the plugin.
OnShutdown() is called on all registered plugins when RmlUi is shut down, immediately after all the contexts and elements are destroyed. Plugins must release any resources they have allocated, including themselves, during this call.
OnDocumentOpen() is called when a RML stream is opened,
OnDocumentUnload() are global callbacks called before and after the documents load and unload respectively.
OnContextDestroy() are called on every registered plugin when a context is successfully created or destroyed.
OnElementDestroy() are called on every registered plugin when an element is successfully created or destroyed.
Registering a plugin
To register a plugin, call the
Rml::Plugin* plugin = new CustomPlugin(); Rml::RegisterPlugin(plugin);