layerAdded

Layeradded is a term used in software engineering to describe the event or notification that a new layer has been added to a layered system. In graphics, user interfaces, and game engines, a layer often represents a visual or logical grouping within a scene graph or rendering stack. The label layeradded is usually a convention rather than a universal standard, appearing as an event name or callback such as layerAdded, onLayerAdded, or similar, depending on the framework.

When a layer is added, implementations typically perform several steps. They may update the hierarchical structure to include the new layer as a child of a parent layer, allocate or initialize resources, set up coordinate transforms, and integrate the layer into rendering, hit testing, and layout pipelines. The timing of the event relative to rendering and layout varies by framework; some fire the notification immediately after attachment, others during the next layout pass. In event-driven designs, handlers often use the signal or listener pattern to react, perform initialization, or adjust ordering within the layer stack.

Variations exist across platforms. In some toolkits, the equivalent may be called a different name, such as a childAdded, itemInserted, or layerCreated. The concept generally exists wherever a scene or UI is composed of layered elements.

See also: layerremoved, scene graph, rendering pipeline, event-driven architecture.