ButtonUpEvent

ButtonUpEvent is a user interface event that is raised when the primary input button on a button control is released. It signals the end of a press action and is often used to trigger a command or activation in response to a completed interaction. The exact timing and conditions for firing ButtonUpEvent vary by framework, and some systems distinguish ButtonUpEvent from a separate Click event.

In many toolkits, ButtonUpEvent is considered valid when the input button is released while the press began on the same control. Some implementations also fire the event if the release occurs while still over the control, while others require the pointer to remain within bounds at release to count as a click. It may be used in drag or cancel interactions, and can be part of a broader input model that tracks pointer state across a press-drag-release sequence.

Event payload typically includes the identity of the button or pointer, the position at release, a timestamp, and references to the target control. Handlers can inspect these fields to decide whether to perform the associated action, prevent further processing, or initiate follow-up gestures. Accessibility considerations may map ButtonUpEvent to corresponding activation semantics for keyboard or screen-reader users.

Platform examples vary but share a common role. Web environments expose pointerup or mouseup events that serve a ButtonUp-like function; many frameworks provide a ButtonUpEvent alias or translation. Desktop toolkits use MouseUp or MouseReleased events, while touch systems generate corresponding POINTER_UP or ACTION_UP events. Related events include ButtonDownEvent and ClickEvent, as well as PointerUp and TouchEnd in systems that separate raw pointer events from high-level button actions.