class MouseEventHandler

The MouseEventHandler class encapsulates a mouse event handler callback function.

class MouseEventHandler : public ListElement<MouseEventHandler>

MouseEventHandler(HandlerCallback *callback, void *cookie = nullptr);

callback	The callback function to invoke when a mouse event occurs.
cookie	The cookie that is passed to the event handler as its last parameter.

The MouseEventHandler class encapsulates a callback function that is invoked when a mouse event occurs. Once an instance of the MouseEventHandler class has been constructed, it can be installed by calling the Engine::InstallMouseEventHandler function.

When a mouse event occurs, the callback functions corresponding to all installed mouse event handlers are invoked. The HandlerCallback type is defined as follows.

typedef bool HandlerCallback(const MouseEventData *eventData, void *cookie);

The eventType field of the MouseEventData structure specifies what type of mouse event occurred and can be one of the following constants.

kEventMouseDown	The left mouse button was pressed.
kEventMouseUp	The left mouse button was released.
kEventRightMouseDown	The right mouse button was pressed.
kEventRightMouseUp	The right mouse button was released.
kEventMiddleMouseDown	The middle mouse button was pressed.
kEventMiddleMouseUp	The middle mouse button was released.
kEventMouseMoved	The mouse location was moved.
kEventMouseWheel	The mouse wheel was moved.

For mouse down, mouse up, mouse moved, and mouse wheel events, the mousePosition field of the MouseEventData structure specifies the screen coordinates at which the mouse event occurred. For the kEventMouseWheel event, the wheelDelta member specifies how far the wheel was moved in the x and y directions. (Currently, the x delta is always zero.)

The cookie parameter is the value passed to the MouseEventHandler constructor.

The value returned by the callback function specifies whether the mouse event was successfully handled. If the callback function returns true, then the mouse event is considered handled, and no further mouse event handlers will be called for the same event. If the callback function returns false, then the event is passed to the next mouse event handler.

A mouse event handler is uninstalled by destroying its associated class instance.

ListElement<MouseEventHandler>

Used internally to store all instances of MouseEventHandler in a list.