package ui import ( "sync" "git.kirsle.net/apps/doodle/events" "git.kirsle.net/apps/doodle/render" ) // Event is a named event that the supervisor will send. type Event int // Events. const ( NullEvent Event = iota MouseOver MouseOut MouseDown MouseUp Click KeyDown KeyUp KeyPress ) // Supervisor keeps track of widgets of interest to notify them about // interaction events such as mouse hovers and clicks in their general // vicinity. type Supervisor struct { lock sync.RWMutex widgets []Widget hovering map[int]interface{} clicked map[int]interface{} } // NewSupervisor creates a supervisor. func NewSupervisor() *Supervisor { return &Supervisor{ widgets: []Widget{}, hovering: map[int]interface{}{}, clicked: map[int]interface{}{}, } } // Loop to check events and pass them to managed widgets. func (s *Supervisor) Loop(ev *events.State) { var ( XY = render.Point{ X: ev.CursorX.Now, Y: ev.CursorY.Now, } ) // See if we are hovering over any widgets. for id, w := range s.widgets { if w.Hidden() { // TODO: somehow the Supervisor wasn't triggering hidden widgets // anyway, but I don't know why. Adding this check for safety. continue } var ( P = w.Point() S = w.Size() P2 = render.Point{ X: P.X + S.W, Y: P.Y + S.H, } ) if XY.X >= P.X && XY.X <= P2.X && XY.Y >= P.Y && XY.Y <= P2.Y { // Cursor has intersected the widget. if _, ok := s.hovering[id]; !ok { w.Event(MouseOver, XY) s.hovering[id] = nil } _, isClicked := s.clicked[id] if ev.Button1.Now { if !isClicked { w.Event(MouseDown, XY) s.clicked[id] = nil } } else if isClicked { w.Event(MouseUp, XY) w.Event(Click, XY) delete(s.clicked, id) } } else { // Cursor is not intersecting the widget. if _, ok := s.hovering[id]; ok { w.Event(MouseOut, XY) delete(s.hovering, id) } if _, ok := s.clicked[id]; ok { w.Event(MouseUp, XY) delete(s.clicked, id) } } } } // Present all widgets managed by the supervisor. func (s *Supervisor) Present(e render.Engine) { s.lock.RLock() defer s.lock.RUnlock() for _, w := range s.widgets { w.Present(e, w.Point()) } } // Add a widget to be supervised. func (s *Supervisor) Add(w Widget) { s.lock.Lock() s.widgets = append(s.widgets, w) s.lock.Unlock() }