package ui import ( "sync/atomic" "github.com/gdamore/tcell/v2" ) // Use unbuffered channels (always blocking unless somebody can read // immediately) We are merely using this as a proxy to tcell screen internal // event channel. var Events = make(chan tcell.Event) var Quit = make(chan struct{}) var Callbacks = make(chan func(), 50) // QueueFunc queues a function to be called in the main goroutine. This can be // used to prevent race conditions from delayed functions func QueueFunc(fn func()) { Callbacks <- fn } // Use a buffered channel of size 1 to avoid blocking callers of Invalidate() var Redraw = make(chan bool, 1) // Invalidate marks the entire UI as invalid and request a redraw as soon as // possible. Invalidate can be called from any goroutine and will never block. func Invalidate() { if atomic.SwapUint32(&state.dirty, 1) != 1 { Redraw <- true } } var state struct { content DrawableInteractive ctx *Context screen tcell.Screen popover *Popover dirty uint32 // == 1 if render has been queued in Redraw channel } func Initialize(content DrawableInteractive) error { screen, err := tcell.NewScreen() if err != nil { return err } if err = screen.Init(); err != nil { return err } screen.Clear() screen.HideCursor() screen.EnablePaste() width, height := screen.Size() state.content = content state.screen = screen state.ctx = NewContext(width, height, state.screen, onPopover) Invalidate() if beeper, ok := content.(DrawableInteractiveBeeper); ok { beeper.OnBeep(screen.Beep) } content.Focus(true) go state.screen.ChannelEvents(Events, Quit) return nil } func onPopover(p *Popover) { state.popover = p } func Exit() { close(Quit) } func Close() { state.screen.Fini() } func Render() { if atomic.SwapUint32(&state.dirty, 0) != 0 { // reset popover for the next Draw state.popover = nil state.content.Draw(state.ctx) if state.popover != nil { // if the Draw resulted in a popover, draw it state.popover.Draw(state.ctx) } state.screen.Show() } } func EnableMouse() { state.screen.EnableMouse() } func HandleEvent(event tcell.Event) { if event, ok := event.(*tcell.EventResize); ok { state.screen.Clear() width, height := event.Size() state.ctx = NewContext(width, height, state.screen, onPopover) Invalidate() } // if we have a popover, and it can handle the event, it does so if state.popover == nil || !state.popover.Event(event) { // otherwise, we send the event to the main content state.content.Event(event) } }