Migrated window.go and sysdata.go to the new API. Controls will need to be migrated as well.

sysdata.go

@@ -2,21 +2,15 @@
 
 package ui
 
-const eventbufsiz = 100 // suggested by skelterjohn
-
-// newEvent returns a new channel suitable for listening for events.
-func newEvent() chan struct{} {
-	return make(chan struct{}, eventbufsiz)
-}
-
 // The sysData type contains all system data. It provides the system-specific underlying implementation. It is guaranteed to have the following by embedding:
 type cSysData struct {
 	ctype     int
-	event     chan struct{}
 	allocate    func(x int, y int, width int, height int, d *sysSizeData) []*allocation
 	spaced	bool
 	alternate bool        // editable for Combobox, multi-select for listbox, password for lineedit
-	handler   AreaHandler // for Areas
+	handler   AreaHandler // for Areas; TODO rename to areahandler
+	winhandler	WindowHandler	// for Windows
+	event	func()		// provided by each widget
 }
 
 // this interface is used to make sure all sysDatas are synced
@@ -44,19 +38,6 @@ var _xSysData interface {
 	setChecked(bool)
 } = &sysData{} // this line will error if there's an inconsistency
 
-// signal sends the event signal. This raise is done asynchronously to avoid deadlocking the UI task.
-// Thanks skelterjohn for this techinque: if we can't queue any more events, drop them
-func (s *cSysData) signal() {
-	if s.event != nil {
-		go func() {
-			select {
-			case s.event <- struct{}{}:
-			default:
-			}
-		}()
-	}
-}
-
 const (
 	c_window = iota
 	c_button

window.go

@@ -4,17 +4,10 @@ package ui
 
 import (
 	"fmt"
-	"sync"
 )
 
 // Window represents an on-screen window.
 type Window struct {
-	// Closing gets a message when the user clicks the window's close button.
-	// You cannot change it once the Window has been created.
-	// If you do not respond to this signal, nothing will happen; regardless of whether you handle the signal or not, the window will not be closed.
-	Closing chan struct{}
-
-	lock       sync.Mutex
 	created    bool
 	sysData    *sysData
 	initTitle  string
@@ -22,24 +15,44 @@ type Window struct {
 	initHeight int
 	shownOnce  bool
 	spaced	bool
+	handler	WindowHandler
 }
 
+// WindowHandler represents an event handler for a Window and all its child Controls.
+// 
+// When an event on a Window or one of its child Controls comes in, the respect Window's handler's Event() method is called. The method call occurs on the main thread, and thus any call to any package ui method can be performed.
+// 
+// Each Event() call takes two parameters: the event ID and a data argument. For most events, the data argument is a pointer to the Control that triggered the event.
+// 
+// For Closing, the data argument is [TODO].
+// 
+// For any event >= CustomEvent, the data argument is the argument passed to the Window's SendEvent() method.
+type WindowHandler interface {
+	Event(e Event, data interface{})
+}
+
+// Event represents an event; see WindowHandler for details.
+// All event values >= CustomEvent are available for program use.
+type Event int
+const (
+	Closing Event = iota			// Window close
+	Clicked					// Button click
+	CustomEvent = 5000		// very high number; higher than the package would ever need, anyway
+)
+
 // NewWindow allocates a new Window with the given title and size. The window is not created until a call to Create() or Open().
-func NewWindow(title string, width int, height int) *Window {
+func NewWindow(title string, width int, height int, handler WindowHandler) *Window {
 	return &Window{
 		sysData:    mksysdata(c_window),
 		initTitle:  title,
 		initWidth:  width,
 		initHeight: height,
-		Closing:    newEvent(),
+		handler:		handler,
 	}
 }
 
 // SetTitle sets the window's title.
 func (w *Window) SetTitle(title string) {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
 	if w.created {
 		w.sysData.setText(title)
 		return
@@ -49,9 +62,6 @@ func (w *Window) SetTitle(title string) {
 
 // SetSize sets the window's size.
 func (w *Window) SetSize(width int, height int) (err error) {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
 	if w.created {
 		err := w.sysData.setWindowSize(width, height)
 		if err != nil {
@@ -70,9 +80,6 @@ func (w *Window) SetSize(width int, height int) (err error) {
 // This property is visible recursively throughout the widget hierarchy of the Window.
 // This property cannot be set after the Window has been created.
 func (w *Window) SetSpaced(spaced bool) {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
 	if w.created {
 		panic(fmt.Errorf("Window.SetSpaced() called after window created"))
 	}
@@ -87,14 +94,10 @@ func (w *Window) Open(control Control) {
 
 // Create creates the Window, setting its control to the given control. It does not show the window. This can only be called once per window, and finalizes all initialization of the control.
 func (w *Window) Create(control Control) {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
 	if w.created {
 		panic("window already open")
 	}
 	w.sysData.spaced = w.spaced
-	w.sysData.event = w.Closing
 	err := w.sysData.make(nil)
 	if err != nil {
 		panic(fmt.Errorf("error opening window: %v", err))
@@ -116,9 +119,6 @@ func (w *Window) Create(control Control) {
 
 // Show shows the window.
 func (w *Window) Show() {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
 	if !w.shownOnce {
 		w.shownOnce = true
 		err := w.sysData.firstShow()
@@ -132,9 +132,6 @@ func (w *Window) Show() {
 
 // Hide hides the window.
 func (w *Window) Hide() {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
 	w.sysData.hide()
 }
 
@@ -142,9 +139,6 @@ func (w *Window) Hide() {
 // The concept of "screen" in the case of a multi-monitor setup is implementation-defined.
 // It presently panics if the Window has not been created.
 func (w *Window) Center() {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
 	if !w.created {
 		panic("attempt to center Window before it has been created")
 	}