Add method for controlling focus

box.go

@@ -10,6 +10,8 @@ type Box struct {
 
 	children []Widget
 
+	focus bool
+
 	sync.Mutex
 }
 
@@ -31,6 +33,14 @@ func (b *Box) SetRect(r image.Rectangle) {
 	b.rect = r
 }
 
+func (b *Box) SetFocus(focus bool) {
+	b.focus = focus
+}
+
+func (b *Box) Focus() bool {
+	return b.focus
+}
+
 func (b *Box) Children() []Widget {
 	b.Lock()
 	defer b.Unlock()

examples/showcase/main.go

@@ -34,16 +34,13 @@ func main() {
 	w := etk.NewWindow()
 
 	// Input demo.
+	buffer := etk.NewText("Press enter to append input below to this buffer.")
+	onselected := func(text string) (handled bool) {
+		buffer.Write([]byte("\nInput: " + text))
+		return true
+	}
+	input := etk.NewInput(">", "", onselected)
 	{
-		buffer := etk.NewText("Press enter to append input below to this buffer.")
-
-		onselected := func(text string) (handled bool) {
-			buffer.Write([]byte("\nInput: " + text))
-			return true
-		}
-
-		input := etk.NewInput(">", "", onselected)
-
 		inputDemo := etk.NewFlex()
 		inputDemo.SetVertical(true)
 
@@ -85,6 +82,7 @@ func main() {
 	}
 
 	etk.SetRoot(w)
+	etk.SetFocus(input)
 
 	err := ebiten.RunGame(g)
 	if err != nil {

game.go

@@ -17,6 +17,8 @@ var (
 	lastX, lastY = -math.MaxInt, -math.MaxInt
 
 	touchIDs []ebiten.TouchID
+
+	focusedWidget Widget
 )
 
 func SetRoot(w Widget) {
@@ -24,6 +26,17 @@ func SetRoot(w Widget) {
 	if lastWidth != 0 || lastHeight != 0 {
 		root.SetRect(image.Rect(0, 0, lastWidth, lastHeight))
 	}
+	SetFocus(root)
+}
+
+func SetFocus(w Widget) {
+	if focusedWidget != nil {
+		focusedWidget.SetFocus(false)
+	}
+	focusedWidget = w
+	if w != nil {
+		w.SetFocus(true)
+	}
 }
 
 func Layout(outsideWidth, outsideHeight int) {
@@ -88,6 +101,21 @@ func Update() error {
 	return err
 }
 
+func getWidgetAt(w Widget, cursor image.Point) Widget {
+	if !cursor.In(w.Rect()) {
+		return nil
+	}
+	for _, child := range w.Children() {
+		if cursor.In(child.Rect()) {
+			result := getWidgetAt(child, cursor)
+			if result != nil {
+				return result
+			}
+		}
+	}
+	return w
+}
+
 func update(w Widget, cursor image.Point, pressed bool, clicked bool, mouseHandled bool, keyboardHandled bool) (bool, bool, error) {
 	var err error
 	children := w.Children()
@@ -105,7 +133,7 @@ func update(w Widget, cursor image.Point, pressed bool, clicked bool, mouseHandl
 			return false, false, fmt.Errorf("failed to handle widget mouse input: %s", err)
 		}
 	}
-	if !keyboardHandled {
+	if !keyboardHandled && w == focusedWidget {
 		keyboardHandled, err = w.HandleKeyboard()
 		if err != nil {
 			return false, false, fmt.Errorf("failed to handle widget keyboard input: %s", err)

input.go

@@ -3,14 +3,14 @@ package etk
 import (
 	"image"
 
-	"github.com/hajimehoshi/ebiten/v2"
-
 	"code.rocketnine.space/tslocum/messeji"
+	"github.com/hajimehoshi/ebiten/v2"
 )
 
 type Input struct {
 	*Box
-	Field *messeji.InputField
+	Field  *messeji.InputField
+	Cursor string
 }
 
 func NewInput(prefix string, text string, onSelected func(text string) (handled bool)) *Input {
@@ -30,8 +30,9 @@ func NewInput(prefix string, text string, onSelected func(text string) (handled
 	})
 
 	return &Input{
-		Box:   NewBox(),
-		Field: i,
+		Box:    NewBox(),
+		Field:  i,
+		Cursor: "_",
 	}
 }
 
@@ -55,6 +56,16 @@ func (i *Input) SetRect(r image.Rectangle) {
 	i.Field.SetRect(r)
 }
 
+func (i *Input) SetFocus(focus bool) {
+	i.focus = focus
+
+	cursor := i.Cursor
+	if !focus {
+		cursor = ""
+	}
+	i.Field.SetSuffix(cursor)
+}
+
 func (i *Input) HandleMouse(cursor image.Point, pressed bool, clicked bool) (handled bool, err error) {
 	return false, nil
 }

text.go

@@ -27,6 +27,10 @@ func NewText(text string) *Text {
 	}
 }
 
+func (t *Text) SetFocus(focus bool) {
+	// Do nothing.
+}
+
 func (t *Text) Children() []Widget {
 	t.Lock()
 	defer t.Unlock()

widget.go

@@ -9,6 +9,7 @@ import (
 type Widget interface {
 	Rect() image.Rectangle
 	SetRect(r image.Rectangle)
+	SetFocus(focus bool)
 	HandleMouse(cursor image.Point, pressed bool, clicked bool) (handled bool, err error)
 	HandleKeyboard() (handled bool, err error)
 	Draw(screen *ebiten.Image) error

window.go

@@ -66,7 +66,7 @@ func (w *Window) AddChildWithLabel(wgt Widget, label string) {
 	if label != "" {
 		w.hasLabel = true
 	}
-	
+
 	w.childrenUpdated()
 }