io/key: [API] introduce FocusFilter for matching focus and editor events

Signed-off-by: Elias Naur <mail@eliasnaur.com>

io/input/key.go

@@ -36,13 +36,14 @@ type keyQueue struct {
 type keyHandler struct {
 	// visible will be true if the InputOp is present
 	// in the current frame.
-	visible  bool
-	new      bool
-	hint     key.InputHint
-	order    int
-	dirOrder int
-	filter   key.Set
-	trans    f32.Affine2D
+	visible   bool
+	new       bool
+	focusable bool
+	hint      key.InputHint
+	order     int
+	dirOrder  int
+	filter    key.Set
+	trans     f32.Affine2D
 }
 
 type dirFocusEntry struct {
@@ -87,11 +88,7 @@ func (q *keyQueue) InputHint() (key.InputHint, bool) {
 }
 
 func (q *keyQueue) Reset() {
-	if q.handlers == nil {
-		q.handlers = make(map[event.Tag]*keyHandler)
-	}
 	for _, h := range q.handlers {
-		h.visible, h.new = false, false
 		h.order = -1
 		h.hint = key.HintAny
 	}
@@ -101,17 +98,24 @@ func (q *keyQueue) Reset() {
 
 func (q *keyQueue) Frame(events *handlerEvents) {
 	for k, h := range q.handlers {
-		if !h.visible {
-			delete(q.handlers, k)
+		if !h.visible || !h.focusable {
 			if q.focus == k {
-				// Remove focus from the handler that is no longer visible.
+				// Remove focus from the handler that is no longer focusable.
 				q.focus = nil
 				q.state = TextInputClose
 			}
-		} else if h.new && k != q.focus {
+			if !h.visible && !h.focusable {
+				delete(q.handlers, k)
+				continue
+			}
+		}
+		if h.new && k != q.focus {
 			// Reset the handler on (each) first appearance, but don't trigger redraw.
 			events.AddNoRedraw(k, key.FocusEvent{Focus: false})
 		}
+		h.new = false
+		h.visible = false
+		h.focusable = false
 	}
 	q.updateFocusLayout()
 }
@@ -284,10 +288,18 @@ func (q *keyQueue) softKeyboard(show bool) {
 	}
 }
 
+func (q *keyQueue) focusable(tag event.Tag) {
+	h := q.handlerFor(tag)
+	h.focusable = true
+}
+
 func (q *keyQueue) handlerFor(tag event.Tag) *keyHandler {
 	h, ok := q.handlers[tag]
 	if !ok {
 		h = &keyHandler{new: true, order: -1}
+		if q.handlers == nil {
+			q.handlers = make(map[event.Tag]*keyHandler)
+		}
 		q.handlers[tag] = h
 	}
 	return h
@@ -300,8 +312,8 @@ func (q *keyQueue) inputOp(op key.InputOp, t f32.Affine2D, area int, bounds imag
 		q.order = append(q.order, op.Tag)
 		q.dirOrder = append(q.dirOrder, dirFocusEntry{tag: op.Tag, area: area, bounds: bounds})
 	}
-	h.visible = true
 	h.filter = op.Keys
+	h.visible = true
 	h.trans = t
 }
 

io/input/key_test.go

@@ -22,12 +22,13 @@ func TestKeyWakeup(t *testing.T) {
 
 	var r Router
 	// Test that merely adding a handler doesn't trigger redraw.
+	r.Events(handler, key.FocusFilter{})
 	r.Frame(&ops)
 	if _, wake := r.WakeupTime(); wake {
 		t.Errorf("adding key.InputOp triggered a redraw")
 	}
 	// However, adding a handler queues a Focus(false) event.
-	if evts := r.Events(handler); len(evts) != 1 {
+	if evts := r.Events(handler, key.FocusFilter{}); len(evts) != 1 {
 		t.Errorf("no Focus event for newly registered key.InputOp")
 	}
 }
@@ -45,11 +46,15 @@ func TestKeyMultiples(t *testing.T) {
 	// The last one must be focused:
 	key.InputOp{Tag: &handlers[2]}.Add(ops)
 
+	for i := range handlers {
+		r.Events(&handlers[i], key.FocusFilter{})
+	}
+
 	r.Frame(ops)
 
-	assertKeyEvent(t, r.Events(&handlers[0]), false)
-	assertKeyEvent(t, r.Events(&handlers[1]), false)
-	assertKeyEvent(t, r.Events(&handlers[2]), true)
+	assertKeyEvent(t, r.Events(&handlers[0], key.FocusFilter{}), false)
+	assertKeyEvent(t, r.Events(&handlers[1], key.FocusFilter{}), false)
+	assertKeyEvent(t, r.Events(&handlers[2], key.FocusFilter{}), true)
 	assertFocus(t, r, &handlers[2])
 	assertKeyboard(t, r, TextInputOpen)
 }
@@ -68,12 +73,16 @@ func TestKeyStacked(t *testing.T) {
 	r.Source().Queue(key.SoftKeyboardCmd{Show: true})
 	key.InputOp{Tag: &handlers[3]}.Add(ops)
 
+	for i := range handlers {
+		r.Events(&handlers[i], key.FocusFilter{})
+	}
+
 	r.Frame(ops)
 
-	assertKeyEvent(t, r.Events(&handlers[0]), false)
-	assertKeyEvent(t, r.Events(&handlers[1]), true)
-	assertKeyEvent(t, r.Events(&handlers[2]), false)
-	assertKeyEvent(t, r.Events(&handlers[3]), false)
+	assertKeyEvent(t, r.Events(&handlers[0], key.FocusFilter{}), false)
+	assertKeyEvent(t, r.Events(&handlers[1], key.FocusFilter{}), true)
+	assertKeyEvent(t, r.Events(&handlers[2], key.FocusFilter{}), false)
+	assertKeyEvent(t, r.Events(&handlers[3], key.FocusFilter{}), false)
 	assertFocus(t, r, &handlers[1])
 	assertKeyboard(t, r, TextInputOpen)
 }
@@ -105,14 +114,18 @@ func TestKeyRemoveFocus(t *testing.T) {
 	// New InputOp without any focus:
 	key.InputOp{Tag: &handlers[1], Keys: "Short-Tab"}.Add(ops)
 
+	for i := range handlers {
+		r.Events(&handlers[i], key.FocusFilter{})
+	}
+
 	r.Frame(ops)
 
 	// Add some key events:
 	event := event.Event(key.Event{Name: key.NameTab, Modifiers: key.ModShortcut, State: key.Press})
 	r.Queue(event)
 
-	assertKeyEvent(t, r.Events(&handlers[0]), true, event)
-	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertKeyEvent(t, r.Events(&handlers[0], key.FocusFilter{}), true, event)
+	assertKeyEvent(t, r.Events(&handlers[1], key.FocusFilter{}), false)
 	assertFocus(t, r, &handlers[0])
 	assertKeyboard(t, r, TextInputOpen)
 
@@ -129,7 +142,7 @@ func TestKeyRemoveFocus(t *testing.T) {
 
 	r.Frame(ops)
 
-	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1], key.FocusFilter{}))
 	assertFocus(t, r, nil)
 	assertKeyboard(t, r, TextInputClose)
 
@@ -141,8 +154,8 @@ func TestKeyRemoveFocus(t *testing.T) {
 
 	r.Frame(ops)
 
-	assertKeyEventUnexpected(t, r.Events(&handlers[0]))
-	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[0], key.FocusFilter{}))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1], key.FocusFilter{}))
 	assertFocus(t, r, nil)
 	assertKeyboard(t, r, TextInputClose)
 
@@ -160,7 +173,7 @@ func TestKeyRemoveFocus(t *testing.T) {
 
 	r.Frame(ops)
 
-	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1], key.FocusFilter{}))
 	assertFocus(t, r, nil)
 	assertKeyboard(t, r, TextInputClose)
 }
@@ -178,10 +191,14 @@ func TestKeyFocusedInvisible(t *testing.T) {
 	// Set new InputOp without focus:
 	key.InputOp{Tag: &handlers[1]}.Add(ops)
 
+	for i := range handlers {
+		r.Events(&handlers[i], key.FocusFilter{})
+	}
+
 	r.Frame(ops)
 
-	assertKeyEvent(t, r.Events(&handlers[0]), true)
-	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertKeyEvent(t, r.Events(&handlers[0], key.FocusFilter{}), true)
+	assertKeyEvent(t, r.Events(&handlers[1], key.FocusFilter{}), false)
 	assertFocus(t, r, &handlers[0])
 	assertKeyboard(t, r, TextInputOpen)
 
@@ -196,11 +213,18 @@ func TestKeyFocusedInvisible(t *testing.T) {
 
 	r.Frame(ops)
 
-	assertKeyEventUnexpected(t, r.Events(&handlers[0]))
-	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[0], key.FocusFilter{}))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1], key.FocusFilter{}))
 	assertFocus(t, r, nil)
 	assertKeyboard(t, r, TextInputClose)
 
+	r.Frame(ops)
+
+	// Unchanged
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	r.Frame(ops)
+
 	ops.Reset()
 
 	// Respawn the first element:
@@ -210,13 +234,16 @@ func TestKeyFocusedInvisible(t *testing.T) {
 	// Unchanged
 	key.InputOp{Tag: &handlers[1]}.Add(ops)
 
+	for i := range handlers {
+		r.Events(&handlers[i], key.FocusFilter{})
+	}
+
 	r.Frame(ops)
 
-	assertKeyEvent(t, r.Events(&handlers[0]), false)
-	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertKeyEvent(t, r.Events(&handlers[0], key.FocusFilter{}), false)
+	assertKeyEventUnexpected(t, r.Events(&handlers[1], key.FocusFilter{}))
 	assertFocus(t, r, nil)
 	assertKeyboard(t, r, TextInputClose)
-
 }
 
 func TestNoOps(t *testing.T) {
@@ -238,6 +265,7 @@ func TestDirectionalFocus(t *testing.T) {
 		cl := clip.Rect(bounds).Push(ops)
 		key.InputOp{Tag: &handlers[i]}.Add(ops)
 		cl.Pop()
+		r.Events(&handlers[i], key.FocusFilter{})
 	}
 	r.Frame(ops)
 
@@ -269,11 +297,14 @@ func TestFocusScroll(t *testing.T) {
 	r := new(Router)
 	h := new(int)
 
-	f := pointer.Filter{
-		Kinds:        pointer.Scroll,
-		ScrollBounds: image.Rect(-100, -100, 100, 100),
+	filters := []event.Filter{
+		key.FocusFilter{},
+		pointer.Filter{
+			Kinds:        pointer.Scroll,
+			ScrollBounds: image.Rect(-100, -100, 100, 100),
+		},
 	}
-	r.Events(h, f)
+	r.Events(h, filters...)
 	parent := clip.Rect(image.Rect(1, 1, 14, 39)).Push(ops)
 	cl := clip.Rect(image.Rect(10, -20, 20, 30)).Push(ops)
 	key.InputOp{Tag: h}.Add(ops)
@@ -286,7 +317,7 @@ func TestFocusScroll(t *testing.T) {
 
 	r.MoveFocus(key.FocusLeft)
 	r.RevealFocus(image.Rect(0, 0, 15, 40))
-	evts := r.Events(h, f)
+	evts := r.Events(h, filters...)
 	assertScrollEvent(t, evts[len(evts)-1], f32.Pt(6, -9))
 }
 
@@ -295,10 +326,13 @@ func TestFocusClick(t *testing.T) {
 	r := new(Router)
 	h := new(int)
 
-	f := pointer.Filter{
-		Kinds: pointer.Press | pointer.Release,
+	filters := []event.Filter{
+		key.FocusFilter{},
+		pointer.Filter{
+			Kinds: pointer.Press | pointer.Release,
+		},
 	}
-	assertEventPointerTypeSequence(t, r.Events(h, f), pointer.Cancel)
+	assertEventPointerTypeSequence(t, r.Events(h, filters...), pointer.Cancel)
 	cl := clip.Rect(image.Rect(0, 0, 10, 10)).Push(ops)
 	key.InputOp{Tag: h}.Add(ops)
 	event.InputOp(ops, h)
@@ -308,7 +342,7 @@ func TestFocusClick(t *testing.T) {
 	r.MoveFocus(key.FocusLeft)
 	r.ClickFocus()
 
-	assertEventPointerTypeSequence(t, r.Events(h, f), pointer.Press, pointer.Release)
+	assertEventPointerTypeSequence(t, r.Events(h, filters...), pointer.Press, pointer.Release)
 }
 
 func TestNoFocus(t *testing.T) {
@@ -337,6 +371,10 @@ func TestKeyRouting(t *testing.T) {
 	call := macro.Stop()
 	call.Add(ops)
 
+	for i := range handlers {
+		r.Events(&handlers[i], key.FocusFilter{})
+	}
+
 	r.Frame(ops)
 
 	A, B := key.Event{Name: "A"}, key.Event{Name: "B"}
@@ -344,14 +382,18 @@ func TestKeyRouting(t *testing.T) {
 
 	// With no focus, the events should traverse the final branch of the hit tree
 	// searching for handlers.
-	assertKeyEvent(t, r.Events(&handlers[4]), false, A)
-	assertKeyEvent(t, r.Events(&handlers[3]), false)
-	assertKeyEvent(t, r.Events(&handlers[2]), false)
-	assertKeyEvent(t, r.Events(&handlers[1]), false, B)
-	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEvent(t, r.Events(&handlers[4], key.FocusFilter{}), false, A)
+	assertKeyEvent(t, r.Events(&handlers[3], key.FocusFilter{}), false)
+	assertKeyEvent(t, r.Events(&handlers[2], key.FocusFilter{}), false)
+	assertKeyEvent(t, r.Events(&handlers[1], key.FocusFilter{}), false, B)
+	assertKeyEvent(t, r.Events(&handlers[0], key.FocusFilter{}), false)
 
 	r2 := new(Router)
 
+	for i := range handlers {
+		r2.Events(&handlers[i], key.FocusFilter{})
+	}
+
 	r2.Source().Queue(key.FocusCmd{Tag: &handlers[3]})
 	r2.Frame(ops)
 
@@ -359,11 +401,11 @@ func TestKeyRouting(t *testing.T) {
 
 	// With focus, the events should traverse the branch of the hit tree
 	// containing the focused element.
-	assertKeyEvent(t, r2.Events(&handlers[4]), false)
-	assertKeyEvent(t, r2.Events(&handlers[3]), true)
-	assertKeyEvent(t, r2.Events(&handlers[2]), false)
-	assertKeyEvent(t, r2.Events(&handlers[1]), false)
-	assertKeyEvent(t, r2.Events(&handlers[0]), false, A)
+	assertKeyEvent(t, r2.Events(&handlers[4], key.FocusFilter{}), false)
+	assertKeyEvent(t, r2.Events(&handlers[3], key.FocusFilter{}), true)
+	assertKeyEvent(t, r2.Events(&handlers[2], key.FocusFilter{}), false)
+	assertKeyEvent(t, r2.Events(&handlers[1], key.FocusFilter{}), false)
+	assertKeyEvent(t, r2.Events(&handlers[0], key.FocusFilter{}), false, A)
 }
 
 func assertKeyEvent(t *testing.T, events []event.Event, expectedFocus bool, expectedInputs ...event.Event) {

io/input/router.go

@@ -131,6 +131,8 @@ func (s Source) Events(k event.Tag, filters ...event.Filter) []event.Event {
 func (q *Router) Events(k event.Tag, filters ...event.Filter) []event.Event {
 	for _, f := range filters {
 		switch f := f.(type) {
+		case key.FocusFilter:
+			q.key.queue.focusable(k)
 		case pointer.Filter:
 			q.pointer.queue.filterTag(k, f, &q.handlers)
 		case transfer.SourceFilter:
@@ -581,6 +583,12 @@ func (h *handlerEvents) Events(k event.Tag, filters ...event.Filter) []event.Eve
 
 func filtersMatches(filters []event.Filter, e event.Event) bool {
 	switch e := e.(type) {
+	case key.FocusEvent, key.SnippetEvent, key.EditEvent, key.SelectionEvent:
+		for _, f := range filters {
+			if _, ok := f.(key.FocusFilter); ok {
+				return true
+			}
+		}
 	case pointer.Event:
 		for _, f := range filters {
 			if f, ok := f.(pointer.Filter); ok && f.Kinds&e.Kind == e.Kind {

io/key/key.go

@@ -128,6 +128,9 @@ type EditEvent struct {
 	Text  string
 }
 
+// FocusFilter matches [FocusEvent]s.
+type FocusFilter struct{}
+
 // InputHint changes the on-screen-keyboard type. That hints the
 // type of data that might be entered by the user.
 type InputHint uint8
@@ -357,6 +360,8 @@ func (SoftKeyboardCmd) ImplementsCommand() {}
 func (SelectionCmd) ImplementsCommand()    {}
 func (SnippetCmd) ImplementsCommand()      {}
 
+func (FocusFilter) ImplementsFilter() {}
+
 func (m Modifiers) String() string {
 	var strs []string
 	if m.Contain(ModCtrl) {

widget/button.go

@@ -162,7 +162,7 @@ func (b *Clickable) Update(gtx layout.Context) []Click {
 			})
 		}
 	}
-	for _, e := range gtx.Events(&b.keyTag) {
+	for _, e := range gtx.Events(&b.keyTag, key.FocusFilter{}) {
 		switch e := e.(type) {
 		case key.FocusEvent:
 			b.focused = e.Focus

widget/editor.go

@@ -332,7 +332,7 @@ func (e *Editor) processKey(gtx layout.Context) {
 	}
 	// adjust keeps track of runes dropped because of MaxLen.
 	var adjust int
-	for _, ke := range gtx.Events(&e.eventKey, transfer.TargetFilter{Type: "application/text"}) {
+	for _, ke := range gtx.Events(&e.eventKey, transfer.TargetFilter{Type: "application/text"}, key.FocusFilter{}) {
 		e.blinkStart = gtx.Now
 		switch ke := ke.(type) {
 		case key.FocusEvent:

widget/enum.go

@@ -59,7 +59,7 @@ func (e *Enum) Update(gtx layout.Context) bool {
 				}
 			}
 		}
-		for _, ev := range gtx.Events(&state.tag) {
+		for _, ev := range gtx.Events(&state.tag, key.FocusFilter{}) {
 			switch ev := ev.(type) {
 			case key.FocusEvent:
 				if ev.Focus {

widget/selectable.go

@@ -304,7 +304,7 @@ func (e *Selectable) clickDragEvents(gtx layout.Context) []event.Event {
 }
 
 func (e *Selectable) processKey(gtx layout.Context) {
-	for _, ke := range gtx.Events(e) {
+	for _, ke := range gtx.Events(e, key.FocusFilter{}) {
 		switch ke := ke.(type) {
 		case key.FocusEvent:
 			e.focused = ke.Focus