io/key: [API] add InputHintOp for specifying the input hint for a tag

We're about to replace key.InputOp with a filter; this change separates
the input hint into its own operation.

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

io/input/key.go

@@ -58,6 +58,11 @@ const (
 	TextInputOpen
 )
 
+func (q *keyQueue) inputHint(op key.InputHintOp) {
+	h := q.handlerFor(op.Tag)
+	h.hint = op.Hint
+}
+
 // InputState returns the last text input state as
 // determined in Frame.
 func (q *keyQueue) InputState() TextInputState {
@@ -66,7 +71,8 @@ func (q *keyQueue) InputState() TextInputState {
 	return state
 }
 
-// InputHint returns the input mode from the most recent key.InputOp.
+// InputHint returns the input hint from the focused handler and whether it was
+// changed since the last call.
 func (q *keyQueue) InputHint() (key.InputHint, bool) {
 	if q.focus == nil {
 		return q.hint, false
@@ -87,6 +93,7 @@ func (q *keyQueue) Reset() {
 	for _, h := range q.handlers {
 		h.visible, h.new = false, false
 		h.order = -1
+		h.hint = key.HintAny
 	}
 	q.order = q.order[:0]
 	q.dirOrder = q.dirOrder[:0]
@@ -277,24 +284,23 @@ func (q *keyQueue) softKeyboard(show bool) {
 	}
 }
 
-func (q *keyQueue) handlerFor(tag event.Tag, area int, bounds image.Rectangle) *keyHandler {
+func (q *keyQueue) handlerFor(tag event.Tag) *keyHandler {
 	h, ok := q.handlers[tag]
 	if !ok {
 		h = &keyHandler{new: true, order: -1}
 		q.handlers[tag] = h
 	}
-	if h.order == -1 {
-		h.order = len(q.order)
-		q.order = append(q.order, tag)
-		q.dirOrder = append(q.dirOrder, dirFocusEntry{tag: tag, area: area, bounds: bounds})
-	}
 	return h
 }
 
 func (q *keyQueue) inputOp(op key.InputOp, t f32.Affine2D, area int, bounds image.Rectangle) {
-	h := q.handlerFor(op.Tag, area, bounds)
+	h := q.handlerFor(op.Tag)
+	if h.order == -1 {
+		h.order = len(q.order)
+		q.order = append(q.order, op.Tag)
+		q.dirOrder = append(q.dirOrder, dirFocusEntry{tag: op.Tag, area: area, bounds: bounds})
+	}
 	h.visible = true
-	h.hint = op.Hint
 	h.filter = op.Keys
 	h.trans = t
 }

io/input/router.go

@@ -494,13 +494,18 @@ func (q *Router) collect() {
 			filter := key.Set(*encOp.Refs[1].(*string))
 			op := key.InputOp{
 				Tag:  encOp.Refs[0].(event.Tag),
-				Hint: key.InputHint(encOp.Data[1]),
 				Keys: filter,
 			}
 			a := pc.currentArea()
 			b := pc.currentAreaBounds()
 			pc.keyInputOp(op)
 			kq.inputOp(op, t, a, b)
+		case ops.TypeKeyInputHint:
+			op := key.InputHintOp{
+				Tag:  encOp.Refs[0].(event.Tag),
+				Hint: key.InputHint(encOp.Data[1]),
+			}
+			kq.inputHint(op)
 
 		// Semantic ops.
 		case ops.TypeSemanticLabel:

io/key/key.go

@@ -23,8 +23,6 @@ import (
 // focused key handler.
 type InputOp struct {
 	Tag event.Tag
-	// Hint describes the type of text expected by Tag.
-	Hint InputHint
 	// Keys is the set of keys Tag can handle. That is, Tag will only
 	// receive an Event if its key and modifiers are accepted by Keys.Contains.
 	// As a special case, the topmost (first added) InputOp handler receives all
@@ -32,6 +30,12 @@ type InputOp struct {
 	Keys Set
 }
 
+// InputHintOp describes the type of text expected by a tag.
+type InputHintOp struct {
+	Tag  event.Tag
+	Hint InputHint
+}
+
 // SoftKeyboardCmd shows or hides the on-screen keyboard, if available.
 type SoftKeyboardCmd struct {
 	Show bool
@@ -331,6 +335,14 @@ func (h InputOp) Add(o *op.Ops) {
 	}
 	data := ops.Write2String(&o.Internal, ops.TypeKeyInputLen, h.Tag, string(h.Keys))
 	data[0] = byte(ops.TypeKeyInput)
+}
+
+func (h InputHintOp) Add(o *op.Ops) {
+	if h.Tag == nil {
+		panic("Tag must be non-nil")
+	}
+	data := ops.Write1(&o.Internal, ops.TypeKeyInputHintLen, h.Tag)
+	data[0] = byte(ops.TypeKeyInputHint)
 	data[1] = byte(h.Hint)
 }