io/pointer: added CursorNameOp

The cursor can now be customized for a given area.

Signed-off-by: pierre <pierre.curto@gmail.com>

app/window.go

@@ -48,7 +48,8 @@ type Window struct {
 	nextFrame    time.Time
 	delayedDraw  *time.Timer
 
-	queue queue
+	queue  queue
+	cursor pointer.CursorName
 
 	callbacks callbacks
 }
@@ -414,6 +415,10 @@ func (w *Window) run(opts *window.Options) {
 					w.setNextFrame(time.Time{})
 					w.updateAnimation()
 				}
+				if c := w.queue.q.Cursor(); c != w.cursor {
+					w.cursor = c
+					w.SetCursorName(c)
+				}
 				w.out <- e
 			}
 			w.ack <- struct{}{}

internal/opconst/ops.go

@@ -30,6 +30,7 @@ const (
 	TypeAux
 	TypeClip
 	TypeProfile
+	TypeCursor
 )
 
 const (
@@ -55,6 +56,7 @@ const (
 	TypeAuxLen             = 1
 	TypeClipLen            = 1 + 4*4 + 4 + 2 + 4
 	TypeProfileLen         = 1
+	TypeCursorLen          = 1 + 1
 )
 
 func (t OpType) Size() int {
@@ -81,12 +83,13 @@ func (t OpType) Size() int {
 		TypeAuxLen,
 		TypeClipLen,
 		TypeProfileLen,
+		TypeCursorLen,
 	}[t-firstOpIndex]
 }
 
 func (t OpType) NumRefs() int {
 	switch t {
-	case TypeKeyInput, TypePointerInput, TypeProfile, TypeCall, TypeClipboardRead, TypeClipboardWrite:
+	case TypeKeyInput, TypePointerInput, TypeProfile, TypeCall, TypeClipboardRead, TypeClipboardWrite, TypeCursor:
 		return 1
 	case TypeImage:
 		return 2

io/pointer/pointer.go

@@ -49,6 +49,11 @@ type AreaOp struct {
 	rect image.Rectangle
 }
 
+// CursorNameOp sets the cursor for the current area.
+type CursorNameOp struct {
+	Name CursorName
+}
+
 // InputOp declares an input handler ready for pointer
 // events.
 type InputOp struct {
@@ -178,6 +183,11 @@ func (op AreaOp) Add(o *op.Ops) {
 	bo.PutUint32(data[14:], uint32(op.rect.Max.Y))
 }
 
+func (op CursorNameOp) Add(o *op.Ops) {
+	data := o.Write1(opconst.TypeCursorLen, op.Name)
+	data[0] = byte(opconst.TypeCursor)
+}
+
 func (h InputOp) Add(o *op.Ops) {
 	data := o.Write1(opconst.TypePointerInputLen, h.Tag)
 	data[0] = byte(opconst.TypePointerInput)

io/router/pointer.go

@@ -17,6 +17,8 @@ import (
 type pointerQueue struct {
 	hitTree  []hitNode
 	areas    []areaNode
+	cursors  []cursorNode
+	cursor   pointer.CursorName
 	handlers map[event.Tag]*pointerHandler
 	pointers []pointerInfo
 	reader   ops.Reader
@@ -34,6 +36,11 @@ type hitNode struct {
 	tag event.Tag
 }
 
+type cursorNode struct {
+	name pointer.CursorName
+	area int
+}
+
 type pointerInfo struct {
 	id       pointer.ID
 	pressed  bool
@@ -114,6 +121,11 @@ func (q *pointerQueue) collectHandlers(r *ops.Reader, events *handlerEvents, t f
 			h.area = area
 			h.wantsGrab = h.wantsGrab || op.Grab
 			h.types = h.types | op.Types
+		case opconst.TypeCursor:
+			q.cursors = append(q.cursors, cursorNode{
+				name: encOp.Refs[0].(pointer.CursorName),
+				area: len(q.areas) - 1,
+			})
 		}
 	}
 }
@@ -177,6 +189,7 @@ func (q *pointerQueue) Frame(root *op.Ops, events *handlerEvents) {
 	}
 	q.hitTree = q.hitTree[:0]
 	q.areas = q.areas[:0]
+	q.cursors = q.cursors[:0]
 	q.reader.Reset(root)
 	q.collectHandlers(&q.reader, events, f32.Affine2D{}, -1, -1, false)
 	for k, h := range q.handlers {
@@ -314,6 +327,7 @@ func (q *pointerQueue) deliverEnterLeaveEvents(p *pointerInfo, hits []event.Tag,
 
 		if e.Type&h.types == e.Type {
 			events.Add(k, e)
+			q.cursor = pointer.CursorDefault
 		}
 	}
 	// Deliver Enter events.
@@ -327,11 +341,25 @@ func (q *pointerQueue) deliverEnterLeaveEvents(p *pointerInfo, hits []event.Tag,
 
 		if e.Type&h.types == e.Type {
 			events.Add(k, e)
+			q.hitCursor(h.area)
 		}
 	}
 	p.entered = append(p.entered[:0], hits...)
 }
 
+func (q *pointerQueue) hitCursor(want int) {
+	for _, c := range q.cursors {
+		idx := c.area
+		for idx != -1 {
+			if idx == want {
+				q.cursor = c.name
+				return
+			}
+			idx = q.areas[idx].next
+		}
+	}
+}
+
 func searchTag(tags []event.Tag, tag event.Tag) (int, bool) {
 	for i, t := range tags {
 		if t == tag {

io/router/router.go

@@ -115,6 +115,11 @@ func (q *Router) ReadClipboard() bool {
 	return q.cqueue.ReadClipboard()
 }
 
+// Cursor returns the last cursor set.
+func (q *Router) Cursor() pointer.CursorName {
+	return q.pqueue.cursor
+}
+
 func (q *Router) collect() {
 	for encOp, ok := q.reader.Decode(); ok; encOp, ok = q.reader.Decode() {
 		switch opconst.OpType(encOp.Data[0]) {

widget/editor.go

@@ -379,7 +379,10 @@ func (e *Editor) Layout(gtx layout.Context, sh text.Shaper, font text.Font, size
 	}
 	e.makeValid()
 
-	return e.layout(gtx)
+	dims := e.layout(gtx)
+	pointer.Rect(image.Rectangle{Max: dims.Size}).Add(gtx.Ops)
+	pointer.CursorNameOp{Name: pointer.CursorText}.Add(gtx.Ops)
+	return dims
 }
 
 func (e *Editor) layout(gtx layout.Context) layout.Dimensions {