update gio version

go.mod

@@ -3,6 +3,6 @@ module gophercon2019
 go 1.13
 
 require (
-	gioui.org/ui v0.0.0-20190925074315-9c33550644a7
+	gioui.org/ui v0.0.0-20190926171558-ce74bc0cbaea
 	golang.org/x/image v0.0.0-20190703141733-d6a02ce849c9
 )

go.sum

@@ -1,5 +1,5 @@
-gioui.org/ui v0.0.0-20190925074315-9c33550644a7 h1:l/WdLfRQnDRjipqy7NP9iJcq/zXABhsCd7vGX8oapYo=
-gioui.org/ui v0.0.0-20190925074315-9c33550644a7/go.mod h1:PssKPKlqVIeyaed+0w492Xc2NgX5M3n6oZKOAj5rxoE=
+gioui.org/ui v0.0.0-20190926171558-ce74bc0cbaea h1:rv21Wx1Inf27NY453rrrP6tuEG65PyWPhnP2Jx+Qb8k=
+gioui.org/ui v0.0.0-20190926171558-ce74bc0cbaea/go.mod h1:PssKPKlqVIeyaed+0w492Xc2NgX5M3n6oZKOAj5rxoE=
 golang.org/x/image v0.0.0-20190703141733-d6a02ce849c9 h1:uc17S921SPw5F2gJo7slQ3aqvr2RwpL7eb3+DZncu3s=
 golang.org/x/image v0.0.0-20190703141733-d6a02ce849c9/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a h1:aYOabOQFp6Vj6W1F80affTUvO9UxmJRx8K0gsfABByQ=

gophercon-2019.slide

@@ -507,7 +507,7 @@ Lay out widgets on an axis.
 	// Queue maps an event handler key to the events
 	// available to the handler.
 	type Queue interface {
-		Next(k Key) (Event, bool)
+		Events(k Key) []Event
 	}
 
 	// Key is the stable identifier for an event handler.
@@ -567,7 +567,7 @@ Detect clicks
 
 	var queue ui.Queue
 	var c gesture.Click
-	for event, ok := c.Next(queue); ok; event, ok = c.Next(queue) {
+	for _, event := range c.Events(queue) {
 		// event is a gesture.ClickEvent, not a raw pointer.Event.
 	}
 

pointer.go

@@ -37,7 +37,7 @@ type Button struct {
 
 // START OMIT
 func (b *Button) Layout(queue ui.Queue, ops *ui.Ops) {
-	for e, ok := queue.Next(b); ok; e, ok = queue.Next(b) { // HLevent
+	for _, e := range queue.Events(b) { // HLevent
 		if e, ok := e.(pointer.Event); ok { // HLevent
 			switch e.Type { // HLevent
 			case pointer.Press: // HLevent