diff --git a/layout/context.go b/layout/context.go
index ee84a5c1..39317e96 100644
--- a/layout/context.go
+++ b/layout/context.go
@@ -4,13 +4,18 @@ package layout
 
 import (
 	"image"
+	"math"
+	"time"
 
 	"gioui.org/io/event"
 	"gioui.org/io/system"
 	"gioui.org/op"
+	"gioui.org/unit"
 )
 
 // Context carries the state needed by almost all layouts and widgets.
+// A zero value Context never returns events, map units to pixels
+// with a scale of 1.0, and returns the zero time from Now.
 type Context struct {
 	// Constraints track the constraints for the active widget or
 	// layout.
@@ -19,11 +24,18 @@ type Context struct {
 	// operation.
 	Dimensions Dimensions
 
-	system.Config
-	event.Queue
+	cfg   system.Config
+	queue event.Queue
 	*op.Ops
 }
 
+// NewContext returns a Context for an event queue.
+func NewContext(q event.Queue) *Context {
+	return &Context{
+		queue: q,
+	}
+}
+
 // layout a widget with a set of constraints and return its
 // dimensions. The widget dimensions are constrained abd the previous
 // constraints are restored after layout.
@@ -42,9 +54,35 @@ func ctxLayout(gtx *Context, cs Constraints, w Widget) Dimensions {
 func (c *Context) Reset(cfg system.Config, size image.Point) {
 	c.Constraints = RigidConstraints(size)
 	c.Dimensions = Dimensions{}
-	c.Config = cfg
+	c.cfg = cfg
 	if c.Ops == nil {
 		c.Ops = new(op.Ops)
 	}
 	c.Ops.Reset()
 }
+
+// Now returns the configuration time or the the zero time.
+func (c *Context) Now() time.Time {
+	if c.cfg == nil {
+		return time.Time{}
+	}
+	return c.cfg.Now()
+}
+
+// Px maps the value to pixels. If no configuration is set,
+// Px returns the rounded value of v.
+func (c *Context) Px(v unit.Value) int {
+	if c.cfg == nil {
+		return int(math.Round(float64(v.V)))
+	}
+	return c.cfg.Px(v)
+}
+
+// Events returns the events available for the key. If no
+// queue is configured, Events returns nil.
+func (c *Context) Events(k event.Key) []event.Event {
+	if c.queue == nil {
+		return nil
+	}
+	return c.queue.Events(k)
+}
diff --git a/layout/layout_test.go b/layout/layout_test.go
index fc45171d..0cc59cf0 100644
--- a/layout/layout_test.go
+++ b/layout/layout_test.go
@@ -3,23 +3,14 @@ package layout_test
 import (
 	"fmt"
 	"image"
-	"time"
 
-	"gioui.org/io/event"
 	"gioui.org/layout"
 	"gioui.org/unit"
 )
 
-type queue struct{}
-
-type config struct{}
-
-var q queue
-var cfg = new(config)
-
 func ExampleInset() {
-	gtx := &layout.Context{Queue: q}
-	gtx.Reset(cfg, image.Point{X: 100, Y: 100})
+	gtx := new(layout.Context)
+	gtx.Reset(nil, image.Point{X: 100, Y: 100})
 	// Loose constraints with no minimal size.
 	gtx.Constraints.Width.Min = 0
 	gtx.Constraints.Height.Min = 0
@@ -40,9 +31,9 @@ func ExampleInset() {
 }
 
 func ExampleAlign() {
-	gtx := &layout.Context{Queue: q}
+	gtx := new(layout.Context)
 	// Rigid constraints with both minimum and maximum set.
-	gtx.Reset(cfg, image.Point{X: 100, Y: 100})
+	gtx.Reset(nil, image.Point{X: 100, Y: 100})
 
 	align := layout.Align(layout.Center)
 	align.Layout(gtx, func() {
@@ -59,8 +50,8 @@ func ExampleAlign() {
 }
 
 func ExampleFlex() {
-	gtx := &layout.Context{Queue: q}
-	gtx.Reset(cfg, image.Point{X: 100, Y: 100})
+	gtx := new(layout.Context)
+	gtx.Reset(nil, image.Point{X: 100, Y: 100})
 
 	flex := layout.Flex{}
 
@@ -84,8 +75,8 @@ func ExampleFlex() {
 }
 
 func ExampleStack() {
-	gtx := &layout.Context{Queue: q}
-	gtx.Reset(cfg, image.Point{X: 100, Y: 100})
+	gtx := new(layout.Context)
+	gtx.Reset(nil, image.Point{X: 100, Y: 100})
 
 	stack := layout.Stack{}
 
@@ -107,8 +98,8 @@ func ExampleStack() {
 }
 
 func ExampleList() {
-	gtx := &layout.Context{Queue: q}
-	gtx.Reset(cfg, image.Point{X: 100, Y: 100})
+	gtx := new(layout.Context)
+	gtx.Reset(nil, image.Point{X: 100, Y: 100})
 
 	// The list is 1e6 elements, but only 5 fit the constraints.
 	const listLen = 1e6
@@ -134,15 +125,3 @@ func layoutWidget(ctx *layout.Context, width, height int) {
 		},
 	}
 }
-
-func (config) Now() time.Time {
-	return time.Now()
-}
-
-func (config) Px(v unit.Value) int {
-	return int(v.V + .5)
-}
-
-func (queue) Events(k event.Key) []event.Event {
-	return nil
-}
diff --git a/layout/list.go b/layout/list.go
index 6af3da04..c585ce6a 100644
--- a/layout/list.go
+++ b/layout/list.go
@@ -122,7 +122,7 @@ func (l *List) Dragging() bool {
 }
 
 func (l *List) update() {
-	d := l.scroll.Scroll(l.ctx.Config, l.ctx.Queue, l.ctx.Now(), gesture.Axis(l.Axis))
+	d := l.scroll.Scroll(l.ctx, l.ctx, l.ctx.Now(), gesture.Axis(l.Axis))
 	l.scrollDelta = d
 	l.Position.Offset += d
 }
diff --git a/widget/editor.go b/widget/editor.go
index 8ae14ae3..ef282c7f 100644
--- a/widget/editor.go
+++ b/widget/editor.go
@@ -114,7 +114,7 @@ func (e *Editor) processPointer(gtx *layout.Context) {
 		axis = gesture.Vertical
 		smin, smax = sbounds.Min.Y, sbounds.Max.Y
 	}
-	sdist := e.scroller.Scroll(gtx.Config, gtx.Queue, gtx.Now(), axis)
+	sdist := e.scroller.Scroll(gtx, gtx, gtx.Now(), axis)
 	var soff int
 	if e.SingleLine {
 		e.scrollRel(sdist, 0)