diff --git a/ui/app/internal/gpu/caches.go b/ui/app/internal/gpu/caches.go
index 7b6f9559..4de57bfd 100644
--- a/ui/app/internal/gpu/caches.go
+++ b/ui/app/internal/gpu/caches.go
@@ -3,7 +3,7 @@ package gpu
 import (
 	"fmt"
 
-	"gioui.org/ui"
+	"gioui.org/ui/internal/ops"
 )
 
 type resourceCache struct {
@@ -11,11 +11,11 @@ type resourceCache struct {
 	newRes map[interface{}]resource
 }
 
-// opCache is like a resourceCache using the concrete OpKey
+// opCache is like a resourceCache using the concrete Key
 // key type to avoid allocations.
 type opCache struct {
-	res    map[ui.OpKey]resource
-	newRes map[ui.OpKey]resource
+	res    map[ops.Key]resource
+	newRes map[ops.Key]resource
 }
 
 func newResourceCache() *resourceCache {
@@ -64,12 +64,12 @@ func (r *resourceCache) release(ctx *context) {
 
 func newOpCache() *opCache {
 	return &opCache{
-		res:    make(map[ui.OpKey]resource),
-		newRes: make(map[ui.OpKey]resource),
+		res:    make(map[ops.Key]resource),
+		newRes: make(map[ops.Key]resource),
 	}
 }
 
-func (r *opCache) get(key ui.OpKey) (resource, bool) {
+func (r *opCache) get(key ops.Key) (resource, bool) {
 	v, exists := r.res[key]
 	if exists {
 		r.newRes[key] = v
@@ -77,7 +77,7 @@ func (r *opCache) get(key ui.OpKey) (resource, bool) {
 	return v, exists
 }
 
-func (r *opCache) put(key ui.OpKey, val resource) {
+func (r *opCache) put(key ops.Key, val resource) {
 	if _, exists := r.newRes[key]; exists {
 		panic(fmt.Errorf("key exists, %p", key))
 	}
diff --git a/ui/app/internal/gpu/gpu.go b/ui/app/internal/gpu/gpu.go
index d2a7da45..1f2521b6 100644
--- a/ui/app/internal/gpu/gpu.go
+++ b/ui/app/internal/gpu/gpu.go
@@ -16,6 +16,7 @@ import (
 	"gioui.org/ui/app/internal/gl"
 	gdraw "gioui.org/ui/draw"
 	"gioui.org/ui/f32"
+	"gioui.org/ui/internal/opconst"
 	"gioui.org/ui/internal/ops"
 	"golang.org/x/image/draw"
 )
@@ -58,7 +59,7 @@ type renderer struct {
 }
 
 type drawOps struct {
-	reader     ui.OpsReader
+	reader     ops.Reader
 	cache      *resourceCache
 	viewport   image.Point
 	clearColor [3]float32
@@ -90,7 +91,7 @@ type pathOp struct {
 	// clip is the union of all
 	// later clip rectangles.
 	clip      image.Rectangle
-	pathKey   ui.OpKey
+	pathKey   ops.Key
 	path      bool
 	pathVerts []byte
 	parent    *pathOp
@@ -124,7 +125,7 @@ type opClip struct {
 }
 
 func (op *opClip) decode(data []byte) {
-	if ops.OpType(data[0]) != ops.TypeClip {
+	if opconst.OpType(data[0]) != opconst.TypeClip {
 		panic("invalid op")
 	}
 	bo := binary.LittleEndian
@@ -641,20 +642,20 @@ func (d *drawOps) newPathOp() *pathOp {
 	return &d.pathOpCache[len(d.pathOpCache)-1]
 }
 
-func (d *drawOps) collectOps(r *ui.OpsReader, state drawState) int {
+func (d *drawOps) collectOps(r *ops.Reader, state drawState) int {
 	var aux []byte
-	var auxKey ui.OpKey
+	var auxKey ops.Key
 loop:
 	for encOp, ok := r.Decode(); ok; encOp, ok = r.Decode() {
-		switch ops.OpType(encOp.Data[0]) {
-		case ops.TypeTransform:
+		switch opconst.OpType(encOp.Data[0]) {
+		case opconst.TypeTransform:
 			var op ui.TransformOp
 			op.Decode(encOp.Data)
 			state.t = state.t.Multiply(op)
-		case ops.TypeAux:
-			aux = encOp.Data[ops.TypeAuxLen:]
+		case opconst.TypeAux:
+			aux = encOp.Data[opconst.TypeAuxLen:]
 			auxKey = encOp.Key
-		case ops.TypeClip:
+		case opconst.TypeClip:
 			var op opClip
 			op.decode(encOp.Data)
 			off := state.t.Transform(f32.Point{})
@@ -676,18 +677,18 @@ loop:
 				d.pathOps = append(d.pathOps, state.cpath)
 			}
 			aux = nil
-			auxKey = ui.OpKey{}
-		case ops.TypeColor:
+			auxKey = ops.Key{}
+		case opconst.TypeColor:
 			var op gdraw.ColorOp
 			op.Decode(encOp.Data, encOp.Refs)
 			state.img = nil
 			state.color = op.Color
-		case ops.TypeImage:
+		case opconst.TypeImage:
 			var op gdraw.ImageOp
 			op.Decode(encOp.Data, encOp.Refs)
 			state.img = op.Src
 			state.imgRect = op.Rect
-		case ops.TypeDraw:
+		case opconst.TypeDraw:
 			var op gdraw.DrawOp
 			op.Decode(encOp.Data, encOp.Refs)
 			off := state.t.Transform(f32.Point{})
@@ -723,9 +724,9 @@ loop:
 			} else {
 				d.imageOps = append(d.imageOps, img)
 			}
-		case ops.TypePush:
+		case opconst.TypePush:
 			state.z = d.collectOps(r, state)
-		case ops.TypePop:
+		case opconst.TypePop:
 			break loop
 		}
 	}
diff --git a/ui/app/internal/input/key.go b/ui/app/internal/input/key.go
index bbcd7fc2..252a7a70 100644
--- a/ui/app/internal/input/key.go
+++ b/ui/app/internal/input/key.go
@@ -5,6 +5,7 @@ package input
 import (
 	"gioui.org/ui"
 	"gioui.org/ui/input"
+	"gioui.org/ui/internal/opconst"
 	"gioui.org/ui/internal/ops"
 	"gioui.org/ui/key"
 )
@@ -14,7 +15,7 @@ type TextInputState uint8
 type keyQueue struct {
 	focus    input.Key
 	handlers map[input.Key]*keyHandler
-	reader   ui.OpsReader
+	reader   ops.Reader
 	state    TextInputState
 }
 
@@ -94,8 +95,8 @@ func (q *keyQueue) resolveFocus(events *handlerEvents) (input.Key, listenerPrior
 	var hide bool
 loop:
 	for encOp, ok := q.reader.Decode(); ok; encOp, ok = q.reader.Decode() {
-		switch ops.OpType(encOp.Data[0]) {
-		case ops.TypeKeyHandler:
+		switch opconst.OpType(encOp.Data[0]) {
+		case opconst.TypeKeyHandler:
 			var op key.HandlerOp
 			op.Decode(encOp.Data, encOp.Refs)
 			var newPri listenerPriority
@@ -119,15 +120,15 @@ loop:
 				events.Set(op.Key, []input.Event{key.FocusEvent{Focus: false}})
 			}
 			h.active = true
-		case ops.TypeHideInput:
+		case opconst.TypeHideInput:
 			hide = true
-		case ops.TypePush:
+		case opconst.TypePush:
 			newK, newPri, h := q.resolveFocus(events)
 			hide = hide || h
 			if newPri.replaces(pri) {
 				k, pri = newK, newPri
 			}
-		case ops.TypePop:
+		case opconst.TypePop:
 			break loop
 		}
 	}
diff --git a/ui/app/internal/input/pointer.go b/ui/app/internal/input/pointer.go
index 9e761293..47175352 100644
--- a/ui/app/internal/input/pointer.go
+++ b/ui/app/internal/input/pointer.go
@@ -9,6 +9,7 @@ import (
 	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/input"
+	"gioui.org/ui/internal/opconst"
 	"gioui.org/ui/internal/ops"
 	"gioui.org/ui/pointer"
 )
@@ -18,7 +19,7 @@ type pointerQueue struct {
 	areas    []areaNode
 	handlers map[input.Key]*pointerHandler
 	pointers []pointerInfo
-	reader   ui.OpsReader
+	reader   ops.Reader
 	scratch  []input.Key
 }
 
@@ -63,18 +64,18 @@ const (
 	areaEllipse
 )
 
-func (q *pointerQueue) collectHandlers(r *ui.OpsReader, events *handlerEvents, t ui.TransformOp, area, node int, pass bool) {
+func (q *pointerQueue) collectHandlers(r *ops.Reader, events *handlerEvents, t ui.TransformOp, area, node int, pass bool) {
 	for encOp, ok := r.Decode(); ok; encOp, ok = r.Decode() {
-		switch ops.OpType(encOp.Data[0]) {
-		case ops.TypePush:
+		switch opconst.OpType(encOp.Data[0]) {
+		case opconst.TypePush:
 			q.collectHandlers(r, events, t, area, node, pass)
-		case ops.TypePop:
+		case opconst.TypePop:
 			return
-		case ops.TypePass:
+		case opconst.TypePass:
 			var op pointer.PassOp
 			op.Decode(encOp.Data)
 			pass = op.Pass
-		case ops.TypeArea:
+		case opconst.TypeArea:
 			var op areaOp
 			op.Decode(encOp.Data)
 			q.areas = append(q.areas, areaNode{trans: t, next: area, area: op})
@@ -85,11 +86,11 @@ func (q *pointerQueue) collectHandlers(r *ui.OpsReader, events *handlerEvents, t
 				pass: pass,
 			})
 			node = len(q.hitTree) - 1
-		case ops.TypeTransform:
+		case opconst.TypeTransform:
 			var op ui.TransformOp
 			op.Decode(encOp.Data)
 			t = t.Multiply(op)
-		case ops.TypePointerHandler:
+		case opconst.TypePointerHandler:
 			var op pointer.HandlerOp
 			op.Decode(encOp.Data, encOp.Refs)
 			q.hitTree = append(q.hitTree, hitNode{
@@ -264,7 +265,7 @@ func (q *pointerQueue) Push(e pointer.Event, events *handlerEvents) {
 }
 
 func (op *areaOp) Decode(d []byte) {
-	if ops.OpType(d[0]) != ops.TypeArea {
+	if opconst.OpType(d[0]) != opconst.TypeArea {
 		panic("invalid op")
 	}
 	bo := binary.LittleEndian
diff --git a/ui/app/internal/input/router.go b/ui/app/internal/input/router.go
index 912ad20e..e3171245 100644
--- a/ui/app/internal/input/router.go
+++ b/ui/app/internal/input/router.go
@@ -7,6 +7,7 @@ import (
 
 	"gioui.org/ui"
 	"gioui.org/ui/input"
+	"gioui.org/ui/internal/opconst"
 	"gioui.org/ui/internal/ops"
 	"gioui.org/ui/key"
 	"gioui.org/ui/pointer"
@@ -21,7 +22,7 @@ type Router struct {
 
 	handlers handlerEvents
 
-	reader ui.OpsReader
+	reader ops.Reader
 
 	// InvalidateOp summary.
 	wakeup     bool
@@ -71,15 +72,15 @@ func (q *Router) TextInputState() TextInputState {
 
 func (q *Router) collect() {
 	for encOp, ok := q.reader.Decode(); ok; encOp, ok = q.reader.Decode() {
-		switch ops.OpType(encOp.Data[0]) {
-		case ops.TypeInvalidate:
+		switch opconst.OpType(encOp.Data[0]) {
+		case opconst.TypeInvalidate:
 			var op ui.InvalidateOp
 			op.Decode(encOp.Data)
 			if !q.wakeup || op.At.Before(q.wakeupTime) {
 				q.wakeup = true
 				q.wakeupTime = op.At
 			}
-		case ops.TypeProfile:
+		case opconst.TypeProfile:
 			var op system.ProfileOp
 			op.Decode(encOp.Data, encOp.Refs)
 			q.profHandlers = append(q.profHandlers, op.Key)
diff --git a/ui/draw/draw.go b/ui/draw/draw.go
index 2ddb8159..fad9df5b 100644
--- a/ui/draw/draw.go
+++ b/ui/draw/draw.go
@@ -10,7 +10,7 @@ import (
 
 	"gioui.org/ui"
 	"gioui.org/ui/f32"
-	"gioui.org/ui/internal/ops"
+	"gioui.org/ui/internal/opconst"
 )
 
 type ImageOp struct {
@@ -27,8 +27,8 @@ type DrawOp struct {
 }
 
 func (i ImageOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypeImageLen)
-	data[0] = byte(ops.TypeImage)
+	data := make([]byte, opconst.TypeImageLen)
+	data[0] = byte(opconst.TypeImage)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[1:], uint32(i.Rect.Min.X))
 	bo.PutUint32(data[5:], uint32(i.Rect.Min.Y))
@@ -39,7 +39,7 @@ func (i ImageOp) Add(o *ui.Ops) {
 
 func (i *ImageOp) Decode(data []byte, refs []interface{}) {
 	bo := binary.LittleEndian
-	if ops.OpType(data[0]) != ops.TypeImage {
+	if opconst.OpType(data[0]) != opconst.TypeImage {
 		panic("invalid op")
 	}
 	sr := image.Rectangle{
@@ -59,8 +59,8 @@ func (i *ImageOp) Decode(data []byte, refs []interface{}) {
 }
 
 func (c ColorOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypeColorLen)
-	data[0] = byte(ops.TypeColor)
+	data := make([]byte, opconst.TypeColorLen)
+	data[0] = byte(opconst.TypeColor)
 	data[1] = c.Color.R
 	data[2] = c.Color.G
 	data[3] = c.Color.B
@@ -69,7 +69,7 @@ func (c ColorOp) Add(o *ui.Ops) {
 }
 
 func (c *ColorOp) Decode(data []byte, refs []interface{}) {
-	if ops.OpType(data[0]) != ops.TypeColor {
+	if opconst.OpType(data[0]) != opconst.TypeColor {
 		panic("invalid op")
 	}
 	*c = ColorOp{
@@ -83,8 +83,8 @@ func (c *ColorOp) Decode(data []byte, refs []interface{}) {
 }
 
 func (d DrawOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypeDrawLen)
-	data[0] = byte(ops.TypeDraw)
+	data := make([]byte, opconst.TypeDrawLen)
+	data[0] = byte(opconst.TypeDraw)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[1:], math.Float32bits(d.Rect.Min.X))
 	bo.PutUint32(data[5:], math.Float32bits(d.Rect.Min.Y))
@@ -95,7 +95,7 @@ func (d DrawOp) Add(o *ui.Ops) {
 
 func (d *DrawOp) Decode(data []byte, refs []interface{}) {
 	bo := binary.LittleEndian
-	if ops.OpType(data[0]) != ops.TypeDraw {
+	if opconst.OpType(data[0]) != opconst.TypeDraw {
 		panic("invalid op")
 	}
 	r := f32.Rectangle{
diff --git a/ui/draw/path.go b/ui/draw/path.go
index df6a3456..d2fa7f40 100644
--- a/ui/draw/path.go
+++ b/ui/draw/path.go
@@ -9,7 +9,7 @@ import (
 
 	"gioui.org/ui"
 	"gioui.org/ui/f32"
-	"gioui.org/ui/internal/ops"
+	"gioui.org/ui/internal/opconst"
 	"gioui.org/ui/internal/path"
 )
 
@@ -30,8 +30,8 @@ type ClipOp struct {
 }
 
 func (p ClipOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypeClipLen)
-	data[0] = byte(ops.TypeClip)
+	data := make([]byte, opconst.TypeClipLen)
+	data[0] = byte(opconst.TypeClip)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[1:], math.Float32bits(p.bounds.Min.X))
 	bo.PutUint32(data[5:], math.Float32bits(p.bounds.Min.Y))
@@ -239,7 +239,7 @@ func (p *PathBuilder) vertex(cornerx, cornery int16, ctrl, to f32.Point) {
 		ToY:     to.Y,
 	}
 	data := make([]byte, path.VertStride+1)
-	data[0] = byte(ops.TypeAux)
+	data[0] = byte(opconst.TypeAux)
 	bo := binary.LittleEndian
 	data[1] = byte(uint16(v.CornerX))
 	data[2] = byte(uint16(v.CornerX) >> 8)
diff --git a/ui/internal/ops/ops.go b/ui/internal/opconst/ops.go
similarity index 98%
rename from ui/internal/ops/ops.go
rename to ui/internal/opconst/ops.go
index 0cb6fe02..c848cc9c 100644
--- a/ui/internal/ops/ops.go
+++ b/ui/internal/opconst/ops.go
@@ -1,4 +1,4 @@
-package ops
+package opconst
 
 type OpType byte
 
diff --git a/ui/internal/ops/reader.go b/ui/internal/ops/reader.go
new file mode 100644
index 00000000..859d67e9
--- /dev/null
+++ b/ui/internal/ops/reader.go
@@ -0,0 +1,177 @@
+package ops
+
+import (
+	"encoding/binary"
+
+	"gioui.org/ui"
+	"gioui.org/ui/internal/opconst"
+)
+
+// Reader parses an ops list.
+type Reader struct {
+	pc    pc
+	stack []macro
+	ops   *ui.Ops
+}
+
+// EncodedOp represents an encoded op returned by
+// Reader.
+type EncodedOp struct {
+	Key  Key
+	Data []byte
+	Refs []interface{}
+}
+
+// Key is a unique key for a given op.
+type Key struct {
+	ops     *ui.Ops
+	pc      int
+	version int
+}
+
+// Shadow of ui.MacroOp.
+type macroOp struct {
+	recording bool
+	ops       *ui.Ops
+	version   int
+	pc        pc
+}
+
+type pc struct {
+	data int
+	refs int
+}
+
+type macro struct {
+	ops   *ui.Ops
+	retPC pc
+	endPC pc
+}
+
+type opMacroDef struct {
+	endpc pc
+}
+
+type opAux struct {
+	len int
+}
+
+// Reset start reading from the op list.
+func (r *Reader) Reset(ops *ui.Ops) {
+	r.stack = r.stack[:0]
+	r.pc = pc{}
+	r.ops = nil
+	if ops == nil {
+		return
+	}
+	r.ops = ops
+}
+
+func (r *Reader) Decode() (EncodedOp, bool) {
+	if r.ops == nil {
+		return EncodedOp{}, false
+	}
+	for {
+		if len(r.stack) > 0 {
+			b := r.stack[len(r.stack)-1]
+			if r.pc == b.endPC {
+				r.ops = b.ops
+				r.pc = b.retPC
+				r.stack = r.stack[:len(r.stack)-1]
+				continue
+			}
+		}
+		if r.pc.data == len(r.ops.Data) {
+			return EncodedOp{}, false
+		}
+		key := Key{ops: r.ops, pc: r.pc.data, version: r.ops.Version}
+		t := opconst.OpType(r.ops.Data[r.pc.data])
+		n := t.Size()
+		nrefs := t.NumRefs()
+		data := r.ops.Data[r.pc.data : r.pc.data+n]
+		refs := r.ops.Refs[r.pc.refs : r.pc.refs+nrefs]
+		switch t {
+		case opconst.TypeAux:
+			var op opAux
+			op.decode(data)
+			n += op.len
+			data = r.ops.Data[r.pc.data : r.pc.data+n]
+		case opconst.TypeMacro:
+			var op macroOp
+			op.decode(data, refs)
+			macroOps := op.ops
+			if opconst.OpType(macroOps.Data[op.pc.data]) != opconst.TypeMacroDef {
+				panic("invalid macro reference")
+			}
+			if op.version != op.ops.Version {
+				panic("invalid MacroOp reference to reset Ops")
+			}
+			var opDef opMacroDef
+			opDef.decode(macroOps.Data[op.pc.data : op.pc.data+opconst.TypeMacroDef.Size()])
+			retPC := r.pc
+			retPC.data += n
+			retPC.refs += nrefs
+			r.stack = append(r.stack, macro{
+				ops:   r.ops,
+				retPC: retPC,
+				endPC: opDef.endpc,
+			})
+			r.ops = macroOps
+			r.pc = op.pc
+			r.pc.data += opconst.TypeMacroDef.Size()
+			r.pc.refs += opconst.TypeMacroDef.NumRefs()
+			continue
+		case opconst.TypeMacroDef:
+			var op opMacroDef
+			op.decode(data)
+			r.pc = op.endpc
+			continue
+		}
+		r.pc.data += n
+		r.pc.refs += nrefs
+		return EncodedOp{Key: key, Data: data, Refs: refs}, true
+	}
+}
+
+func (op *opMacroDef) decode(data []byte) {
+	if opconst.OpType(data[0]) != opconst.TypeMacroDef {
+		panic("invalid op")
+	}
+	bo := binary.LittleEndian
+	dataIdx := int(int32(bo.Uint32(data[1:])))
+	refsIdx := int(int32(bo.Uint32(data[5:])))
+	*op = opMacroDef{
+		endpc: pc{
+			data: dataIdx,
+			refs: refsIdx,
+		},
+	}
+}
+
+func (op *opAux) decode(data []byte) {
+	if opconst.OpType(data[0]) != opconst.TypeAux {
+		panic("invalid op")
+	}
+	bo := binary.LittleEndian
+	*op = opAux{
+		len: int(int32(bo.Uint32(data[1:]))),
+	}
+}
+
+func (m *macroOp) decode(data []byte, refs []interface{}) {
+	if opconst.OpType(data[0]) != opconst.TypeMacro {
+		panic("invalid op")
+	}
+	bo := binary.LittleEndian
+	dataIdx := int(int32(bo.Uint32(data[1:])))
+	refsIdx := int(int32(bo.Uint32(data[5:])))
+	version := int(int32(bo.Uint32(data[9:])))
+	*m = macroOp{
+		ops: refs[0].(*ui.Ops),
+		pc: pc{
+			data: dataIdx,
+			refs: refsIdx,
+		},
+		version: version,
+	}
+}
diff --git a/ui/key/key.go b/ui/key/key.go
index 5c009a26..34c58cd4 100644
--- a/ui/key/key.go
+++ b/ui/key/key.go
@@ -5,7 +5,7 @@ package key
 import (
 	"gioui.org/ui"
 	"gioui.org/ui/input"
-	"gioui.org/ui/internal/ops"
+	"gioui.org/ui/internal/opconst"
 )
 
 type HandlerOp struct {
@@ -56,8 +56,8 @@ func (m Modifiers) Contain(m2 Modifiers) bool {
 }
 
 func (h HandlerOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypeKeyHandlerLen)
-	data[0] = byte(ops.TypeKeyHandler)
+	data := make([]byte, opconst.TypeKeyHandlerLen)
+	data[0] = byte(opconst.TypeKeyHandler)
 	if h.Focus {
 		data[1] = 1
 	}
@@ -65,7 +65,7 @@ func (h HandlerOp) Add(o *ui.Ops) {
 }
 
 func (h *HandlerOp) Decode(d []byte, refs []interface{}) {
-	if ops.OpType(d[0]) != ops.TypeKeyHandler {
+	if opconst.OpType(d[0]) != opconst.TypeKeyHandler {
 		panic("invalid op")
 	}
 	*h = HandlerOp{
@@ -75,8 +75,8 @@ func (h *HandlerOp) Decode(d []byte, refs []interface{}) {
 }
 
 func (h HideInputOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypeHideInputLen)
-	data[0] = byte(ops.TypeHideInput)
+	data := make([]byte, opconst.TypeHideInputLen)
+	data[0] = byte(opconst.TypeHideInput)
 	o.Write(data)
 }
 
diff --git a/ui/ops.go b/ui/ops.go
index 1f5eda0a..a00abf99 100644
--- a/ui/ops.go
+++ b/ui/ops.go
@@ -3,16 +3,16 @@ package ui
 import (
 	"encoding/binary"
 
-	"gioui.org/ui/internal/ops"
+	"gioui.org/ui/internal/opconst"
 )
 
 // Ops holds a list of serialized Ops.
 type Ops struct {
-	version int
+	Version int
 	// Serialized ops.
-	data []byte
+	Data []byte
 	// Op references.
-	refs []interface{}
+	Refs []interface{}
 
 	stackDepth int
 
@@ -21,39 +21,6 @@ type Ops struct {
 	auxLen int
 }
 
-// OpsReader parses an ops list. Internal use only.
-type OpsReader struct {
-	pc    pc
-	stack []macro
-	ops   *Ops
-}
-
-// EncodedOp represents an encoded op returned by
-// OpsReader. Internal use only.
-type EncodedOp struct {
-	Key  OpKey
-	Data []byte
-	Refs []interface{}
-}
-
-// OpKey is a unique key for a given op. Internal use only.
-type OpKey struct {
-	ops     *Ops
-	pc      int
-	version int
-}
-
-type macro struct {
-	ops   *Ops
-	retPC pc
-	endPC pc
-}
-
-type pc struct {
-	data int
-	refs int
-}
-
 type StackOp struct {
 	depth  int
 	active bool
@@ -67,12 +34,9 @@ type MacroOp struct {
 	pc        pc
 }
 
-type opMacroDef struct {
-	endpc pc
-}
-
-type opAux struct {
-	len int
+type pc struct {
+	data int
+	refs int
 }
 
 func (s *StackOp) Push(o *Ops) {
@@ -83,7 +47,7 @@ func (s *StackOp) Push(o *Ops) {
 	s.ops = o
 	o.stackDepth++
 	s.depth = o.stackDepth
-	o.Write([]byte{byte(ops.TypePush)})
+	o.Write([]byte{byte(opconst.TypePush)})
 }
 
 func (s *StackOp) Pop() {
@@ -96,32 +60,7 @@ func (s *StackOp) Pop() {
 	}
 	s.active = false
 	s.ops.stackDepth--
-	s.ops.Write([]byte{byte(ops.TypePop)})
-}
-
-func (op *opAux) decode(data []byte) {
-	if ops.OpType(data[0]) != ops.TypeAux {
-		panic("invalid op")
-	}
-	bo := binary.LittleEndian
-	*op = opAux{
-		len: int(int32(bo.Uint32(data[1:]))),
-	}
-}
-
-func (op *opMacroDef) decode(data []byte) {
-	if ops.OpType(data[0]) != ops.TypeMacroDef {
-		panic("invalid op")
-	}
-	bo := binary.LittleEndian
-	dataIdx := int(int32(bo.Uint32(data[1:])))
-	refsIdx := int(int32(bo.Uint32(data[5:])))
-	*op = opMacroDef{
-		endpc: pc{
-			data: dataIdx,
-			refs: refsIdx,
-		},
-	}
+	s.ops.Write([]byte{byte(opconst.TypePop)})
 }
 
 // Reset the Ops, preparing it for re-use.
@@ -129,12 +68,12 @@ func (o *Ops) Reset() {
 	o.inAux = false
 	o.stackDepth = 0
 	// Leave references to the GC.
-	for i := range o.refs {
-		o.refs[i] = nil
+	for i := range o.Refs {
+		o.Refs[i] = nil
 	}
-	o.data = o.data[:0]
-	o.refs = o.refs[:0]
-	o.version++
+	o.Data = o.Data[:0]
+	o.Refs = o.Refs[:0]
+	o.Version++
 }
 
 // Internal use only.
@@ -142,29 +81,29 @@ func (o *Ops) Aux() []byte {
 	if !o.inAux {
 		return nil
 	}
-	return o.data[o.auxOff+ops.TypeAuxLen : o.auxOff+ops.TypeAuxLen+o.auxLen]
+	return o.Data[o.auxOff+opconst.TypeAuxLen : o.auxOff+opconst.TypeAuxLen+o.auxLen]
 }
 
 func (d *Ops) write(op []byte, refs ...interface{}) {
-	d.data = append(d.data, op...)
-	d.refs = append(d.refs, refs...)
+	d.Data = append(d.Data, op...)
+	d.Refs = append(d.Refs, refs...)
 }
 
 func (o *Ops) Write(op []byte, refs ...interface{}) {
-	t := ops.OpType(op[0])
+	t := opconst.OpType(op[0])
 	if len(refs) != t.NumRefs() {
 		panic("invalid ref count")
 	}
 	switch t {
-	case ops.TypeAux:
+	case opconst.TypeAux:
 		// Write only the data.
 		op = op[1:]
 		if !o.inAux {
 			o.inAux = true
 			o.auxOff = o.pc().data
 			o.auxLen = 0
-			header := make([]byte, ops.TypeAuxLen)
-			header[0] = byte(ops.TypeAux)
+			header := make([]byte, opconst.TypeAuxLen)
+			header[0] = byte(opconst.TypeAux)
 			o.write(header)
 		}
 		o.auxLen += len(op)
@@ -172,14 +111,14 @@ func (o *Ops) Write(op []byte, refs ...interface{}) {
 		if o.inAux {
 			o.inAux = false
 			bo := binary.LittleEndian
-			bo.PutUint32(o.data[o.auxOff+1:], uint32(o.auxLen))
+			bo.PutUint32(o.Data[o.auxOff+1:], uint32(o.auxLen))
 		}
 	}
 	o.write(op, refs...)
 }
 
 func (d *Ops) pc() pc {
-	return pc{data: len(d.data), refs: len(d.refs)}
+	return pc{data: len(d.Data), refs: len(d.Refs)}
 }
 
 // Record a macro of operations.
@@ -191,7 +130,7 @@ func (m *MacroOp) Record(o *Ops) {
 	m.ops = o
 	m.pc = o.pc()
 	// Make room for a macro definition. Filled out in Stop.
-	m.ops.Write(make([]byte, ops.TypeMacroDefLen))
+	m.ops.Write(make([]byte, opconst.TypeMacroDefLen))
 }
 
 // Stop recording the macro.
@@ -202,30 +141,12 @@ func (m *MacroOp) Stop() {
 	m.recording = false
 	pc := m.ops.pc()
 	// Fill out the macro definition reserved in Record.
-	data := m.ops.data[m.pc.data : m.pc.data+ops.TypeMacroDefLen]
-	data[0] = byte(ops.TypeMacroDef)
+	data := m.ops.Data[m.pc.data : m.pc.data+opconst.TypeMacroDefLen]
+	data[0] = byte(opconst.TypeMacroDef)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[1:], uint32(pc.data))
 	bo.PutUint32(data[5:], uint32(pc.refs))
-	m.version = m.ops.version
-}
-
-func (m *MacroOp) decode(data []byte, refs []interface{}) {
-	if ops.OpType(data[0]) != ops.TypeMacro {
-		panic("invalid op")
-	}
-	bo := binary.LittleEndian
-	dataIdx := int(int32(bo.Uint32(data[1:])))
-	refsIdx := int(int32(bo.Uint32(data[5:])))
-	version := int(int32(bo.Uint32(data[9:])))
-	*m = MacroOp{
-		ops: refs[0].(*Ops),
-		pc: pc{
-			data: dataIdx,
-			refs: refsIdx,
-		},
-		version: version,
-	}
+	m.version = m.ops.Version
 }
 
 func (m MacroOp) Add(o *Ops) {
@@ -235,88 +156,11 @@ func (m MacroOp) Add(o *Ops) {
 	if m.ops == nil {
 		return
 	}
-	data := make([]byte, ops.TypeMacroLen)
-	data[0] = byte(ops.TypeMacro)
+	data := make([]byte, opconst.TypeMacroLen)
+	data[0] = byte(opconst.TypeMacro)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[1:], uint32(m.pc.data))
 	bo.PutUint32(data[5:], uint32(m.pc.refs))
 	bo.PutUint32(data[9:], uint32(m.version))
 	o.Write(data, m.ops)
 }
-
-// Reset start reading from the op list.
-func (r *OpsReader) Reset(ops *Ops) {
-	r.stack = r.stack[:0]
-	r.pc = pc{}
-	r.ops = nil
-	if ops == nil {
-		return
-	}
-	r.ops = ops
-}
-
-func (r *OpsReader) Decode() (EncodedOp, bool) {
-	if r.ops == nil {
-		return EncodedOp{}, false
-	}
-	for {
-		if len(r.stack) > 0 {
-			b := r.stack[len(r.stack)-1]
-			if r.pc == b.endPC {
-				r.ops = b.ops
-				r.pc = b.retPC
-				r.stack = r.stack[:len(r.stack)-1]
-				continue
-			}
-		}
-		if r.pc.data == len(r.ops.data) {
-			return EncodedOp{}, false
-		}
-		key := OpKey{ops: r.ops, pc: r.pc.data, version: r.ops.version}
-		t := ops.OpType(r.ops.data[r.pc.data])
-		n := t.Size()
-		nrefs := t.NumRefs()
-		data := r.ops.data[r.pc.data : r.pc.data+n]
-		refs := r.ops.refs[r.pc.refs : r.pc.refs+nrefs]
-		switch t {
-		case ops.TypeAux:
-			var op opAux
-			op.decode(data)
-			n += op.len
-			data = r.ops.data[r.pc.data : r.pc.data+n]
-		case ops.TypeMacro:
-			var op MacroOp
-			op.decode(data, refs)
-			macroOps := op.ops
-			if ops.OpType(macroOps.data[op.pc.data]) != ops.TypeMacroDef {
-				panic("invalid macro reference")
-			}
-			if op.version != op.ops.version {
-				panic("invalid MacroOp reference to reset Ops")
-			}
-			var opDef opMacroDef
-			opDef.decode(macroOps.data[op.pc.data : op.pc.data+ops.TypeMacroDef.Size()])
-			retPC := r.pc
-			retPC.data += n
-			retPC.refs += nrefs
-			r.stack = append(r.stack, macro{
-				ops:   r.ops,
-				retPC: retPC,
-				endPC: opDef.endpc,
-			})
-			r.ops = macroOps
-			r.pc = op.pc
-			r.pc.data += ops.TypeMacroDef.Size()
-			r.pc.refs += ops.TypeMacroDef.NumRefs()
-			continue
-		case ops.TypeMacroDef:
-			var op opMacroDef
-			op.decode(data)
-			r.pc = op.endpc
-			continue
-		}
-		r.pc.data += n
-		r.pc.refs += nrefs
-		return EncodedOp{Key: key, Data: data, Refs: refs}, true
-	}
-}
diff --git a/ui/pointer/pointer.go b/ui/pointer/pointer.go
index 922a9588..2753dad7 100644
--- a/ui/pointer/pointer.go
+++ b/ui/pointer/pointer.go
@@ -10,7 +10,7 @@ import (
 	"gioui.org/ui"
 	"gioui.org/ui/f32"
 	"gioui.org/ui/input"
-	"gioui.org/ui/internal/ops"
+	"gioui.org/ui/internal/opconst"
 )
 
 type Event struct {
@@ -95,8 +95,8 @@ func (op EllipseAreaOp) Add(ops *ui.Ops) {
 }
 
 func (op areaOp) add(o *ui.Ops) {
-	data := make([]byte, ops.TypeAreaLen)
-	data[0] = byte(ops.TypeArea)
+	data := make([]byte, opconst.TypeAreaLen)
+	data[0] = byte(opconst.TypeArea)
 	data[1] = byte(op.kind)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[2:], uint32(op.rect.Min.X))
@@ -107,8 +107,8 @@ func (op areaOp) add(o *ui.Ops) {
 }
 
 func (h HandlerOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypePointerHandlerLen)
-	data[0] = byte(ops.TypePointerHandler)
+	data := make([]byte, opconst.TypePointerHandlerLen)
+	data[0] = byte(opconst.TypePointerHandler)
 	if h.Grab {
 		data[1] = 1
 	}
@@ -116,7 +116,7 @@ func (h HandlerOp) Add(o *ui.Ops) {
 }
 
 func (h *HandlerOp) Decode(d []byte, refs []interface{}) {
-	if ops.OpType(d[0]) != ops.TypePointerHandler {
+	if opconst.OpType(d[0]) != opconst.TypePointerHandler {
 		panic("invalid op")
 	}
 	*h = HandlerOp{
@@ -126,8 +126,8 @@ func (h *HandlerOp) Decode(d []byte, refs []interface{}) {
 }
 
 func (op PassOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypePassLen)
-	data[0] = byte(ops.TypePass)
+	data := make([]byte, opconst.TypePassLen)
+	data[0] = byte(opconst.TypePass)
 	if op.Pass {
 		data[1] = 1
 	}
@@ -135,7 +135,7 @@ func (op PassOp) Add(o *ui.Ops) {
 }
 
 func (op *PassOp) Decode(d []byte) {
-	if ops.OpType(d[0]) != ops.TypePass {
+	if opconst.OpType(d[0]) != opconst.TypePass {
 		panic("invalid op")
 	}
 	*op = PassOp{
diff --git a/ui/system/system.go b/ui/system/system.go
index 51c22766..71c5615e 100644
--- a/ui/system/system.go
+++ b/ui/system/system.go
@@ -7,7 +7,7 @@ package system
 import (
 	"gioui.org/ui"
 	"gioui.org/ui/input"
-	"gioui.org/ui/internal/ops"
+	"gioui.org/ui/internal/opconst"
 )
 
 // ProfileOp registers a handler for receiving
@@ -24,13 +24,13 @@ type ProfileEvent struct {
 }
 
 func (p ProfileOp) Add(o *ui.Ops) {
-	data := make([]byte, ops.TypeProfileLen)
-	data[0] = byte(ops.TypeProfile)
+	data := make([]byte, opconst.TypeProfileLen)
+	data[0] = byte(opconst.TypeProfile)
 	o.Write(data, p.Key)
 }
 
 func (p *ProfileOp) Decode(d []byte, refs []interface{}) {
-	if ops.OpType(d[0]) != ops.TypeProfile {
+	if opconst.OpType(d[0]) != opconst.TypeProfile {
 		panic("invalid op")
 	}
 	*p = ProfileOp{
diff --git a/ui/ui.go b/ui/ui.go
index f743e075..92174097 100644
--- a/ui/ui.go
+++ b/ui/ui.go
@@ -8,7 +8,7 @@ import (
 	"time"
 
 	"gioui.org/ui/f32"
-	"gioui.org/ui/internal/ops"
+	"gioui.org/ui/internal/opconst"
 )
 
 // Config represents the essential configuration for
@@ -33,8 +33,8 @@ type TransformOp struct {
 }
 
 func (r InvalidateOp) Add(o *Ops) {
-	data := make([]byte, ops.TypeRedrawLen)
-	data[0] = byte(ops.TypeInvalidate)
+	data := make([]byte, opconst.TypeRedrawLen)
+	data[0] = byte(opconst.TypeInvalidate)
 	bo := binary.LittleEndian
 	// UnixNano cannot represent the zero time.
 	if t := r.At; !t.IsZero() {
@@ -48,7 +48,7 @@ func (r InvalidateOp) Add(o *Ops) {
 
 func (r *InvalidateOp) Decode(d []byte) {
 	bo := binary.LittleEndian
-	if ops.OpType(d[0]) != ops.TypeInvalidate {
+	if opconst.OpType(d[0]) != opconst.TypeInvalidate {
 		panic("invalid op")
 	}
 	if nanos := bo.Uint64(d[1:]); nanos > 0 {
@@ -79,8 +79,8 @@ func (t TransformOp) Multiply(t2 TransformOp) TransformOp {
 }
 
 func (t TransformOp) Add(o *Ops) {
-	data := make([]byte, ops.TypeTransformLen)
-	data[0] = byte(ops.TypeTransform)
+	data := make([]byte, opconst.TypeTransformLen)
+	data[0] = byte(opconst.TypeTransform)
 	bo := binary.LittleEndian
 	bo.PutUint32(data[1:], math.Float32bits(t.offset.X))
 	bo.PutUint32(data[5:], math.Float32bits(t.offset.Y))
@@ -89,7 +89,7 @@ func (t TransformOp) Add(o *Ops) {
 
 func (t *TransformOp) Decode(d []byte) {
 	bo := binary.LittleEndian
-	if ops.OpType(d[0]) != ops.TypeTransform {
+	if opconst.OpType(d[0]) != opconst.TypeTransform {
 		panic("invalid op")
 	}
 	*t = TransformOp{f32.Point{