diff --git a/font/opentype/opentype.go b/font/opentype/opentype.go
index 58dd4366..7dcee2b0 100644
--- a/font/opentype/opentype.go
+++ b/font/opentype/opentype.go
@@ -85,11 +85,11 @@ func (c *Collection) Font(i int) (*Font, error) {
 	return &Font{font: fnt}, nil
 }
 
-func (f *Font) Layout(ppem fixed.Int26_6, str string, opts text.LayoutOptions) *text.Layout {
+func (f *Font) Layout(ppem fixed.Int26_6, str string, opts text.LayoutOptions) []text.Line {
 	return layoutText(&f.buf, ppem, str, &opentype{Font: f.font, Hinting: font.HintingFull}, opts)
 }
 
-func (f *Font) Shape(ppem fixed.Int26_6, str text.String) op.CallOp {
+func (f *Font) Shape(ppem fixed.Int26_6, str []text.Glyph) op.CallOp {
 	return textPath(&f.buf, ppem, &opentype{Font: f.font, Hinting: font.HintingFull}, str)
 }
 
@@ -98,7 +98,7 @@ func (f *Font) Metrics(ppem fixed.Int26_6) font.Metrics {
 	return o.Metrics(&f.buf, ppem)
 }
 
-func layoutText(buf *sfnt.Buffer, ppem fixed.Int26_6, str string, f *opentype, opts text.LayoutOptions) *text.Layout {
+func layoutText(buf *sfnt.Buffer, ppem fixed.Int26_6, str string, f *opentype, opts text.LayoutOptions) []text.Line {
 	m := f.Metrics(buf, ppem)
 	lineTmpl := text.Line{
 		Ascent: m.Ascent,
@@ -110,18 +110,18 @@ func layoutText(buf *sfnt.Buffer, ppem fixed.Int26_6, str string, f *opentype, o
 	var lines []text.Line
 	maxDotX := fixed.I(opts.MaxWidth)
 	type state struct {
-		r     rune
-		advs  []fixed.Int26_6
-		adv   fixed.Int26_6
-		x     fixed.Int26_6
-		idx   int
-		valid bool
+		r      rune
+		layout []text.Glyph
+		adv    fixed.Int26_6
+		x      fixed.Int26_6
+		idx    int
+		valid  bool
 	}
 	var prev, word state
 	endLine := func() {
 		line := lineTmpl
-		line.Text.Advances = prev.advs
-		line.Text.String = str[:prev.idx]
+		line.Layout = prev.layout
+		line.Len = prev.idx
 		line.Width = prev.x + prev.adv
 		line.Bounds.Max.X += prev.x
 		lines = append(lines, line)
@@ -133,17 +133,17 @@ func layoutText(buf *sfnt.Buffer, ppem fixed.Int26_6, str string, f *opentype, o
 		c, s := utf8.DecodeRuneInString(str[prev.idx:])
 		a, valid := f.GlyphAdvance(buf, ppem, c)
 		next := state{
-			r:     c,
-			advs:  prev.advs,
-			idx:   prev.idx + s,
-			x:     prev.x + prev.adv,
-			adv:   a,
-			valid: valid,
+			r:      c,
+			layout: prev.layout,
+			idx:    prev.idx + s,
+			x:      prev.x + prev.adv,
+			adv:    a,
+			valid:  valid,
 		}
 		if c == '\n' {
 			// The newline is zero width; use the previous
 			// character for line measurements.
-			prev.advs = append(prev.advs, 0)
+			prev.layout = append(prev.layout, text.Glyph{Rune: c, Advance: 0})
 			prev.idx = next.idx
 			endLine()
 			continue
@@ -160,33 +160,32 @@ func layoutText(buf *sfnt.Buffer, ppem fixed.Int26_6, str string, f *opentype, o
 			}
 			next.x -= word.x + word.adv
 			next.idx -= word.idx
-			next.advs = next.advs[len(word.advs):]
+			next.layout = next.layout[len(word.layout):]
 			prev = word
 			endLine()
 		} else if k != 0 {
-			next.advs[len(next.advs)-1] += k
+			next.layout[len(next.layout)-1].Advance += k
 			next.x += k
 		}
-		next.advs = append(next.advs, next.adv)
-		if unicode.IsSpace(next.r) {
+		next.layout = append(next.layout, text.Glyph{Rune: c, Advance: next.adv})
+		if unicode.IsSpace(c) {
 			word = next
 		}
 		prev = next
 	}
 	endLine()
-	return &text.Layout{Lines: lines}
+	return lines
 }
 
-func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, f *opentype, str text.String) op.CallOp {
+func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, f *opentype, str []text.Glyph) op.CallOp {
 	var lastPos f32.Point
 	var builder clip.Path
 	ops := new(op.Ops)
 	var x fixed.Int26_6
-	var advIdx int
 	builder.Begin(ops)
-	for _, r := range str.String {
-		if !unicode.IsSpace(r) {
-			segs, ok := f.LoadGlyph(buf, ppem, r)
+	for _, g := range str {
+		if !unicode.IsSpace(g.Rune) {
+			segs, ok := f.LoadGlyph(buf, ppem, g.Rune)
 			if !ok {
 				continue
 			}
@@ -232,8 +231,7 @@ func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, f *opentype, str text.String
 			}
 			lastPos = lastPos.Add(lastArg)
 		}
-		x += str.Advances[advIdx]
-		advIdx++
+		x += g.Advance
 	}
 	builder.End().Add(ops)
 	return op.CallOp{Ops: ops}
diff --git a/text/lru.go b/text/lru.go
index 343e7aee..3ff9b6d1 100644
--- a/text/lru.go
+++ b/text/lru.go
@@ -20,7 +20,7 @@ type pathCache struct {
 type layoutElem struct {
 	next, prev *layoutElem
 	key        layoutKey
-	layout     *Layout
+	layout     []Line
 }
 
 type path struct {
@@ -42,7 +42,7 @@ type pathKey struct {
 
 const maxSize = 1000
 
-func (l *layoutCache) Get(k layoutKey) (*Layout, bool) {
+func (l *layoutCache) Get(k layoutKey) ([]Line, bool) {
 	if lt, ok := l.m[k]; ok {
 		l.remove(lt)
 		l.insert(lt)
@@ -51,7 +51,7 @@ func (l *layoutCache) Get(k layoutKey) (*Layout, bool) {
 	return nil, false
 }
 
-func (l *layoutCache) Put(k layoutKey, lt *Layout) {
+func (l *layoutCache) Put(k layoutKey, lt []Line) {
 	if l.m == nil {
 		l.m = make(map[layoutKey]*layoutElem)
 		l.head = new(layoutElem)
diff --git a/text/shaper.go b/text/shaper.go
index 39bc459b..d2cacb1d 100644
--- a/text/shaper.go
+++ b/text/shaper.go
@@ -3,8 +3,6 @@
 package text
 
 import (
-	"unicode/utf8"
-
 	"golang.org/x/image/font"
 
 	"gioui.org/op"
@@ -14,8 +12,10 @@ import (
 
 // Shaper implements layout and shaping of text.
 type Shaper interface {
-	Layout(c unit.Converter, font Font, str string, opts LayoutOptions) *Layout
-	Shape(c unit.Converter, font Font, str String) op.CallOp
+	// Layout a text according to a set of options.
+	Layout(c unit.Converter, font Font, str string, opts LayoutOptions) []Line
+	// Shape a line of text previously laid out by Layout.
+	Shape(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp
 	Metrics(c unit.Converter, font Font) font.Metrics
 }
 
@@ -50,14 +50,14 @@ func (s *FontRegistry) Register(font Font, tf Face) {
 	}
 }
 
-func (s *FontRegistry) Layout(c unit.Converter, font Font, str string, opts LayoutOptions) *Layout {
+func (s *FontRegistry) Layout(c unit.Converter, font Font, str string, opts LayoutOptions) []Line {
 	tf := s.faceForFont(font)
 	return tf.layout(fixed.I(c.Px(font.Size)), str, opts)
 }
 
-func (s *FontRegistry) Shape(c unit.Converter, font Font, str String) op.CallOp {
+func (s *FontRegistry) Shape(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp {
 	tf := s.faceForFont(font)
-	return tf.shape(fixed.I(c.Px(font.Size)), str)
+	return tf.shape(fixed.I(c.Px(font.Size)), str, layout)
 }
 
 func (s *FontRegistry) Metrics(c unit.Converter, font Font) font.Metrics {
@@ -96,9 +96,9 @@ func (s *FontRegistry) faceForFont(font Font) *face {
 	return tf
 }
 
-func (t *face) layout(ppem fixed.Int26_6, str string, opts LayoutOptions) *Layout {
+func (t *face) layout(ppem fixed.Int26_6, str string, opts LayoutOptions) []Line {
 	if t == nil {
-		return fallbackLayout(str)
+		return nil
 	}
 	lk := layoutKey{
 		ppem: ppem,
@@ -113,18 +113,18 @@ func (t *face) layout(ppem fixed.Int26_6, str string, opts LayoutOptions) *Layou
 	return l
 }
 
-func (t *face) shape(ppem fixed.Int26_6, str String) op.CallOp {
+func (t *face) shape(ppem fixed.Int26_6, str string, layout []Glyph) op.CallOp {
 	if t == nil {
 		return op.CallOp{}
 	}
 	pk := pathKey{
 		ppem: ppem,
-		str:  str.String,
+		str:  str,
 	}
 	if clip, ok := t.pathCache.Get(pk); ok {
 		return clip
 	}
-	clip := t.face.Shape(ppem, str)
+	clip := t.face.Shape(ppem, layout)
 	t.pathCache.Put(pk, clip)
 	return clip
 }
@@ -132,16 +132,3 @@ func (t *face) shape(ppem fixed.Int26_6, str String) op.CallOp {
 func (t *face) metrics(ppem fixed.Int26_6) font.Metrics {
 	return t.face.Metrics(ppem)
 }
-
-func fallbackLayout(str string) *Layout {
-	l := &Layout{
-		Lines: []Line{
-			{Text: String{
-				String: str,
-			}},
-		},
-	}
-	strlen := utf8.RuneCountInString(str)
-	l.Lines[0].Text.Advances = make([]fixed.Int26_6, strlen)
-	return l
-}
diff --git a/text/text.go b/text/text.go
index 9f3c59e4..703a994d 100644
--- a/text/text.go
+++ b/text/text.go
@@ -11,7 +11,9 @@ import (
 
 // A Line contains the measurements of a line of text.
 type Line struct {
-	Text String
+	Layout []Glyph
+	// Len is the length in UTF8 bytes of the line.
+	Len int
 	// Width is the width of the line.
 	Width fixed.Int26_6
 	// Ascent is the height above the baseline.
@@ -23,16 +25,9 @@ type Line struct {
 	Bounds fixed.Rectangle26_6
 }
 
-type String struct {
-	String string
-	// Advances contain the advance of each rune in String.
-	Advances []fixed.Int26_6
-}
-
-// A Layout contains the measurements of a body of text as
-// a list of Lines.
-type Layout struct {
-	Lines []Line
+type Glyph struct {
+	Rune    rune
+	Advance fixed.Int26_6
 }
 
 // LayoutOptions specify the constraints of a text layout.
@@ -59,8 +54,8 @@ type Font struct {
 
 // Face implements text layout and shaping for a particular font.
 type Face interface {
-	Layout(ppem fixed.Int26_6, str string, opts LayoutOptions) *Layout
-	Shape(ppem fixed.Int26_6, str String) op.CallOp
+	Layout(ppem fixed.Int26_6, str string, opts LayoutOptions) []Line
+	Shape(ppem fixed.Int26_6, str []Glyph) op.CallOp
 	Metrics(ppem fixed.Int26_6) font.Metrics
 }
 
diff --git a/widget/editor.go b/widget/editor.go
index 0ae7d359..aed6dd22 100644
--- a/widget/editor.go
+++ b/widget/editor.go
@@ -273,11 +273,13 @@ func (e *Editor) layout(gtx *layout.Context, sh text.Shaper) {
 	}
 	e.shapes = e.shapes[:0]
 	for {
-		str, off, ok := it.Next()
+		start, end, layout, off, ok := it.Next()
 		if !ok {
 			break
 		}
-		path := sh.Shape(gtx, e.font, str)
+		// TODO: remove
+		str := e.rr.String()[start:end]
+		path := sh.Shape(gtx, e.font, str, layout)
 		e.shapes = append(e.shapes, line{off, path})
 	}
 
@@ -433,15 +435,13 @@ func (e *Editor) moveCoord(c unit.Converter, pos image.Point) {
 func (e *Editor) layoutText(c unit.Converter, s text.Shaper, font text.Font) ([]text.Line, layout.Dimensions) {
 	txt := e.rr.String()
 	opts := text.LayoutOptions{MaxWidth: e.maxWidth}
-	textLayout := s.Layout(c, font, txt, opts)
-	lines := textLayout.Lines
+	lines := s.Layout(c, font, txt, opts)
 	dims := linesDimens(lines)
 	for i := 0; i < len(lines)-1; i++ {
-		s := lines[i].Text.String
 		// To avoid layout flickering while editing, assume a soft newline takes
 		// up all available space.
-		if len(s) > 0 {
-			r, _ := utf8.DecodeLastRuneInString(s)
+		if layout := lines[i].Layout; len(layout) > 0 {
+			r := layout[len(layout)-1].Rune
 			if r != '\n' {
 				dims.Size.X = e.maxWidth
 				break
@@ -459,21 +459,18 @@ loop:
 		l := e.lines[carLine]
 		y += (prevDesc + l.Ascent).Ceil()
 		prevDesc = l.Descent
-		if carLine == len(e.lines)-1 || idx+len(l.Text.String) > e.rr.caret {
-			str := l.Text.String
-			for _, adv := range l.Text.Advances {
+		if carLine == len(e.lines)-1 || idx+len(l.Layout) > e.rr.caret {
+			for _, g := range l.Layout {
 				if idx == e.rr.caret {
 					break loop
 				}
-				x += adv
-				_, s := utf8.DecodeRuneInString(str)
-				idx += s
-				str = str[s:]
+				x += g.Advance
+				idx += utf8.RuneLen(g.Rune)
 				carCol++
 			}
 			break
 		}
-		idx += len(l.Text.String)
+		idx += l.Len
 	}
 	x += align(e.Alignment, e.lines[carLine].Width, e.viewSize.X)
 	return
@@ -553,11 +550,11 @@ func (e *Editor) moveToLine(carX fixed.Int26_6, carLine2 int) fixed.Int26_6 {
 		// Move to start of line2.
 		if carLine2 > carLine {
 			for i := carLine; i < carLine2; i++ {
-				e.rr.caret += len(e.lines[i].Text.String)
+				e.rr.caret += e.lines[i].Len
 			}
 		} else {
 			for i := carLine - 1; i >= carLine2; i-- {
-				e.rr.caret -= len(e.lines[i].Text.String)
+				e.rr.caret -= e.lines[i].Len
 			}
 		}
 	}
@@ -569,15 +566,15 @@ func (e *Editor) moveToLine(carX fixed.Int26_6, carLine2 int) fixed.Int26_6 {
 		end = 1
 	}
 	// Move to rune closest to previous horizontal position.
-	for i := 0; i < len(l2.Text.Advances)-end; i++ {
-		adv := l2.Text.Advances[i]
+	for i := 0; i < len(l2.Layout)-end; i++ {
+		g := l2.Layout[i]
 		if carX2 >= carX {
 			break
 		}
-		if carX2+adv-carX >= carX-carX2 {
+		if carX2+g.Advance-carX >= carX-carX2 {
 			break
 		}
-		carX2 += adv
+		carX2 += g.Advance
 		_, s := e.rr.runeAt(e.rr.caret)
 		e.rr.caret += s
 	}
@@ -593,11 +590,11 @@ func (e *Editor) Move(distance int) {
 
 func (e *Editor) moveStart() {
 	carLine, carCol, x, _ := e.layoutCaret()
-	advances := e.lines[carLine].Text.Advances
+	layout := e.lines[carLine].Layout
 	for i := carCol - 1; i >= 0; i-- {
 		_, s := e.rr.runeBefore(e.rr.caret)
 		e.rr.caret -= s
-		x -= advances[i]
+		x -= layout[i].Advance
 	}
 	e.carXOff = -x
 }
@@ -610,8 +607,9 @@ func (e *Editor) moveEnd() {
 	if carLine < len(e.lines)-1 {
 		end = 1
 	}
-	for i := carCol; i < len(l.Text.Advances)-end; i++ {
-		adv := l.Text.Advances[i]
+	layout := l.Layout
+	for i := carCol; i < len(layout)-end; i++ {
+		adv := layout[i].Advance
 		_, s := e.rr.runeAt(e.rr.caret)
 		e.rr.caret += s
 		x += adv
diff --git a/widget/label.go b/widget/label.go
index 768ae797..7e9cd158 100644
--- a/widget/label.go
+++ b/widget/label.go
@@ -32,11 +32,12 @@ type lineIterator struct {
 	Offset    image.Point
 
 	y, prevDesc fixed.Int26_6
+	txtOff      int
 }
 
 const inf = 1e6
 
-func (l *lineIterator) Next() (text.String, f32.Point, bool) {
+func (l *lineIterator) Next() (int, int, []text.Glyph, f32.Point, bool) {
 	for len(l.Lines) > 0 {
 		line := l.Lines[0]
 		l.Lines = l.Lines[1:]
@@ -50,42 +51,41 @@ func (l *lineIterator) Next() (text.String, f32.Point, bool) {
 		if (off.Y + line.Bounds.Min.Y).Floor() > l.Clip.Max.Y {
 			break
 		}
+		layout := line.Layout
+		start := l.txtOff
+		l.txtOff += line.Len
 		if (off.Y + line.Bounds.Max.Y).Ceil() < l.Clip.Min.Y {
 			continue
 		}
-		str := line.Text
-		for len(str.Advances) > 0 {
-			adv := str.Advances[0]
+		for len(layout) > 0 {
+			g := layout[0]
+			adv := g.Advance
 			if (off.X + adv + line.Bounds.Max.X - line.Width).Ceil() >= l.Clip.Min.X {
 				break
 			}
 			off.X += adv
-			_, s := utf8.DecodeRuneInString(str.String)
-			str.String = str.String[s:]
-			str.Advances = str.Advances[1:]
+			layout = layout[1:]
+			start += utf8.RuneLen(g.Rune)
 		}
-		n := 0
+		end := start
 		endx := off.X
-		for i, adv := range str.Advances {
+		for i, g := range layout {
 			if (endx + line.Bounds.Min.X).Floor() > l.Clip.Max.X {
-				str.String = str.String[:n]
-				str.Advances = str.Advances[:i]
+				layout = layout[:i]
 				break
 			}
-			_, s := utf8.DecodeRuneInString(str.String[n:])
-			n += s
-			endx += adv
+			end += utf8.RuneLen(g.Rune)
+			endx += g.Advance
 		}
 		offf := f32.Point{X: float32(off.X) / 64, Y: float32(off.Y) / 64}
-		return str, offf, true
+		return start, end, layout, offf, true
 	}
-	return text.String{}, f32.Point{}, false
+	return 0, 0, nil, f32.Point{}, false
 }
 
 func (l Label) Layout(gtx *layout.Context, s text.Shaper, font text.Font, txt string) {
 	cs := gtx.Constraints
-	textLayout := s.Layout(gtx, font, txt, text.LayoutOptions{MaxWidth: cs.Width.Max})
-	lines := textLayout.Lines
+	lines := s.Layout(gtx, font, txt, text.LayoutOptions{MaxWidth: cs.Width.Max})
 	if max := l.MaxLines; max > 0 && len(lines) > max {
 		lines = lines[:max]
 	}
@@ -100,7 +100,7 @@ func (l Label) Layout(gtx *layout.Context, s text.Shaper, font text.Font, txt st
 		Width:     dims.Size.X,
 	}
 	for {
-		str, off, ok := it.Next()
+		start, end, layout, off, ok := it.Next()
 		if !ok {
 			break
 		}
@@ -108,7 +108,8 @@ func (l Label) Layout(gtx *layout.Context, s text.Shaper, font text.Font, txt st
 		var stack op.StackOp
 		stack.Push(gtx.Ops)
 		op.TransformOp{}.Offset(off).Add(gtx.Ops)
-		s.Shape(gtx, font, str).Add(gtx.Ops)
+		str := txt[start:end]
+		s.Shape(gtx, font, str, layout).Add(gtx.Ops)
 		paint.PaintOp{Rect: lclip}.Add(gtx.Ops)
 		stack.Pop()
 	}