diff --git a/chart_brush.go b/chart_brush.go
index edaad4f..08070e0 100644
--- a/chart_brush.go
+++ b/chart_brush.go
@@ -75,20 +75,21 @@ func ChartBrush(c *ui.Context, value *[2]float64, opts ChartBrushOptions) Choice
 		track.Draw(func(p *ui.Painter, r ui.Rect) { brushPaint(p, r, *value, opts, k) })
 		track.Children(func() {
 			x0, x1 := at(value[0]), at(value[1])
-			window := ui.Box(c).Absolute().Left(x0).Top(0).Width(max(x1-x0, 1)).Height(h).Focusable().
-				Role(ui.RoleGroup).Label(fmt.Sprintf(msg(c, "chart_brush.window"), opts.Label, val(value[0]), val(value[1])))
-			internal.Ring(window, k.Focus, theme.ControlRadius)
-			ends := [2]*ui.Element{}
-			for i, x := range []float32{x0, x1} {
-				end := ui.Box(c).Absolute().Left(x - theme.MinHitSize/2).Top(0).Size(theme.MinHitSize, h).Focusable().
+			end := func(i int, x float32) *ui.Element {
+				e := ui.Box(c).Absolute().Left(x - theme.MinHitSize/2).Top(0).Size(theme.MinHitSize, h).Focusable().
 					Role(ui.RoleSlider).Label(fmt.Sprintf(msg(c, []string{"chart_brush.start", "chart_brush.end"}[i]), val(value[i])))
-				internal.Ring(end, k.Focus, theme.ControlRadius)
-				end.Draw(func(p *ui.Painter, r ui.Rect) {
+				internal.Ring(e, k.Focus, theme.ControlRadius)
+				return e.Draw(func(p *ui.Painter, r ui.Rect) {
 					cx := internal.Snap(p, r.X+r.W/2)
 					p.Fill(ui.Rect{X: cx - 3, Y: r.Y + r.H/2 - 10, W: 6, H: 20}, k.Text, 2)
 				})
-				ends[i] = end
 			}
+			// Tab order runs start, window, end.
+			ends := [2]*ui.Element{end(0, x0)}
+			window := ui.Box(c).Absolute().Left(x0 + theme.MinHitSize/2).Top(0).Width(max(x1-x0-theme.MinHitSize, 1)).Height(h).Focusable().
+				Role(ui.RoleGroup).Label(fmt.Sprintf(msg(c, "chart_brush.window"), opts.Label, val(value[0]), val(value[1])))
+			internal.Ring(window, k.Focus, theme.ControlRadius)
+			ends[1] = end(1, x1)
 			if res.Element.IsDisabled() {
 				return
 			}
diff --git a/chart_brush_test.go b/chart_brush_test.go
new file mode 100644
index 0000000..17c9490
--- /dev/null
+++ b/chart_brush_test.go
@@ -0,0 +1,123 @@
+package mujica
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+type brushHarness struct {
+	value    [2]float64
+	changes  int
+	disabled bool
+	el       *ui.Element
+}
+
+func (h *brushHarness) view(c *ui.Context) {
+	Use(c, Settings{Mode: Light})
+	ui.Column(c).Padding(10).Width(420).Children(func() {
+		r := ChartBrush(c, &h.value, ChartBrushOptions{Label: "Months", Min: 0, Max: 100, Step: 1, Disabled: h.disabled})
+		h.el = r.Element
+		if r.Changed() {
+			h.changes++
+		}
+	})
+}
+
+func TestChartBrushKeyboard(t *testing.T) {
+	h := &brushHarness{value: [2]float64{20, 40}}
+	tt := ui.NewTester(h.view, 460, 200)
+	tabTo(t, tt, "Months: 20 to 40")
+	tt.Key(0, ui.KeyRight)
+	tt.Key(0, ui.KeyRight)
+	if h.value != [2]float64{22, 42} || h.changes != 2 {
+		t.Fatalf("window moved to %v (%d)", h.value, h.changes)
+	}
+	tt.Key(0, ui.KeyTab)
+	if !tt.Focused("Range end 42") {
+		t.Fatal("Tab did not reach the end handle")
+	}
+	tt.Key(0, ui.KeyPageUp)
+	tt.Key(0, ui.KeyEnd)
+	if h.value != [2]float64{22, 100} {
+		t.Fatalf("end handle: %v", h.value)
+	}
+	tt.Key(ui.Shift, ui.KeyTab)
+	tt.Key(ui.Shift, ui.KeyTab)
+	tt.Key(0, ui.KeyEnd) // the start cannot pass the end
+	if h.value != [2]float64{99, 100} || !tt.HasText("99 – 100") {
+		t.Fatalf("start to End: %v %q", h.value, tt.Texts())
+	}
+}
+
+func TestChartBrushDrag(t *testing.T) {
+	h := &brushHarness{value: [2]float64{20, 40}}
+	tt := ui.NewTester(h.view, 460, 200)
+	b := h.el.Bounds()
+	x := func(v float32) float32 { return b.X + 400*v/100 }
+	y := b.Y + 24
+	tt.Press(x(30), y) // inside the window
+	tt.Move(x(40), y)
+	tt.Move(x(50), y)
+	tt.Release(x(50), y)
+	if h.value != [2]float64{40, 60} {
+		t.Fatalf("window drag: %v", h.value)
+	}
+	tt.Press(x(60), y) // the end handle
+	tt.Move(x(70), y)
+	tt.Move(x(75), y)
+	tt.Release(x(75), y)
+	if h.value != [2]float64{40, 75} {
+		t.Fatalf("end drag: %v", h.value)
+	}
+	tt.Press(x(85), y) // outside: a new range
+	tt.Move(x(90), y)
+	tt.Move(x(95), y)
+	tt.Release(x(95), y)
+	if h.value != [2]float64{85, 95} {
+		t.Fatalf("new range: %v", h.value)
+	}
+}
+
+func TestChartBrushDisabledAndBad(t *testing.T) {
+	h := &brushHarness{value: [2]float64{20, 40}, disabled: true}
+	tt := ui.NewTester(h.view, 460, 200)
+	b := h.el.Bounds()
+	tt.Press(b.X+120, b.Y+24)
+	tt.Move(b.X+200, b.Y+24)
+	tt.Release(b.X+200, b.Y+24)
+	for range 3 {
+		tt.Key(0, ui.KeyTab)
+		tt.Key(0, ui.KeyRight)
+	}
+	if h.value != [2]float64{20, 40} || h.changes != 0 {
+		t.Fatalf("disabled brush moved: %v", h.value)
+	}
+	for _, v := range [][2]float64{{50, 40}, {-1, 10}} {
+		func() {
+			defer func() {
+				if recover() == nil {
+					t.Errorf("%v: no panic", v)
+				}
+			}()
+			ui.NewTester(func(c *ui.Context) {
+				Use(c, Settings{})
+				ChartBrush(c, &v, ChartBrushOptions{Label: "x", Max: 100})
+			}, 300, 100)
+		}()
+	}
+}
+
+func TestChartBrushSnapshot(t *testing.T) {
+	vals := make([]float64, 60)
+	for i := range vals {
+		vals[i] = float64((i*7)%13) + float64(i)/6
+	}
+	snapshot(t, "chart_brush", 460, 110, func(c *ui.Context) {
+		v := [2]float64{18, 42}
+		ui.Column(c).Padding(16).Children(func() {
+			ChartBrush(c, &v, ChartBrushOptions{Label: "Months", Min: 0, Max: 59, Step: 1, Values: vals, Format: func(f float64) string { return fmt.Sprintf("week %.0f", f) }})
+		})
+	})
+}
diff --git a/chart_empty_state_test.go b/chart_empty_state_test.go
new file mode 100644
index 0000000..2a94b95
--- /dev/null
+++ b/chart_empty_state_test.go
@@ -0,0 +1,61 @@
+package mujica
+
+import (
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+func TestChartEmptyStateKeepsSizeAndRetries(t *testing.T) {
+	status := DataReady
+	retries, disabled := 0, false
+	var heights []float32
+	var el *ui.Element
+	tt := ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		ui.Column(c).Width(400).Disabled(disabled).Children(func() {
+			r := ChartEmptyState(c, status, ChartEmptyStateOptions{Height: 180, Empty: "No hymns this week", Error: "The choir did not answer"})
+			el = r.Element
+			if r.Changed() {
+				retries++
+			}
+		})
+	}, 440, 300)
+	heights = append(heights, el.Bounds().H)
+	if !tt.HasText("No hymns this week") {
+		t.Fatalf("empty: %q", tt.Texts())
+	}
+	status = DataLoading
+	tt.Frame()
+	heights = append(heights, el.Bounds().H)
+	if !tt.HasText("Loading") {
+		t.Fatalf("loading: %q", tt.Texts())
+	}
+	status = DataFailed
+	tt.Frame()
+	heights = append(heights, el.Bounds().H)
+	if err := tt.Click("Retry"); err != nil || retries != 1 || !tt.HasText("The choir did not answer") {
+		t.Fatalf("retry: %v %d", err, retries)
+	}
+	if heights[0] != 180 || heights[1] != 180 || heights[2] != 180 {
+		t.Fatalf("heights %v", heights)
+	}
+	disabled = true
+	tt.Frame()
+	_ = tt.Click("Retry")
+	if retries != 1 {
+		t.Fatal("disabled retry fired")
+	}
+}
+
+func TestChartEmptyStateSnapshot(t *testing.T) {
+	snapshot(t, "chart_empty_state", 640, 220, func(c *ui.Context) {
+		ui.Row(c).Padding(16).Gap(16).Children(func() {
+			for _, st := range []DataStatus{DataReady, DataLoading, DataFailed} {
+				ui.Column(c).Width(192).Border(1, Tokens(c).Border).Children(func() {
+					ChartEmptyState(c, st, ChartEmptyStateOptions{Height: 180})
+				})
+			}
+		})
+	})
+}
diff --git a/chart_export_test.go b/chart_export_test.go
new file mode 100644
index 0000000..14eef3f
--- /dev/null
+++ b/chart_export_test.go
@@ -0,0 +1,73 @@
+package mujica
+
+import (
+	"bytes"
+	"image/color"
+	"image/png"
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/theme"
+)
+
+func TestChartExportPNGInTheme(t *testing.T) {
+	for _, mode := range []Mode{Light, Dark} {
+		var out []byte
+		ui.NewTester(func(c *ui.Context) {
+			Use(c, Settings{Mode: mode})
+			if out != nil {
+				return
+			}
+			b, err := ChartExport(c, func(c *ui.Context) {
+				BarChart(c, barCats, barSeries(), BarChartOptions{Frame: ChartFrame{Label: "Tithes", Height: 160}})
+			}, ChartExportOptions{Width: 300, Height: 220, Scale: 1.5})
+			if err != nil {
+				t.Fatal(err)
+			}
+			out = b
+		}, 100, 100)
+		img, err := png.Decode(bytes.NewReader(out))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if b := img.Bounds(); b.Dx() != 450 || b.Dy() != 330 {
+			t.Fatalf("%v: size %v", mode, b)
+		}
+		k := theme.Light()
+		if mode == Dark {
+			k = theme.Dark()
+		}
+		if got := color.RGBAModel.Convert(img.At(3, 3)).(color.RGBA); got != toRGBA(k.Surface) {
+			t.Fatalf("%v: corner %v, want the theme's Surface", mode, got)
+		}
+	}
+}
+
+func TestChartExportBad(t *testing.T) {
+	defer func() {
+		if recover() == nil {
+			t.Fatal("no panic for a zero size")
+		}
+	}()
+	ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		_, _ = ChartExport(c, func(*ui.Context) {}, ChartExportOptions{})
+	}, 100, 100)
+}
+
+func TestChartExportSnapshot(t *testing.T) {
+	snapshot(t, "chart_export", 340, 300, func(c *ui.Context) {
+		b, err := ChartExport(c, func(c *ui.Context) {
+			PieChart(c, pieSlices, PieChartOptions{Frame: ChartFrame{Label: "Stores", Height: 150}, Donut: true, MinAngle: 20})
+		}, ChartExportOptions{Width: 300, Height: 260, Scale: 1})
+		if err != nil {
+			t.Fatal(err)
+		}
+		bmp, err := ui.DecodeBitmap(b)
+		if err != nil {
+			t.Fatal(err)
+		}
+		ui.Column(c).Padding(20).Children(func() { ui.Image(c, bmp).Size(300, 260) })
+	})
+}
diff --git a/pie_chart.go b/pie_chart.go
index dba6d1d..ae5b479 100644
--- a/pie_chart.go
+++ b/pie_chart.go
@@ -105,7 +105,10 @@ func PieChart(c *ui.Context, slices []ChartSlice, opts PieChartOptions) ChartRes
 				mx, my := internal.Polar(cx, cy, (r0+r1)/2+float32(chartBool(r0 == 0))*r1*0.12, (a0+a1)/2)
 				ink := chartInk(k, keys[i].Color)
 				internal.Marker(p, i, mx, my-8, 9, ink)
-				chartText(p, share(i), mx, my+2, size, ink, 0.5, 0)
+				// The percent shows where the ring is wide enough to hold it.
+				if w, _ := p.MeasureText(0, ui.Span{Text: share(i), Size: size}); r1-r0 >= w+6 {
+					chartText(p, share(i), mx, my+2, size, ink, 0.5, 0)
+				}
 			}
 		}
 		if opts.Donut {
diff --git a/testdata/snapshots/darwin/chart_brush-dark.png b/testdata/snapshots/darwin/chart_brush-dark.png
new file mode 100644
index 0000000..37a558e
Binary files /dev/null and b/testdata/snapshots/darwin/chart_brush-dark.png differ
diff --git a/testdata/snapshots/darwin/chart_brush-light.png b/testdata/snapshots/darwin/chart_brush-light.png
new file mode 100644
index 0000000..b29cac6
Binary files /dev/null and b/testdata/snapshots/darwin/chart_brush-light.png differ
diff --git a/testdata/snapshots/darwin/chart_empty_state-dark.png b/testdata/snapshots/darwin/chart_empty_state-dark.png
new file mode 100644
index 0000000..719b5e1
Binary files /dev/null and b/testdata/snapshots/darwin/chart_empty_state-dark.png differ
diff --git a/testdata/snapshots/darwin/chart_empty_state-light.png b/testdata/snapshots/darwin/chart_empty_state-light.png
new file mode 100644
index 0000000..c8c2add
Binary files /dev/null and b/testdata/snapshots/darwin/chart_empty_state-light.png differ
diff --git a/testdata/snapshots/darwin/chart_export-dark.png b/testdata/snapshots/darwin/chart_export-dark.png
new file mode 100644
index 0000000..6173296
Binary files /dev/null and b/testdata/snapshots/darwin/chart_export-dark.png differ
diff --git a/testdata/snapshots/darwin/chart_export-light.png b/testdata/snapshots/darwin/chart_export-light.png
new file mode 100644
index 0000000..1bb86bf
Binary files /dev/null and b/testdata/snapshots/darwin/chart_export-light.png differ