theme/material: add the material theme

Signed-off-by: Elias Naur <mail@eliasnaur.com>

go.mod

@@ -3,6 +3,7 @@ module gioui.org
 go 1.13
 
 require (
-	golang.org/x/image v0.0.0-20190703141733-d6a02ce849c9
+	golang.org/x/exp v0.0.0-20191002040644-a1355ae1e2c3
+	golang.org/x/image v0.0.0-20190802002840-cff245a6509b
 	golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a
 )

go.sum

@@ -1,6 +1,25 @@
-golang.org/x/image v0.0.0-20190703141733-d6a02ce849c9 h1:uc17S921SPw5F2gJo7slQ3aqvr2RwpL7eb3+DZncu3s=
+dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
-golang.org/x/image v0.0.0-20190703141733-d6a02ce849c9/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
+github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
+github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
+golang.org/x/exp v0.0.0-20191002040644-a1355ae1e2c3 h1:n9HxLrNxWWtEb1cA950nuEEj3QnKbtsCJ6KjcgisNUs=
+golang.org/x/exp v0.0.0-20191002040644-a1355ae1e2c3/go.mod h1:NOZ3BPKG0ec/BKJQgnvsSFpcKLM5xXVWnvZS97DWHgE=
+golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
+golang.org/x/image v0.0.0-20190802002840-cff245a6509b h1:+qEpEAPhDZ1o0x3tHzZTQDArnOixOzGD9HUJfcg0mb4=
+golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
+golang.org/x/mobile v0.0.0-20190719004257-d2bd2a29d028/go.mod h1:E/iHnbuqvinMTCcRqshq8CkpyQDoeVncDDYHnLhea+o=
+golang.org/x/mod v0.1.0/go.mod h1:0QHyrYULN0/3qlju5TqG8bIK38QM8yzMo5ekMj3DlcY=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a h1:aYOabOQFp6Vj6W1F80affTUvO9UxmJRx8K0gsfABByQ=
 golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20190927191325-030b2cf1153e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

widget/button.go

@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package widget
+
+import (
+	"time"
+
+	"gioui.org/f32"
+	"gioui.org/gesture"
+	"gioui.org/layout"
+	"gioui.org/op"
+)
+
+type Button struct {
+	click   gesture.Click
+	clicks  int
+	history []Click
+}
+
+// Click represents a historic click.
+type Click struct {
+	Position f32.Point
+	Time     time.Time
+}
+
+func (b *Button) Clicked(gtx *layout.Context) bool {
+	for _, e := range b.click.Events(gtx) {
+		switch e.Type {
+		case gesture.TypeClick:
+			b.clicks++
+		case gesture.TypePress:
+			b.history = append(b.history, Click{
+				Position: e.Position,
+				Time:     gtx.Now(),
+			})
+		}
+	}
+	if b.clicks > 0 {
+		b.clicks--
+		if b.clicks > 0 {
+			// Ensure timely delivery of remaining clicks.
+			op.InvalidateOp{}.Add(gtx.Ops)
+		}
+		return true
+	}
+	return false
+}
+
+func (b *Button) Active() bool {
+	return b.click.Active()
+}
+
+func (b *Button) History() []Click {
+	return b.history
+}
+
+func (b *Button) Layout(gtx *layout.Context) {
+	b.click.Add(gtx.Ops)
+	if !b.Active() {
+		b.clicks = 0
+	}
+	for len(b.history) > 0 {
+		c := b.history[0]
+		if gtx.Now().Sub(c.Time) < 1*time.Second {
+			break
+		}
+		copy(b.history, b.history[1:])
+		b.history = b.history[:len(b.history)-1]
+	}
+}

widget/doc.go

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// Package widget implements common user interface controls. Widgets
+// contain peristent state and process user events. Theme packages
+// such as `widget/material` implements drawing of widgets.
+package widget

widget/material/button.go

@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// Package material implements the Material design.
+package material
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+
+	"gioui.org/f32"
+	"gioui.org/io/pointer"
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/op/paint"
+	"gioui.org/text"
+	"gioui.org/unit"
+	"gioui.org/widget"
+	"golang.org/x/exp/shiny/iconvg"
+)
+
+type Button struct {
+	Text string
+	// Color is the text color.
+	Color      color.RGBA
+	Font       text.Font
+	Background color.RGBA
+
+	shaper *text.Shaper
+}
+
+type IconButton struct {
+	Background color.RGBA
+	Icon       *Icon
+	Size       unit.Value
+	Padding    unit.Value
+}
+
+type Icon struct {
+	src  []byte
+	size unit.Value
+
+	// Cached values.
+	img     image.Image
+	imgSize int
+}
+
+func (t *Theme) Button(txt string) Button {
+	return Button{
+		Text:       txt,
+		Color:      rgb(0xffffff),
+		Background: t.Color.Primary,
+		Font: text.Font{
+			Size: t.TextSize.Scale(14.0 / 16.0),
+		},
+		shaper: t.Shaper,
+	}
+}
+
+// NewIcon returns a new Icon from IconVG data.
+func NewIcon(data []byte) (*Icon, error) {
+	_, err := iconvg.DecodeMetadata(data)
+	if err != nil {
+		return nil, err
+	}
+	return &Icon{src: data}, nil
+}
+
+func (t *Theme) IconButton(icon *Icon) IconButton {
+	return IconButton{
+		Background: t.Color.Primary,
+		Icon:       icon,
+		Size:       unit.Dp(56),
+		Padding:    unit.Dp(20),
+	}
+}
+
+func (b Button) Layout(gtx *layout.Context, button *widget.Button) {
+	col := b.Color
+	bgcol := b.Background
+	if !button.Active() {
+		col.A = 0xaa
+		bgcol.A = 0xaa
+	}
+	st := layout.Stack{}
+	lbl := st.Rigid(gtx, func() {
+		layout.UniformInset(unit.Dp(16)).Layout(gtx, func() {
+			paint.ColorOp{Color: col}.Add(gtx.Ops)
+			widget.Label{Alignment: text.Middle}.Layout(gtx, b.shaper, b.Font, b.Text)
+		})
+		pointer.RectAreaOp{Rect: image.Rectangle{Max: gtx.Dimensions.Size}}.Add(gtx.Ops)
+		button.Layout(gtx)
+	})
+	bg := st.Expand(gtx, func() {
+		rr := float32(gtx.Px(unit.Dp(4)))
+		rrect(gtx.Ops,
+			float32(gtx.Constraints.Width.Max),
+			float32(gtx.Constraints.Height.Max),
+			rr, rr, rr, rr,
+		)
+		fill(gtx, bgcol)
+		for _, c := range button.History() {
+			drawInk(gtx, c)
+		}
+	})
+	st.Layout(gtx, bg, lbl)
+}
+
+func (b IconButton) Layout(gtx *layout.Context, button *widget.Button) {
+	st := layout.Stack{}
+	ico := st.Rigid(gtx, func() {
+		layout.UniformInset(b.Padding).Layout(gtx, func() {
+			size := gtx.Px(b.Size) - gtx.Px(b.Padding)
+			ico := b.Icon.image(size)
+			paint.ImageOp{Src: ico, Rect: ico.Bounds()}.Add(gtx.Ops)
+			paint.PaintOp{
+				Rect: toRectF(ico.Bounds()),
+			}.Add(gtx.Ops)
+			gtx.Dimensions = layout.Dimensions{
+				Size: image.Point{X: size, Y: size},
+			}
+		})
+		pointer.EllipseAreaOp{Rect: image.Rectangle{Max: gtx.Dimensions.Size}}.Add(gtx.Ops)
+		button.Layout(gtx)
+	})
+	bgcol := b.Background
+	if !button.Active() {
+		bgcol.A = 0xaa
+	}
+	bg := st.Expand(gtx, func() {
+		size := float32(gtx.Constraints.Width.Max)
+		rr := float32(size) * .5
+		rrect(gtx.Ops,
+			size,
+			size,
+			rr, rr, rr, rr,
+		)
+		fill(gtx, bgcol)
+		for _, c := range button.History() {
+			drawInk(gtx, c)
+		}
+	})
+	st.Layout(gtx, bg, ico)
+}
+
+func (ic *Icon) image(sz int) image.Image {
+	if sz == ic.imgSize {
+		return ic.img
+	}
+	m, _ := iconvg.DecodeMetadata(ic.src)
+	dx, dy := m.ViewBox.AspectRatio()
+	img := image.NewRGBA(image.Rectangle{Max: image.Point{X: sz, Y: int(float32(sz) * dy / dx)}})
+	var ico iconvg.Rasterizer
+	ico.SetDstImage(img, img.Bounds(), draw.Src)
+	// Use white for icons.
+	m.Palette[0] = color.RGBA{A: 0xff, R: 0xff, G: 0xff, B: 0xff}
+	iconvg.Decode(&ico, ic.src, &iconvg.DecodeOptions{
+		Palette: &m.Palette,
+	})
+	ic.img = img
+	ic.imgSize = sz
+	return img
+}
+
+func fab(gtx *layout.Context, ico image.Image, col color.RGBA, size int) {
+	dp := image.Point{X: (size - ico.Bounds().Dx()) / 2, Y: (size - ico.Bounds().Dy()) / 2}
+	dims := image.Point{X: size, Y: size}
+	rr := float32(size) * .5
+	rrect(gtx.Ops, float32(size), float32(size), rr, rr, rr, rr)
+	paint.ColorOp{Color: col}.Add(gtx.Ops)
+	paint.PaintOp{Rect: f32.Rectangle{Max: f32.Point{X: float32(size), Y: float32(size)}}}.Add(gtx.Ops)
+	paint.ImageOp{Src: ico, Rect: ico.Bounds()}.Add(gtx.Ops)
+	paint.PaintOp{
+		Rect: toRectF(ico.Bounds().Add(dp)),
+	}.Add(gtx.Ops)
+	gtx.Dimensions = layout.Dimensions{Size: dims}
+}
+
+func toRectF(r image.Rectangle) f32.Rectangle {
+	return f32.Rectangle{
+		Min: f32.Point{X: float32(r.Min.X), Y: float32(r.Min.Y)},
+		Max: f32.Point{X: float32(r.Max.X), Y: float32(r.Max.Y)},
+	}
+}
+
+func drawInk(gtx *layout.Context, c widget.Click) {
+	d := gtx.Now().Sub(c.Time)
+	t := float32(d.Seconds())
+	const duration = 0.5
+	if t > duration {
+		return
+	}
+	t = t / duration
+	var stack op.StackOp
+	stack.Push(gtx.Ops)
+	size := float32(gtx.Px(unit.Dp(700))) * t
+	rr := size * .5
+	col := byte(0xaa * (1 - t*t))
+	ink := paint.ColorOp{Color: color.RGBA{A: col, R: col, G: col, B: col}}
+	ink.Add(gtx.Ops)
+	op.TransformOp{}.Offset(c.Position).Offset(f32.Point{
+		X: -rr,
+		Y: -rr,
+	}).Add(gtx.Ops)
+	rrect(gtx.Ops, float32(size), float32(size), rr, rr, rr, rr)
+	paint.PaintOp{Rect: f32.Rectangle{Max: f32.Point{X: float32(size), Y: float32(size)}}}.Add(gtx.Ops)
+	stack.Pop()
+	op.InvalidateOp{}.Add(gtx.Ops)
+}

widget/material/editor.go

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package material
+
+import (
+	"image/color"
+
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/op/paint"
+	"gioui.org/text"
+	"gioui.org/unit"
+	"gioui.org/widget"
+)
+
+type Editor struct {
+	Font text.Font
+	// Color is the text color.
+	Color color.RGBA
+	// Hint contains the text displayed when the editor is empty.
+	Hint string
+	// HintColor is the color of hint text.
+	HintColor color.RGBA
+
+	shaper *text.Shaper
+}
+
+func (t *Theme) Editor(hint string) Editor {
+	return Editor{
+		Font: text.Font{
+			Size: unit.Sp(16),
+		},
+		Color:     t.Color.Text,
+		shaper:    t.Shaper,
+		Hint:      hint,
+		HintColor: t.Color.Hint,
+	}
+}
+
+func (e Editor) Layout(gtx *layout.Context, editor *widget.Editor) {
+	var stack op.StackOp
+	stack.Push(gtx.Ops)
+	var macro op.MacroOp
+	macro.Record(gtx.Ops)
+	paint.ColorOp{Color: e.HintColor}.Add(gtx.Ops)
+	tl := widget.Label{Alignment: editor.Alignment}
+	tl.Layout(gtx, e.shaper, e.Font, e.Hint)
+	macro.Stop()
+	if w := gtx.Dimensions.Size.X; gtx.Constraints.Width.Min < w {
+		gtx.Constraints.Width.Min = w
+	}
+	if h := gtx.Dimensions.Size.Y; gtx.Constraints.Height.Min < h {
+		gtx.Constraints.Height.Min = h
+	}
+	editor.Layout(gtx, e.shaper, e.Font)
+	if editor.Len() > 0 {
+		paint.ColorOp{Color: e.Color}.Add(gtx.Ops)
+		editor.PaintText(gtx)
+	} else {
+		macro.Add(gtx.Ops)
+	}
+	paint.ColorOp{Color: e.Color}.Add(gtx.Ops)
+	editor.PaintCaret(gtx)
+	stack.Pop()
+}

widget/material/image.go

@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-// Package widget implements common widgets.
+package material
-package widget
 
 import (
 	"image"
@@ -19,22 +18,22 @@ type Image struct {
 	// Rect is the source rectangle.
 	Rect image.Rectangle
 	// Scale is the ratio of image pixels to
-	// device pixels. If zero, a scale that
+	// dps.
-	// makes the image appear at approximately
-	// 72 DPI is used.
 	Scale float32
 }
 
+func (t *Theme) Image(img image.Image) Image {
+	return Image{
+		Src:   img,
+		Rect:  img.Bounds(),
+		Scale: 160 / 72, // About 72 DPI.
+	}
+}
+
 func (im Image) Layout(gtx *layout.Context) {
 	size := im.Src.Bounds()
 	wf, hf := float32(size.Dx()), float32(size.Dy())
-	var w, h int
+	w, h := gtx.Px(unit.Dp(wf*im.Scale)), gtx.Px(unit.Dp(hf*im.Scale))
-	if im.Scale == 0 {
-		const dpPrPx = 160 / 72
-		w, h = gtx.Px(unit.Dp(wf*dpPrPx)), gtx.Px(unit.Dp(hf*dpPrPx))
-	} else {
-		w, h = int(wf*im.Scale+.5), int(hf*im.Scale+.5)
-	}
 	cs := gtx.Constraints
 	d := image.Point{X: cs.Width.Constrain(w), Y: cs.Height.Constrain(h)}
 	aspect := float32(w) / float32(h)

widget/material/label.go

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package material
+
+import (
+	"image/color"
+
+	"gioui.org/layout"
+	"gioui.org/op/paint"
+	"gioui.org/text"
+	"gioui.org/unit"
+	"gioui.org/widget"
+)
+
+type Label struct {
+	// Face defines the text style.
+	Font text.Font
+	// Color is the text color.
+	Color color.RGBA
+	// Alignment specify the text alignment.
+	Alignment text.Alignment
+	// MaxLines limits the number of lines. Zero means no limit.
+	MaxLines int
+	Text     string
+
+	shaper *text.Shaper
+}
+
+func (t *Theme) H1(txt string) Label {
+	return t.Label(t.TextSize.Scale(96.0/16.0), txt)
+}
+
+func (t *Theme) H2(txt string) Label {
+	return t.Label(t.TextSize.Scale(60.0/16.0), txt)
+}
+
+func (t *Theme) H3(txt string) Label {
+	return t.Label(t.TextSize.Scale(48.0/16.0), txt)
+}
+
+func (t *Theme) H4(txt string) Label {
+	return t.Label(t.TextSize.Scale(34.0/16.0), txt)
+}
+
+func (t *Theme) H5(txt string) Label {
+	return t.Label(t.TextSize.Scale(24.0/16.0), txt)
+}
+
+func (t *Theme) H6(txt string) Label {
+	return t.Label(t.TextSize.Scale(20.0/16.0), txt)
+}
+
+func (t *Theme) Body1(txt string) Label {
+	return t.Label(t.TextSize, txt)
+}
+
+func (t *Theme) Body2(txt string) Label {
+	return t.Label(t.TextSize.Scale(14.0/16.0), txt)
+}
+
+func (t *Theme) Caption(txt string) Label {
+	return t.Label(t.TextSize.Scale(12.0/16.0), txt)
+}
+
+func (t *Theme) Label(size unit.Value, txt string) Label {
+	return Label{
+		Text:  txt,
+		Color: t.Color.Text,
+		Font: text.Font{
+			Size: size,
+		},
+		shaper: t.Shaper,
+	}
+}
+
+func (l Label) Layout(gtx *layout.Context) {
+	paint.ColorOp{Color: l.Color}.Add(gtx.Ops)
+	tl := widget.Label{Alignment: l.Alignment, MaxLines: l.MaxLines}
+	tl.Layout(gtx, l.shaper, l.Font, l.Text)
+}

widget/material/material.go

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// Package material implements the Material design.
+package material
+
+import (
+	"image"
+	"image/color"
+
+	"gioui.org/f32"
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/op/paint"
+	"gioui.org/text"
+	"gioui.org/unit"
+)
+
+type Theme struct {
+	Shaper *text.Shaper
+	Color  struct {
+		Primary color.RGBA
+		Text    color.RGBA
+		Hint    color.RGBA
+	}
+	TextSize unit.Value
+}
+
+func NewTheme(shaper *text.Shaper) *Theme {
+	t := &Theme{
+		Shaper: shaper,
+	}
+	t.Color.Primary = rgb(0x3f51b5)
+	t.Color.Text = rgb(0x000000)
+	t.Color.Hint = rgb(0xbbbbbb)
+	t.TextSize = unit.Sp(16)
+	return t
+}
+
+func rgb(c uint32) color.RGBA {
+	return argb(0xff000000 | c)
+}
+
+func argb(c uint32) color.RGBA {
+	return color.RGBA{A: uint8(c >> 24), R: uint8(c >> 16), G: uint8(c >> 8), B: uint8(c)}
+}
+
+func fill(gtx *layout.Context, col color.RGBA) {
+	cs := gtx.Constraints
+	d := image.Point{X: cs.Width.Max, Y: cs.Height.Max}
+	dr := f32.Rectangle{
+		Max: f32.Point{X: float32(d.X), Y: float32(d.Y)},
+	}
+	paint.ColorOp{Color: col}.Add(gtx.Ops)
+	paint.PaintOp{Rect: dr}.Add(gtx.Ops)
+	gtx.Dimensions = layout.Dimensions{Size: d, Baseline: d.Y}
+}
+
+// https://pomax.github.io/bezierinfo/#circles_cubic.
+func rrect(ops *op.Ops, width, height, se, sw, nw, ne float32) {
+	w, h := float32(width), float32(height)
+	const c = 0.55228475 // 4*(sqrt(2)-1)/3
+	var b paint.Path
+	b.Begin(ops)
+	b.Move(f32.Point{X: w, Y: h - se})
+	b.Cube(f32.Point{X: 0, Y: se * c}, f32.Point{X: -se + se*c, Y: se}, f32.Point{X: -se, Y: se}) // SE
+	b.Line(f32.Point{X: sw - w + se, Y: 0})
+	b.Cube(f32.Point{X: -sw * c, Y: 0}, f32.Point{X: -sw, Y: -sw + sw*c}, f32.Point{X: -sw, Y: -sw}) // SW
+	b.Line(f32.Point{X: 0, Y: nw - h + sw})
+	b.Cube(f32.Point{X: 0, Y: -nw * c}, f32.Point{X: nw - nw*c, Y: -nw}, f32.Point{X: nw, Y: -nw}) // NW
+	b.Line(f32.Point{X: w - ne - nw, Y: 0})
+	b.Cube(f32.Point{X: ne * c, Y: 0}, f32.Point{X: ne, Y: ne - ne*c}, f32.Point{X: ne, Y: ne}) // NE
+	b.End().Add(ops)
+}