chore(merge): branch 'v2-exp' into v2-area

.gitignore

@@ -1 +1,2 @@
 .DS_Store
+dist/

.goreleaser.yml

@@ -1,5 +1,5 @@
+# yaml-language-server: $schema=https://goreleaser.com/static/schema-pro.json
+version: 2
 includes:
   - from_url:
       url: charmbracelet/meta/main/goreleaser-lib.yaml
-# yaml-language-server: $schema=https://goreleaser.com/static/schema-pro.json
-

go.mod

@@ -5,33 +5,30 @@ go 1.18
 require (
 	github.com/MakeNowJust/heredoc v1.0.0
 	github.com/atotto/clipboard v0.1.4
-	github.com/charmbracelet/bubbletea/v2 v2.0.0-alpha.2.0.20241126192050-a8ed96118b08
+	github.com/charmbracelet/bubbletea/v2 v2.0.0-alpha.2.0.20250114201644-43a5b4dd0af0
 	github.com/charmbracelet/harmonica v0.2.0
-	github.com/charmbracelet/lipgloss/v2 v2.0.0-alpha.2.0.20241121164047-8448a9be4804
-	github.com/charmbracelet/x/ansi v0.5.1
-	github.com/charmbracelet/x/exp/golden v0.0.0-20241011142426-46044092ad91
+	github.com/charmbracelet/lipgloss/v2 v2.0.0-alpha.2.0.20250114171829-b67eb015d607
+	github.com/charmbracelet/x/ansi v0.7.0
+	github.com/charmbracelet/x/exp/golden v0.0.0-20241212170349-ad4b7ae0f25f
 	github.com/dustin/go-humanize v1.0.1
 	github.com/lucasb-eyer/go-colorful v1.2.0
 	github.com/mattn/go-runewidth v0.0.16
-	github.com/muesli/termenv v0.15.2
 	github.com/rivo/uniseg v0.4.7
 	github.com/sahilm/fuzzy v0.1.1
 )
 
 require (
-	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/aymanbagabas/go-udiff v0.2.0 // indirect
-	github.com/charmbracelet/colorprofile v0.1.8 // indirect
-	github.com/charmbracelet/x/cellbuf v0.0.6 // indirect
+	github.com/charmbracelet/colorprofile v0.1.9 // indirect
+	github.com/charmbracelet/x/cellbuf v0.0.7-0.20250113065325-800d48271e72 // indirect
+	github.com/charmbracelet/x/input v0.3.0 // indirect
 	github.com/charmbracelet/x/term v0.2.1 // indirect
-	github.com/charmbracelet/x/vt v0.0.0-20241121165045-a3720547cbb4 // indirect
 	github.com/charmbracelet/x/wcwidth v0.0.0-20241113152101-0af7d04e9f32 // indirect
 	github.com/charmbracelet/x/windows v0.2.0 // indirect
 	github.com/kylelemons/godebug v1.1.0 // indirect
-	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/muesli/cancelreader v0.2.2 // indirect
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
-	golang.org/x/sync v0.9.0 // indirect
-	golang.org/x/sys v0.27.0 // indirect
+	golang.org/x/sync v0.10.0 // indirect
+	golang.org/x/sys v0.29.0 // indirect
 	golang.org/x/text v0.20.0 // indirect
 )

go.sum

@@ -2,28 +2,26 @@ github.com/MakeNowJust/heredoc v1.0.0 h1:cXCdzVdstXyiTqTvfqk9SDHpKNjxuom+DOlyEeQ
 github.com/MakeNowJust/heredoc v1.0.0/go.mod h1:mG5amYoWBHf8vpLOuehzbGGw0EHxpZZ6lCpQ4fNJ8LE=
 github.com/atotto/clipboard v0.1.4 h1:EH0zSVneZPSuFR11BlR9YppQTVDbh5+16AmcJi4g1z4=
 github.com/atotto/clipboard v0.1.4/go.mod h1:ZY9tmq7sm5xIbd9bOK4onWV4S6X0u6GY7Vn0Yu86PYI=
-github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
-github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
 github.com/aymanbagabas/go-udiff v0.2.0 h1:TK0fH4MteXUDspT88n8CKzvK0X9O2xu9yQjWpi6yML8=
 github.com/aymanbagabas/go-udiff v0.2.0/go.mod h1:RE4Ex0qsGkTAJoQdQQCA0uG+nAzJO/pI/QwceO5fgrA=
-github.com/charmbracelet/bubbletea/v2 v2.0.0-alpha.2.0.20241126192050-a8ed96118b08 h1:8hwULvCHjF6JjaeosebMGbB06oCv46d4s+Lbs5ytAT4=
-github.com/charmbracelet/bubbletea/v2 v2.0.0-alpha.2.0.20241126192050-a8ed96118b08/go.mod h1:BbC4R+6e9TLjbskxrjISt/DDCn4OiB6v+ArqfYiPyyg=
-github.com/charmbracelet/colorprofile v0.1.8 h1:PywDeXsiAzlPtkiiKgMEVLvb6nlEuKrMj9+FJBtj4jU=
-github.com/charmbracelet/colorprofile v0.1.8/go.mod h1:+jpmObxZl1Dab3H3IMVIPSZTsKcFpjJUv97G0dLqM60=
+github.com/charmbracelet/bubbletea/v2 v2.0.0-alpha.2.0.20250114201644-43a5b4dd0af0 h1:BWjXQRSwBjoCpLeNu8zT93n+NHhZZhkQQLveXMmnkYc=
+github.com/charmbracelet/bubbletea/v2 v2.0.0-alpha.2.0.20250114201644-43a5b4dd0af0/go.mod h1:hT2875Ank3ylgW13kqu6cjDc9XIk9sE5JsOFYdl09b8=
+github.com/charmbracelet/colorprofile v0.1.9 h1:5JnfvX+I9D6rRNu8xK3pgIqknaBVTXHU9pGu1jkZxLw=
+github.com/charmbracelet/colorprofile v0.1.9/go.mod h1:+jpmObxZl1Dab3H3IMVIPSZTsKcFpjJUv97G0dLqM60=
 github.com/charmbracelet/harmonica v0.2.0 h1:8NxJWRWg/bzKqqEaaeFNipOu77YR5t8aSwG4pgaUBiQ=
 github.com/charmbracelet/harmonica v0.2.0/go.mod h1:KSri/1RMQOZLbw7AHqgcBycp8pgJnQMYYT8QZRqZ1Ao=
-github.com/charmbracelet/lipgloss/v2 v2.0.0-alpha.2.0.20241121164047-8448a9be4804 h1:7CYjb9YMZA4kMhLgGdtlXvq+nu1oyENpMyMQlTvqSFw=
-github.com/charmbracelet/lipgloss/v2 v2.0.0-alpha.2.0.20241121164047-8448a9be4804/go.mod h1:F/6E/LGdH3eHCJf2rG8/O3CjlW8cZFL5YJCknJs1GkI=
-github.com/charmbracelet/x/ansi v0.5.1 h1:+mg6abP9skvsu/JQZrIJ9Z/4O1YDnLVkpfutar3dUnc=
-github.com/charmbracelet/x/ansi v0.5.1/go.mod h1:KBUFw1la39nl0dLl10l5ORDAqGXaeurTQmwyyVKse/Q=
-github.com/charmbracelet/x/cellbuf v0.0.6 h1:pJUWN/G1jbt1Nj/+ILfC2/ABQoZzWu1vG73yHQEYELI=
-github.com/charmbracelet/x/cellbuf v0.0.6/go.mod h1:d72o71glp8flkCz54PHLe3+nuw5u2v3UxmKqruUERWQ=
-github.com/charmbracelet/x/exp/golden v0.0.0-20241011142426-46044092ad91 h1:payRxjMjKgx2PaCWLZ4p3ro9y97+TVLZNaRZgJwSVDQ=
-github.com/charmbracelet/x/exp/golden v0.0.0-20241011142426-46044092ad91/go.mod h1:wDlXFlCrmJ8J+swcL/MnGUuYnqgQdW9rhSD61oNMb6U=
+github.com/charmbracelet/lipgloss/v2 v2.0.0-alpha.2.0.20250114171829-b67eb015d607 h1:lERE4ow371r5WMqQAt7Eqlg1A4tBNA8T4RLwdXnKyBo=
+github.com/charmbracelet/lipgloss/v2 v2.0.0-alpha.2.0.20250114171829-b67eb015d607/go.mod h1:MD7Vb+O1zFRgBo+F94JHHuME7df8XBByNKuX5k/L/qs=
+github.com/charmbracelet/x/ansi v0.7.0 h1:/QfFmiXOGGwN6fRbzvQaYp7fu1pkxpZ3qFBZWBsP404=
+github.com/charmbracelet/x/ansi v0.7.0/go.mod h1:KBUFw1la39nl0dLl10l5ORDAqGXaeurTQmwyyVKse/Q=
+github.com/charmbracelet/x/cellbuf v0.0.7-0.20250113065325-800d48271e72 h1:P90NI2rZuBISjB1HIHdkBDE+riKtVzIOi6Xun3qjUn8=
+github.com/charmbracelet/x/cellbuf v0.0.7-0.20250113065325-800d48271e72/go.mod h1:VXZSjC/QYH0t+9CG1qtcEx3XZubTDJb5ilWS6qJg4/0=
+github.com/charmbracelet/x/exp/golden v0.0.0-20241212170349-ad4b7ae0f25f h1:UytXHv0UxnsDFmL/7Z9Q5SBYPwSuRLXHbwx+6LycZ2w=
+github.com/charmbracelet/x/exp/golden v0.0.0-20241212170349-ad4b7ae0f25f/go.mod h1:wDlXFlCrmJ8J+swcL/MnGUuYnqgQdW9rhSD61oNMb6U=
+github.com/charmbracelet/x/input v0.3.0 h1:lVzEz92E2u9jCU0mUwcyKeSOxkoeat+1eUkjzL0WCYI=
+github.com/charmbracelet/x/input v0.3.0/go.mod h1:M8CHPIYnmmiNHA17hqXmvSfeZLO2lj9pzJFX3aWvzgw=
 github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
 github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
-github.com/charmbracelet/x/vt v0.0.0-20241121165045-a3720547cbb4 h1:EacjHxcQEEgOZ7TbkAU3b84hd1Bn5NwA8YV5uyJ9EI4=
-github.com/charmbracelet/x/vt v0.0.0-20241121165045-a3720547cbb4/go.mod h1:1/jFoHl7/I4br0StC9OXXEondkK9qi3nUtKoqI35HcI=
 github.com/charmbracelet/x/wcwidth v0.0.0-20241113152101-0af7d04e9f32 h1:14czE6R5CgOlvONsJYa2B1uTyLvXzGXpBqw2AyZeTh4=
 github.com/charmbracelet/x/wcwidth v0.0.0-20241113152101-0af7d04e9f32/go.mod h1:hyua5CY63kyl7IfyIxv1SjVEqoKze/XmDkEglItuVjA=
 github.com/charmbracelet/x/windows v0.2.0 h1:ilXA1GJjTNkgOm94CLPeSz7rar54jtFatdmoiONPuEw=
@@ -34,14 +32,10 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
-github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
-github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=
 github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELUXHmA=
 github.com/muesli/cancelreader v0.2.2/go.mod h1:3XuTXfFS2VjM+HTLZY9Ak0l6eUKfijIfMUZ4EgX0QYo=
-github.com/muesli/termenv v0.15.2 h1:GohcuySI0QmI3wN8Ok9PtKGkgkFIk7y6Vpb5PvrY+Wo=
-github.com/muesli/termenv v0.15.2/go.mod h1:Epx+iuz8sNs7mNKhxzH4fWXGNpZwUaJKRS1noLXviQ8=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
@@ -50,10 +44,9 @@ github.com/sahilm/fuzzy v0.1.1/go.mod h1:VFvziUEIMCrT6A6tw2RFIXPXXmzXbOsSHF0DOI8
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
 golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
-golang.org/x/sync v0.9.0 h1:fEo0HyrW1GIgZdpbhCRO0PkJajUS5H9IFUztCgEo2jQ=
-golang.org/x/sync v0.9.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
-golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
+golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.20.0 h1:gK/Kv2otX8gz+wn7Rmb3vT96ZwuoxnQlY+HlJVj7Qug=
 golang.org/x/text v0.20.0/go.mod h1:D4IsuqiFMhST5bX19pQ9ikHC2GsaKyk/oF+pn3ducp4=

progress/progress.go

@@ -2,6 +2,7 @@ package progress
 
 import (
 	"fmt"
+	"image/color"
 	"math"
 	"strings"
 	"sync/atomic"
@@ -12,7 +13,6 @@ import (
 	"github.com/charmbracelet/lipgloss/v2"
 	"github.com/charmbracelet/x/ansi"
 	"github.com/lucasb-eyer/go-colorful"
-	"github.com/muesli/termenv"
 )
 
 // Internal ID management. Used during animating to assure that frame messages
@@ -65,7 +65,7 @@ func WithScaledGradient(colorA, colorB string) Option {
 }
 
 // WithSolidFill sets the progress to use a solid fill with the given color.
-func WithSolidFill(color string) Option {
+func WithSolidFill(color color.Color) Option {
 	return func(m *Model) {
 		m.FullColor = color
 		m.useRamp = false
@@ -108,13 +108,6 @@ func WithSpringOptions(frequency, damping float64) Option {
 	}
 }
 
-// WithColorProfile sets the color profile to use for the progress bar.
-func WithColorProfile(p termenv.Profile) Option {
-	return func(m *Model) {
-		m.colorProfile = p
-	}
-}
-
 // FrameMsg indicates that an animation step should occur.
 type FrameMsg struct {
 	id  int
@@ -135,11 +128,11 @@ type Model struct {
 
 	// "Filled" sections of the progress bar.
 	Full      rune
-	FullColor string
+	FullColor color.Color
 
 	// "Empty" sections of the progress bar.
 	Empty      rune
-	EmptyColor string
+	EmptyColor color.Color
 
 	// Settings for rendering the numeric percentage.
 	ShowPercentage  bool
@@ -162,9 +155,6 @@ type Model struct {
 	// of the progress bar. When false, the width of the gradient will be set
 	// to the full width of the progress bar.
 	scaleRamp bool
-
-	// Color profile for the progress bar.
-	colorProfile termenv.Profile
 }
 
 // New returns a model with default values.
@@ -173,12 +163,11 @@ func New(opts ...Option) Model {
 		id:             nextID(),
 		width:          defaultWidth,
 		Full:           '█',
-		FullColor:      "#7571F9",
+		FullColor:      lipgloss.Color("#7571F9"),
 		Empty:          '░',
-		EmptyColor:     "#606060",
+		EmptyColor:     lipgloss.Color("#606060"),
 		ShowPercentage: true,
 		PercentFormat:  " %3.0f%%",
-		colorProfile:   termenv.ColorProfile(),
 	}
 
 	for _, opt := range opts {
@@ -316,23 +305,21 @@ func (m Model) barView(b *strings.Builder, percent float64, textWidth int) {
 			} else {
 				p = float64(i) / float64(tw-1)
 			}
-			c := m.rampColorA.BlendLuv(m.rampColorB, p).Hex()
-			b.WriteString(termenv.
-				String(string(m.Full)).
-				Foreground(m.color(c)).
-				String(),
-			)
+			c := m.rampColorA.BlendLuv(m.rampColorB, p)
+			b.WriteString(lipgloss.NewStyle().Foreground(c).Render(string(m.Full)))
 		}
 	} else {
 		// Solid fill
-		s := termenv.String(string(m.Full)).Foreground(m.color(m.FullColor)).String()
-		b.WriteString(strings.Repeat(s, fw))
+		b.WriteString(lipgloss.NewStyle().
+			Foreground(m.FullColor).
+			Render(strings.Repeat(string(m.Full), fw)))
 	}
 
 	// Empty fill
-	e := termenv.String(string(m.Empty)).Foreground(m.color(m.EmptyColor)).String()
 	n := max(0, tw-fw)
-	b.WriteString(strings.Repeat(e, n))
+	b.WriteString(lipgloss.NewStyle().
+		Foreground(m.EmptyColor).
+		Render(strings.Repeat(string(m.Empty), n)))
 }
 
 func (m Model) percentageView(percent float64) string {
@@ -358,10 +345,6 @@ func (m *Model) setRamp(colorA, colorB string, scaled bool) {
 	m.rampColorB = b
 }
 
-func (m Model) color(c string) termenv.Color {
-	return m.colorProfile.Color(c)
-}
-
 func max(a, b int) int {
 	if a > b {
 		return a

progress/progress_test.go

@@ -4,15 +4,14 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/muesli/termenv"
+	"github.com/charmbracelet/lipgloss/v2"
 )
 
 const (
-	AnsiReset = "\x1b[0m"
+	AnsiReset = "\x1b[m"
 )
 
 func TestGradient(t *testing.T) {
-
 	colA := "#FF0000"
 	colB := "#00FF00"
 
@@ -21,7 +20,7 @@ func TestGradient(t *testing.T) {
 
 	for _, scale := range []bool{false, true} {
 		opts := []Option{
-			WithColorProfile(termenv.TrueColor), WithoutPercentage(),
+			WithoutPercentage(),
 		}
 		if scale {
 			descr = "progress bar with scaled gradient"
@@ -36,10 +35,10 @@ func TestGradient(t *testing.T) {
 
 			// build the expected colors by colorizing an empty string and then cutting off the following reset sequence
 			sb := strings.Builder{}
-			sb.WriteString(termenv.String("").Foreground(p.color(colA)).String())
+			sb.WriteString(lipgloss.NewStyle().Foreground(lipgloss.Color(colA)).String())
 			expFirst := strings.Split(sb.String(), AnsiReset)[0]
 			sb.Reset()
-			sb.WriteString(termenv.String("").Foreground(p.color(colB)).String())
+			sb.WriteString(lipgloss.NewStyle().Foreground(lipgloss.Color(colB)).String())
 			expLast := strings.Split(sb.String(), AnsiReset)[0]
 
 			for _, width := range []int{3, 5, 50} {
@@ -62,5 +61,4 @@ func TestGradient(t *testing.T) {
 			}
 		})
 	}
-
 }

textinput/textinput.go

@@ -703,10 +703,12 @@ func (m Model) View() string {
 func (m Model) placeholderView() string {
 	var (
 		v     string
-		p     = []rune(m.Placeholder)
 		style = m.PlaceholderStyle.Inline(true).Render
 	)
 
+	p := make([]rune, m.Width()+1)
+	copy(p, []rune(m.Placeholder))
+
 	m.Cursor.TextStyle = m.PlaceholderStyle
 	m.Cursor.SetChar(string(p[:1]))
 	v += m.Cursor.View()

textinput/textinput_test.go

@@ -30,3 +30,10 @@ func Test_CurrentSuggestion(t *testing.T) {
 		t.Fatalf("Error: expected first suggestion but was %s", suggestion)
 	}
 }
+
+func Test_SlicingOutsideCap(t *testing.T) {
+	textinput := New()
+	textinput.Placeholder = "作業ディレクトリを指定してください"
+	textinput.SetWidth(32)
+	textinput.View()
+}

viewport/keymap.go

@@ -13,6 +13,8 @@ type KeyMap struct {
 	HalfPageDown key.Binding
 	Down         key.Binding
 	Up           key.Binding
+	Left         key.Binding
+	Right        key.Binding
 }
 
 // DefaultKeyMap returns a set of pager-like default keybindings.
@@ -42,5 +44,13 @@ func DefaultKeyMap() KeyMap {
 			key.WithKeys("down", "j"),
 			key.WithHelp("↓/j", "down"),
 		),
+		Left: key.NewBinding(
+			key.WithKeys("left", "h"),
+			key.WithHelp("←/h", "move left"),
+		),
+		Right: key.NewBinding(
+			key.WithKeys("right", "l"),
+			key.WithHelp("→/l", "move right"),
+		),
 	}
 }

viewport/viewport.go

@@ -7,6 +7,11 @@ import (
 	"github.com/charmbracelet/bubbles/v2/key"
 	tea "github.com/charmbracelet/bubbletea/v2"
 	"github.com/charmbracelet/lipgloss/v2"
+	"github.com/charmbracelet/x/ansi"
+)
+
+const (
+	defaultHorizontalStep = 6
 )
 
 // Option is a configuration option that works in conjunction with [New]. For
@@ -57,12 +62,24 @@ type Model struct {
 	// YOffset is the vertical scroll position.
 	YOffset int
 
+	// xOffset is the horizontal scroll position.
+	xOffset int
+
+	// horizontalStep is the number of columns we move left or right during a
+	// default horizontal scroll.
+	horizontalStep int
+
+	// YPosition is the position of the viewport in relation to the terminal
+	// window. It's used in high performance rendering only.
+	YPosition int
+
 	// Style applies a lipgloss style to the viewport. Realistically, it's most
 	// useful for setting borders, margins and padding.
 	Style lipgloss.Style
 
-	initialized bool
-	lines       []string
+	initialized      bool
+	lines            []string
+	longestLineWidth int
 }
 
 func (m *Model) setInitialValues() {
@@ -70,6 +87,7 @@ func (m *Model) setInitialValues() {
 	m.MouseWheelEnabled = true
 	m.MouseWheelDelta = 3
 	m.initialized = true
+	m.horizontalStep = defaultHorizontalStep
 }
 
 // Init exists to satisfy the tea.Model interface for composability purposes.
@@ -126,10 +144,24 @@ func (m Model) ScrollPercent() float64 {
 	return math.Max(0.0, math.Min(1.0, v))
 }
 
+// HorizontalScrollPercent returns the amount horizontally scrolled as a float
+// between 0 and 1.
+func (m Model) HorizontalScrollPercent() float64 {
+	if m.xOffset >= m.longestLineWidth-m.Width() {
+		return 1.0
+	}
+	y := float64(m.xOffset)
+	h := float64(m.Width())
+	t := float64(m.longestLineWidth)
+	v := y / (t - h)
+	return math.Max(0.0, math.Min(1.0, v))
+}
+
 // SetContent set the pager's text content.
 func (m *Model) SetContent(s string) {
 	s = strings.ReplaceAll(s, "\r\n", "\n") // normalize line endings
 	m.lines = strings.Split(s, "\n")
+	m.longestLineWidth = findLongestLineWidth(m.lines)
 
 	if m.YOffset > len(m.lines)-1 {
 		m.GotoBottom()
@@ -145,12 +177,24 @@ func (m Model) maxYOffset() int {
 // visibleLines returns the lines that should currently be visible in the
 // viewport.
 func (m Model) visibleLines() (lines []string) {
+	h := m.Height() - m.Style.GetVerticalFrameSize()
+	w := m.Width() - m.Style.GetHorizontalFrameSize()
+
 	if len(m.lines) > 0 {
 		top := max(0, m.YOffset)
-		bottom := clamp(m.YOffset+m.Height(), top, len(m.lines))
+		bottom := clamp(m.YOffset+h, top, len(m.lines))
 		lines = m.lines[top:bottom]
 	}
-	return lines
+
+	if (m.xOffset == 0 && m.longestLineWidth <= w) || w == 0 {
+		return lines
+	}
+
+	cutLines := make([]string, len(lines))
+	for i := range lines {
+		cutLines[i] = ansi.Cut(lines[i], m.xOffset, m.xOffset+w)
+	}
+	return cutLines
 }
 
 // SetYOffset sets the Y offset.
@@ -245,6 +289,39 @@ func (m *Model) GotoBottom() (lines []string) {
 	return m.visibleLines()
 }
 
+// SetHorizontalStep sets the amount of cells that the viewport moves in the
+// default viewport keymapping. If set to 0 or less, horizontal scrolling is
+// disabled.
+func (m *Model) SetHorizontalStep(n int) {
+	if n < 0 {
+		n = 0
+	}
+
+	m.horizontalStep = n
+}
+
+// MoveLeft moves the viewport to the left by the given number of columns.
+func (m *Model) MoveLeft(cols int) {
+	m.xOffset -= cols
+	if m.xOffset < 0 {
+		m.xOffset = 0
+	}
+}
+
+// MoveRight moves viewport to the right by the given number of columns.
+func (m *Model) MoveRight(cols int) {
+	// prevents over scrolling to the right
+	if m.xOffset >= m.longestLineWidth-m.Width() {
+		return
+	}
+	m.xOffset += cols
+}
+
+// Resets lines indent to zero.
+func (m *Model) ResetIndent() {
+	m.xOffset = 0
+}
+
 // Update handles standard message-based viewport updates.
 func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 	m = m.updateAsModel(msg)
@@ -278,6 +355,12 @@ func (m Model) updateAsModel(msg tea.Msg) Model {
 
 		case key.Matches(msg, m.KeyMap.Up):
 			m.LineUp(1)
+
+		case key.Matches(msg, m.KeyMap.Left):
+			m.MoveLeft(m.horizontalStep)
+
+		case key.Matches(msg, m.KeyMap.Right):
+			m.MoveRight(m.horizontalStep)
 		}
 
 	case tea.MouseWheelMsg:
@@ -339,3 +422,13 @@ func max(a, b int) int {
 	}
 	return b
 }
+
+func findLongestLineWidth(lines []string) int {
+	w := 0
+	for _, l := range lines {
+		if ww := ansi.StringWidth(l); ww > w {
+			w = ww
+		}
+	}
+	return w
+}

viewport/viewport_test.go

@@ -0,0 +1,383 @@
+package viewport
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestNew(t *testing.T) {
+	t.Parallel()
+
+	t.Run("default values on create by New", func(t *testing.T) {
+		t.Parallel()
+
+		m := New(WithHeight(10), WithWidth(10))
+
+		if !m.initialized {
+			t.Errorf("on create by New, Model should be initialized")
+		}
+
+		if m.horizontalStep != defaultHorizontalStep {
+			t.Errorf("default horizontalStep should be %d, got %d", defaultHorizontalStep, m.horizontalStep)
+		}
+
+		if m.MouseWheelDelta != 3 {
+			t.Errorf("default MouseWheelDelta should be 3, got %d", m.MouseWheelDelta)
+		}
+
+		if !m.MouseWheelEnabled {
+			t.Error("mouse wheel should be enabled by default")
+		}
+	})
+}
+
+func TestSetInitialValues(t *testing.T) {
+	t.Parallel()
+
+	t.Run("default horizontalStep", func(t *testing.T) {
+		t.Parallel()
+
+		m := Model{}
+		m.setInitialValues()
+
+		if m.horizontalStep != defaultHorizontalStep {
+			t.Errorf("default horizontalStep should be %d, got %d", defaultHorizontalStep, m.horizontalStep)
+		}
+	})
+}
+
+func TestSetHorizontalStep(t *testing.T) {
+	t.Parallel()
+
+	t.Run("change default", func(t *testing.T) {
+		t.Parallel()
+
+		m := New(WithHeight(10), WithWidth(10))
+
+		if m.horizontalStep != defaultHorizontalStep {
+			t.Errorf("default horizontalStep should be %d, got %d", defaultHorizontalStep, m.horizontalStep)
+		}
+
+		newStep := 8
+		m.SetHorizontalStep(newStep)
+		if m.horizontalStep != newStep {
+			t.Errorf("horizontalStep should be %d, got %d", newStep, m.horizontalStep)
+		}
+	})
+
+	t.Run("no negative", func(t *testing.T) {
+		t.Parallel()
+
+		m := New(WithHeight(10), WithWidth(10))
+
+		if m.horizontalStep != defaultHorizontalStep {
+			t.Errorf("default horizontalStep should be %d, got %d", defaultHorizontalStep, m.horizontalStep)
+		}
+
+		zero := 0
+		m.SetHorizontalStep(-1)
+		if m.horizontalStep != zero {
+			t.Errorf("horizontalStep should be %d, got %d", zero, m.horizontalStep)
+		}
+	})
+}
+
+func TestMoveLeft(t *testing.T) {
+	t.Parallel()
+
+	zeroPosition := 0
+
+	t.Run("zero position", func(t *testing.T) {
+		t.Parallel()
+
+		m := New(WithHeight(10), WithWidth(10))
+		if m.xOffset != zeroPosition {
+			t.Errorf("default indent should be %d, got %d", zeroPosition, m.xOffset)
+		}
+
+		m.MoveLeft(m.horizontalStep)
+		if m.xOffset != zeroPosition {
+			t.Errorf("indent should be %d, got %d", zeroPosition, m.xOffset)
+		}
+	})
+
+	t.Run("move", func(t *testing.T) {
+		t.Parallel()
+		m := New(WithHeight(10), WithWidth(10))
+		if m.xOffset != zeroPosition {
+			t.Errorf("default indent should be %d, got %d", zeroPosition, m.xOffset)
+		}
+
+		m.xOffset = defaultHorizontalStep * 2
+		m.MoveLeft(m.horizontalStep)
+		newIndent := defaultHorizontalStep
+		if m.xOffset != newIndent {
+			t.Errorf("indent should be %d, got %d", newIndent, m.xOffset)
+		}
+	})
+}
+
+func TestMoveRight(t *testing.T) {
+	t.Parallel()
+
+	t.Run("move", func(t *testing.T) {
+		t.Parallel()
+
+		zeroPosition := 0
+
+		m := New(WithHeight(10), WithWidth(10))
+		m.SetContent("Some line that is longer than width")
+		if m.xOffset != zeroPosition {
+			t.Errorf("default indent should be %d, got %d", zeroPosition, m.xOffset)
+		}
+
+		m.MoveRight(m.horizontalStep)
+		newIndent := defaultHorizontalStep
+		if m.xOffset != newIndent {
+			t.Errorf("indent should be %d, got %d", newIndent, m.xOffset)
+		}
+	})
+}
+
+func TestResetIndent(t *testing.T) {
+	t.Parallel()
+
+	t.Run("reset", func(t *testing.T) {
+		t.Parallel()
+
+		zeroPosition := 0
+
+		m := New(WithHeight(10), WithWidth(10))
+		m.xOffset = 500
+
+		m.ResetIndent()
+		if m.xOffset != zeroPosition {
+			t.Errorf("indent should be %d, got %d", zeroPosition, m.xOffset)
+		}
+	})
+}
+
+func TestVisibleLines(t *testing.T) {
+	t.Parallel()
+
+	defaultList := []string{
+		`57 Precepts of narcissistic comedy character Zote from an awesome "Hollow knight" game (https://store.steampowered.com/app/367520/Hollow_Knight/).`,
+		`Precept One: 'Always Win Your Battles'. Losing a battle earns you nothing and teaches you nothing. Win your battles, or don't engage in them at all!`,
+		`Precept Two: 'Never Let Them Laugh at You'. Fools laugh at everything, even at their superiors. But beware, laughter isn't harmless! Laughter spreads like a disease, and soon everyone is laughing at you. You need to strike at the source of this perverse merriment quickly to stop it from spreading.`,
+		`Precept Three: 'Always Be Rested'. Fighting and adventuring take their toll on your body. When you rest, your body strengthens and repairs itself. The longer you rest, the stronger you become.`,
+		`Precept Four: 'Forget Your Past'. The past is painful, and thinking about your past can only bring you misery. Think about something else instead, such as the future, or some food.`,
+		`Precept Five: 'Strength Beats Strength'. Is your opponent strong? No matter! Simply overcome their strength with even more strength, and they'll soon be defeated.`,
+		`Precept Six: 'Choose Your Own Fate'. Our elders teach that our fate is chosen for us before we are even born. I disagree.`,
+		`Precept Seven: 'Mourn Not the Dead'. When we die, do things get better for us or worse? There's no way to tell, so we shouldn't bother mourning. Or celebrating for that matter.`,
+		`Precept Eight: 'Travel Alone'. You can rely on nobody, and nobody will always be loyal. Therefore, nobody should be your constant companion.`,
+		`Precept Nine: 'Keep Your Home Tidy'. Your home is where you keep your most prized possession - yourself. Therefore, you should make an effort to keep it nice and clean.`,
+		`Precept Ten: 'Keep Your Weapon Sharp'. I make sure that my weapon, 'Life Ender', is kept well-sharpened at all times. This makes it much easier to cut things.`,
+		`Precept Eleven: 'Mothers Will Always Betray You'. This Precept explains itself.`,
+		`Precept Twelve: 'Keep Your Cloak Dry'. If your cloak gets wet, dry it as soon as you can. Wearing wet cloaks is unpleasant, and can lead to illness.`,
+		`Precept Thirteen: 'Never Be Afraid'. Fear can only hold you back. Facing your fears can be a tremendous effort. Therefore, you should just not be afraid in the first place.`,
+		`Precept Fourteen: 'Respect Your Superiors'. If someone is your superior in strength or intellect or both, you need to show them your respect. Don't ignore them or laugh at them.`,
+		`Precept Fifteen: 'One Foe, One Blow'. You should only use a single blow to defeat an enemy. Any more is a waste. Also, by counting your blows as you fight, you'll know how many foes you've defeated.`,
+		`...`,
+	}
+
+	t.Run("empty list", func(t *testing.T) {
+		t.Parallel()
+
+		m := New(WithHeight(10), WithWidth(10))
+		list := m.visibleLines()
+
+		if len(list) != 0 {
+			t.Errorf("list should be empty, got %d", len(list))
+		}
+	})
+
+	t.Run("empty list: with indent", func(t *testing.T) {
+		t.Parallel()
+
+		m := New(WithHeight(10), WithWidth(10))
+		list := m.visibleLines()
+		m.xOffset = 5
+
+		if len(list) != 0 {
+			t.Errorf("list should be empty, got %d", len(list))
+		}
+	})
+
+	t.Run("list", func(t *testing.T) {
+		t.Parallel()
+		numberOfLines := 10
+
+		m := New(WithHeight(numberOfLines), WithWidth(10))
+		m.SetContent(strings.Join(defaultList, "\n"))
+
+		list := m.visibleLines()
+		if len(list) != numberOfLines {
+			t.Errorf("list should have %d lines, got %d", numberOfLines, len(list))
+		}
+
+		lastItemIdx := numberOfLines - 1
+		// we trim line if it doesn't fit to width of the viewport
+		shouldGet := defaultList[lastItemIdx][:m.Width()]
+		if list[lastItemIdx] != shouldGet {
+			t.Errorf(`%dth list item should be '%s', got '%s'`, lastItemIdx, shouldGet, list[lastItemIdx])
+		}
+	})
+
+	t.Run("list: with y offset", func(t *testing.T) {
+		t.Parallel()
+		numberOfLines := 10
+
+		m := New(WithHeight(numberOfLines), WithWidth(10))
+		m.SetContent(strings.Join(defaultList, "\n"))
+		m.YOffset = 5
+
+		list := m.visibleLines()
+		if len(list) != numberOfLines {
+			t.Errorf("list should have %d lines, got %d", numberOfLines, len(list))
+		}
+
+		if list[0] == defaultList[0] {
+			t.Error("first item of list should not be the first item of initial list because of Y offset")
+		}
+
+		lastItemIdx := numberOfLines - 1
+		// we trim line if it doesn't fit to width of the viewport
+		shouldGet := defaultList[m.YOffset+lastItemIdx][:m.Width()]
+		if list[lastItemIdx] != shouldGet {
+			t.Errorf(`%dth list item should be '%s', got '%s'`, lastItemIdx, shouldGet, list[lastItemIdx])
+		}
+	})
+
+	t.Run("list: with y offset: horizontal scroll", func(t *testing.T) {
+		t.Parallel()
+		numberOfLines := 10
+
+		m := New(WithHeight(numberOfLines), WithWidth(10))
+		m.lines = defaultList
+		m.YOffset = 7
+
+		// default list
+		list := m.visibleLines()
+		if len(list) != numberOfLines {
+			t.Errorf("list should have %d lines, got %d", numberOfLines, len(list))
+		}
+
+		lastItem := numberOfLines - 1
+		defaultLastItem := len(defaultList) - 1
+		if list[lastItem] != defaultList[defaultLastItem] {
+			t.Errorf("%dth list item should the the same as %dth default list item", lastItem, defaultLastItem)
+		}
+
+		perceptPrefix := "Precept"
+		if !strings.HasPrefix(list[0], perceptPrefix) {
+			t.Errorf("first list item has to have prefix %s", perceptPrefix)
+		}
+
+		// move right
+		m.MoveRight(m.horizontalStep)
+		list = m.visibleLines()
+
+		newPrefix := perceptPrefix[m.xOffset:]
+		if !strings.HasPrefix(list[0], newPrefix) {
+			t.Errorf("first list item has to have prefix %s, get %s", newPrefix, list[0])
+		}
+
+		if list[lastItem] != "..." {
+			t.Errorf("last item should be empty, got %s", list[lastItem])
+		}
+
+		// move left
+		m.MoveLeft(m.horizontalStep)
+		list = m.visibleLines()
+		if !strings.HasPrefix(list[0], perceptPrefix) {
+			t.Errorf("first list item has to have prefix %s", perceptPrefix)
+		}
+
+		if list[lastItem] != defaultList[defaultLastItem] {
+			t.Errorf("%dth list item should the the same as %dth default list item", lastItem, defaultLastItem)
+		}
+	})
+
+	t.Run("list: with 2 cells symbols: horizontal scroll", func(t *testing.T) {
+		t.Parallel()
+
+		const horizontalStep = 5
+
+		initList := []string{
+			"あいうえお",
+			"Aあいうえお",
+			"あいうえお",
+			"Aあいうえお",
+		}
+		numberOfLines := len(initList)
+
+		m := New(WithHeight(numberOfLines), WithWidth(20))
+		m.lines = initList
+		m.longestLineWidth = 30 // dirty hack: not checking right overscroll for this test case
+
+		// default list
+		list := m.visibleLines()
+		if len(list) != numberOfLines {
+			t.Errorf("list should have %d lines, got %d", numberOfLines, len(list))
+		}
+
+		lastItemIdx := numberOfLines - 1
+		initLastItem := len(initList) - 1
+		shouldGet := initList[initLastItem]
+		if list[lastItemIdx] != shouldGet {
+			t.Errorf("%dth list item should the the same as %dth default list item", lastItemIdx, initLastItem)
+		}
+
+		// move right
+		m.MoveRight(horizontalStep)
+		list = m.visibleLines()
+
+		for i := range list {
+			cutLine := "うえお"
+			if list[i] != cutLine {
+				t.Errorf("line must be `%s`, get `%s`", cutLine, list[i])
+			}
+		}
+
+		// move left
+		m.MoveLeft(horizontalStep)
+		list = m.visibleLines()
+		for i := range list {
+			if list[i] != initList[i] {
+				t.Errorf("line must be `%s`, get `%s`", list[i], initList[i])
+			}
+		}
+
+		// move left second times do not change lites if indent == 0
+		m.xOffset = 0
+		m.MoveLeft(horizontalStep)
+		list = m.visibleLines()
+		for i := range list {
+			if list[i] != initList[i] {
+				t.Errorf("line must be `%s`, get `%s`", list[i], initList[i])
+			}
+		}
+	})
+}
+
+func TestRightOverscroll(t *testing.T) {
+	t.Parallel()
+
+	t.Run("prevent right overscroll", func(t *testing.T) {
+		t.Parallel()
+		content := "Content is short"
+		m := New(WithHeight(5), WithWidth(len(content)+1))
+		m.SetContent(content)
+
+		for i := 0; i < 10; i++ {
+			m.MoveRight(m.horizontalStep)
+		}
+
+		visibleLines := m.visibleLines()
+		visibleLine := visibleLines[0]
+
+		if visibleLine != content {
+			t.Error("visible line should stay the same as content")
+		}
+	})
+}