Return the value of paginator.TotalPages in SetTotalPages...

when the given number of items is below 1.

.github/workflows/build.yml

@@ -0,0 +1,28 @@
+name: build
+on: [push, pull_request]
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [~1.13, ^1]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    env:
+      GO111MODULE: "on"
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Download Go modules
+        run: go mod download
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Test
+        run: go test ./...

.github/workflows/coverage.yml

@@ -0,0 +1,28 @@
+name: coverage
+on: [push, pull_request]
+
+jobs:
+  coverage:
+    strategy:
+      matrix:
+        go-version: [^1]
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
+    env:
+      GO111MODULE: "on"
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Coverage
+        env:
+          COVERALLS_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          go test -race -covermode atomic -coverprofile=profile.cov ./...
+          GO111MODULE=off go get github.com/mattn/goveralls
+          $(go env GOPATH)/bin/goveralls -coverprofile=profile.cov -service=github

.github/workflows/lint.yml

@@ -0,0 +1,20 @@
+name: lint
+on: [push, pull_request]
+
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
+          version: v1.30
+          # Optional: golangci-lint command line arguments.
+          args: --issues-exit-code=0
+          # Optional: working directory, useful for monorepos
+          # working-directory: somedir
+          # Optional: show only new issues if it's a pull request. The default value is `false`.
+          only-new-issues: true

.golangci.yml

@@ -0,0 +1,26 @@
+run:
+  tests: false
+
+issues:
+  max-issues-per-linter: 0
+  max-same-issues: 0
+
+linters:
+  enable:
+    - bodyclose
+    - dupl
+    - exportloopref
+    - goconst
+    - godot
+    - godox
+    - goimports
+    - gomnd
+    - goprintffuncname
+    - gosec
+    - misspell
+    - prealloc
+    - rowserrcheck
+    - sqlclosecheck
+    - unconvert
+    - unparam
+    - whitespace

README.md

@@ -1,10 +1,10 @@
 Bubbles
 =======
 
-<p>
-    <a href="https://pkg.go.dev/github.com/charmbracelet/bubbles?tab=doc"><img src="https://godoc.org/github.com/golang/gddo?status.svg" alt="GoDoc"></a>
-    <a href="https://github.com/charmbracelet/bubbles/actions"><img src="https://github.com/charmbracelet/glow/workflows/build/badge.svg" alt="Build Status"></a>
-</p>
+[![Latest Release](https://img.shields.io/github/release/charmbracelet/bubbles.svg)](https://github.com/charmbracelet/bubbles/releases)
+[![GoDoc](https://godoc.org/github.com/golang/gddo?status.svg)](https://pkg.go.dev/github.com/charmbracelet/bubbles)
+[![Build Status](https://github.com/charmbracelet/bubbles/workflows/build/badge.svg)](https://github.com/charmbracelet/bubbles/actions)
+[![Go ReportCard](http://goreportcard.com/badge/charmbracelet/bubbles)](http://goreportcard.com/report/charmbracelet/bubbles)
 
 Some components for [Bubble Tea](https://github.com/charmbracelet/bubbletea) applications.
 
@@ -33,7 +33,7 @@ pasting, in-place scrolling when the value exceeds the width of the element and
 the common, and many customization options.
 
 * [Example code, one field](https://github.com/charmbracelet/tea/tree/master/examples/textinput/main.go)
-* [Example code, many fields](https://github.com/charmbracelet/tea/tree/master/examples/textinput/main.go)
+* [Example code, many fields](https://github.com/charmbracelet/tea/tree/master/examples/textinputs/main.go)
 
 
 ## Paginator
@@ -59,7 +59,7 @@ for applications which make use of the alterate screen buffer.
 
 * [Example code](https://github.com/charmbracelet/tea/tree/master/examples/pager/main.go)
 
-This compoent is well complimented with [Reflow][reflow] for ANSI-aware
+This component is well complimented with [Reflow][reflow] for ANSI-aware
 indenting and text wrapping.
 
 [reflow]: https://github.com/muesli/reflow
@@ -72,8 +72,9 @@ indenting and text wrapping.
 
 ***
 
-A [Charm](https://charm.sh) project.
+Part of [Charm](https://charm.sh).
 
-<img alt="the Charm logo" src="https://stuff.charm.sh/charm-badge.jpg" width="400">
+<a href="https://charm.sh/"><img alt="the Charm logo" src="https://stuff.charm.sh/charm-badge.jpg" width="400"></a>
+
+Charm热爱开源! / Charm loves open source!
 
-Charm热爱开源!

go.mod

@@ -4,8 +4,9 @@ go 1.13
 
 require (
 	github.com/atotto/clipboard v0.1.2
-	github.com/charmbracelet/bubbletea v0.12.0
+	github.com/charmbracelet/bubbletea v0.12.1
 	github.com/mattn/go-runewidth v0.0.9
 	github.com/muesli/termenv v0.7.4
-	golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211 // indirect
+	golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897 // indirect
+	golang.org/x/sys v0.0.0-20201020230747-6e5568b54d1a // indirect
 )

go.sum

@@ -1,7 +1,7 @@
 github.com/atotto/clipboard v0.1.2 h1:YZCtFu5Ie8qX2VmVTBnrqLSiU9XOWwqNRmdT3gIQzbY=
 github.com/atotto/clipboard v0.1.2/go.mod h1:ZY9tmq7sm5xIbd9bOK4onWV4S6X0u6GY7Vn0Yu86PYI=
-github.com/charmbracelet/bubbletea v0.12.0 h1:/pUHp1GWRDyK1TJAWkXrnRH1u8Xc5076oH/J0NHxH+M=
-github.com/charmbracelet/bubbletea v0.12.0/go.mod h1:3gZkYELUOiEUOp0bTInkxguucy/xRbGSOcbMs1geLxg=
+github.com/charmbracelet/bubbletea v0.12.1 h1:t21pkG2IDBRduPbt2J64Dx5yt8yIidAkXwhhrc11SzY=
+github.com/charmbracelet/bubbletea v0.12.1/go.mod h1:3gZkYELUOiEUOp0bTInkxguucy/xRbGSOcbMs1geLxg=
 github.com/containerd/console v1.0.1 h1:u7SFAJyRqWcG6ogaMAx3KjSTy1e3hT9QxqX7Jco7dRc=
 github.com/containerd/console v1.0.1/go.mod h1:XUsP6YE/mKtz6bxc+I8UiKKTP04qjQL4qcS3XoQ5xkw=
 github.com/google/goterm v0.0.0-20190703233501-fc88cf888a3f h1:5CjVwnuUcp5adK4gmY6i72gpVFVnZDP2h5TmPScB6u4=
@@ -21,6 +21,8 @@ github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20201012173705-84dcc777aaee h1:4yd7jl+vXjalO5ztz6Vc1VADv+S/80LGJmyl1ROJ2AI=
 golang.org/x/crypto v0.0.0-20201012173705-84dcc777aaee/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897 h1:pLI5jrR7OSLijeIDcmRxNmw2api+jEfxLoykJVice/E=
+golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -28,6 +30,6 @@ golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200916030750-2334cc1a136f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201009025420-dfb3f7c4e634 h1:bNEHhJCnrwMKNMmOx3yAynp5vs5/gRy+XWFtZFu7NBM=
 golang.org/x/sys v0.0.0-20201009025420-dfb3f7c4e634/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211 h1:9UQO31fZ+0aKQOFldThf7BKPMJTiBfWycGh/u3UoO88=
-golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201020230747-6e5568b54d1a h1:e3IU37lwO4aq3uoRKINC7JikojFmE5gO7xhfxs8VC34=
+golang.org/x/sys v0.0.0-20201020230747-6e5568b54d1a/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

paginator/paginator.go

@@ -40,8 +40,8 @@ type Model struct {
 // used for other things beyond navigating sets. Note that it both returns the
 // number of total pages and alters the model.
 func (m *Model) SetTotalPages(items int) int {
-	if items == 0 {
-		return 0
+	if items < 1 {
+		return m.TotalPages
 	}
 	n := items / m.PerPage
 	if items%m.PerPage > 0 {

textinput/textinput.go

@@ -11,27 +11,49 @@ import (
 	"github.com/muesli/termenv"
 )
 
+const defaultBlinkSpeed = time.Millisecond * 530
+
 const (
-	defaultBlinkSpeed = time.Millisecond * 600
+	// EchoNormal displays text as is. This is the default behavior.
+	EchoNormal EchoMode = iota
+
+	// EchoPassword displays the EchoCharacter mask instead of actual
+	// characters.  This is commonly used for password fields.
+	EchoPassword
+
+	// EchoNone displays nothing as characters are entered. This is commonly
+	// seen for password fields on the command line.
+	EchoNone
+
+	// EchoOnEdit
 )
 
+// EchoMode sets the input behavior of the text input field.
+type EchoMode int
+
 var (
 	// color is a helper for returning colors.
 	color func(s string) termenv.Color = termenv.ColorProfile().Color
 )
 
-// Model is the Tea model for this text input element.
+// Model is the Bubble Tea model for this text input element.
 type Model struct {
 	Err error
+
 	Prompt      string
+	Placeholder string
+
 	Cursor     string
 	BlinkSpeed time.Duration
-	Placeholder      string
+
 	TextColor        string
 	BackgroundColor  string
 	PlaceholderColor string
 	CursorColor      string
 
+	EchoMode      EchoMode
+	EchoCharacter rune
+
 	// CharLimit is the maximum amount of characters this input element will
 	// accept. If 0 or less, there's no limit.
 	CharLimit int
@@ -41,21 +63,21 @@ type Model struct {
 	// viewport. If 0 or less this setting is ignored.
 	Width int
 
-	// Underlying text value
+	// Underlying text value.
 	value []rune
 
 	// Focus indicates whether user input focus should be on this input
 	// component. When false, don't blink and ignore keyboard input.
 	focus bool
 
-	// Cursor blink state
+	// Cursor blink state.
 	blink bool
 
-	// Cursor position
+	// Cursor position.
 	pos int
 
 	// Used to emulate a viewport when width is set and the content is
-	// overflowing
+	// overflowing.
 	offset      int
 	offsetRight int
 }
@@ -69,7 +91,7 @@ func (m *Model) SetValue(s string) {
 		m.value = runes
 	}
 	if m.pos > len(m.value) {
-		m.pos = len(m.value)
+		m.SetCursor(len(m.value))
 	}
 	m.handleOverflow()
 }
@@ -79,23 +101,22 @@ func (m Model) Value() string {
 	return string(m.value)
 }
 
-// Cursor start moves the cursor to the given position. If the position is out
-// of bounds the cursor will be moved to the start or end accordingly.
+// SetCursor start moves the cursor to the given position. If the position is
+// out of bounds the cursor will be moved to the start or end accordingly.
 func (m *Model) SetCursor(pos int) {
 	m.pos = clamp(pos, 0, len(m.value))
+	m.blink = false
 	m.handleOverflow()
 }
 
 // CursorStart moves the cursor to the start of the field.
 func (m *Model) CursorStart() {
-	m.pos = 0
-	m.handleOverflow()
+	m.SetCursor(0)
 }
 
 // CursorEnd moves the cursor to the end of the field.
 func (m *Model) CursorEnd() {
-	m.pos = len(m.value)
-	m.handleOverflow()
+	m.SetCursor(len(m.value))
 }
 
 // Focused returns the focus state on the model.
@@ -118,8 +139,7 @@ func (m *Model) Blur() {
 // Reset sets the input to its default state with no input.
 func (m *Model) Reset() {
 	m.value = nil
-	m.pos = 0
-	m.blink = false
+	m.SetCursor(0)
 }
 
 // Paste pastes the contents of the clipboard into the text area (if supported).
@@ -130,7 +150,10 @@ func (m *Model) Paste() {
 	}
 	paste := []rune(pasteString)
 
-	availSpace := m.CharLimit - len(m.value)
+	var availSpace int
+	if m.CharLimit > 0 {
+		availSpace = m.CharLimit - len(m.value)
+	}
 
 	// If the char limit's been reached cancel
 	if m.CharLimit > 0 && availSpace <= 0 {
@@ -139,7 +162,7 @@ func (m *Model) Paste() {
 
 	// If there's not enough space to paste the whole thing cut the pasted
 	// runes down so they'll fit
-	if availSpace < len(paste) {
+	if m.CharLimit > 0 && availSpace < len(paste) {
 		paste = paste[:len(paste)-availSpace]
 	}
 
@@ -152,15 +175,20 @@ func (m *Model) Paste() {
 	// Insert pasted runes
 	for _, r := range paste {
 		head = append(head, r)
-		availSpace--
 		m.pos++
-		if m.CharLimit > 0 && availSpace <= 0 {
+		if m.CharLimit > 0 {
+			availSpace--
+			if availSpace <= 0 {
 				break
 			}
 		}
+	}
 
 	// Put it all back together
 	m.value = append(head, tail...)
+
+	// Reset blink state and run overflow checks
+	m.SetCursor(m.pos)
 }
 
 // If a max width is defined, perform some logic to treat the visible area
@@ -228,6 +256,67 @@ func (m *Model) colorPlaceholder(s string) string {
 		String()
 }
 
+// deleteWordLeft deletes the word left to the cursor.
+func (m *Model) deleteWordLeft() {
+	if m.pos == 0 || len(m.value) == 0 {
+		return
+	}
+
+	i := m.pos
+	m.SetCursor(m.pos - 1)
+	for unicode.IsSpace(m.value[m.pos]) {
+		// ignore series of whitespace before cursor
+		m.SetCursor(m.pos - 1)
+	}
+
+	for m.pos > 0 {
+		if !unicode.IsSpace(m.value[m.pos]) {
+			m.SetCursor(m.pos - 1)
+		} else {
+			if m.pos > 0 {
+				// keep the previous space
+				m.SetCursor(m.pos + 1)
+			}
+			break
+		}
+	}
+
+	if i > len(m.value) {
+		m.value = m.value[:m.pos]
+	} else {
+		m.value = append(m.value[:m.pos], m.value[i:]...)
+	}
+}
+
+// deleteWordRight deletes the word right to the cursor.
+func (m *Model) deleteWordRight() {
+	if m.pos >= len(m.value) || len(m.value) == 0 {
+		return
+	}
+
+	i := m.pos
+	m.SetCursor(m.pos + 1)
+	for unicode.IsSpace(m.value[m.pos]) {
+		// ignore series of whitespace after cursor
+		m.SetCursor(m.pos + 1)
+	}
+
+	for m.pos < len(m.value) {
+		if !unicode.IsSpace(m.value[m.pos]) {
+			m.SetCursor(m.pos + 1)
+		} else {
+			break
+		}
+	}
+
+	if m.pos > len(m.value) {
+		m.value = m.value[:i]
+	} else {
+		m.value = append(m.value[:i], m.value[m.pos:]...)
+	}
+	m.SetCursor(i)
+}
+
 func (m *Model) wordLeft() {
 	if m.pos == 0 || len(m.value) == 0 {
 		return
@@ -237,7 +326,7 @@ func (m *Model) wordLeft() {
 
 	for i >= 0 {
 		if unicode.IsSpace(m.value[i]) {
-			m.pos--
+			m.SetCursor(m.pos - 1)
 			i--
 		} else {
 			break
@@ -246,7 +335,7 @@ func (m *Model) wordLeft() {
 
 	for i >= 0 {
 		if !unicode.IsSpace(m.value[i]) {
-			m.pos--
+			m.SetCursor(m.pos - 1)
 			i--
 		} else {
 			break
@@ -263,7 +352,7 @@ func (m *Model) wordRight() {
 
 	for i < len(m.value) {
 		if unicode.IsSpace(m.value[i]) {
-			m.pos++
+			m.SetCursor(m.pos + 1)
 			i++
 		} else {
 			break
@@ -272,7 +361,7 @@ func (m *Model) wordRight() {
 
 	for i < len(m.value) {
 		if !unicode.IsSpace(m.value[i]) {
-			m.pos++
+			m.SetCursor(m.pos + 1)
 			i++
 		} else {
 			break
@@ -280,6 +369,18 @@ func (m *Model) wordRight() {
 	}
 }
 
+func (m Model) echoTransform(v string) string {
+	switch m.EchoMode {
+	case EchoPassword:
+		return strings.Repeat(string(m.EchoCharacter), rw.StringWidth(v))
+	case EchoNone:
+		return ""
+
+	default:
+		return v
+	}
+}
+
 // BlinkMsg is sent when the cursor should alternate it's blinking state.
 type BlinkMsg struct{}
 
@@ -287,11 +388,16 @@ type BlinkMsg struct{}
 func NewModel() Model {
 	return Model{
 		Prompt:      "> ",
-		BlinkSpeed:       defaultBlinkSpeed,
 		Placeholder: "",
+
+		BlinkSpeed: defaultBlinkSpeed,
+
 		TextColor:        "",
 		PlaceholderColor: "240",
 		CursorColor:      "",
+
+		EchoCharacter: '*',
+
 		CharLimit: 0,
 
 		value: nil,
@@ -311,13 +417,15 @@ func Update(msg tea.Msg, m Model) (Model, tea.Cmd) {
 	switch msg := msg.(type) {
 	case tea.KeyMsg:
 		switch msg.Type {
-		case tea.KeyBackspace:
-			fallthrough
-		case tea.KeyDelete:
+		case tea.KeyBackspace: // delete character before cursor
+			if msg.Alt {
+				m.deleteWordLeft()
+			} else {
 				if len(m.value) > 0 {
 					m.value = append(m.value[:max(0, m.pos-1)], m.value[m.pos:]...)
 					if m.pos > 0 {
-					m.pos--
+						m.SetCursor(m.pos - 1)
+					}
 				}
 			}
 		case tea.KeyLeft:
@@ -326,7 +434,7 @@ func Update(msg tea.Msg, m Model) (Model, tea.Cmd) {
 				break
 			}
 			if m.pos > 0 {
-				m.pos--
+				m.SetCursor(m.pos - 1)
 			}
 		case tea.KeyRight:
 			if msg.Alt { // alt+right arrow, forward one word
@@ -334,32 +442,37 @@ func Update(msg tea.Msg, m Model) (Model, tea.Cmd) {
 				break
 			}
 			if m.pos < len(m.value) {
-				m.pos++
+				m.SetCursor(m.pos + 1)
 			}
+		case tea.KeyCtrlW: // ^W, delete word left of cursor
+			m.deleteWordLeft()
 		case tea.KeyCtrlF: // ^F, forward one character
 			fallthrough
 		case tea.KeyCtrlB: // ^B, back one charcter
 			fallthrough
-		case tea.KeyCtrlA: // ^A, go to beginning
+		case tea.KeyHome, tea.KeyCtrlA: // ^A, go to beginning
 			m.CursorStart()
-		case tea.KeyCtrlD: // ^D, delete char under cursor
+		case tea.KeyDelete, tea.KeyCtrlD: // ^D, delete char under cursor
 			if len(m.value) > 0 && m.pos < len(m.value) {
 				m.value = append(m.value[:m.pos], m.value[m.pos+1:]...)
 			}
-		case tea.KeyCtrlE: // ^E, go to end
+		case tea.KeyCtrlE, tea.KeyEnd: // ^E, go to end
 			m.CursorEnd()
 		case tea.KeyCtrlK: // ^K, kill text after cursor
 			m.value = m.value[:m.pos]
-			m.pos = len(m.value)
+			m.SetCursor(len(m.value))
 		case tea.KeyCtrlU: // ^U, kill text before cursor
 			m.value = m.value[m.pos:]
-			m.pos = 0
+			m.SetCursor(0)
 			m.offset = 0
 		case tea.KeyCtrlV: // ^V paste
 			m.Paste()
 		case tea.KeyRune: // input a regular character
-
 			if msg.Alt {
+				if msg.Rune == 'd' { // alt+d, delete word right of cursor
+					m.deleteWordRight()
+					break
+				}
 				if msg.Rune == 'b' { // alt+b, back one word
 					m.wordLeft()
 					break
@@ -373,7 +486,7 @@ func Update(msg tea.Msg, m Model) (Model, tea.Cmd) {
 			// Input a regular character
 			if m.CharLimit <= 0 || len(m.value) < m.CharLimit {
 				m.value = append(m.value[:m.pos], append([]rune{msg.Rune}, m.value[m.pos:]...)...)
-				m.pos++
+				m.SetCursor(m.pos + 1)
 			}
 		}
 
@@ -396,12 +509,11 @@ func View(m Model) string {
 
 	value := m.value[m.offset:m.offsetRight]
 	pos := max(0, m.pos-m.offset)
-
-	v := m.colorText(string(value[:pos]))
+	v := m.colorText(m.echoTransform(string(value[:pos])))
 
 	if pos < len(value) {
-		v += cursorView(string(value[pos]), m)  // cursor and text under it
-		v += m.colorText(string(value[pos+1:])) // text after cursor
+		v += cursorView(m.echoTransform(string(value[pos])), m)  // cursor and text under it
+		v += m.colorText(m.echoTransform(string(value[pos+1:]))) // text after cursor
 	} else {
 		v += cursorView(" ", m)
 	}

viewport/viewport.go

@@ -77,7 +77,7 @@ func (m *Model) SetContent(s string) {
 func (m Model) visibleLines() (lines []string) {
 	if len(m.lines) > 0 {
 		top := max(0, m.YOffset)
-		bottom := min(len(m.lines), m.YOffset+m.Height)
+		bottom := clamp(m.YOffset+m.Height, top, len(m.lines))
 		lines = m.lines[top:bottom]
 	}
 	return lines
@@ -125,7 +125,7 @@ func (m *Model) HalfViewDown() (lines []string) {
 
 	if len(m.lines) > 0 {
 		top := max(m.YOffset+m.Height/2, 0)
-		bottom := min(m.YOffset+m.Height, len(m.lines)-1)
+		bottom := clamp(m.YOffset+m.Height, top, len(m.lines)-1)
 		lines = m.lines[top:bottom]
 	}
 
@@ -145,7 +145,7 @@ func (m *Model) HalfViewUp() (lines []string) {
 
 	if len(m.lines) > 0 {
 		top := max(m.YOffset, 0)
-		bottom := min(m.YOffset+m.Height/2, len(m.lines)-1)
+		bottom := clamp(m.YOffset+m.Height/2, top, len(m.lines)-1)
 		lines = m.lines[top:bottom]
 	}
 
@@ -171,7 +171,7 @@ func (m *Model) LineDown(n int) (lines []string) {
 
 	if len(m.lines) > 0 {
 		top := max(m.YOffset+m.Height-n, 0)
-		bottom := min(m.YOffset+m.Height, len(m.lines)-1)
+		bottom := clamp(m.YOffset+m.Height, top, len(m.lines)-1)
 		lines = m.lines[top:bottom]
 	}
 
@@ -193,7 +193,7 @@ func (m *Model) LineUp(n int) (lines []string) {
 
 	if len(m.lines) > 0 {
 		top := max(0, m.YOffset)
-		bottom := min(m.YOffset+n, len(m.lines)-1)
+		bottom := clamp(m.YOffset+n, top, len(m.lines)-1)
 		lines = m.lines[top:bottom]
 	}
 
@@ -210,7 +210,7 @@ func (m *Model) GotoTop() (lines []string) {
 
 	if len(m.lines) > 0 {
 		top := m.YOffset
-		bottom := min(m.YOffset+m.Height, len(m.lines)-1)
+		bottom := clamp(m.YOffset+m.Height, top, len(m.lines)-1)
 		lines = m.lines[top:bottom]
 	}
 
@@ -245,7 +245,7 @@ func Sync(m Model) tea.Cmd {
 	// TODO: we should probably use m.visibleLines() rather than these two
 	// expressions.
 	top := max(m.YOffset, 0)
-	bottom := min(m.YOffset+m.Height, len(m.lines)-1)
+	bottom := clamp(m.YOffset+m.Height, 0, len(m.lines)-1)
 
 	return tea.SyncScrollArea(
 		m.lines[top:bottom],
@@ -304,14 +304,14 @@ func Update(msg tea.Msg, m Model) (Model, tea.Cmd) {
 			}
 
 		// Down half page
-		case "d":
+		case "d", "ctrl+d":
 			lines := m.HalfViewDown()
 			if m.HighPerformanceRendering {
 				cmd = ViewDown(m, lines)
 			}
 
 		// Up half page
-		case "u":
+		case "u", "ctrl+u":
 			lines := m.HalfViewUp()
 			if m.HighPerformanceRendering {
 				cmd = ViewUp(m, lines)
@@ -376,6 +376,10 @@ func View(m Model) string {
 
 // ETC
 
+func clamp(v, low, high int) int {
+	return min(high, max(low, v))
+}
+
 func min(a, b int) int {
 	if a < b {
 		return a