Tree widget

README.md

@@ -55,6 +55,7 @@ func main() {
 - [Gauge](./_examples/gauge.go)
 - [Image](./_examples/image.go)
 - [List](./_examples/list.go)
+- [Tree](./_examples/tree.go)
 - [Paragraph](./_examples/paragraph.go)
 - [PieChart](./_examples/piechart.go)
 - [Plot](./_examples/plot.go) (for scatterplots and linecharts)

_examples/tree.go

@@ -0,0 +1,127 @@
+/// +build ignore
+
+package main
+
+import (
+	"log"
+
+	ui "github.com/gizak/termui/v3"
+	"github.com/gizak/termui/v3/widgets"
+)
+
+type nodeValue string
+
+func (nv nodeValue) String() string {
+	return string(nv)
+}
+
+func main() {
+	if err := ui.Init(); err != nil {
+		log.Fatalf("failed to initialize termui: %v", err)
+	}
+	defer ui.Close()
+
+	nodes := []*widgets.TreeNode{
+		{
+			Value: nodeValue("Key 1"),
+			Nodes: []*widgets.TreeNode{
+				{
+					Value: nodeValue("Key 1.1"),
+					Nodes: []*widgets.TreeNode{
+						{
+							Value: nodeValue("Key 1.1.1"),
+							Nodes: nil,
+						},
+						{
+							Value: nodeValue("Key 1.1.2"),
+							Nodes: nil,
+						},
+					},
+				},
+				{
+					Value: nodeValue("Key 1.2"),
+					Nodes: nil,
+				},
+			},
+		},
+		{
+			Value: nodeValue("Key 2"),
+			Nodes: []*widgets.TreeNode{
+				{
+					Value: nodeValue("Key 2.1"),
+					Nodes: nil,
+				},
+				{
+					Value: nodeValue("Key 2.2"),
+					Nodes: nil,
+				},
+				{
+					Value: nodeValue("Key 2.3"),
+					Nodes: nil,
+				},
+			},
+		},
+		{
+			Value: nodeValue("Key 3"),
+			Nodes: nil,
+		},
+	}
+
+	l := widgets.NewTree()
+	l.TextStyle = ui.NewStyle(ui.ColorYellow)
+	l.WrapText = false
+	l.Nodes = nodes
+
+	x, y := ui.TerminalDimensions()
+
+	l.SetRect(0, 0, x, y)
+
+	ui.Render(l)
+
+	previousKey := ""
+	uiEvents := ui.PollEvents()
+	for {
+		e := <-uiEvents
+		switch e.ID {
+		case "q", "<C-c>":
+			return
+		case "j", "<Down>":
+			l.ScrollDown()
+		case "k", "<Up>":
+			l.ScrollUp()
+		case "<C-d>":
+			l.ScrollHalfPageDown()
+		case "<C-u>":
+			l.ScrollHalfPageUp()
+		case "<C-f>":
+			l.ScrollPageDown()
+		case "<C-b>":
+			l.ScrollPageUp()
+		case "g":
+			if previousKey == "g" {
+				l.ScrollTop()
+			}
+		case "<Home>":
+			l.ScrollTop()
+		case "<Enter>":
+			l.ToggleExpand()
+		case "G", "<End>":
+			l.ScrollBottom()
+		case "E":
+			l.ExpandAll()
+		case "C":
+			l.CollapseAll()
+		case "<Resize>":
+			x, y := ui.TerminalDimensions()
+			l.SetRect(0, 0, x, y)
+		}
+
+		if previousKey == "g" {
+			previousKey = ""
+		} else {
+			previousKey = e.ID
+		}
+
+		ui.Render(l)
+	}
+}

go.mod

@@ -5,5 +5,4 @@ require (
 	github.com/mattn/go-runewidth v0.0.2
 	github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7
 	github.com/nsf/termbox-go v0.0.0-20190121233118-02980233997d
-	golang.org/x/arch v0.0.0-20181203225421-5a4828bb7045 // indirect
 )

go.sum

@@ -6,5 +6,3 @@ github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7 h1:DpOJ2HYzC
 github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7/go.mod h1:ZXFpozHsX6DPmq2I0TCekCxypsnAUbP2oI0UX1GXzOo=
 github.com/nsf/termbox-go v0.0.0-20190121233118-02980233997d h1:x3S6kxmy49zXVVyhcnrFqxvNVCBPb2KZ9hV2RBdS840=
 github.com/nsf/termbox-go v0.0.0-20190121233118-02980233997d/go.mod h1:IuKpRQcYE1Tfu+oAQqaLisqDeXgjyyltCfsaoYN18NQ=
-golang.org/x/arch v0.0.0-20181203225421-5a4828bb7045 h1:Pn8fQdvx+z1avAi7fdM2kRYWQNxGlavNDSyzrQg2SsU=
-golang.org/x/arch v0.0.0-20181203225421-5a4828bb7045/go.mod h1:cYlCBUl1MsqxdiKgmc4uh7TxZfWSFLOGSRR090WDxt8=

symbols.go

@@ -6,6 +6,9 @@ const (
 
 	UP_ARROW   = '▲'
 	DOWN_ARROW = '▼'
+
+	COLLAPSED = '+'
+	EXPANDED  = '−'
 )
 
 var (

theme.go

@@ -33,6 +33,7 @@ type RootTheme struct {
 	Gauge           GaugeTheme
 	Plot            PlotTheme
 	List            ListTheme
+	Tree            TreeTheme
 	Paragraph       ParagraphTheme
 	PieChart        PieChartTheme
 	Sparkline       SparklineTheme
@@ -66,6 +67,12 @@ type ListTheme struct {
 	Text Style
 }
 
+type TreeTheme struct {
+	Text     Style
+	Collapse rune
+	Expand   rune
+}
+
 type ParagraphTheme struct {
 	Text Style
 }
@@ -122,6 +129,12 @@ var Theme = RootTheme{
 		Text: NewStyle(ColorWhite),
 	},
 
+	Tree: TreeTheme{
+		Text:     NewStyle(ColorWhite),
+		Collapse: COLLAPSED,
+		Expand:   EXPANDED,
+	},
+
 	StackedBarChart: StackedBarChartTheme{
 		Bars:   StandardColors,
 		Nums:   StandardStyles,

widgets/tree.go

@@ -0,0 +1,242 @@
+package widgets
+
+import (
+	"fmt"
+	"image"
+	"strings"
+
+	. "github.com/gizak/termui/v3"
+	rw "github.com/mattn/go-runewidth"
+)
+
+const treeIndent = "  "
+
+// TreeNode is a tree node.
+type TreeNode struct {
+	Value    fmt.Stringer
+	Expanded bool
+	Nodes    []*TreeNode
+
+	//level stores the node level in the tree.
+	level int
+}
+
+// TreeWalkFn is a function used for walking a Tree.
+// To interrupt the walking process function should return false.
+type TreeWalkFn func(*TreeNode) bool
+
+func (self *TreeNode) parseStyles(style Style) []Cell {
+	var sb strings.Builder
+	if len(self.Nodes) == 0 {
+		sb.WriteString(strings.Repeat(treeIndent, self.level+1))
+	} else {
+		sb.WriteString(strings.Repeat(treeIndent, self.level))
+		if self.Expanded {
+			sb.WriteRune(Theme.Tree.Expand)
+		} else {
+			sb.WriteRune(Theme.Tree.Collapse)
+		}
+		sb.WriteByte(' ')
+	}
+	sb.WriteString(self.Value.String())
+	return ParseStyles(sb.String(), style)
+}
+
+// Tree is a tree widget.
+type Tree struct {
+	Block
+	Nodes            []*TreeNode
+	TextStyle        Style
+	SelectedRowStyle Style
+	WrapText         bool
+	SelectedRow      int
+	topRow           int
+
+	//rows is flatten nodes for rendering.
+	rows []*TreeNode
+}
+
+// NewTree creates a new Tree widget.
+func NewTree() *Tree {
+	return &Tree{
+		Block:            *NewBlock(),
+		TextStyle:        Theme.Tree.Text,
+		SelectedRowStyle: Theme.Tree.Text,
+		WrapText:         true,
+	}
+}
+
+func (self *Tree) prepareNodes() {
+	self.rows = self.rows[:0]
+	for _, node := range self.Nodes {
+		self.prepareNode(node, 0)
+	}
+}
+
+func (self *Tree) prepareNode(node *TreeNode, level int) {
+	self.rows = append(self.rows, node)
+	node.level = level
+
+	if node.Expanded {
+		for _, n := range node.Nodes {
+			self.prepareNode(n, level+1)
+		}
+	}
+}
+
+func (self *Tree) Walk(fn TreeWalkFn) {
+	for _, n := range self.Nodes {
+		if !self.walk(n, fn) {
+			break
+		}
+	}
+}
+
+func (self *Tree) walk(n *TreeNode, fn TreeWalkFn) bool {
+	if !fn(n) {
+		return false
+	}
+
+	for _, node := range n.Nodes {
+		if !self.walk(node, fn) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (self *Tree) Draw(buf *Buffer) {
+	self.Block.Draw(buf)
+	self.prepareNodes()
+
+	point := self.Inner.Min
+
+	// adjusts view into widget
+	if self.SelectedRow >= self.Inner.Dy()+self.topRow {
+		self.topRow = self.SelectedRow - self.Inner.Dy() + 1
+	} else if self.SelectedRow < self.topRow {
+		self.topRow = self.SelectedRow
+	}
+
+	// draw rows
+	for row := self.topRow; row < len(self.rows) && point.Y < self.Inner.Max.Y; row++ {
+		cells := self.rows[row].parseStyles(self.TextStyle)
+		if self.WrapText {
+			cells = WrapCells(cells, uint(self.Inner.Dx()))
+		}
+		for j := 0; j < len(cells) && point.Y < self.Inner.Max.Y; j++ {
+			style := cells[j].Style
+			if row == self.SelectedRow {
+				style = self.SelectedRowStyle
+			}
+			if point.X+1 == self.Inner.Max.X+1 && len(cells) > self.Inner.Dx() {
+				buf.SetCell(NewCell(ELLIPSES, style), point.Add(image.Pt(-1, 0)))
+			} else {
+				buf.SetCell(NewCell(cells[j].Rune, style), point)
+				point = point.Add(image.Pt(rw.RuneWidth(cells[j].Rune), 0))
+			}
+		}
+		point = image.Pt(self.Inner.Min.X, point.Y+1)
+	}
+
+	// draw UP_ARROW if needed
+	if self.topRow > 0 {
+		buf.SetCell(
+			NewCell(UP_ARROW, NewStyle(ColorWhite)),
+			image.Pt(self.Inner.Max.X-1, self.Inner.Min.Y),
+		)
+	}
+
+	// draw DOWN_ARROW if needed
+	if len(self.rows) > int(self.topRow)+self.Inner.Dy() {
+		buf.SetCell(
+			NewCell(DOWN_ARROW, NewStyle(ColorWhite)),
+			image.Pt(self.Inner.Max.X-1, self.Inner.Max.Y-1),
+		)
+	}
+}
+
+// ScrollAmount scrolls by amount given. If amount is < 0, then scroll up.
+// There is no need to set self.topRow, as this will be set automatically when drawn,
+// since if the selected item is off screen then the topRow variable will change accordingly.
+func (self *Tree) ScrollAmount(amount int) {
+	if len(self.rows)-int(self.SelectedRow) <= amount {
+		self.SelectedRow = len(self.rows) - 1
+	} else if int(self.SelectedRow)+amount < 0 {
+		self.SelectedRow = 0
+	} else {
+		self.SelectedRow += amount
+	}
+}
+
+func (self *Tree) ScrollUp() {
+	self.ScrollAmount(-1)
+}
+
+func (self *Tree) ScrollDown() {
+	self.ScrollAmount(1)
+}
+
+func (self *Tree) ScrollPageUp() {
+	// If an item is selected below top row, then go to the top row.
+	if self.SelectedRow > self.topRow {
+		self.SelectedRow = self.topRow
+	} else {
+		self.ScrollAmount(-self.Inner.Dy())
+	}
+}
+
+func (self *Tree) ScrollPageDown() {
+	self.ScrollAmount(self.Inner.Dy())
+}
+
+func (self *Tree) ScrollHalfPageUp() {
+	self.ScrollAmount(-int(FloorFloat64(float64(self.Inner.Dy()) / 2)))
+}
+
+func (self *Tree) ScrollHalfPageDown() {
+	self.ScrollAmount(int(FloorFloat64(float64(self.Inner.Dy()) / 2)))
+}
+
+func (self *Tree) ScrollTop() {
+	self.SelectedRow = 0
+}
+
+func (self *Tree) ScrollBottom() {
+	self.SelectedRow = len(self.rows) - 1
+}
+
+func (self *Tree) Collapse() {
+	self.rows[self.SelectedRow].Expanded = false
+}
+
+func (self *Tree) Expand() {
+	node := self.rows[self.SelectedRow]
+	if len(node.Nodes) > 0 {
+		self.rows[self.SelectedRow].Expanded = true
+	}
+}
+
+func (self *Tree) ToggleExpand() {
+	node := self.rows[self.SelectedRow]
+	if len(node.Nodes) > 0 {
+		node.Expanded = !node.Expanded
+	}
+}
+
+func (self *Tree) ExpandAll() {
+	self.Walk(func(n *TreeNode) bool {
+		if len(n.Nodes) > 0 {
+			n.Expanded = true
+		}
+		return true
+	})
+}
+
+func (self *Tree) CollapseAll() {
+	self.Walk(func(n *TreeNode) bool {
+		n.Expanded = false
+		return true
+	})
+}