Add spinner widget.

Signed-off-by: Andreas Krennmair <ak@synflood.at>

README.md

@@ -56,3 +56,4 @@ func main() {
 * percentage mode gauge
 * utilisation mode gauge
 * message dialog (info and error)
+* spinner

demos/spinner/README.md

@@ -0,0 +1 @@
+![Screenshot](screenshot.png)

demos/spinner/main.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"time"
+
+	"github.com/navidys/tvxwidgets"
+	"github.com/rivo/tview"
+)
+
+func main() {
+	app := tview.NewApplication()
+	grid := tview.NewGrid()
+	grid.SetBorder(true).SetTitle("Spinners")
+
+	spinners := [][]*tvxwidgets.Spinner{
+		{
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerDotsCircling),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerDotsUpDown),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerBounce),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerLine),
+		},
+		{
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerCircleQuarters),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerSquareCorners),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerCircleHalves),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerCorners),
+		},
+		{
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerArrows),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerHamburger),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerStack),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerStar),
+		},
+		{
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerGrowHorizontal),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerGrowVertical),
+			tvxwidgets.NewSpinner().SetStyle(tvxwidgets.SpinnerBoxBounce),
+			tvxwidgets.NewSpinner().SetCustomStyle([]rune{'🕛', '🕐', '🕑', '🕒', '🕓', '🕔', '🕕', '🕖', '🕗', '🕘', '🕙', '🕚'}),
+		},
+	}
+
+	for rowIdx, row := range spinners {
+		for colIdx, spinner := range row {
+			grid.AddItem(spinner, rowIdx, colIdx, 1, 1, 1, 1, false)
+		}
+	}
+
+	update := func() {
+		tick := time.NewTicker(100 * time.Millisecond)
+		for {
+			select {
+			case <-tick.C:
+				for _, row := range spinners {
+					for _, spinner := range row {
+						spinner.Pulse()
+					}
+				}
+				app.Draw()
+			}
+		}
+	}
+	go update()
+
+	if err := app.SetRoot(grid, false).EnableMouse(true).Run(); err != nil {
+		panic(err)
+	}
+}

spinner.go

@@ -0,0 +1,101 @@
+package tvxwidgets
+
+import (
+	"github.com/gdamore/tcell/v2"
+	"github.com/rivo/tview"
+)
+
+// Spinner represents a spinner widget
+type Spinner struct {
+	*tview.Box
+
+	counter      int
+	currentStyle SpinnerStyle
+
+	styles map[SpinnerStyle][]rune
+}
+
+type SpinnerStyle int
+
+const (
+	SpinnerDotsCircling SpinnerStyle = iota
+	SpinnerDotsUpDown
+	SpinnerBounce
+	SpinnerLine
+	SpinnerCircleQuarters
+	SpinnerSquareCorners
+	SpinnerCircleHalves
+	SpinnerCorners
+	SpinnerArrows
+	SpinnerHamburger
+	SpinnerStack
+	SpinnerGrowHorizontal
+	SpinnerGrowVertical
+	SpinnerStar
+	SpinnerBoxBounce
+	spinnerCustom // non-public constant to indicate that a custom style has been set by the user.
+)
+
+// NewSpinner returns a new spinner widget.
+func NewSpinner() *Spinner {
+	return &Spinner{
+		Box:          tview.NewBox(),
+		currentStyle: SpinnerDotsCircling,
+		styles: map[SpinnerStyle][]rune{
+			SpinnerDotsCircling:   []rune(`⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏`),
+			SpinnerDotsUpDown:     []rune(`⠋⠙⠚⠞⠖⠦⠴⠲⠳⠓`),
+			SpinnerBounce:         []rune(`⠄⠆⠇⠋⠙⠸⠰⠠⠰⠸⠙⠋⠇⠆`),
+			SpinnerLine:           []rune(`|/-\`),
+			SpinnerCircleQuarters: []rune(`◴◷◶◵`),
+			SpinnerSquareCorners:  []rune(`◰◳◲◱`),
+			SpinnerCircleHalves:   []rune(`◐◓◑◒`),
+			SpinnerCorners:        []rune(`⌜⌝⌟⌞`),
+			SpinnerArrows:         []rune(`⇑⇗⇒⇘⇓⇙⇐⇖`),
+			SpinnerHamburger:      []rune(`☰☱☳☷☶☴`),
+			SpinnerStack:          []rune(`䷀䷪䷡䷊䷒䷗䷁䷖䷓䷋䷠䷫`),
+			SpinnerGrowHorizontal: []rune(`▉▊▋▌▍▎▏▎▍▌▋▊▉`),
+			SpinnerGrowVertical:   []rune(`▁▃▄▅▆▇▆▅▄▃`),
+			SpinnerStar:           []rune(`✶✸✹✺✹✷`),
+			SpinnerBoxBounce:      []rune(`▌▀▐▄`),
+		},
+	}
+}
+
+// Draw draws this primitive onto the screen.
+func (s *Spinner) Draw(screen tcell.Screen) {
+	s.Box.DrawForSubclass(screen, s)
+	x, y, width, _ := s.Box.GetInnerRect()
+	tview.Print(screen, s.getCurrentFrame(), x, y, width, tview.AlignLeft, tcell.ColorDefault)
+}
+
+// Pulse updates the spinner to the next frame.
+func (s *Spinner) Pulse() {
+	s.counter++
+}
+
+// Reset sets the frame counter to 0.
+func (s *Spinner) Reset() {
+	s.counter = 0
+}
+
+// SetStyle sets the spinner style.
+func (s *Spinner) SetStyle(style SpinnerStyle) *Spinner {
+	s.currentStyle = style
+	return s
+}
+
+func (s *Spinner) getCurrentFrame() string {
+	frames := s.styles[s.currentStyle]
+	if len(frames) == 0 {
+		return ""
+	}
+
+	return string(frames[s.counter%len(frames)])
+}
+
+// SetCustomStyle sets a list of runes as custom frames to show as the spinner.
+func (s *Spinner) SetCustomStyle(frames []rune) *Spinner {
+	s.styles[spinnerCustom] = frames
+	s.currentStyle = spinnerCustom
+	return s
+}