Add progressbar example

examples/progress/main.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/charmbracelet/bubbles/progress"
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+const (
+	fps              = 60
+	stepSize float64 = 1.0 / (float64(fps) * 2.0)
+	padding          = 2
+	maxWidth         = 80
+)
+
+func main() {
+	prog, err := progress.NewModel(progress.WithScaledGradient("#FF7CCB", "#FDFF8C"))
+	if err != nil {
+		fmt.Println("Could not initialize progress model:", err)
+		os.Exit(1)
+	}
+
+	if err = tea.NewProgram(example{progress: prog}).Start(); err != nil {
+		fmt.Println("Oh no!", err)
+		os.Exit(1)
+	}
+}
+
+type tickMsg time.Time
+
+type example struct {
+	percent  float64
+	progress *progress.Model
+}
+
+func (e example) Init() tea.Cmd {
+	return tickCmd()
+}
+
+func (e example) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "q", "ctrl+c":
+			return e, tea.Quit
+		default:
+			return e, nil
+		}
+
+	case tea.WindowSizeMsg:
+		e.progress.Width = msg.Width - padding*2 - 4
+		if e.progress.Width > maxWidth {
+			e.progress.Width = maxWidth
+		}
+		return e, nil
+
+	case tickMsg:
+		e.percent += stepSize
+		if e.percent > 1.0 {
+			e.percent = 1.0
+			return e, tea.Quit
+		}
+		return e, tickCmd()
+
+	default:
+		return e, nil
+	}
+}
+
+func (e example) View() string {
+	pad := strings.Repeat(" ", padding)
+	return "\n" + pad + e.progress.View(e.percent) + "\n\n"
+}
+
+func tickCmd() tea.Cmd {
+	return tea.Tick(time.Second/fps, func(t time.Time) tea.Msg {
+		return tickMsg(t)
+	})
+}

examples/views/main.go

@@ -1,6 +1,10 @@
 package main
 
 // An example demonstrating an application with multiple views.
+//
+// Note that this example was produced before the Bubbles progress component
+// was available (github.com/charmbracelet/bubbles/progress) and thus, we're
+// implementing a progress bar from scratch here.
 
 import (
 	"fmt"