progress: option to override tracker rendering logic (#369)

Author: ptxmac

cmd/demo-progress/demo.go

@@ -4,6 +4,7 @@ import (
 	"flag"
 	"fmt"
 	"math/rand"
+	"strings"
 	"time"
 
 	"github.com/jedib0t/go-pretty/v6/progress"
@@ -26,6 +27,7 @@ var (
 	flagRandomDefer        = flag.Bool("rnd-defer", false, "Introduce random deferred starts")
 	flagRandomRemove       = flag.Bool("rnd-remove", false, "Introduce random remove of trackers on completion")
 	flagRandomLogs         = flag.Bool("rnd-logs", false, "Output random logs in the middle of tracking")
+	flagCustomRender       = flag.Bool("custom-render", false, "Use custom render functions with rainbow colors")
 
 	messageColors = []text.Color{
 		text.FgRed,
@@ -119,6 +121,51 @@ func trackSomething(pw progress.Writer, idx int64, updateMessage bool) {
 	}
 }
 
+// customTrackerRender creates a progress bar using rainbow colors for determinate progress
+func customTrackerRender(value int64, total int64, maxLen int) string {
+	progress := float64(value) / float64(total)
+	completed := int(progress * float64(maxLen))
+
+	var result strings.Builder
+	for i := 0; i < maxLen; i++ {
+		if i < completed {
+			// Use rainbow colors based on position in the progress bar
+			colorIdx := (i * 6) / maxLen // Map position to 6 rainbow colors
+			colors := []text.Color{
+				text.FgRed,
+				text.FgYellow,
+				text.FgGreen,
+				text.FgCyan,
+				text.FgBlue,
+				text.FgMagenta,
+			}
+			if colorIdx >= len(colors) {
+				colorIdx = len(colors) - 1
+			}
+			result.WriteString(colors[colorIdx].Sprint("█"))
+		} else {
+			result.WriteString(text.FgHiBlack.Sprint("░"))
+		}
+	}
+
+	return result.String()
+}
+
+// customTrackerIndeterminateRender creates a progress bar using rotating rainbow colors for indeterminate progress
+func customTrackerIndeterminateRender(maxLen int) string {
+	// For indeterminate progress, use rotating rainbow colors
+	colors := []text.Color{
+		text.FgRed,
+		text.FgYellow,
+		text.FgGreen,
+		text.FgCyan,
+		text.FgBlue,
+		text.FgMagenta,
+	}
+	idx := int(time.Now().UnixNano()/100000000) % len(colors)
+	return colors[idx].Sprint(strings.Repeat("█", maxLen))
+}
+
 func main() {
 	flag.Parse()
 	fmt.Printf("Tracking Progress of %d trackers ...\n\n", *flagNumTrackers)
@@ -145,6 +192,13 @@ func main() {
 	pw.Style().Visibility.Value = !*flagHideValue
 	pw.Style().Visibility.Pinned = *flagShowPinned
 
+	// set up custom render functions if flag is enabled
+	if *flagCustomRender {
+		pw.Style().Renderer.TrackerDeterminate = customTrackerRender
+		pw.Style().Renderer.TrackerIndeterminate = customTrackerIndeterminateRender
+		fmt.Println("Using custom render functions with rainbow colors!")
+	}
+
 	// call Render() in async mode; yes we don't have any trackers at the moment
 	go pw.Render()
 

progress/render.go

@@ -107,6 +107,10 @@ func (p *Progress) generateTrackerStr(t *Tracker, maxLen int, hint renderHint) s
 // generateTrackerStrDeterminate generates the tracker string for the case where
 // the Total value is known, and the progress percentage can be calculated.
 func (p *Progress) generateTrackerStrDeterminate(value int64, total int64, maxLen int) string {
+	if p.style.Renderer.TrackerDeterminate != nil {
+		return p.style.Renderer.TrackerDeterminate(value, total, maxLen)
+	}
+
 	pFinishedDots, pFinishedDotsFraction := 0.0, 0.0
 	pDotValue := float64(total) / float64(maxLen)
 	if pDotValue > 0 {
@@ -139,9 +143,13 @@ func (p *Progress) generateTrackerStrDeterminate(value int64, total int64, maxLe
 	)
 }
 
-// generateTrackerStrDeterminate generates the tracker string for the case where
+// generateTrackerStrIndeterminate generates the tracker string for the case where
 // the Total value is unknown, and the progress percentage cannot be calculated.
 func (p *Progress) generateTrackerStrIndeterminate(maxLen int) string {
+	if p.style.Renderer.TrackerIndeterminate != nil {
+		return p.style.Renderer.TrackerIndeterminate(maxLen)
+	}
+
 	indicator := p.style.Chars.Indeterminate(maxLen)
 
 	pUnfinished := ""

progress/render_test.go

@@ -938,3 +938,87 @@ func TestProgress_RenderSomeTrackers_WithPinnedMessages_MultiLines(t *testing.T)
 	}
 	showOutputOnFailure(t, out)
 }
+
+func TestProgress_RenderSomeTrackers_WithCustomTrackerDeterminate(t *testing.T) {
+	renderOutput := outputWriter{}
+
+	pw := generateWriter()
+	pw.SetOutputWriter(&renderOutput)
+	pw.SetTrackerPosition(PositionRight)
+
+	symbols := []string{"♠", "♥", "♦", "♣", "🂡", "🂱"}
+
+	pw.Style().Renderer.TrackerDeterminate = func(value int64, total int64, maxLen int) string {
+		v := float64(value) / float64(total)
+		b := &strings.Builder{}
+		fmt.Fprintf(b, "[")
+		inner := maxLen - 2
+		for i := 0; i < inner; i++ {
+			delta := float64(i) / float64(inner)
+			symbolIdx := int(delta * float64(len(symbols)))
+			if symbolIdx >= len(symbols) {
+				symbolIdx = len(symbols) - 1
+			}
+			if delta < v {
+				fmt.Fprintf(b, "%s", symbols[symbolIdx])
+			} else {
+				fmt.Fprintf(b, " ")
+			}
+		}
+		fmt.Fprintf(b, "]")
+		return b.String()
+	}
+
+	go trackSomething(pw, &Tracker{Message: "Custom Tracker #1", Total: 1000, Units: UnitsDefault})
+	go trackSomething(pw, &Tracker{Message: "Custom Tracker #2", Total: 1000, Units: UnitsBytes})
+	renderAndWait(pw, false)
+
+	expectedOutPatterns := []*regexp.Regexp{
+		regexp.MustCompile(`Custom Tracker #1 \.\.\. done! \[\d+\.\d+K in [\d.]+ms]`),
+		regexp.MustCompile(`Custom Tracker #2 \.\.\. done! \[\d+\.\d+KB in [\d.]+ms]`),
+	}
+	out := renderOutput.String()
+	for _, expectedOutPattern := range expectedOutPatterns {
+		if !expectedOutPattern.MatchString(out) {
+			assert.Fail(t, "Failed to find a pattern in the Output.", expectedOutPattern.String())
+		}
+	}
+	showOutputOnFailure(t, out)
+}
+
+func TestProgress_RenderSomeTrackers_WithCustomTrackerIndeterminate(t *testing.T) {
+	renderOutput := outputWriter{}
+
+	pw := generateWriter()
+	pw.SetOutputWriter(&renderOutput)
+	pw.SetTrackerPosition(PositionRight)
+
+	pw.Style().Renderer.TrackerIndeterminate = func(maxLen int) string {
+		b := &strings.Builder{}
+		fmt.Fprintf(b, "[")
+		inner := maxLen - 2
+		for i := 0; i < inner; i++ {
+			if i == 0 {
+				fmt.Fprintf(b, "★")
+			} else {
+				fmt.Fprintf(b, "☆")
+			}
+		}
+		fmt.Fprintf(b, "]")
+		return b.String()
+	}
+
+	go trackSomethingIndeterminate(pw, &Tracker{Message: "Indeterminate Tracker", Total: 0, Units: UnitsDefault})
+	renderAndWait(pw, false)
+
+	expectedOutPatterns := []*regexp.Regexp{
+		regexp.MustCompile(`Indeterminate Tracker \.\.\. done! \[\d+ in [\d.]+ms]`),
+	}
+	out := renderOutput.String()
+	for _, expectedOutPattern := range expectedOutPatterns {
+		if !expectedOutPattern.MatchString(out) {
+			assert.Fail(t, "Failed to find a pattern in the Output.", expectedOutPattern.String())
+		}
+	}
+	showOutputOnFailure(t, out)
+}

progress/style.go

@@ -13,6 +13,7 @@ type Style struct {
 	Colors     StyleColors     // colors to use on the progress bar
 	Options    StyleOptions    // misc. options for the progress bar
 	Visibility StyleVisibility // show/hide components of the progress bar(s)
+	Renderer   StyleRenderer   // custom render functions for the progress bar
 }
 
 var (
@@ -215,3 +216,16 @@ var StyleVisibilityDefault = StyleVisibility{
 	TrackerOverall: false,
 	Value:          true,
 }
+
+type StyleRenderer struct {
+	// TrackerDeterminate will override how the progress bar is rendered.
+	// value is the current value of the tracker out of total.
+	// maxLen is the number of characters available for the progress bar.
+	// return the complete progress bar string. E.g. [===----]
+	TrackerDeterminate func(value int64, total int64, maxLen int) string
+
+	// TrackerIndeterminate will override how the indeterminate progress bar is rendered.
+	// maxLen is the number of characters available for the progress bar.
+	// return the complete progress bar string. E.g. [<#>----]
+	TrackerIndeterminate func(maxLen int) string
+}