Add -fire option to fps for a fire effect and i key to toggle info text

ansipixels/ansipixels.go

@@ -309,11 +309,11 @@ func (ap *AnsiPixels) ClearEndOfLine() {
 
 var cursPosRegexp = regexp.MustCompile(`^(.*)\033\[(\d+);(\d+)R(.*)$`)
 
-// This also synchronizes the display.
+// This also synchronizes the display and ends the syncmode.
 func (ap *AnsiPixels) ReadCursorPos() (int, int, error) {
 	x := -1
 	y := -1
-	reqPosStr := "\033[6n"
+	reqPosStr := "\033[?2026l\033[6n" // also ends sync mode
 	n, err := ap.Out.WriteString(reqPosStr)
 	if err != nil {
 		return x, y, err

fps/fire.go

@@ -0,0 +1,152 @@
+package main
+
+import (
+	"fmt"
+	"math/rand/v2"
+
+	"fortio.org/safecast"
+	"fortio.org/terminal/ansipixels"
+)
+
+type FireState struct {
+	h      int
+	w      int
+	buffer []byte
+	on     bool
+}
+
+var fire *FireState
+
+var (
+	v2colTrueColor [256]string
+	v2col256       [256]string
+)
+
+func init() {
+	for i := range 256 {
+		r := min(255, 3*i)
+		g := min(255, max(0, (i-84)*2))
+		b := min(255, max(0, (i-208)*5))
+		v2colTrueColor[i] = fmt.Sprintf("\033[38;2;%d;%d;%dm█", r, g, b)
+	}
+	//                          0   1   2   3    4    5    6    7    8    9    10   11
+	for i, color := range []int{16, 52, 88, 124, 166, 202, 208, 214, 220, 226, 228, 231} {
+		v2col256[i] = fmt.Sprintf("\033[38;5;%dm█", color)
+	}
+}
+
+func InitFire(ap *ansipixels.AnsiPixels) *FireState {
+	f := &FireState{h: ap.H - 2*ap.Margin, w: ap.W - 2*ap.Margin}
+	f.buffer = make([]byte, f.h*f.w)
+	return f
+}
+
+func ToggleFire() {
+	if fire == nil {
+		return
+	}
+	if fire.on {
+		fire.Off()
+	} else {
+		fire.Start()
+	}
+}
+
+func (f *FireState) At(x, y int) byte {
+	return f.buffer[y*f.w+x]
+}
+
+func (f *FireState) Set(x, y int, v byte) {
+	f.buffer[y*f.w+x] = v
+}
+
+func (f *FireState) Start() {
+	for x := range f.w {
+		f.Set(x, f.h-1, 255)
+	}
+	f.on = true
+}
+
+// Turn off the fire at the bottom.
+func (f *FireState) Off() {
+	for x := range f.w {
+		f.Set(x, f.h-1, 1)
+	}
+	f.on = false
+}
+
+func (f *FireState) Update() {
+	for y := f.h - 2; y >= 0; y-- {
+		for x := range f.w {
+			r := rand.Float32()                         //nolint:gosec // this _is_ randv2!
+			dx := safecast.MustTruncate[int](3*r - 1.5) // -1, 0, 1
+			v := f.At((x+dx+f.w)%f.w, y+1)
+			pv := f.At(x, y)
+			if pv > v { // slow-ish decay when "off"
+				delta := max(1, byte(r*float32(pv-v)))
+				v = max(1, pv-delta)
+				f.Set(x, y, v)
+				continue
+			}
+			newV := byte(max(0, float32(v)-r*3.2*255./(float32(f.h-1))))
+			if newV == 0 && pv != 0 {
+				newV = 1
+			}
+			f.Set(x, y, newV)
+		}
+	}
+}
+
+func (f *FireState) Render(ap *ansipixels.AnsiPixels) {
+	for y := range f.h {
+		first := true
+		prevX := -999
+		prevColor := ""
+		for x := range f.w {
+			v := f.At(x, y)
+			if v == 0 {
+				continue
+			}
+			switch {
+			case first:
+				ap.MoveCursor(x+ap.Margin, y+ap.Margin)
+				first = false
+			case x != prevX+1:
+				ap.MoveHorizontally(x + ap.Margin)
+			}
+			prevX = x
+			var newColor string
+			if ap.TrueColor {
+				newColor = v2colTrueColor[v]
+			} else {
+				newColor = v2col256[3*int(v)/64]
+			}
+			if newColor != prevColor {
+				ap.WriteString(newColor)
+				prevColor = newColor
+			} else {
+				ap.WriteRune(ansipixels.FullPixel)
+			}
+		}
+	}
+}
+
+func AnimateFire(ap *ansipixels.AnsiPixels, frame int64) {
+	if frame == 0 {
+		fire = InitFire(ap)
+		fire.Start()
+	}
+	fire.Update()
+	fire.Render(ap)
+}
+
+func ShowPalette(ap *ansipixels.AnsiPixels) {
+	f := InitFire(ap)
+	// Show/debug the palette:
+	for x := range f.w {
+		v := safecast.MustConvert[byte]((255 * (x + 1)) / f.w)
+		f.Set(x, f.h-3, v)
+		f.Set(x, f.h-2, v)
+	}
+	f.Render(ap)
+}

fps/fps.go

@@ -19,7 +19,7 @@ import (
 	"fortio.org/safecast"
 	"fortio.org/terminal"
 	"fortio.org/terminal/ansipixels"
-	"github.com/loov/hrtime"
+	"github.com/loov/hrtime" // To test hrtime correctness: hrtime "time".
 )
 
 const defaultMonoImageColor = ansipixels.Blue // ansi blue-ish
@@ -319,10 +319,16 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 	imagesOnlyFlag := flag.Bool("i", false, "Arguments are now images files to show, no FPS test (hit any key to continue)")
 	exactlyFlag := flag.Int64("n", 0, "Start immediately an FPS test with the specified `number of frames` (default is interactive)")
 	noMouseFlag := flag.Bool("nomouse", false, "Disable mouse tracking")
+	fireFlag := flag.Bool("fire", false, "Show fire animation instead of RGB around the image")
 	cli.MinArgs = 0
 	cli.MaxArgs = -1
 	cli.ArgsHelp = "[maxfps] or fps -i imagefiles..."
 	cli.Main()
+	fireMode := *fireFlag
+	fireStr := "no_fire"
+	if fireMode {
+		fireStr = "fire"
+	}
 	imagesOnly := *imagesOnlyFlag
 	fpsLimit := -1.0
 	fpsStr := "unlimited"
@@ -340,9 +346,6 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 		fpsStr = fmt.Sprintf("%.1f", fpsLimit)
 		hasFPSLimit = true
 		perfResults.hist = stats.NewHistogram(0, .01/fpsLimit)
-	} else {
-		// with max fps expect values in the tens of usec range with usec precision (at max fps for fast terminals)
-		perfResults.hist = stats.NewHistogram(0, 0.0000001)
 	}
 	perfResults.Exactly = *exactlyFlag
 	perfResults.RequestedQPS = fpsStr
@@ -394,6 +397,10 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 		e := ap.ShowImage(background, 1.0, 0, 0, defaultMonoImageColor)
 		if !imagesOnly {
 			drawBox(ap, true)
+			if fireMode {
+				ShowPalette(ap)
+			}
+			ap.WriteCentered(ap.H/2+4, "In -fire mode, space bar to toggle on/off; i to hide text")
 			ap.WriteCentered(ap.H/2+3, "FPS %s test... any key to start; q, ^C, or ^D to exit... %s",
 				fpsStr, ansipixels.MoveLeft)
 			ap.ShowCursor()
@@ -425,6 +432,8 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 	if !*noMouseFlag {
 		ap.MouseTrackingOn()
 	}
+	var frames int64
+	var hideText bool
 	ap.OnResize = func() error {
 		ap.StartSyncMode()
 		ap.ClearScreen()
@@ -433,12 +442,16 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 			drawBox(ap, false) // no boxed Width x Height in pure fps mode, keeping it simple.
 		}
 		ap.EndSyncMode()
+		// with max fps expect values in the tens of usec range with usec precision (at max fps for fast terminals)
+		perfResults.hist = stats.NewHistogram(0, 0.0000001)
+		frames = 0
+		setLabels("fps "+strings.TrimSuffix(fpsStr, ".0"), tenv, fmt.Sprintf("%dx%d", ap.W, ap.H), fireStr)
+		hideText = false
 		return e
 	}
 	if err = ap.OnResize(); err != nil {
 		return log.FErrf("Error showing image: %v", err)
 	}
-	frames := int64(0)
 	var elapsed time.Duration
 	var entry []byte
 	sendableTickerChan := make(chan time.Time, 1)
@@ -447,13 +460,12 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 	startTime := hrtime.Now()
 	now := startTime
 	if hasFPSLimit {
-		ticker := time.NewTicker(time.Second / time.Duration(fpsLimit))
+		ticker := time.NewTicker(time.Duration(float64(time.Second) / fpsLimit))
 		tickerChan = ticker.C
 	} else {
 		tickerChan = sendableTickerChan
 		sendableTickerChan <- perfResults.StartTime
 	}
-	setLabels("fps "+strings.TrimSuffix(fpsStr, ".0"), tenv, fmt.Sprintf("%dx%d", ap.W, ap.H))
 	for {
 		select {
 		case s := <-ap.C:
@@ -468,24 +480,43 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 		case v := <-tickerChan:
 			elapsed = hrtime.Since(now)
 			sec := elapsed.Seconds()
-			if frames > 0 {
-				perfResults.hist.Record(sec) // record in milliseconds
-			}
 			fps = 1. / sec
 			now = hrtime.Now()
-			perfResults.ActualDuration = (now - startTime)
+			// perfResults.ActualDuration = now.Sub(startTime)
+			perfResults.ActualDuration = now - startTime
 			perfResults.ActualQPS = float64(frames) / perfResults.ActualDuration.Seconds()
+			if frames > 0 {
+				perfResults.hist.Record(sec) // record in milliseconds
+			}
+			if fireMode {
+				ap.StartSyncMode()
+				AnimateFire(ap, frames)
+			}
 			// stats.Record("fps", fps)
-			ap.WriteAt(ap.W/2-20, ap.H/2+2, " Last frame %s%v%s FPS: %s%.0f%s Avg %s%.2f%s ",
-				ansipixels.Green, elapsed.Round(10*time.Microsecond), ansipixels.Reset,
-				ansipixels.BrightRed, fps, ansipixels.Reset,
-				ansipixels.Cyan, perfResults.ActualQPS, ansipixels.Reset)
-			ap.WriteAt(ap.W/2-20, ap.H/2+3, " Best %.1f Worst %.1f: %.1f +/- %.1f ",
-				1/perfResults.hist.Min, 1/perfResults.hist.Max, 1/perfResults.hist.Avg(), 1/perfResults.hist.StdDev())
+			if !hideText {
+				ap.WriteAt(ap.W/2-20, ap.H/2+2, "%s Last frame %s%v%s FPS: %s%.0f%s Avg %s%.2f%s ",
+					ansipixels.Reset, ansipixels.Green, elapsed.Round(10*time.Microsecond), ansipixels.Reset,
+					ansipixels.BrightRed, fps, ansipixels.Reset,
+					ansipixels.Cyan, perfResults.ActualQPS, ansipixels.Reset)
+				ap.WriteAt(ap.W/2-20, ap.H/2+3, " Best %.1f Worst %.1f: %.1f +/- %.1f ",
+					1/perfResults.hist.Min, 1/perfResults.hist.Max, 1/perfResults.hist.Avg(), 1/perfResults.hist.StdDev())
+			}
 			if perfResults.Exactly > 0 && frames >= perfResults.Exactly {
 				return 0
 			}
-			animate(ap, frames)
+			if !fireMode {
+				animate(ap, frames)
+			}
+			if !hideText {
+				invert := ""
+				if ap.Mouse {
+					invert = ansipixels.Reverse
+				}
+				ap.WriteRight(ap.H-1-ap.Margin, " Target %sFPS %s%s%s, %dx%d, typed so far: %s[%s%q%s]%s %sMouse %d,%d (%06b)%s",
+					ansipixels.Cyan, ansipixels.Green, fpsStr, ansipixels.Reset, ap.W, ap.H,
+					ansipixels.DarkGray, ansipixels.Reset, entry, ansipixels.DarkGray, ansipixels.Reset,
+					invert, ap.Mx, ap.My, ap.Mbuttons, ansipixels.Reset)
+			}
 			// Request cursor position (note that FPS is about the same without it, the Flush seems to be enough)
 			_, _, err = ap.ReadCursorPos()
 			if err != nil {
@@ -495,15 +526,15 @@ func Main() int { //nolint:funlen,gocognit,gocyclo,maintidx // color and mode if
 			if isStopKey(ap) {
 				return 0
 			}
-			entry = append(entry, ap.Data...)
-			invert := ""
-			if ap.Mouse {
-				invert = ansipixels.Reverse
+			if len(ap.Data) > 0 {
+				switch {
+				case fireMode && ap.Data[0] == ' ':
+					ToggleFire()
+				case ap.Data[0] == 'i':
+					hideText = !hideText
+				}
 			}
-			ap.WriteRight(ap.H-1-ap.Margin, " Target %sFPS %s%s%s, %dx%d, typed so far: %s[%s%q%s]%s %sMouse %d,%d (%06b)%s",
-				ansipixels.Cyan, ansipixels.Green, fpsStr, ansipixels.Reset, ap.W, ap.H,
-				ansipixels.DarkGray, ansipixels.Reset, entry, ansipixels.DarkGray, ansipixels.Reset,
-				invert, ap.Mx, ap.My, ap.Mbuttons, ansipixels.Reset)
+			entry = append(entry, ap.Data...)
 			ap.Data = ap.Data[0:0:cap(ap.Data)] // reset buffer
 			frames++
 			if !hasFPSLimit {