Merge branch 'realtime-plot-cli'

README.rst

@@ -115,6 +115,26 @@ Feed it data points via stdin:
 
 ..
 
+Realtime graph for data points via stdin:
+
+::
+
+ $ ping -i.2 google.com | grep -oP '(?<=time=).*(?=ms)' --line-buffered | asciigraph -r -h 10 -w 40 -c "realtime plot data (google ping in ms) from stdin"
+ 8.26 ┤                 ╭╮
+ 7.77 ┤                 ││
+ 7.27 ┤                 ││
+ 6.78 ┤                 ││             ╭╮
+ 6.29 ┤    ╭╮ ╭╮        ││             ││
+ 5.79 ┤    ││ ││        ││             │╰╮
+ 5.30 ┤    ││ ││      ╭╮││             │ │   ╭
+ 4.81 ┤    ││ ││      ││││             │ │   │
+ 4.32 ┤ ╭╮ ││╭╯│   ╭╮ ││││             │ │  ╭╯
+ 3.82 ┼╮│╰─╯╰╯ │╭──╯╰─╯╰╯╰──╮ ╭───╮╭───╯ ╰──╯
+ 3.33 ┤╰╯      ╰╯           ╰─╯   ╰╯
+         realtime plot data (google ping in ms) from stdin
+
+..
+
 
 Acknowledgement
 ----------------

cmd/asciigraph/main.go

@@ -12,10 +12,12 @@ import (
 )
 
 var (
-	height  uint
-	width   uint
-	offset  uint = 3
-	caption string
+	height             uint
+	width              uint
+	offset             uint = 3
+	caption            string
+	enableRealTime     bool
+	realTimeDataBuffer int
 )
 
 func main() {
@@ -30,10 +32,16 @@ func main() {
 	flag.UintVar(&width, "w", width, "`width` in columns, 0 for auto-scaling")
 	flag.UintVar(&offset, "o", offset, "`offset` in columns, for the label")
 	flag.StringVar(&caption, "c", caption, "`caption` for the graph")
+	flag.BoolVar(&enableRealTime, "r", enableRealTime, "enables `realtime` graph for data stream")
+	flag.IntVar(&realTimeDataBuffer, "b", realTimeDataBuffer, "data points `buffer` when realtime graph enabled, default equal to `width`")
 	flag.Parse()
 
 	data := make([]float64, 0, 64)
 
+	if realTimeDataBuffer == 0 {
+		realTimeDataBuffer = int(width)
+	}
+
 	s := bufio.NewScanner(os.Stdin)
 	s.Split(bufio.ScanWords)
 	for s.Scan() {
@@ -44,20 +52,34 @@ func main() {
 			continue
 		}
 		data = append(data, p)
+		if enableRealTime {
+			if realTimeDataBuffer > 0 && len(data) > realTimeDataBuffer {
+				data = data[len(data)-realTimeDataBuffer:]
+			}
+			plot := asciigraph.Plot(data,
+				asciigraph.Height(int(height)),
+				asciigraph.Width(int(width)),
+				asciigraph.Offset(int(offset)),
+				asciigraph.Caption(caption))
+			asciigraph.Clear()
+			fmt.Println(plot)
+		}
 	}
-	if err := s.Err(); err != nil {
-		log.Fatal(err)
-	}
+	if !enableRealTime {
+		if err := s.Err(); err != nil {
+			log.Fatal(err)
+		}
 
-	if len(data) == 0 {
-		log.Fatal("no data")
-	}
+		if len(data) == 0 {
+			log.Fatal("no data")
+		}
 
-	plot := asciigraph.Plot(data,
-		asciigraph.Height(int(height)),
-		asciigraph.Width(int(width)),
-		asciigraph.Offset(int(offset)),
-		asciigraph.Caption(caption))
+		plot := asciigraph.Plot(data,
+			asciigraph.Height(int(height)),
+			asciigraph.Width(int(width)),
+			asciigraph.Offset(int(offset)),
+			asciigraph.Caption(caption))
 
-	fmt.Println(plot)
+		fmt.Println(plot)
+	}
 }

utils.go

@@ -1,6 +1,12 @@
 package asciigraph
 
-import "math"
+import (
+	"fmt"
+	"math"
+	"os"
+	"os/exec"
+	"runtime"
+)
 
 func minMaxFloat64Slice(v []float64) (min, max float64) {
 	min = math.Inf(1)
@@ -61,3 +67,22 @@ func interpolateArray(data []float64, fitCount int) []float64 {
 	interpolatedData = append(interpolatedData, data[len(data)-1])
 	return interpolatedData
 }
+
+// clear terminal screen
+var Clear func()
+
+func init() {
+	platform := runtime.GOOS
+
+	if platform == "windows" {
+		Clear = func() {
+			cmd := exec.Command("cmd", "/c", "cls")
+			cmd.Stdout = os.Stdout
+			cmd.Run()
+		}
+	} else {
+		Clear = func() {
+			fmt.Print("\033[2J\033[H")
+		}
+	}
+}