Multiple blank lines in the result of executing the example

[TCP404]

I ran this two example

bar := progressbar.Default(100)
for i := 0; i < 100; i++ {
    bar.Add(1)
    time.Sleep(40 * time.Millisecond)
}

req, _ := http.NewRequest("GET", "https://dl.google.com/go/go1.14.2.src.tar.gz", nil)
resp, _ := http.DefaultClient.Do(req)
defer resp.Body.Close()

f, _ := os.OpenFile("go1.14.2.src.tar.gz", os.O_CREATE|os.O_WRONLY, 0644)
defer f.Close()

bar := progressbar.DefaultBytes(
    resp.ContentLength,
    "downloading",
)
io.Copy(io.MultiWriter(f, bar), resp.Body)

and I got many blank lines

$ go run main.go











100% |█████████████████████████████████████| (100/100, 25bit/s) 

$ go run main.go







downloading 100% |██████████████████████████████████████████| (21/21 MB, 2.616 MB/s)

This problem occurred on both Manjaro and Win10.

When I modify the clearProgressBar()

func clearProgressBar(c config, s state) error {
	if c.useANSICodes {
		// write the "clear current line" ANSI escape sequence
		return writeString(c, "\033[2K\r")
	}
	// fill the empty content
	// to overwrite the progress bar and jump
	// back to the beginning of the line
	str := fmt.Sprintf("\r%s\r", strings.Repeat(" ", s.maxLineWidth))
	return writeString(c, str)
	// the following does not show correctly if the previous line is longer than subsequent line
	// return writeString(c, "\r")
}

to

func clearProgressBar(c config, s state) error {
	if c.useANSICodes {
		// write the "clear current line" ANSI escape sequence
		return writeString(c, "\033[2K\r")
	}
	// fill the empty content
	// to overwrite the progress bar and jump
	// back to the beginning of the line
	// str := fmt.Sprintf("\r%s\r", strings.Repeat(" ", s.maxLineWidth))
	// return writeString(c, str)
	// the following does not show correctly if the previous line is longer than subsequent line
	return writeString(c, "\r")
}

Done!
It's back to normal.

$ go run main.go
100% |█████████████████████████████████████| (100/100, 25bit/s) 

Now my problem was resolved. But I don't know whether it is a bug.

[zhao1911]

I run into the same problem on win10. It works fine on macos.

I modify the clearProgressBar()

 func clearProgressBar(c config, s state) error {
 	if c.useANSICodes {
 		// write the "clear current line" ANSI escape sequence
 		return writeString(c, "\033[2K\r")
 	}
	// fill the empty content
 	// to overwrite the progress bar and jump
 	// back to the beginning of the line
 	str := fmt.Sprintf("\r%s\r", strings.Repeat(" ", s.maxLineWidth))
 	return writeString(c, str)
	// the following does not show correctly if the previous line is longer than subsequent line
 	// return writeString(c, "\r")
 }

to

func clearProgressBar(c config, s state) error {
	if c.useANSICodes {
		// write the "clear current line" ANSI escape sequence
		return writeString(c, "\033[2K\r")
	}
	fmt.Print("\x0D\x1B[2K")
        return nil
}

Then it works on both Win10 and mac.

[nicoxiang]

Same to me on Win11 Windows Terminal ( PowerShell ), fix it by set OptionUseANSICodes(true)

[jeyrce]

Same to me on macos 11 and centos7.5，works by @nicoxiang 's

Same to me on Win11 Windows Terminal ( PowerShell ), fix it by set OptionUseANSICodes(true)