diff --git a/progress/progress.go b/progress/progress.go index 102830a82..0cd0ea1f9 100644 --- a/progress/progress.go +++ b/progress/progress.go @@ -1,6 +1,7 @@ package progress import ( + "bufio" "fmt" "io" "sync" @@ -13,7 +14,8 @@ type State interface { type Progress struct { mu sync.Mutex - w io.Writer + // buffer output to minimize flickering on all terminals + w *bufio.Writer pos int @@ -22,7 +24,7 @@ type Progress struct { } func NewProgress(w io.Writer) *Progress { - p := &Progress{w: w} + p := &Progress{w: bufio.NewWriter(w)} go p.start() return p } @@ -48,11 +50,14 @@ func (p *Progress) Stop() bool { stopped := p.stop() if stopped { fmt.Fprint(p.w, "\n") + p.w.Flush() } return stopped } func (p *Progress) StopAndClear() bool { + defer p.w.Flush() + fmt.Fprint(p.w, "\033[?25l") defer fmt.Fprint(p.w, "\033[?25h") @@ -81,20 +86,24 @@ func (p *Progress) render() { p.mu.Lock() defer p.mu.Unlock() + defer p.w.Flush() + + // eliminate flickering on terminals that support synchronized output + fmt.Fprint(p.w, "\033[?2026h") + defer fmt.Fprint(p.w, "\033[?2026l") + fmt.Fprint(p.w, "\033[?25l") defer fmt.Fprint(p.w, "\033[?25h") - // clear already rendered progress lines - for i := range p.pos { - if i > 0 { - fmt.Fprint(p.w, "\033[A") - } - fmt.Fprint(p.w, "\033[2K\033[1G") + // move the cursor back to the beginning + for range p.pos - 1 { + fmt.Fprint(p.w, "\033[A") } + fmt.Fprint(p.w, "\033[1G") // render progress lines for i, state := range p.states { - fmt.Fprint(p.w, state.String()) + fmt.Fprint(p.w, state.String(), "\033[K") if i < len(p.states)-1 { fmt.Fprint(p.w, "\n") }