Fix multiline prefixes for double width chars

CHANGELOG.md

@@ -45,6 +45,7 @@ This release aims to make the code a bit cleaner, fix a couple of bugs and provi
 - Make `prefix` and `completer` optional in `prompt.Input`. Change the signature of `prompt.Input` from `func Input(string, Completer, ...Option) string` to `func Input(...Option) string`.
 - Rename `prompt.ConsoleParser` to `prompt.Reader` and make it embed `io.ReadCloser`
 - Rename `prompt.ConsoleWriter` to `prompt.Writer` and make it embed `io.Writer` and `io.StringWriter`
+- Rename `prompt.Render` to `prompt.Renderer`
 - Rename `prompt.OptionTitle` to `prompt.WithTitle`
 - Rename `prompt.OptionPrefix` to `prompt.WithPrefix`
 - Rename `prompt.OptionInitialBufferText` to `prompt.WithInitialText`

constructor.go

@@ -312,32 +312,9 @@ func DefaultPrefixCallback() string {
 
 // New returns a Prompt with powerful auto-completion.
 func New(executor Executor, opts ...Option) *Prompt {
-	defaultWriter := NewStdoutWriter()
-	registerWriter(defaultWriter)
-
 	pt := &Prompt{
-		reader: NewStdinReader(),
-		renderer: &Render{
-			out:                          defaultWriter,
-			indentSize:                   DefaultIndentSize,
-			prefixCallback:               DefaultPrefixCallback,
-			prefixTextColor:              Blue,
-			prefixBGColor:                DefaultColor,
-			inputTextColor:               DefaultColor,
-			inputBGColor:                 DefaultColor,
-			previewSuggestionTextColor:   Green,
-			previewSuggestionBGColor:     DefaultColor,
-			suggestionTextColor:          White,
-			suggestionBGColor:            Cyan,
-			selectedSuggestionTextColor:  Black,
-			selectedSuggestionBGColor:    Turquoise,
-			descriptionTextColor:         Black,
-			descriptionBGColor:           Turquoise,
-			selectedDescriptionTextColor: White,
-			selectedDescriptionBGColor:   Cyan,
-			scrollbarThumbColor:          DarkGray,
-			scrollbarBGColor:             Cyan,
-		},
+		reader:                 NewStdinReader(),
+		renderer:               NewRenderer(),
 		buf:                    NewBuffer(),
 		executor:               executor,
 		history:                NewHistory(),

prompt.go

@@ -43,7 +43,7 @@ type Completer func(Document) []Suggest
 type Prompt struct {
 	reader                 Reader
 	buf                    *Buffer
-	renderer               *Render
+	renderer               *Renderer
 	executor               Executor
 	history                *History
 	lexer                  Lexer
@@ -74,7 +74,7 @@ func (p *Prompt) Run() {
 		p.completion.Update(*p.buf.Document())
 	}
 
-	p.renderer.Render(p.buf, p.completion, p.lexer)
+	p.renderer.Renderer(p.buf, p.completion, p.lexer)
 
 	bufCh := make(chan []byte, 128)
 	stopReadBufCh := make(chan struct{})
@@ -105,7 +105,7 @@ func (p *Prompt) Run() {
 
 				p.completion.Update(*p.buf.Document())
 
-				p.renderer.Render(p.buf, p.completion, p.lexer)
+				p.renderer.Renderer(p.buf, p.completion, p.lexer)
 
 				if p.exitChecker != nil && p.exitChecker(e.input, true) {
 					p.skipClose = true
@@ -117,11 +117,11 @@ func (p *Prompt) Run() {
 				go p.handleSignals(exitCh, winSizeCh, stopHandleSignalCh)
 			} else {
 				p.completion.Update(*p.buf.Document())
-				p.renderer.Render(p.buf, p.completion, p.lexer)
+				p.renderer.Renderer(p.buf, p.completion, p.lexer)
 			}
 		case w := <-winSizeCh:
 			p.renderer.UpdateWinSize(w)
-			p.renderer.Render(p.buf, p.completion, p.lexer)
+			p.renderer.Renderer(p.buf, p.completion, p.lexer)
 		case code := <-exitCh:
 			p.renderer.BreakLine(p.buf, p.lexer)
 			p.Close()
@@ -337,7 +337,7 @@ func (p *Prompt) Input() string {
 		p.completion.Update(*p.buf.Document())
 	}
 
-	p.renderer.Render(p.buf, p.completion, p.lexer)
+	p.renderer.Renderer(p.buf, p.completion, p.lexer)
 	bufCh := make(chan []byte, 128)
 	stopReadBufCh := make(chan struct{})
 	go p.readBuffer(bufCh, stopReadBufCh)
@@ -355,7 +355,7 @@ func (p *Prompt) Input() string {
 				return e.input
 			} else {
 				p.completion.Update(*p.buf.Document())
-				p.renderer.Render(p.buf, p.completion, p.lexer)
+				p.renderer.Renderer(p.buf, p.completion, p.lexer)
 			}
 		default:
 			time.Sleep(10 * time.Millisecond)

render.go

@@ -11,8 +11,8 @@ import (
 
 const multilinePrefixCharacter = '.'
 
-// Render to render prompt information from state of Buffer.
-type Render struct {
+// Renderer to render prompt information from state of Buffer.
+type Renderer struct {
 	out               Writer
 	prefixCallback    PrefixCallback
 	breakLineCallback func(*Document)
@@ -42,15 +42,43 @@ type Render struct {
 	scrollbarBGColor             Color
 }
 
+// Build a new Renderer.
+func NewRenderer() *Renderer {
+	defaultWriter := NewStdoutWriter()
+	registerWriter(defaultWriter)
+
+	return &Renderer{
+		out:                          defaultWriter,
+		indentSize:                   DefaultIndentSize,
+		prefixCallback:               DefaultPrefixCallback,
+		prefixTextColor:              Blue,
+		prefixBGColor:                DefaultColor,
+		inputTextColor:               DefaultColor,
+		inputBGColor:                 DefaultColor,
+		previewSuggestionTextColor:   Green,
+		previewSuggestionBGColor:     DefaultColor,
+		suggestionTextColor:          White,
+		suggestionBGColor:            Cyan,
+		selectedSuggestionTextColor:  Black,
+		selectedSuggestionBGColor:    Turquoise,
+		descriptionTextColor:         Black,
+		descriptionBGColor:           Turquoise,
+		selectedDescriptionTextColor: White,
+		selectedDescriptionBGColor:   Cyan,
+		scrollbarThumbColor:          DarkGray,
+		scrollbarBGColor:             Cyan,
+	}
+}
+
 // Setup to initialize console output.
-func (r *Render) Setup() {
+func (r *Renderer) Setup() {
 	if r.title != "" {
 		r.out.SetTitle(r.title)
 		debug.AssertNoError(r.out.Flush())
 	}
 }
 
-func (r *Render) renderPrefix(prefix string) {
+func (r *Renderer) renderPrefix(prefix string) {
 	r.out.SetColor(r.prefixTextColor, r.prefixBGColor, false)
 	if _, err := r.out.WriteString("\r"); err != nil {
 		panic(err)
@@ -62,13 +90,13 @@ func (r *Render) renderPrefix(prefix string) {
 }
 
 // Close to clear title and erasing.
-func (r *Render) Close() {
+func (r *Renderer) Close() {
 	r.out.ClearTitle()
 	r.out.EraseDown()
 	debug.AssertNoError(r.out.Flush())
 }
 
-func (r *Render) prepareArea(lines int) {
+func (r *Renderer) prepareArea(lines int) {
 	for i := 0; i < lines; i++ {
 		r.out.ScrollDown()
 	}
@@ -78,12 +106,12 @@ func (r *Render) prepareArea(lines int) {
 }
 
 // UpdateWinSize called when window size is changed.
-func (r *Render) UpdateWinSize(ws *WinSize) {
+func (r *Renderer) UpdateWinSize(ws *WinSize) {
 	r.row = ws.Row
 	r.col = istrings.Width(ws.Col)
 }
 
-func (r *Render) renderWindowTooSmall() {
+func (r *Renderer) renderWindowTooSmall() {
 	r.out.CursorGoTo(0, 0)
 	r.out.EraseScreen()
 	r.out.SetColor(DarkRed, White, false)
@@ -92,7 +120,7 @@ func (r *Render) renderWindowTooSmall() {
 	}
 }
 
-func (r *Render) renderCompletion(buf *Buffer, completions *CompletionManager) {
+func (r *Renderer) renderCompletion(buf *Buffer, completions *CompletionManager) {
 	suggestions := completions.GetSuggestions()
 	if len(suggestions) == 0 {
 		return
@@ -178,8 +206,8 @@ func (r *Render) renderCompletion(buf *Buffer, completions *CompletionManager) {
 	r.out.SetColor(DefaultColor, DefaultColor, false)
 }
 
-// Render renders to the console.
-func (r *Render) Render(buffer *Buffer, completion *CompletionManager, lexer Lexer) {
+// Renderer renders to the console.
+func (r *Renderer) Renderer(buffer *Buffer, completion *CompletionManager, lexer Lexer) {
 	// In situations where a pseudo tty is allocated (e.g. within a docker container),
 	// window size via TIOCGWINSZ is not immediately available and will result in 0,0 dimensions.
 	if r.col == 0 {
@@ -244,7 +272,7 @@ func (r *Render) Render(buffer *Buffer, completion *CompletionManager, lexer Lex
 	r.previousCursor = cursor
 }
 
-func (r *Render) renderText(lexer Lexer, text string) {
+func (r *Renderer) renderText(lexer Lexer, text string) {
 	if lexer != nil {
 		r.lex(lexer, text)
 		return
@@ -271,19 +299,19 @@ func (r *Render) renderText(lexer Lexer, text string) {
 	r.renderLine(prefix, lineBuffer.String(), r.inputTextColor)
 }
 
-func (r *Render) renderLine(prefix, line string, color Color) {
+func (r *Renderer) renderLine(prefix, line string, color Color) {
 	r.renderPrefix(prefix)
 	r.writeString(line, color)
 }
 
-func (r *Render) writeString(text string, color Color) {
+func (r *Renderer) writeString(text string, color Color) {
 	r.out.SetColor(color, r.inputBGColor, false)
 	if _, err := r.out.WriteString(text); err != nil {
 		panic(err)
 	}
 }
 
-func (r *Render) getMultilinePrefix(prefix string) string {
+func (r *Renderer) getMultilinePrefix(prefix string) string {
 	var spaceCount int
 	var dotCount int
 	var nonSpaceCharSeen bool
@@ -293,16 +321,17 @@ func (r *Render) getMultilinePrefix(prefix string) string {
 		}
 		char, size := utf8.DecodeLastRuneInString(prefix)
 		prefix = prefix[:len(prefix)-size]
+		charWidth := istrings.GetRuneWidth(char)
 		if nonSpaceCharSeen {
-			dotCount++
+			dotCount += int(charWidth)
 			continue
 		}
 		if char != ' ' {
 			nonSpaceCharSeen = true
-			dotCount++
+			dotCount += int(charWidth)
 			continue
 		}
-		spaceCount++
+		spaceCount += int(charWidth)
 	}
 
 	var multilinePrefixBuilder strings.Builder
@@ -319,7 +348,7 @@ func (r *Render) getMultilinePrefix(prefix string) string {
 
 // lex processes the given input with the given lexer
 // and writes the result
-func (r *Render) lex(lexer Lexer, input string) {
+func (r *Renderer) lex(lexer Lexer, input string) {
 	lexer.Init(input)
 	s := input
 
@@ -351,8 +380,8 @@ func (r *Render) lex(lexer Lexer, input string) {
 }
 
 // BreakLine to break line.
-func (r *Render) BreakLine(buffer *Buffer, lexer Lexer) {
-	// Erasing and Render
+func (r *Renderer) BreakLine(buffer *Buffer, lexer Lexer) {
+	// Erasing and Renderer
 	cursor := positionAtEndOfString(buffer.Document().TextBeforeCursor()+r.prefixCallback(), r.col)
 	r.clear(cursor)
 
@@ -371,27 +400,27 @@ func (r *Render) BreakLine(buffer *Buffer, lexer Lexer) {
 
 // clear erases the screen from a beginning of input
 // even if there is line break which means input length exceeds a window's width.
-func (r *Render) clear(cursor Position) {
+func (r *Renderer) clear(cursor Position) {
 	r.move(cursor, Position{})
 	r.out.EraseDown()
 }
 
 // backward moves cursor to backward from a current cursor position
 // regardless there is a line break.
-func (r *Render) backward(from Position, n istrings.Width) Position {
+func (r *Renderer) backward(from Position, n istrings.Width) Position {
 	return r.move(from, Position{X: from.X - n, Y: from.Y})
 }
 
 // move moves cursor to specified position from the beginning of input
 // even if there is a line break.
-func (r *Render) move(from, to Position) Position {
+func (r *Renderer) move(from, to Position) Position {
 	newPosition := from.Subtract(to)
 	r.out.CursorUp(newPosition.Y)
 	r.out.CursorBackward(int(newPosition.X))
 	return to
 }
 
-func (r *Render) lineWrap(cursor *Position) {
+func (r *Renderer) lineWrap(cursor *Position) {
 	if runtime.GOOS != "windows" && cursor.X > 0 && cursor.X%r.col == 0 {
 		cursor.X = 0
 		cursor.Y += 1
@@ -410,7 +439,7 @@ func clamp(high, low, x float64) float64 {
 	}
 }
 
-func alignNextLine(r *Render, col istrings.Width) {
+func alignNextLine(r *Renderer, col istrings.Width) {
 	r.out.CursorDown(1)
 	if _, err := r.out.WriteString("\r"); err != nil {
 		panic(err)