Render CR and LF as ␍ and ␊

Close #2529

2 files changed, 71 insertions, 45 deletions

diff --git a/src/tui/light.go b/src/tui/light.go
index 322584dd..411238d4 100644
--- a/src/tui/light.go
+++ b/src/tui/light.go
@@ -32,20 +32,26 @@ var offsetRegexp *regexp.Regexp = regexp.MustCompile("(.*)\x1b\\[([0-9]+);([0-9]
 var offsetRegexpBegin *regexp.Regexp = regexp.MustCompile("^\x1b\\[[0-9]+;[0-9]+R")
 
 func (r *LightRenderer) stderr(str string) {
-	r.stderrInternal(str, true)
+	r.stderrInternal(str, true, "")
 }
 
-// FIXME: Need better handling of non-displayable characters
-func (r *LightRenderer) stderrInternal(str string, allowNLCR bool) {
+const CR string = "\x1b[2m␍"
+const LF string = "\x1b[2m␊"
+
+func (r *LightRenderer) stderrInternal(str string, allowNLCR bool, resetCode string) {
 	bytes := []byte(str)
 	runes := []rune{}
 	for len(bytes) > 0 {
 		r, sz := utf8.DecodeRune(bytes)
 		nlcr := r == '\n' || r == '\r'
 		if r >= 32 || r == '\x1b' || nlcr {
-			if r == utf8.RuneError || nlcr && !allowNLCR {
-				runes = append(runes, ' ')
-			} else {
+			if nlcr && !allowNLCR {
+				if r == '\r' {
+					runes = append(runes, []rune(CR+resetCode)...)
+				} else {
+					runes = append(runes, []rune(LF+resetCode)...)
+				}
+			} else if r != utf8.RuneError {
 				runes = append(runes, r)
 			}
 		}
@@ -54,8 +60,10 @@ func (r *LightRenderer) stderrInternal(str string, allowNLCR bool) {
 	r.queued.WriteString(string(runes))
 }
 
-func (r *LightRenderer) csi(code string) {
-	r.stderr("\x1b[" + code)
+func (r *LightRenderer) csi(code string) string {
+	fullcode := "\x1b[" + code
+	r.stderr(fullcode)
+	return fullcode
 }
 
 func (r *LightRenderer) flush() {
@@ -825,12 +833,12 @@ func (w *LightWindow) drawBorderAround(onlyHorizontal bool) {
 	w.CPrint(color, string(w.border.bottomLeft)+repeat(w.border.horizontal, (w.width-bcw)/hw)+repeat(' ', rem)+string(w.border.bottomRight))
 }
 
-func (w *LightWindow) csi(code string) {
-	w.renderer.csi(code)
+func (w *LightWindow) csi(code string) string {
+	return w.renderer.csi(code)
 }
 
-func (w *LightWindow) stderrInternal(str string, allowNLCR bool) {
-	w.renderer.stderrInternal(str, allowNLCR)
+func (w *LightWindow) stderrInternal(str string, allowNLCR bool, resetCode string) {
+	w.renderer.stderrInternal(str, allowNLCR, resetCode)
 }
 
 func (w *LightWindow) Top() int {
@@ -936,10 +944,10 @@ func colorCodes(fg Color, bg Color) []string {
 	return codes
 }
 
-func (w *LightWindow) csiColor(fg Color, bg Color, attr Attr) bool {
+func (w *LightWindow) csiColor(fg Color, bg Color, attr Attr) (bool, string) {
 	codes := append(attrCodes(attr), colorCodes(fg, bg)...)
-	w.csi(";" + strings.Join(codes, ";") + "m")
-	return len(codes) > 0
+	code := w.csi(";" + strings.Join(codes, ";") + "m")
+	return len(codes) > 0, code
 }
 
 func (w *LightWindow) Print(text string) {
@@ -951,16 +959,17 @@ func cleanse(str string) string {
 }
 
 func (w *LightWindow) CPrint(pair ColorPair, text string) {
-	w.csiColor(pair.Fg(), pair.Bg(), pair.Attr())
-	w.stderrInternal(cleanse(text), false)
+	_, code := w.csiColor(pair.Fg(), pair.Bg(), pair.Attr())
+	w.stderrInternal(cleanse(text), false, code)
 	w.csi("m")
 }
 
 func (w *LightWindow) cprint2(fg Color, bg Color, attr Attr, text string) {
-	if w.csiColor(fg, bg, attr) {
+	hasColors, code := w.csiColor(fg, bg, attr)
+	if hasColors {
 		defer w.csi("m")
 	}
-	w.stderrInternal(cleanse(text), false)
+	w.stderrInternal(cleanse(text), false, code)
 }
 
 type wrappedLine struct {
@@ -980,6 +989,8 @@ func wrapLine(input string, prefixLength int, max int, tabstop int) []wrappedLin
 		if len(rs) == 1 && rs[0] == '\t' {
 			w = tabstop - (prefixLength+width)%tabstop
 			str = repeat(' ', w)
+		} else if rs[0] == '\r' {
+			w++
 		} else {
 			w = runewidth.StringWidth(str)
 		}
@@ -998,12 +1009,12 @@ func wrapLine(input string, prefixLength int, max int, tabstop int) []wrappedLin
 	return lines
 }
 
-func (w *LightWindow) fill(str string, onMove func()) FillReturn {
+func (w *LightWindow) fill(str string, resetCode string) FillReturn {
 	allLines := strings.Split(str, "\n")
 	for i, line := range allLines {
 		lines := wrapLine(line, w.posx, w.width, w.tabstop)
 		for j, wl := range lines {
-			w.stderrInternal(wl.text, false)
+			w.stderrInternal(wl.text, false, resetCode)
 			w.posx += wl.displayWidth
 
 			// Wrap line
@@ -1013,7 +1024,7 @@ func (w *LightWindow) fill(str string, onMove func()) FillReturn {
 				}
 				w.MoveAndClear(w.posy, w.posx)
 				w.Move(w.posy+1, 0)
-				onMove()
+				w.renderer.stderr(resetCode)
 			}
 		}
 	}
@@ -1022,22 +1033,26 @@ func (w *LightWindow) fill(str string, onMove func()) FillReturn {
 			return FillSuspend
 		}
 		w.Move(w.posy+1, 0)
-		onMove()
+		w.renderer.stderr(resetCode)
 		return FillNextLine
 	}
 	return FillContinue
 }
 
-func (w *LightWindow) setBg() {
+func (w *LightWindow) setBg() string {
 	if w.bg != colDefault {
-		w.csiColor(colDefault, w.bg, AttrRegular)
+		_, code := w.csiColor(colDefault, w.bg, AttrRegular)
+		return code
 	}
+	// Should clear dim attribute after ␍ in the preview window
+	// e.g. printf "foo\rbar" | fzf --ansi --preview 'printf "foo\rbar"'
+	return "\x1b[m"
 }
 
 func (w *LightWindow) Fill(text string) FillReturn {
 	w.Move(w.posy, w.posx)
-	w.setBg()
-	return w.fill(text, w.setBg)
+	code := w.setBg()
+	return w.fill(text, code)
 }
 
 func (w *LightWindow) CFill(fg Color, bg Color, attr Attr, text string) FillReturn {
@@ -1048,11 +1063,11 @@ func (w *LightWindow) CFill(fg Color, bg Color, attr Attr, text string) FillRetu
 	if bg == colDefault {
 		bg = w.bg
 	}
-	if w.csiColor(fg, bg, attr) {
+	if hasColors, resetCode := w.csiColor(fg, bg, attr); hasColors {
 		defer w.csi("m")
-		return w.fill(text, func() { w.csiColor(fg, bg, attr) })
+		return w.fill(text, resetCode)
 	}
-	return w.fill(text, w.setBg)
+	return w.fill(text, w.setBg())
 }
 
 func (w *LightWindow) FinishFill() {
diff --git a/src/tui/tcell.go b/src/tui/tcell.go
index ad0182cf..b2cab0fb 100644
--- a/src/tui/tcell.go
+++ b/src/tui/tcell.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/gdamore/tcell/v2"
 	"github.com/gdamore/tcell/v2/encoding"
+	"github.com/junegunn/fzf/src/util"
 
 	"github.com/mattn/go-runewidth"
 	"github.com/rivo/uniseg"
@@ -572,26 +573,27 @@ func (w *TcellWindow) printString(text string, pair ColorPair) {
 
 	gr := uniseg.NewGraphemes(text)
 	for gr.Next() {
+		st := style
 		rs := gr.Runes()
 
 		if len(rs) == 1 {
 			r := rs[0]
-			if r < rune(' ') { // ignore control characters
-				continue
+			if r == '\r' {
+				st = style.Dim(true)
+				rs[0] = '␍'
 			} else if r == '\n' {
-				w.lastY++
-				lx = 0
-				continue
-			} else if r == '\u000D' { // skip carriage return
+				st = style.Dim(true)
+				rs[0] = '␊'
+			} else if r < rune(' ') { // ignore control characters
 				continue
 			}
 		}
 		var xPos = w.left + w.lastX + lx
 		var yPos = w.top + w.lastY
 		if xPos < (w.left+w.width) && yPos < (w.top+w.height) {
-			_screen.SetContent(xPos, yPos, rs[0], rs[1:], style)
+			_screen.SetContent(xPos, yPos, rs[0], rs[1:], st)
 		}
-		lx += runewidth.StringWidth(string(rs))
+		lx += util.StringWidth(string(rs))
 	}
 	w.lastX += lx
 }
@@ -620,13 +622,22 @@ func (w *TcellWindow) fillString(text string, pair ColorPair) FillReturn {
 		Italic(a&Attr(tcell.AttrItalic) != 0)
 
 	gr := uniseg.NewGraphemes(text)
+Loop:
 	for gr.Next() {
+		st := style
 		rs := gr.Runes()
-		if len(rs) == 1 && rs[0] == '\n' {
-			w.lastY++
-			w.lastX = 0
-			lx = 0
-			continue
+		if len(rs) == 1 {
+			r := rs[0]
+			switch r {
+			case '\r':
+				st = style.Dim(true)
+				rs[0] = '␍'
+			case '\n':
+				w.lastY++
+				w.lastX = 0
+				lx = 0
+				continue Loop
+			}
 		}
 
 		// word wrap:
@@ -643,8 +654,8 @@ func (w *TcellWindow) fillString(text string, pair ColorPair) FillReturn {
 			return FillSuspend
 		}
 
-		_screen.SetContent(xPos, yPos, rs[0], rs[1:], style)
-		lx += runewidth.StringWidth(string(rs))
+		_screen.SetContent(xPos, yPos, rs[0], rs[1:], st)
+		lx += util.StringWidth(string(rs))
 	}
 	w.lastX += lx
 	if w.lastX == w.width {