Add --wrap option and 'toggle-wrap' action (#3887)

* `--wrap`
* `--wrap-sign`
* `toggle-wrap`

Close #3619
Close #2236
Close #577
Close #461

CHANGELOG.md

@@ -3,6 +3,16 @@ CHANGELOG
 
 0.54.0
 ------
+- Implemented line wrap of long items
+    - `--wrap` option enables line wrap
+    - `--wrap-sign` customizes the sign for wrapped lines (default: `↳ `)
+    - `toggle-wrap` action toggles line wrap
+  ```sh
+  history | fzf --tac --wrap --bind 'ctrl-/:toggle-wrap'
+
+  # You can press CTRL-/ to toggle line wrap in CTRL-R binding
+  export FZF_CTRL_R_OPTS=$'--bind ctrl-/:toggle-wrap --wrap-sign "\t↳ "'
+  ```
 - Added `--info-command` option for customizing the info line
   ```sh
   # Prepend the current cursor position in yellow

man/man1/fzf.1

@@ -198,6 +198,13 @@ the details.
 .B "\-\-cycle"
 Enable cyclic scroll
 .TP
+.B "\-\-wrap"
+Enable line wrap
+.TP
+.BI "\-\-wrap\-sign" "=INDICATOR"
+Indicator for wrapped lines. The default is '↳ ' or '> ' depending on
+\fB\-\-no\-unicode\fR.
+.TP
 .B "\-\-no\-multi\-line"
 Disable multi-line display of items when using \fB\-\-read0\fR
 .TP
@@ -1490,6 +1497,7 @@ A key or an event can be bound to one or more of the following actions.
     \fBtoggle\-sort\fR
     \fBtoggle\-track\fR                 (toggle global tracking option (\fB\-\-track\fR))
     \fBtoggle\-track\-current\fR         (toggle tracking of the current item)
+    \fBtoggle\-wrap\fR
     \fBtoggle+up\fR                    \fIbtab    (shift\-tab)\fR
     \fBtrack\-current\fR                (track the current item; automatically disabled if focus changes)
     \fBtransform(...)\fR               (transform states using the output of an external command)

src/actiontype_string.go

@@ -58,73 +58,74 @@ func _() {
 	_ = x[actToggleTrack-47]
 	_ = x[actToggleTrackCurrent-48]
 	_ = x[actToggleHeader-49]
-	_ = x[actTrackCurrent-50]
+	_ = x[actToggleWrap-50]
-	_ = x[actUntrackCurrent-51]
+	_ = x[actTrackCurrent-51]
-	_ = x[actDown-52]
+	_ = x[actUntrackCurrent-52]
-	_ = x[actUp-53]
+	_ = x[actDown-53]
-	_ = x[actPageUp-54]
+	_ = x[actUp-54]
-	_ = x[actPageDown-55]
+	_ = x[actPageUp-55]
-	_ = x[actPosition-56]
+	_ = x[actPageDown-56]
-	_ = x[actHalfPageUp-57]
+	_ = x[actPosition-57]
-	_ = x[actHalfPageDown-58]
+	_ = x[actHalfPageUp-58]
-	_ = x[actOffsetUp-59]
+	_ = x[actHalfPageDown-59]
-	_ = x[actOffsetDown-60]
+	_ = x[actOffsetUp-60]
-	_ = x[actOffsetMiddle-61]
+	_ = x[actOffsetDown-61]
-	_ = x[actJump-62]
+	_ = x[actOffsetMiddle-62]
-	_ = x[actJumpAccept-63]
+	_ = x[actJump-63]
-	_ = x[actPrintQuery-64]
+	_ = x[actJumpAccept-64]
-	_ = x[actRefreshPreview-65]
+	_ = x[actPrintQuery-65]
-	_ = x[actReplaceQuery-66]
+	_ = x[actRefreshPreview-66]
-	_ = x[actToggleSort-67]
+	_ = x[actReplaceQuery-67]
-	_ = x[actShowPreview-68]
+	_ = x[actToggleSort-68]
-	_ = x[actHidePreview-69]
+	_ = x[actShowPreview-69]
-	_ = x[actTogglePreview-70]
+	_ = x[actHidePreview-70]
-	_ = x[actTogglePreviewWrap-71]
+	_ = x[actTogglePreview-71]
-	_ = x[actTransform-72]
+	_ = x[actTogglePreviewWrap-72]
-	_ = x[actTransformBorderLabel-73]
+	_ = x[actTransform-73]
-	_ = x[actTransformHeader-74]
+	_ = x[actTransformBorderLabel-74]
-	_ = x[actTransformPreviewLabel-75]
+	_ = x[actTransformHeader-75]
-	_ = x[actTransformPrompt-76]
+	_ = x[actTransformPreviewLabel-76]
-	_ = x[actTransformQuery-77]
+	_ = x[actTransformPrompt-77]
-	_ = x[actPreview-78]
+	_ = x[actTransformQuery-78]
-	_ = x[actChangePreview-79]
+	_ = x[actPreview-79]
-	_ = x[actChangePreviewWindow-80]
+	_ = x[actChangePreview-80]
-	_ = x[actPreviewTop-81]
+	_ = x[actChangePreviewWindow-81]
-	_ = x[actPreviewBottom-82]
+	_ = x[actPreviewTop-82]
-	_ = x[actPreviewUp-83]
+	_ = x[actPreviewBottom-83]
-	_ = x[actPreviewDown-84]
+	_ = x[actPreviewUp-84]
-	_ = x[actPreviewPageUp-85]
+	_ = x[actPreviewDown-85]
-	_ = x[actPreviewPageDown-86]
+	_ = x[actPreviewPageUp-86]
-	_ = x[actPreviewHalfPageUp-87]
+	_ = x[actPreviewPageDown-87]
-	_ = x[actPreviewHalfPageDown-88]
+	_ = x[actPreviewHalfPageUp-88]
-	_ = x[actPrevHistory-89]
+	_ = x[actPreviewHalfPageDown-89]
-	_ = x[actPrevSelected-90]
+	_ = x[actPrevHistory-90]
-	_ = x[actPrint-91]
+	_ = x[actPrevSelected-91]
-	_ = x[actPut-92]
+	_ = x[actPrint-92]
-	_ = x[actNextHistory-93]
+	_ = x[actPut-93]
-	_ = x[actNextSelected-94]
+	_ = x[actNextHistory-94]
-	_ = x[actExecute-95]
+	_ = x[actNextSelected-95]
-	_ = x[actExecuteSilent-96]
+	_ = x[actExecute-96]
-	_ = x[actExecuteMulti-97]
+	_ = x[actExecuteSilent-97]
-	_ = x[actSigStop-98]
+	_ = x[actExecuteMulti-98]
-	_ = x[actFirst-99]
+	_ = x[actSigStop-99]
-	_ = x[actLast-100]
+	_ = x[actFirst-100]
-	_ = x[actReload-101]
+	_ = x[actLast-101]
-	_ = x[actReloadSync-102]
+	_ = x[actReload-102]
-	_ = x[actDisableSearch-103]
+	_ = x[actReloadSync-103]
-	_ = x[actEnableSearch-104]
+	_ = x[actDisableSearch-104]
-	_ = x[actSelect-105]
+	_ = x[actEnableSearch-105]
-	_ = x[actDeselect-106]
+	_ = x[actSelect-106]
-	_ = x[actUnbind-107]
+	_ = x[actDeselect-107]
-	_ = x[actRebind-108]
+	_ = x[actUnbind-108]
-	_ = x[actBecome-109]
+	_ = x[actRebind-109]
-	_ = x[actShowHeader-110]
+	_ = x[actBecome-110]
-	_ = x[actHideHeader-111]
+	_ = x[actShowHeader-111]
+	_ = x[actHideHeader-112]
 }
 
-const _actionType_name = "actIgnoreactStartactClickactInvalidactCharactMouseactBeginningOfLineactAbortactAcceptactAcceptNonEmptyactAcceptOrPrintQueryactBackwardCharactBackwardDeleteCharactBackwardDeleteCharEofactBackwardWordactCancelactChangeBorderLabelactChangeHeaderactChangeMultiactChangePreviewLabelactChangePromptactChangeQueryactClearScreenactClearQueryactClearSelectionactCloseactDeleteCharactDeleteCharEofactEndOfLineactFatalactForwardCharactForwardWordactKillLineactKillWordactUnixLineDiscardactUnixWordRuboutactYankactBackwardKillWordactSelectAllactDeselectAllactToggleactToggleSearchactToggleAllactToggleDownactToggleUpactToggleInactToggleOutactToggleTrackactToggleTrackCurrentactToggleHeaderactTrackCurrentactUntrackCurrentactDownactUpactPageUpactPageDownactPositionactHalfPageUpactHalfPageDownactOffsetUpactOffsetDownactOffsetMiddleactJumpactJumpAcceptactPrintQueryactRefreshPreviewactReplaceQueryactToggleSortactShowPreviewactHidePreviewactTogglePreviewactTogglePreviewWrapactTransformactTransformBorderLabelactTransformHeaderactTransformPreviewLabelactTransformPromptactTransformQueryactPreviewactChangePreviewactChangePreviewWindowactPreviewTopactPreviewBottomactPreviewUpactPreviewDownactPreviewPageUpactPreviewPageDownactPreviewHalfPageUpactPreviewHalfPageDownactPrevHistoryactPrevSelectedactPrintactPutactNextHistoryactNextSelectedactExecuteactExecuteSilentactExecuteMultiactSigStopactFirstactLastactReloadactReloadSyncactDisableSearchactEnableSearchactSelectactDeselectactUnbindactRebindactBecomeactShowHeaderactHideHeader"
+const _actionType_name = "actIgnoreactStartactClickactInvalidactCharactMouseactBeginningOfLineactAbortactAcceptactAcceptNonEmptyactAcceptOrPrintQueryactBackwardCharactBackwardDeleteCharactBackwardDeleteCharEofactBackwardWordactCancelactChangeBorderLabelactChangeHeaderactChangeMultiactChangePreviewLabelactChangePromptactChangeQueryactClearScreenactClearQueryactClearSelectionactCloseactDeleteCharactDeleteCharEofactEndOfLineactFatalactForwardCharactForwardWordactKillLineactKillWordactUnixLineDiscardactUnixWordRuboutactYankactBackwardKillWordactSelectAllactDeselectAllactToggleactToggleSearchactToggleAllactToggleDownactToggleUpactToggleInactToggleOutactToggleTrackactToggleTrackCurrentactToggleHeaderactToggleWrapactTrackCurrentactUntrackCurrentactDownactUpactPageUpactPageDownactPositionactHalfPageUpactHalfPageDownactOffsetUpactOffsetDownactOffsetMiddleactJumpactJumpAcceptactPrintQueryactRefreshPreviewactReplaceQueryactToggleSortactShowPreviewactHidePreviewactTogglePreviewactTogglePreviewWrapactTransformactTransformBorderLabelactTransformHeaderactTransformPreviewLabelactTransformPromptactTransformQueryactPreviewactChangePreviewactChangePreviewWindowactPreviewTopactPreviewBottomactPreviewUpactPreviewDownactPreviewPageUpactPreviewPageDownactPreviewHalfPageUpactPreviewHalfPageDownactPrevHistoryactPrevSelectedactPrintactPutactNextHistoryactNextSelectedactExecuteactExecuteSilentactExecuteMultiactSigStopactFirstactLastactReloadactReloadSyncactDisableSearchactEnableSearchactSelectactDeselectactUnbindactRebindactBecomeactShowHeaderactHideHeader"
 
-var _actionType_index = [...]uint16{0, 9, 17, 25, 35, 42, 50, 68, 76, 85, 102, 123, 138, 159, 183, 198, 207, 227, 242, 256, 277, 292, 306, 320, 333, 350, 358, 371, 387, 399, 407, 421, 435, 446, 457, 475, 492, 499, 518, 530, 544, 553, 568, 580, 593, 604, 615, 627, 641, 662, 677, 692, 709, 716, 721, 730, 741, 752, 765, 780, 791, 804, 819, 826, 839, 852, 869, 884, 897, 911, 925, 941, 961, 973, 996, 1014, 1038, 1056, 1073, 1083, 1099, 1121, 1134, 1150, 1162, 1176, 1192, 1210, 1230, 1252, 1266, 1281, 1289, 1295, 1309, 1324, 1334, 1350, 1365, 1375, 1383, 1390, 1399, 1412, 1428, 1443, 1452, 1463, 1472, 1481, 1490, 1503, 1516}
+var _actionType_index = [...]uint16{0, 9, 17, 25, 35, 42, 50, 68, 76, 85, 102, 123, 138, 159, 183, 198, 207, 227, 242, 256, 277, 292, 306, 320, 333, 350, 358, 371, 387, 399, 407, 421, 435, 446, 457, 475, 492, 499, 518, 530, 544, 553, 568, 580, 593, 604, 615, 627, 641, 662, 677, 690, 705, 722, 729, 734, 743, 754, 765, 778, 793, 804, 817, 832, 839, 852, 865, 882, 897, 910, 924, 938, 954, 974, 986, 1009, 1027, 1051, 1069, 1086, 1096, 1112, 1134, 1147, 1163, 1175, 1189, 1205, 1223, 1243, 1265, 1279, 1294, 1302, 1308, 1322, 1337, 1347, 1363, 1378, 1388, 1396, 1403, 1412, 1425, 1441, 1456, 1465, 1476, 1485, 1494, 1503, 1516, 1529}
 
 func (i actionType) String() string {
 	if i < 0 || i >= actionType(len(_actionType_index)-1) {

src/options.go

@@ -53,6 +53,8 @@ Usage: fzf [options]
     --no-mouse              Disable mouse
     --bind=KEYBINDS         Custom key bindings. Refer to the man page.
     --cycle                 Enable cyclic scroll
+    --wrap                  Enable line wrap
+    --wrap-sign=STR         Indicator for wrapped lines
     --no-multi-line         Disable multi-line display of items when using --read0
     --keep-right            Keep the right end of the line visible on overflow
     --scroll-off=LINES      Number of screen lines to keep above or below when
@@ -435,6 +437,8 @@ type Options struct {
 	MinHeight    int
 	Layout       layoutType
 	Cycle        bool
+	Wrap         bool
+	WrapSign     *string
 	MultiLine    bool
 	CursorLine   bool
 	KeepRight    bool
@@ -543,6 +547,7 @@ func defaultOptions() *Options {
 		MinHeight:    10,
 		Layout:       layoutDefault,
 		Cycle:        false,
+		Wrap:         false,
 		MultiLine:    true,
 		KeepRight:    false,
 		Hscroll:      true,
@@ -1366,6 +1371,8 @@ func parseActionList(masked string, original string, prevActions []*action, putA
 			appendAction(actToggleTrackCurrent)
 		case "toggle-header":
 			appendAction(actToggleHeader)
+		case "toggle-wrap":
+			appendAction(actToggleWrap)
 		case "show-header":
 			appendAction(actShowHeader)
 		case "hide-header":
@@ -2163,6 +2170,16 @@ func parseOptions(index *int, opts *Options, allArgs []string) error {
 			opts.CursorLine = false
 		case "--no-cycle":
 			opts.Cycle = false
+		case "--wrap":
+			opts.Wrap = true
+		case "--no-wrap":
+			opts.Wrap = false
+		case "--wrap-sign":
+			str, err := nextString(allArgs, &i, "wrap sign required")
+			if err != nil {
+				return err
+			}
+			opts.WrapSign = &str
 		case "--multi-line":
 			opts.MultiLine = true
 		case "--no-multi-line":
@@ -2513,6 +2530,8 @@ func parseOptions(index *int, opts *Options, allArgs []string) error {
 				if err := parseLabelPosition(&opts.PreviewLabel, value); err != nil {
 					return err
 				}
+			} else if match, value := optString(arg, "--wrap-sign="); match {
+				opts.WrapSign = &value
 			} else if match, value := optString(arg, "--prompt="); match {
 				opts.Prompt = value
 			} else if match, value := optString(arg, "--pointer="); match {

src/terminal.go

@@ -155,6 +155,7 @@ type eachLine struct {
 
 type itemLine struct {
 	firstLine int
+	numLines  int
 	cy        int
 	current   bool
 	selected  bool
@@ -215,6 +216,9 @@ type Terminal struct {
 	infoCommand        string
 	infoStyle          infoStyle
 	infoPrefix         string
+	wrap               bool
+	wrapSign           string
+	wrapSignWidth      int
 	separator          labelPrinter
 	separatorLen       int
 	spinner            []string
@@ -446,6 +450,7 @@ const (
 	actToggleTrack
 	actToggleTrackCurrent
 	actToggleHeader
+	actToggleWrap
 	actTrackCurrent
 	actUntrackCurrent
 	actDown
@@ -787,6 +792,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 		input:              input,
 		multi:              opts.Multi,
 		multiLine:          opts.ReadZero && opts.MultiLine,
+		wrap:               opts.Wrap,
 		sort:               opts.Sort > 0,
 		toggleSort:         opts.ToggleSort,
 		track:              opts.Track,
@@ -876,8 +882,15 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 		t.separator, t.separatorLen = t.ansiLabelPrinter(bar, &tui.ColSeparator, true)
 	}
 	if t.unicode {
+		t.wrapSign = "↳ "
 		t.borderWidth = uniseg.StringWidth("│")
+	} else {
+		t.wrapSign = "> "
 	}
+	if opts.WrapSign != nil {
+		t.wrapSign = *opts.WrapSign
+	}
+	t.wrapSign, t.wrapSignWidth = t.processTabs([]rune(t.wrapSign), 0)
 	if opts.Scrollbar == nil {
 		if t.unicode && t.borderWidth == 1 {
 			t.scrollbar = "│"
@@ -1067,8 +1080,11 @@ func (t *Terminal) parsePrompt(prompt string) (func(), int) {
 	}
 	output := func() {
 		line := t.promptLine()
+		wrap := t.wrap
+		t.wrap = false
 		t.printHighlighted(
 			Result{item: item}, tui.ColPrompt, tui.ColPrompt, false, false, line, line, true, nil, nil)
+		t.wrap = wrap
 	}
 	_, promptLen := t.processTabs([]rune(trimmed), 0)
 
@@ -1103,10 +1119,37 @@ func getScrollbar(perLine int, total int, height int, offset int) (int, int) {
 	return barLength, barStart
 }
 
+func (t *Terminal) wrapCols() int {
+	if !t.wrap {
+		return 0 // No wrap
+	}
+	return util.Max(t.window.Width()-(t.pointerLen+t.markerLen+1), 1)
+}
+
+func (t *Terminal) numItemLines(item *Item, atMost int) (int, bool) {
+	if !t.wrap && !t.multiLine {
+		return 1, false
+	}
+	if !t.wrap && t.multiLine {
+		return item.text.NumLines(atMost)
+	}
+	lines, overflow := item.text.Lines(t.multiLine, atMost, t.wrapCols(), t.wrapSignWidth, t.tabstop)
+	return len(lines), overflow
+}
+
+func (t *Terminal) itemLines(item *Item, atMost int) ([][]rune, bool) {
+	if !t.wrap && !t.multiLine {
+		text := make([]rune, item.text.Length())
+		copy(text, item.text.ToRunes())
+		return [][]rune{text}, false
+	}
+	return item.text.Lines(t.multiLine, atMost, t.wrapCols(), t.wrapSignWidth, t.tabstop)
+}
+
 // Estimate the average number of lines per item. Instead of going through all
 // items, we only check a few items around the current cursor position.
 func (t *Terminal) avgNumLines() int {
-	if !t.multiLine {
+	if !t.wrap && !t.multiLine {
 		return 1
 	}
 
@@ -1116,8 +1159,8 @@ func (t *Terminal) avgNumLines() int {
 	total := t.merger.Length()
 	offset := util.Max(0, util.Min(t.offset, total-maxItems-1))
 	for idx := 0; idx < maxItems && idx+offset < total; idx++ {
-		item := t.merger.Get(idx + offset)
+		result := t.merger.Get(idx + offset)
-		lines, _ := item.item.text.NumLines(maxItems)
+		lines, _ := t.numItemLines(result.item, maxItems)
 		numLines += lines
 		count++
 	}
@@ -1964,6 +2007,9 @@ func (t *Terminal) printHeader() {
 	case layoutDefault, layoutReverseList:
 		needReverse = true
 	}
+	// Wrapping is not supported for header
+	wrap := t.wrap
+	t.wrap = false
 	for idx, lineStr := range append(append([]string{}, t.header0...), t.header...) {
 		line := idx
 		if needReverse && idx < len(t.header0) {
@@ -1988,6 +2034,7 @@ func (t *Terminal) printHeader() {
 			tui.ColHeader, tui.ColHeader, false, false, line, line, true,
 			func(markerClass) { t.window.Print("  ") }, nil)
 	}
+	t.wrap = wrap
 }
 
 func (t *Terminal) printList() {
@@ -2015,7 +2062,7 @@ func (t *Terminal) printList() {
 			// If the screen is not filled with the list in non-multi-line mode,
 			// scrollbar is not visible at all. But in multi-line mode, we may need
 			// to redraw the scrollbar character at the end.
-			if t.multiLine {
+			if t.multiLine || t.wrap {
 				t.prevLines[line].hasBar = t.printBar(line, true, barRange)
 			}
 		}
@@ -2048,7 +2095,8 @@ func (t *Terminal) printItem(result Result, line int, maxLine int, index int, cu
 	}
 
 	// Avoid unnecessary redraw
-	newLine := itemLine{firstLine: line, cy: index + t.offset, current: current, selected: selected, label: label,
+	numLines, _ := t.numItemLines(item, maxLine-line+1)
+	newLine := itemLine{firstLine: line, numLines: numLines, cy: index + t.offset, current: current, selected: selected, label: label,
 		result: result, queryLen: len(t.input), width: 0, hasBar: line >= barRange[0] && line < barRange[1]}
 	prevLine := t.prevLines[line]
 	forceRedraw := prevLine.other || prevLine.firstLine != newLine.firstLine
@@ -2057,37 +2105,46 @@ func (t *Terminal) printItem(result Result, line int, maxLine int, index int, cu
 	}
 
 	if !forceRedraw &&
+		prevLine.numLines == newLine.numLines &&
 		prevLine.current == newLine.current &&
 		prevLine.selected == newLine.selected &&
 		prevLine.label == newLine.label &&
 		prevLine.queryLen == newLine.queryLen &&
 		prevLine.result == newLine.result {
 		t.prevLines[line].hasBar = printBar(line, false)
-		if !t.multiLine {
+		if !t.multiLine && !t.wrap {
 			return line
 		}
-		lines, _ := item.text.NumLines(maxLine - line + 1)
+		return line + numLines - 1
-		return line + lines - 1
 	}
 
 	maxWidth := t.window.Width() - (t.pointerLen + t.markerLen + 1)
-	postTask := func(lineNum int, width int) {
+	postTask := func(lineNum int, width int, wrapped bool) {
 		if (current || selected) && t.highlightLine {
 			color := tui.ColSelected
 			if current {
 				color = tui.ColCurrent
 			}
 			fillSpaces := maxWidth - width
+			if wrapped {
+				fillSpaces -= t.wrapSignWidth
+			}
 			if fillSpaces > 0 {
 				t.window.CPrint(color, strings.Repeat(" ", fillSpaces))
 			}
 			newLine.width = maxWidth
 		} else {
 			fillSpaces := t.prevLines[lineNum].width - width
+			if wrapped {
+				fillSpaces -= t.wrapSignWidth
+			}
 			if fillSpaces > 0 {
 				t.window.Print(strings.Repeat(" ", fillSpaces))
 			}
 			newLine.width = width
+			if wrapped {
+				newLine.width += t.wrapSignWidth
+			}
 		}
 		// When width is 0, line is completely cleared. We need to redraw scrollbar
 		newLine.hasBar = printBar(lineNum, forceRedraw || width == 0)
@@ -2185,7 +2242,7 @@ func (t *Terminal) overflow(runes []rune, max int) bool {
 	return t.displayWidthWithLimit(runes, 0, max) > max
 }
 
-func (t *Terminal) printHighlighted(result Result, colBase tui.ColorPair, colMatch tui.ColorPair, current bool, match bool, lineNum int, maxLineNum int, forceRedraw bool, preTask func(markerClass), postTask func(int, int)) int {
+func (t *Terminal) printHighlighted(result Result, colBase tui.ColorPair, colMatch tui.ColorPair, current bool, match bool, lineNum int, maxLineNum int, forceRedraw bool, preTask func(markerClass), postTask func(int, int, bool)) int {
 	var displayWidth int
 	item := result.item
 	matchOffsets := []Offset{}
@@ -2204,57 +2261,63 @@ func (t *Terminal) printHighlighted(result Result, colBase tui.ColorPair, colMat
 	}
 	allOffsets := result.colorOffsets(charOffsets, t.theme, colBase, colMatch, current)
 
-	from := 0
+	maxLines := 1
-	text := make([]rune, item.text.Length())
+	if t.multiLine || t.wrap {
-	copy(text, item.text.ToRunes())
+		maxLines = maxLineNum - lineNum + 1
+	}
+	lines, overflow := t.itemLines(item, maxLines)
+	numItemLines := len(lines)
 
 	finalLineNum := lineNum
-	numItemLines := 1
-	cutoff := 0
-	overflow := false
 	topCutoff := false
-	if t.multiLine {
+	wrapped := false
-		maxLines := maxLineNum - lineNum + 1
+	if t.multiLine || t.wrap {
-		numItemLines, overflow = item.text.NumLines(maxLines)
 		// Cut off the upper lines in the 'default' layout
 		if t.layout == layoutDefault && !current && maxLines == numItemLines && overflow {
-			actualLines, _ := item.text.NumLines(math.MaxInt32)
+			lines, _ = t.itemLines(item, math.MaxInt)
-			cutoff = actualLines - maxLines
+
+			// To see if the first visible line is wrapped, we need to check the last cut-off line
+			prevLine := lines[len(lines)-maxLines-1]
+			if len(prevLine) == 0 || prevLine[len(prevLine)-1] != '\n' {
+				wrapped = true
+			}
+
+			lines = lines[len(lines)-maxLines:]
 			topCutoff = true
 		}
 	}
-	for lineOffset := 0; from <= len(text) && (lineNum <= maxLineNum || maxLineNum == 0); lineOffset++ {
+	from := 0
+	for lineOffset := 0; lineOffset < len(lines) && (lineNum <= maxLineNum || maxLineNum == 0); lineOffset++ {
+		line := lines[lineOffset]
 		finalLineNum = lineNum
-
-		line := text[from:]
-		if t.multiLine {
-			for idx, r := range text[from:] {
-				if r == '\n' {
-					line = line[:idx]
-					break
-				}
-			}
-		}
-
 		offsets := []colorOffset{}
 		for _, offset := range allOffsets {
-			if offset.offset[0] >= int32(from) && offset.offset[1] <= int32(from+len(line)) {
+			if offset.offset[0] >= int32(from+len(line)) {
+				allOffsets = allOffsets[len(offsets):]
+				break
+			}
+
+			if offset.offset[0] < int32(from) {
+				continue
+			}
+
+			if offset.offset[1] < int32(from+len(line)) {
 				offset.offset[0] -= int32(from)
 				offset.offset[1] -= int32(from)
 				offsets = append(offsets, offset)
 			} else {
-				allOffsets = allOffsets[len(offsets):]
+				dupe := offset
+				dupe.offset[0] = int32(from + len(line))
+
+				offset.offset[0] -= int32(from)
+				offset.offset[1] = int32(from + len(line))
+				offsets = append(offsets, offset)
+
+				allOffsets = append([]colorOffset{dupe}, allOffsets[len(offsets):]...)
 				break
 			}
 		}
-
+		from += len(line)
-		from += len(line) + 1
-
-		if cutoff > 0 {
-			cutoff--
-			lineOffset--
-			continue
-		}
 
 		var maxe int
 		for _, offset := range offsets {
@@ -2301,10 +2364,24 @@ func (t *Terminal) printHighlighted(result Result, colBase tui.ColorPair, colMat
 		}
 
 		maxWidth := t.window.Width() - (t.pointerLen + t.markerLen + 1)
+		wasWrapped := false
+		if wrapped {
+			maxWidth -= t.wrapSignWidth
+			t.window.CPrint(colBase.WithAttr(tui.Dim), t.wrapSign)
+			wrapped = false
+			wasWrapped = true
+		}
+
+		if len(line) > 0 && line[len(line)-1] == '\n' {
+			line = line[:len(line)-1]
+		} else {
+			wrapped = true
+		}
+
+		displayWidth = t.displayWidthWithLimit(line, 0, maxWidth)
+		if !t.wrap && displayWidth > maxWidth {
 			ellipsis, ellipsisWidth := util.Truncate(t.ellipsis, maxWidth/2)
 			maxe = util.Constrain(maxe+util.Min(maxWidth/2-ellipsisWidth, t.hscrollOff), 0, len(line))
-		displayWidth = t.displayWidthWithLimit(line, 0, maxWidth)
-		if displayWidth > maxWidth {
 			transformOffsets := func(diff int32, rightTrim bool) {
 				for idx, offset := range offsets {
 					b, e := offset.offset[0], offset.offset[1]
@@ -2357,7 +2434,7 @@ func (t *Terminal) printHighlighted(result Result, colBase tui.ColorPair, colMat
 
 		t.printColoredString(t.window, line, offsets, colBase)
 		if postTask != nil {
-			postTask(actualLineNum, displayWidth)
+			postTask(actualLineNum, displayWidth, wasWrapped)
 		} else {
 			t.markOtherLine(actualLineNum)
 		}
@@ -4369,6 +4446,9 @@ func (t *Terminal) Loop() error {
 			case actToggleHeader:
 				t.headerVisible = !t.headerVisible
 				req(reqList, reqInfo, reqPrompt, reqHeader)
+			case actToggleWrap:
+				t.wrap = !t.wrap
+				req(reqList, reqHeader)
 			case actTrackCurrent:
 				if t.track == trackDisabled {
 					t.track = trackCurrent
@@ -4751,12 +4831,12 @@ func (t *Terminal) constrain() {
 	for tries := 0; tries < maxLines; tries++ {
 		numItems := maxLines
 		// How many items can be fit on screen including the current item?
-		if t.multiLine && t.merger.Length() > 0 {
+		if (t.multiLine || t.wrap) && t.merger.Length() > 0 {
 			numItemsFound := 0
 			linesSum := 0
 
 			add := func(i int) bool {
-				lines, _ := t.merger.Get(i).item.text.NumLines(numItems - linesSum)
+				lines, _ := t.numItemLines(t.merger.Get(i).item, numItems-linesSum)
 				linesSum += lines
 				if linesSum >= numItems {
 					if numItemsFound == 0 {
@@ -4800,14 +4880,14 @@ func (t *Terminal) constrain() {
 					prevOffset := newOffset
 					numItems := t.merger.Length()
 					itemLines := 1
-					if t.multiLine && t.cy < numItems {
+					if (t.multiLine || t.wrap) && t.cy < numItems {
-						itemLines, _ = t.merger.Get(t.cy).item.text.NumLines(maxLines)
+						itemLines, _ = t.numItemLines(t.merger.Get(t.cy).item, maxLines)
 					}
 					linesBefore := t.cy - newOffset
-					if t.multiLine {
+					if t.multiLine || t.wrap {
 						linesBefore = 0
 						for i := newOffset; i < t.cy && i < numItems; i++ {
-							lines, _ := t.merger.Get(i).item.text.NumLines(maxLines - linesBefore - itemLines)
+							lines, _ := t.numItemLines(t.merger.Get(i).item, maxLines-linesBefore-itemLines)
 							linesBefore += lines
 						}
 					}

src/util/chars.go

@@ -226,3 +226,85 @@ func (chars *Chars) Prepend(prefix string) {
 		chars.slice = append([]byte(prefix), chars.slice...)
 	}
 }
+
+func (chars *Chars) Lines(multiLine bool, maxLines int, wrapCols int, wrapSignWidth int, tabstop int) ([][]rune, bool) {
+	text := make([]rune, chars.Length())
+	copy(text, chars.ToRunes())
+
+	lines := [][]rune{}
+	overflow := false
+	if !multiLine {
+		lines = append(lines, text)
+	} else {
+		from := 0
+		for off := 0; off < len(text); off++ {
+			if text[off] == '\n' {
+				lines = append(lines, text[from:off+1]) // Include '\n'
+				from = off + 1
+				if len(lines) >= maxLines {
+					break
+				}
+			}
+		}
+
+		var lastLine []rune
+		if from < len(text) {
+			lastLine = text[from:]
+		}
+
+		overflow = false
+		if len(lines) >= maxLines {
+			overflow = true
+		} else {
+			lines = append(lines, lastLine)
+		}
+	}
+
+	// If wrapping is disabled, we're done
+	if wrapCols == 0 {
+		return lines, overflow
+	}
+
+	wrapped := [][]rune{}
+	for _, line := range lines {
+		// Remove trailing '\n' and remember if it was there
+		newline := len(line) > 0 && line[len(line)-1] == '\n'
+		if newline {
+			line = line[:len(line)-1]
+		}
+
+		for {
+			cols := wrapCols
+			if len(wrapped) > 0 {
+				cols -= wrapSignWidth
+			}
+			_, overflowIdx := RunesWidth(line, 0, tabstop, cols)
+			if overflowIdx >= 0 {
+				// Might be a wide character
+				if overflowIdx == 0 {
+					overflowIdx = 1
+				}
+				if len(wrapped) >= maxLines {
+					return wrapped, true
+				}
+				wrapped = append(wrapped, line[:overflowIdx])
+				line = line[overflowIdx:]
+				continue
+			}
+
+			// Restore trailing '\n'
+			if newline {
+				line = append(line, '\n')
+			}
+
+			if len(wrapped) >= maxLines {
+				return wrapped, true
+			}
+
+			wrapped = append(wrapped, line)
+			break
+		}
+	}
+
+	return wrapped, false
+}

src/util/chars_test.go

@@ -1,6 +1,9 @@
 package util
 
-import "testing"
+import (
+	"fmt"
+	"testing"
+)
 
 func TestToCharsAscii(t *testing.T) {
 	chars := ToChars([]byte("foobar"))
@@ -44,3 +47,37 @@ func TestTrimLength(t *testing.T) {
 	check("  h   o  ", 5)
 	check("         ", 0)
 }
+
+func TestCharsLines(t *testing.T) {
+	chars := ToChars([]byte("abcdef\n가나다\n\tdef"))
+	check := func(multiLine bool, maxLines int, wrapCols int, wrapSignWidth int, tabstop int, expectedNumLines int, expectedOverflow bool) {
+		lines, overflow := chars.Lines(multiLine, maxLines, wrapCols, wrapSignWidth, tabstop)
+		fmt.Println(lines, overflow)
+		if len(lines) != expectedNumLines || overflow != expectedOverflow {
+			t.Errorf("Invalid result: %d %v (expected %d %v)", len(lines), overflow, expectedNumLines, expectedOverflow)
+		}
+	}
+
+	// No wrap
+	check(true, 1, 0, 0, 8, 1, true)
+	check(true, 2, 0, 0, 8, 2, true)
+	check(true, 3, 0, 0, 8, 3, false)
+
+	// Wrap (2)
+	check(true, 4, 2, 0, 8, 4, true)
+	check(true, 5, 2, 0, 8, 5, true)
+	check(true, 6, 2, 0, 8, 6, true)
+	check(true, 7, 2, 0, 8, 7, true)
+	check(true, 8, 2, 0, 8, 8, true)
+	check(true, 9, 2, 0, 8, 9, false)
+	check(true, 9, 2, 0, 1, 8, false) // Smaller tab size
+
+	// With wrap sign (3 + 1)
+	check(true, 100, 3, 1, 1, 8, false)
+
+	// With wrap sign (3 + 2)
+	check(true, 100, 3, 2, 1, 12, false)
+
+	// With wrap sign (3 + 2) and no multi-line
+	check(false, 100, 3, 2, 1, 13, false)
+}