Style change: thinner gutter column (#4521)

src/options.go

@@ -590,6 +590,7 @@ type Options struct {
 	Separator         *string
 	JumpLabels        string
 	Prompt            string
+	Gutter            *string
 	Pointer           *string
 	Marker            *string
 	MarkerMulti       *[3]string
@@ -710,6 +711,7 @@ func defaultOptions() *Options {
 		Separator:    nil,
 		JumpLabels:   defaultJumpLabels,
 		Prompt:       "> ",
+		Gutter:       nil,
 		Pointer:      nil,
 		Marker:       nil,
 		MarkerMulti:  nil,
@@ -2857,6 +2859,13 @@ func parseOptions(index *int, opts *Options, allArgs []string) error {
 			if err != nil {
 				return err
 			}
+		case "--gutter":
+			str, err := nextString("gutter character required")
+			if err != nil {
+				return err
+			}
+			str = firstLine(str)
+			opts.Gutter = &str
 		case "--pointer":
 			str, err := nextString("pointer sign required")
 			if err != nil {
@@ -3355,22 +3364,28 @@ func applyPreset(opts *Options, preset string) error {
 	return nil
 }
 
-func validateSign(sign string, signOptName string) error {
-	if uniseg.StringWidth(sign) > 2 {
-		return fmt.Errorf("%v display width should be up to 2", signOptName)
+func validateSign(sign string, signOptName string, maxWidth int) error {
+	if uniseg.StringWidth(sign) > maxWidth {
+		return fmt.Errorf("%v display width should be up to %d", signOptName, maxWidth)
 	}
 	return nil
 }
 
 func validateOptions(opts *Options) error {
 	if opts.Pointer != nil {
-		if err := validateSign(*opts.Pointer, "pointer"); err != nil {
+		if err := validateSign(*opts.Pointer, "pointer", 2); err != nil {
 			return err
 		}
 	}
 
 	if opts.Marker != nil {
-		if err := validateSign(*opts.Marker, "marker"); err != nil {
+		if err := validateSign(*opts.Marker, "marker", 2); err != nil {
+			return err
+		}
+	}
+
+	if opts.Gutter != nil {
+		if err := validateSign(*opts.Gutter, "gutter", 1); err != nil {
 			return err
 		}
 	}

src/options_test.go

@@ -462,7 +462,7 @@ func TestValidateSign(t *testing.T) {
 	}
 
 	for _, testCase := range testCases {
-		err := validateSign(testCase.inputSign, "")
+		err := validateSign(testCase.inputSign, "", 2)
 		if testCase.isValid && err != nil {
 			t.Errorf("Input sign `%s` caused error", testCase.inputSign)
 		}

src/terminal.go

@@ -272,6 +272,7 @@ type Terminal struct {
 	footerLabel        labelPrinter
 	footerLabelLen     int
 	footerLabelOpts    labelOpts
+	gutterReverse      bool
 	pointer            string
 	pointerLen         int
 	pointerEmpty       string
@@ -1094,10 +1095,27 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 	// This should be called before accessing tui.Color*
 	tui.InitTheme(opts.Theme, renderer.DefaultTheme(), opts.Black, opts.InputBorderShape.Visible(), opts.HeaderBorderShape.Visible())
 
+	// Gutter character
+	var gutterChar string
+	if opts.Gutter != nil {
+		gutterChar = *opts.Gutter
+	} else if t.unicode && !t.theme.Gutter.Color.IsDefault() {
+		gutterChar = "▌"
+	} else {
+		gutterChar = " "
+		t.gutterReverse = true
+	}
+
 	t.prompt, t.promptLen = t.parsePrompt(opts.Prompt)
 	// Pre-calculated empty pointer and marker signs
-	t.pointerEmpty = strings.Repeat(" ", t.pointerLen)
+	if t.pointerLen == 0 {
+		t.pointerEmpty = ""
+	} else {
+		t.pointerEmpty = gutterChar + strings.Repeat(" ", util.Max(0, t.pointerLen-1))
+	}
 	t.markerEmpty = strings.Repeat(" ", t.markerLen)
+
+	// Labels
 	t.listLabel, t.listLabelLen = t.ansiLabelPrinter(opts.ListLabel.label, &tui.ColListLabel, false)
 	t.borderLabel, t.borderLabelLen = t.ansiLabelPrinter(opts.BorderLabel.label, &tui.ColBorderLabel, false)
 	t.previewLabel, t.previewLabelLen = t.ansiLabelPrinter(opts.PreviewLabel.label, &tui.ColPreviewLabel, false)
@@ -3096,9 +3114,21 @@ func (t *Terminal) renderEmptyLine(line int, barRange [2]int) {
 	t.renderBar(line, barRange)
 }
 
+func (t *Terminal) gutter(current bool) {
+	var color tui.ColorPair
+	if current {
+		color = tui.ColCurrentCursorEmpty
+	} else if t.gutterReverse {
+		color = tui.ColCursorEmpty
+	} else {
+		color = tui.ColCursorEmptyChar
+	}
+	t.window.CPrint(color, t.pointerEmpty)
+}
+
 func (t *Terminal) renderGapLine(line int, barRange [2]int, drawLine bool) {
 	t.move(line, 0, false)
-	t.window.CPrint(tui.ColCursorEmpty, t.pointerEmpty)
+	t.gutter(false)
 	t.window.Print(t.markerEmpty)
 	x := t.pointerLen + t.markerLen
 
@@ -3262,7 +3292,7 @@ func (t *Terminal) printItem(result Result, line int, maxLine int, index int, cu
 				return indentSize
 			}
 			if len(label) == 0 {
-				t.window.CPrint(tui.ColCurrentCursorEmpty, t.pointerEmpty)
+				t.gutter(true)
 			} else {
 				t.window.CPrint(tui.ColCurrentCursor, label)
 			}
@@ -3284,7 +3314,7 @@ func (t *Terminal) printItem(result Result, line int, maxLine int, index int, cu
 				return indentSize
 			}
 			if len(label) == 0 {
-				t.window.CPrint(tui.ColCursorEmpty, t.pointerEmpty)
+				t.gutter(false)
 			} else {
 				t.window.CPrint(tui.ColCursor, label)
 			}

src/tui/tui.go

@@ -776,6 +776,7 @@ var (
 	ColMatch                ColorPair
 	ColCursor               ColorPair
 	ColCursorEmpty          ColorPair
+	ColCursorEmptyChar      ColorPair
 	ColMarker               ColorPair
 	ColSelected             ColorPair
 	ColSelectedMatch        ColorPair
@@ -1168,10 +1169,11 @@ func initPalette(theme *ColorTheme) {
 	ColSelectedMatch = pair(theme.SelectedMatch, theme.SelectedBg)
 	ColCursor = pair(theme.Cursor, theme.Gutter)
 	ColCursorEmpty = pair(blank, theme.Gutter)
+	ColCursorEmptyChar = pair(theme.Gutter, theme.ListBg)
 	if theme.SelectedBg.Color != theme.ListBg.Color {
 		ColMarker = pair(theme.Marker, theme.SelectedBg)
 	} else {
-		ColMarker = pair(theme.Marker, theme.Gutter)
+		ColMarker = pair(theme.Marker, theme.ListBg)
 	}
 	ColCurrent = pair(theme.Current, theme.DarkBg)
 	ColCurrentMatch = pair(theme.CurrentMatch, theme.DarkBg)