Merge a020293fc2 into 53788271b3

README.md

@@ -173,6 +173,12 @@ either the `dark` or the `light` style for you.
 glow -s [dark|light]
 ```
 
+For piped output, use `--color=always` to keep colorized output even when stdout is not a terminal.
+
+```bash
+glow --color=always
+```
+
 Alternatively you can also supply a custom JSON stylesheet:
 
 ```bash
@@ -201,6 +207,8 @@ Here's an example config:
 ```yaml
 # style name or JSON path (default "auto")
 style: "light"
+# colorize output when piped (auto|always)
+color: "auto"
 # mouse wheel support (TUI-mode only)
 mouse: true
 # use pager to display markdown

config_cmd.go

@@ -15,6 +15,8 @@ import (
 
 const defaultConfig = `# style name or JSON path (default "auto")
 style: "auto"
+# colorize output when piped (auto|always)
+color: "auto"
 # mouse support (TUI-mode only)
 mouse: false
 # use pager to display markdown

glow_test.go

@@ -2,6 +2,9 @@ package main
 
 import (
 	"testing"
+
+	"github.com/charmbracelet/glamour/styles"
+	"github.com/charmbracelet/lipgloss"
 )
 
 func TestGlowFlags(t *testing.T) {
@@ -27,6 +30,12 @@ func TestGlowFlags(t *testing.T) {
 				return width == 40
 			},
 		},
+		{
+			args: []string{"--color", "always"},
+			check: func() bool {
+				return colorMode == "always"
+			},
+		},
 	}
 
 	for _, v := range tt {
@@ -39,3 +48,69 @@ func TestGlowFlags(t *testing.T) {
 		}
 	}
 }
+
+func TestShouldUseNoTTYStyle(t *testing.T) {
+	cases := []struct {
+		name        string
+		mode        string
+		isTerminal  bool
+		styleFlag   bool
+		expectNoTTY bool
+	}{
+		{name: "auto non-terminal", mode: "auto", isTerminal: false, expectNoTTY: true},
+		{name: "always non-terminal", mode: "always", isTerminal: false, expectNoTTY: false},
+		{name: "auto terminal", mode: "auto", isTerminal: true, expectNoTTY: false},
+		{name: "auto style flag set", mode: "auto", isTerminal: false, styleFlag: true, expectNoTTY: false},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := shouldUseNoTTYStyle(tc.mode, tc.isTerminal, tc.styleFlag); got != tc.expectNoTTY {
+				t.Fatalf("shouldUseNoTTYStyle(%q, %v, %v) = %v, want %v", tc.mode, tc.isTerminal, tc.styleFlag, got, tc.expectNoTTY)
+			}
+		})
+	}
+}
+
+func TestResolveStyleForColorMode(t *testing.T) {
+	cases := []struct {
+		name         string
+		mode         string
+		currentStyle string
+		isTerminal   bool
+		styleFlag    bool
+		expectStyle  string
+	}{
+		{name: "auto non-terminal keeps auto when style explicit", mode: "always", currentStyle: "dark", isTerminal: false, styleFlag: true, expectStyle: "dark"},
+		{name: "auto terminal keeps auto", mode: "always", currentStyle: styles.AutoStyle, isTerminal: true, expectStyle: styles.AutoStyle},
+		{name: "auto mode keeps auto", mode: "auto", currentStyle: styles.AutoStyle, isTerminal: false, expectStyle: styles.AutoStyle},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := resolveStyleForColorMode(tc.mode, tc.currentStyle, tc.isTerminal, tc.styleFlag); got != tc.expectStyle {
+				t.Fatalf("resolveStyleForColorMode(%q, %q, %v, %v) = %q, want %q", tc.mode, tc.currentStyle, tc.isTerminal, tc.styleFlag, got, tc.expectStyle)
+			}
+		})
+	}
+
+	want := styles.DarkStyle
+	if !lipgloss.HasDarkBackground() {
+		want = styles.LightStyle
+	}
+	if got := resolveStyleForColorMode("always", styles.AutoStyle, false, false); got != want {
+		t.Fatalf("resolveStyleForColorMode(always, auto, false, false) = %q, want %q", got, want)
+	}
+}
+
+func TestValidateColorMode(t *testing.T) {
+	if err := validateColorMode("auto"); err != nil {
+		t.Fatalf("expected auto to be valid: %v", err)
+	}
+	if err := validateColorMode("always"); err != nil {
+		t.Fatalf("expected always to be valid: %v", err)
+	}
+	if err := validateColorMode("never"); err == nil {
+		t.Fatal("expected never to be invalid")
+	}
+}

main.go

@@ -23,6 +23,7 @@ import (
 	"github.com/charmbracelet/lipgloss"
 	"github.com/charmbracelet/log"
 	gap "github.com/muesli/go-app-paths"
+	"github.com/muesli/termenv"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 	"golang.org/x/term"
@@ -44,6 +45,7 @@ var (
 	showLineNumbers  bool
 	preserveNewLines bool
 	mouse            bool
+	colorMode        string
 
 	rootCmd = &cobra.Command{
 		Use:   "glow [SOURCE|DIR]",
@@ -164,8 +166,36 @@ func validateStyle(style string) error {
 	return nil
 }
 
+func validateColorMode(mode string) error {
+	switch mode {
+	case "auto", "always":
+		return nil
+	default:
+		return fmt.Errorf("invalid color mode %q: must be one of auto or always", mode)
+	}
+}
+
+func resolveStyleForColorMode(mode string, currentStyle string, isTerminal bool, styleFlagChanged bool) string {
+	if mode != "always" || styleFlagChanged || currentStyle != styles.AutoStyle || isTerminal {
+		return currentStyle
+	}
+	if lipgloss.HasDarkBackground() {
+		return styles.DarkStyle
+	}
+	return styles.LightStyle
+}
+
+func shouldUseNoTTYStyle(mode string, isTerminal bool, styleFlagChanged bool) bool {
+	return mode != "always" && !isTerminal && !styleFlagChanged
+}
+
 func validateOptions(cmd *cobra.Command) error {
 	// grab config values from Viper
+	colorMode = viper.GetString("color")
+	if err := validateColorMode(colorMode); err != nil {
+		return err
+	}
+
 	width = viper.GetUint("width")
 	mouse = viper.GetBool("mouse")
 	pager = viper.GetBool("pager")
@@ -185,10 +215,12 @@ func validateOptions(cmd *cobra.Command) error {
 	}
 
 	isTerminal := term.IsTerminal(int(os.Stdout.Fd()))
+	styleFlagChanged := cmd.Flags().Changed("style")
+	style = resolveStyleForColorMode(colorMode, style, isTerminal, styleFlagChanged)
 	// We want to use a special no-TTY style, when stdout is not a terminal
-	// and there was no specific style passed by arg
-	if !isTerminal && !cmd.Flags().Changed("style") {
-		style = "notty"
+	// and there was no specific style passed by arg.
+	if shouldUseNoTTYStyle(colorMode, isTerminal, styleFlagChanged) {
+		style = styles.NoTTYStyle
 	}
 
 	// Detect terminal width
@@ -290,9 +322,14 @@ func executeCLI(cmd *cobra.Command, src *source, w io.Writer) error {
 
 	isCode := !utils.IsMarkdownFile(src.URL)
 
+	colorProfile := lipgloss.ColorProfile()
+	if colorMode == "always" {
+		colorProfile = termenv.TrueColor
+	}
+
 	// initialize glamour
 	r, err := glamour.NewTermRenderer(
-		glamour.WithColorProfile(lipgloss.ColorProfile()),
+		glamour.WithColorProfile(colorProfile),
 		utils.GlamourStyle(style, isCode),
 		glamour.WithWordWrap(int(width)), //nolint:gosec
 		glamour.WithBaseURL(baseURL),
@@ -403,6 +440,7 @@ func init() {
 	rootCmd.Flags().BoolVarP(&pager, "pager", "p", false, "display with pager")
 	rootCmd.Flags().BoolVarP(&tui, "tui", "t", false, "display with tui")
 	rootCmd.Flags().StringVarP(&style, "style", "s", styles.AutoStyle, "style name or JSON path")
+	rootCmd.Flags().StringVar(&colorMode, "color", "auto", "when to enable colors (auto|always)")
 	rootCmd.Flags().UintVarP(&width, "width", "w", 0, "word-wrap at width (set to 0 to disable)")
 	rootCmd.Flags().BoolVarP(&showAllFiles, "all", "a", false, "show system files and directories (TUI-mode only)")
 	rootCmd.Flags().BoolVarP(&showLineNumbers, "line-numbers", "l", false, "show line numbers (TUI-mode only)")
@@ -414,6 +452,7 @@ func init() {
 	_ = viper.BindPFlag("pager", rootCmd.Flags().Lookup("pager"))
 	_ = viper.BindPFlag("tui", rootCmd.Flags().Lookup("tui"))
 	_ = viper.BindPFlag("style", rootCmd.Flags().Lookup("style"))
+	_ = viper.BindPFlag("color", rootCmd.Flags().Lookup("color"))
 	_ = viper.BindPFlag("width", rootCmd.Flags().Lookup("width"))
 	_ = viper.BindPFlag("debug", rootCmd.Flags().Lookup("debug"))
 	_ = viper.BindPFlag("mouse", rootCmd.Flags().Lookup("mouse"))
@@ -422,6 +461,7 @@ func init() {
 	_ = viper.BindPFlag("all", rootCmd.Flags().Lookup("all"))
 
 	viper.SetDefault("style", styles.AutoStyle)
+	viper.SetDefault("color", "auto")
 	viper.SetDefault("width", 0)
 	viper.SetDefault("all", true)