Use getopt style short/long argument flags (without using getopt package)

README.md

@@ -16,27 +16,24 @@ Produces [colortest.ansi.svg](cli/testdata/colortest.ansi.svg):
 
 ```
 $ ansisvg -h
-Usage of ansisvg:
-  -charboxsize value
-    	Character box size (forces pixel units instead of font-relative units)
-  -colorscheme string
-    	Color scheme (default "Builtin Dark")
-  -fontfile string
-    	Font file to use and embed
-  -fontname string
-    	Font name (default "Courier")
-  -fontref string
-    	External font file to reference
-  -fontsize int
-    	Font size (default 14)
-  -grid
-    	Enable grid mode (sets position for each character)
-  -listcolorschemes
-    	List color schemes
-  -transparent
-    	Transparent background
-  -width int
-    	Terminal width (auto)
+ansisvg - Convert ANSI to SVG
+Usage: ansisvg [FLAGS]
+
+Example usage:
+  program | ansisvg > file.svg
+
+--charboxsize       Character box size (use pixel units instead of font units)
+--colorscheme       Color scheme
+--fontfile          Font file to use and embed
+--fontname          Font name
+--fontref           External font URL to use
+--fontsize          Font size
+--grid              Grid mode (sets position for each character)
+--help, -h          Show help
+--listcolorschemes  List color schemes
+--transparent       Transparent background
+--version, -v       Show version
+--width, -w         Terminal width (auto if not set)
 ```
 
 Color themes are the ones from https://github.com/mbadolato/iTerm2-Color-Schemes

ansitosvg/ansisvg.go

@@ -10,23 +10,23 @@ import (
 )
 
 type Options struct {
-	FontName         string
-	FontEmbedded     []byte
-	FontRef          string
-	FontSize         int
-	TerminalWidth    int
-	CharacterBoxSize svgscreen.BoxSize
-	ColorScheme      string
-	Transparent      bool
-	GridMode         bool
+	FontName      string
+	FontEmbedded  []byte
+	FontRef       string
+	FontSize      int
+	TerminalWidth int
+	CharBoxSize   svgscreen.BoxSize
+	ColorScheme   string
+	Transparent   bool
+	GridMode      bool
 }
 
 var DefaultOptions = Options{
-	FontName:         "Courier",
-	FontSize:         14,
-	CharacterBoxSize: svgscreen.BoxSize{Width: 0, Height: 0},
-	ColorScheme:      "Builtin Dark",
-	Transparent:      false,
+	FontName:    "Courier",
+	FontSize:    14,
+	CharBoxSize: svgscreen.BoxSize{Width: 0, Height: 0},
+	ColorScheme: "Builtin Dark",
+	Transparent: false,
 }
 
 // Convert reads ANSI input from r and writes SVG to w
@@ -130,8 +130,8 @@ func Convert(r io.Reader, w io.Writer, opts Options) error {
 			FontSize:     opts.FontSize,
 		},
 		CharacterBoxSize: svgscreen.BoxSize{
-			Width:  opts.CharacterBoxSize.Width,
-			Height: opts.CharacterBoxSize.Height,
+			Width:  opts.CharBoxSize.Width,
+			Height: opts.CharBoxSize.Height,
 		},
 		TerminalWidth: terminalWidth,
 		Columns:       ad.MaxX + 1,

cli/cli.go

@@ -41,25 +41,77 @@ type Env struct {
 }
 
 func Main(env Env) error {
-	fs := flag.NewFlagSet("ansisvg", flag.ExitOnError)
-	var versionFlag = fs.Bool("version", false, "Show version")
+	fs := flag.NewFlagSet("ansisvg", flag.ContinueOnError)
+	var versionFlag bool
+	fs.BoolVar(&versionFlag, "v", false, "")
+	fs.BoolVar(&versionFlag, "version", false, "Show version")
 	var fontNameFlag = fs.String("fontname", ansitosvg.DefaultOptions.FontName, "Font name")
 	var fontFileFlag = fs.String("fontfile", "", "Font file to use and embed")
-	var fontRefFlag = fs.String("fontref", "", "External font file to reference")
+	var fontRefFlag = fs.String("fontref", "", "External font URL to use")
 	var fontSizeFlag = fs.Int("fontsize", ansitosvg.DefaultOptions.FontSize, "Font size")
-	var terminalWidthFlag = fs.Int("width", 0, "Terminal width (auto)")
+	var terminalWidthFlag int
+	fs.IntVar(&terminalWidthFlag, "w", 0, "")
+	fs.IntVar(&terminalWidthFlag, "width", 0, "Terminal width (auto if not set)")
 	var colorSchemeFlag = fs.String("colorscheme", ansitosvg.DefaultOptions.ColorScheme, "Color scheme")
 	var listColorSchemesFlag = fs.Bool("listcolorschemes", false, "List color schemes")
 	var transparentFlag = fs.Bool("transparent", ansitosvg.DefaultOptions.Transparent, "Transparent background")
-	var gridModeFlag = fs.Bool("grid", false, "Enable grid mode (sets position for each character)")
-	var characterBoxSize = boxSize{
-		Width:  ansitosvg.DefaultOptions.CharacterBoxSize.Width,
-		Height: ansitosvg.DefaultOptions.CharacterBoxSize.Height,
+	var gridModeFlag = fs.Bool("grid", false, "Grid mode (sets position for each character)")
+	var helpFlag bool
+	fs.BoolVar(&helpFlag, "h", false, "")
+	fs.BoolVar(&helpFlag, "help", false, "Show help")
+	var charBoxSize = boxSize{
+		Width:  ansitosvg.DefaultOptions.CharBoxSize.Width,
+		Height: ansitosvg.DefaultOptions.CharBoxSize.Height,
+	}
+	fs.Var(&charBoxSize, "charboxsize", "Character box size (use pixel units instead of font units)")
+	// handle error and usage output ourself
+	fs.Usage = func() {}
+	fs.SetOutput(io.Discard)
+	longToShort := map[string]string{
+		"help":    "h",
+		"version": "v",
+		"width":   "w",
+	}
+	usage := func() {
+		maxNameLen := 0
+		fs.VisitAll(func(f *flag.Flag) {
+			if len(f.Name) > maxNameLen {
+				maxNameLen = len(f.Name)
+			}
+		})
+
+		fmt.Fprintf(env.Stdout, `
+%[1]s - Convert ANSI to SVG
+Usage: %[1]s [FLAGS]
+
+Example usage:
+  program | %[1]s > file.svg
+
+`[1:], fs.Name())
+		fs.VisitAll(func(f *flag.Flag) {
+			if len(f.Name) == 1 {
+				return
+			}
+
+			short := ""
+			if s, ok := longToShort[f.Name]; ok {
+				short = ", -" + s
+			}
+
+			flagNames := f.Name + short
+			pad := strings.Repeat(" ", maxNameLen-len(flagNames))
+			fmt.Fprintf(env.Stdout, "--%s%s%s  %s\n", f.Name, short, pad, f.Usage)
+		})
+	}
+	if err := fs.Parse(env.Args[1:]); err != nil {
+		return err
+	}
+	if helpFlag {
+		usage()
+		return nil
 	}
-	fs.Var(&characterBoxSize, "charboxsize", "Character box size (forces pixel units instead of font-relative units)")
-	_ = fs.Parse(env.Args[1:])
 
-	if *versionFlag {
+	if versionFlag {
 		fmt.Fprintln(env.Stdout, env.Version)
 		return nil
 	}
@@ -96,10 +148,10 @@ func Main(env Env) error {
 			FontEmbedded:  fontEmbedded,
 			FontRef:       *fontRefFlag,
 			FontSize:      *fontSizeFlag,
-			TerminalWidth: *terminalWidthFlag,
-			CharacterBoxSize: svgscreen.BoxSize{
-				Width:  characterBoxSize.Width,
-				Height: characterBoxSize.Height,
+			TerminalWidth: terminalWidthFlag,
+			CharBoxSize: svgscreen.BoxSize{
+				Width:  charBoxSize.Width,
+				Height: charBoxSize.Height,
 			},
 			ColorScheme: *colorSchemeFlag,
 			Transparent: *transparentFlag,

cli/testdata/charboxfontsize.ansi.args

@@ -1 +1 @@
--fontsize 40 -fontname Arial -charboxsize 50x50 -grid
+--fontsize 40 --fontname Arial --charboxsize 50x50 --grid

cli/testdata/colortest_slate.ansi.args

@@ -1 +1 @@
--colorscheme Slate
+--colorscheme Slate

cli/testdata/colortest_transparent.ansi.args

@@ -1 +1 @@
--transparent
+--transparent

cli/testdata/fontembedded.ansi.args

@@ -1 +1 @@
--fontfile UbuntuMonoNerdFontMono-Regular.woff2
+--fontfile UbuntuMonoNerdFontMono-Regular.woff2

cli/testdata/fontname.ansi.args

@@ -1 +1 @@
--fontname Monaco
+--fontname Monaco

cli/testdata/fontref.ansi.args

@@ -1 +1 @@
--fontref font.woff2
+--fontref font.woff2

cli/testdata/powerline.ansi.args

@@ -1 +1 @@
--fontfile UbuntuMonoNerdFontMono-Regular.woff2 -grid
+--fontfile UbuntuMonoNerdFontMono-Regular.woff2 --grid

cli/testdata/terminalwidth4.ansi.args

@@ -1 +1 @@
--width 4
+--width 4

cli/testdata/underlinetabs_backgroundcolor.ansi.args

@@ -1 +1 @@
--colorscheme "Builtin Solarized Light"
+--colorscheme "Builtin Solarized Light"