diff options
Diffstat (limited to 'vendor/github.com/alecthomas/chroma/formatters/svg/svg.go')
| -rw-r--r-- | vendor/github.com/alecthomas/chroma/formatters/svg/svg.go | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/vendor/github.com/alecthomas/chroma/formatters/svg/svg.go b/vendor/github.com/alecthomas/chroma/formatters/svg/svg.go new file mode 100644 index 000000000..5cfd95084 --- /dev/null +++ b/vendor/github.com/alecthomas/chroma/formatters/svg/svg.go @@ -0,0 +1,222 @@ +// Package svg contains an SVG formatter. +package svg + +import ( + "encoding/base64" + "errors" + "fmt" + "io" + "io/ioutil" + "path" + "strings" + + "github.com/alecthomas/chroma" +) + +// Option sets an option of the SVG formatter. +type Option func(f *Formatter) + +// FontFamily sets the font-family. +func FontFamily(fontFamily string) Option { return func(f *Formatter) { f.fontFamily = fontFamily } } + +// EmbedFontFile embeds given font file +func EmbedFontFile(fontFamily string, fileName string) (option Option, err error) { + var format FontFormat + switch path.Ext(fileName) { + case ".woff": + format = WOFF + case ".woff2": + format = WOFF2 + case ".ttf": + format = TRUETYPE + default: + return nil, errors.New("unexpected font file suffix") + } + + var content []byte + if content, err = ioutil.ReadFile(fileName); err == nil { + option = EmbedFont(fontFamily, base64.StdEncoding.EncodeToString(content), format) + } + return +} + +// EmbedFont embeds given base64 encoded font +func EmbedFont(fontFamily string, font string, format FontFormat) Option { + return func(f *Formatter) { f.fontFamily = fontFamily; f.embeddedFont = font; f.fontFormat = format } +} + +// New SVG formatter. +func New(options ...Option) *Formatter { + f := &Formatter{fontFamily: "Consolas, Monaco, Lucida Console, Liberation Mono, DejaVu Sans Mono, Bitstream Vera Sans Mono, Courier New, monospace"} + for _, option := range options { + option(f) + } + return f +} + +// Formatter that generates SVG. +type Formatter struct { + fontFamily string + embeddedFont string + fontFormat FontFormat +} + +func (f *Formatter) Format(w io.Writer, style *chroma.Style, iterator chroma.Iterator) (err error) { + f.writeSVG(w, style, iterator.Tokens()) + return err +} + +var svgEscaper = strings.NewReplacer( + `&`, "&", + `<`, "<", + `>`, ">", + `"`, """, + ` `, " ", + ` `, "    ", +) + +// EscapeString escapes special characters. +func escapeString(s string) string { + return svgEscaper.Replace(s) +} + +func (f *Formatter) writeSVG(w io.Writer, style *chroma.Style, tokens []chroma.Token) { // nolint: gocyclo + svgStyles := f.styleToSVG(style) + lines := chroma.SplitTokensIntoLines(tokens) + + fmt.Fprint(w, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n") + fmt.Fprint(w, "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" \"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd\">\n") + fmt.Fprintf(w, "<svg width=\"%dpx\" height=\"%dpx\" xmlns=\"http://www.w3.org/2000/svg\">\n", 8*maxLineWidth(lines), 10+int(16.8*float64(len(lines)+1))) + + if f.embeddedFont != "" { + f.writeFontStyle(w) + } + + fmt.Fprintf(w, "<rect width=\"100%%\" height=\"100%%\" fill=\"%s\"/>\n", style.Get(chroma.Background).Background.String()) + fmt.Fprintf(w, "<g font-family=\"%s\" font-size=\"14px\" fill=\"%s\">\n", f.fontFamily, style.Get(chroma.Text).Colour.String()) + + f.writeTokenBackgrounds(w, lines, style) + + for index, tokens := range lines { + fmt.Fprintf(w, "<text x=\"0\" y=\"%fem\" xml:space=\"preserve\">", 1.2*float64(index+1)) + + for _, token := range tokens { + text := escapeString(token.String()) + attr := f.styleAttr(svgStyles, token.Type) + if attr != "" { + text = fmt.Sprintf("<tspan %s>%s</tspan>", attr, text) + } + fmt.Fprint(w, text) + } + fmt.Fprint(w, "</text>") + } + + fmt.Fprint(w, "\n</g>\n") + fmt.Fprint(w, "</svg>\n") +} + +func maxLineWidth(lines [][]chroma.Token) int { + maxWidth := 0 + for _, tokens := range lines { + length := 0 + for _, token := range tokens { + length += len(strings.ReplaceAll(token.String(), ` `, " ")) + } + if length > maxWidth { + maxWidth = length + } + } + return maxWidth +} + +// There is no background attribute for text in SVG so simply calculate the position and text +// of tokens with a background color that differs from the default and add a rectangle for each before +// adding the token. +func (f *Formatter) writeTokenBackgrounds(w io.Writer, lines [][]chroma.Token, style *chroma.Style) { + for index, tokens := range lines { + lineLength := 0 + for _, token := range tokens { + length := len(strings.ReplaceAll(token.String(), ` `, " ")) + tokenBackground := style.Get(token.Type).Background + if tokenBackground.IsSet() && tokenBackground != style.Get(chroma.Background).Background { + fmt.Fprintf(w, "<rect id=\"%s\" x=\"%dch\" y=\"%fem\" width=\"%dch\" height=\"1.2em\" fill=\"%s\" />\n", escapeString(token.String()), lineLength, 1.2*float64(index)+0.25, length, style.Get(token.Type).Background.String()) + } + lineLength += length + } + } +} + +type FontFormat int + +// https://transfonter.org/formats +const ( + WOFF FontFormat = iota + WOFF2 + TRUETYPE +) + +var fontFormats = [...]string{ + "woff", + "woff2", + "truetype", +} + +func (f *Formatter) writeFontStyle(w io.Writer) { + fmt.Fprintf(w, `<style> +@font-face { + font-family: '%s'; + src: url(data:application/x-font-%s;charset=utf-8;base64,%s) format('%s');' + font-weight: normal; + font-style: normal; +} +</style>`, f.fontFamily, fontFormats[f.fontFormat], f.embeddedFont, fontFormats[f.fontFormat]) +} + +func (f *Formatter) styleAttr(styles map[chroma.TokenType]string, tt chroma.TokenType) string { + if _, ok := styles[tt]; !ok { + tt = tt.SubCategory() + if _, ok := styles[tt]; !ok { + tt = tt.Category() + if _, ok := styles[tt]; !ok { + return "" + } + } + } + return styles[tt] +} + +func (f *Formatter) styleToSVG(style *chroma.Style) map[chroma.TokenType]string { + converted := map[chroma.TokenType]string{} + bg := style.Get(chroma.Background) + // Convert the style. + for t := range chroma.StandardTypes { + entry := style.Get(t) + if t != chroma.Background { + entry = entry.Sub(bg) + } + if entry.IsZero() { + continue + } + converted[t] = StyleEntryToSVG(entry) + } + return converted +} + +// StyleEntryToSVG converts a chroma.StyleEntry to SVG attributes. +func StyleEntryToSVG(e chroma.StyleEntry) string { + var styles []string + + if e.Colour.IsSet() { + styles = append(styles, "fill=\""+e.Colour.String()+"\"") + } + if e.Bold == chroma.Yes { + styles = append(styles, "font-weight=\"bold\"") + } + if e.Italic == chroma.Yes { + styles = append(styles, "font-style=\"italic\"") + } + if e.Underline == chroma.Yes { + styles = append(styles, "text-decoration=\"underline\"") + } + return strings.Join(styles, " ") +} |