1//
  2// Blackfriday Markdown Processor
  3// Available at http://github.com/russross/blackfriday
  4//
  5// Copyright © 2011 Russ Ross <russ@russross.com>.
  6// Distributed under the Simplified BSD License.
  7// See README.md for details.
  8//
  9
 10//
 11//
 12// LaTeX rendering backend
 13//
 14//
 15
 16package blackfriday
 17
 18import "bytes"
 19
 20// Latex is a type that implements the Renderer interface for LaTeX output.
 21//
 22// Do not create this directly, instead use the LatexRenderer function.
 23type Latex struct {
 24	w HTMLWriter
 25}
 26
 27// LatexRenderer creates and configures a Latex object, which
 28// satisfies the Renderer interface.
 29//
 30// flags is a set of LATEX_* options ORed together (currently no such options
 31// are defined).
 32func LatexRenderer(flags int) Renderer {
 33	var writer HTMLWriter
 34	return &Latex{
 35		w: writer,
 36	}
 37}
 38
 39func (r *Latex) Write(b []byte) (int, error) {
 40	return r.w.Write(b)
 41}
 42
 43// render code chunks using verbatim, or listings if we have a language
 44func (r *Latex) BlockCode(text []byte, lang string) {
 45	if lang == "" {
 46		r.w.WriteString("\n\\begin{verbatim}\n")
 47	} else {
 48		r.w.WriteString("\n\\begin{lstlisting}[language=")
 49		r.w.WriteString(lang)
 50		r.w.WriteString("]\n")
 51	}
 52	r.w.Write(text)
 53	if lang == "" {
 54		r.w.WriteString("\n\\end{verbatim}\n")
 55	} else {
 56		r.w.WriteString("\n\\end{lstlisting}\n")
 57	}
 58}
 59
 60func (r *Latex) TitleBlock(text []byte) {
 61
 62}
 63
 64func (r *Latex) BlockQuote(text []byte) {
 65	r.w.WriteString("\n\\begin{quotation}\n")
 66	r.w.Write(text)
 67	r.w.WriteString("\n\\end{quotation}\n")
 68}
 69
 70func (r *Latex) BlockHtml(text []byte) {
 71	// a pretty lame thing to do...
 72	r.w.WriteString("\n\\begin{verbatim}\n")
 73	r.w.Write(text)
 74	r.w.WriteString("\n\\end{verbatim}\n")
 75}
 76
 77func (r *Latex) BeginHeader(level int, id string) {
 78	switch level {
 79	case 1:
 80		r.w.WriteString("\n\\section{")
 81	case 2:
 82		r.w.WriteString("\n\\subsection{")
 83	case 3:
 84		r.w.WriteString("\n\\subsubsection{")
 85	case 4:
 86		r.w.WriteString("\n\\paragraph{")
 87	case 5:
 88		r.w.WriteString("\n\\subparagraph{")
 89	case 6:
 90		r.w.WriteString("\n\\textbf{")
 91	}
 92}
 93
 94func (r *Latex) EndHeader(level int, id string, header []byte) {
 95	r.w.WriteString("}\n")
 96}
 97
 98func (r *Latex) HRule() {
 99	r.w.WriteString("\n\\HRule\n")
100}
101
102func (r *Latex) BeginList(flags ListType) {
103	if flags&ListTypeOrdered != 0 {
104		r.w.WriteString("\n\\begin{enumerate}\n")
105	} else {
106		r.w.WriteString("\n\\begin{itemize}\n")
107	}
108}
109
110func (r *Latex) EndList(flags ListType) {
111	if flags&ListTypeOrdered != 0 {
112		r.w.WriteString("\n\\end{enumerate}\n")
113	} else {
114		r.w.WriteString("\n\\end{itemize}\n")
115	}
116}
117
118func (r *Latex) ListItem(text []byte, flags ListType) {
119	r.w.WriteString("\n\\item ")
120	r.w.Write(text)
121}
122
123func (r *Latex) BeginParagraph() {
124	r.w.WriteString("\n")
125}
126
127func (r *Latex) EndParagraph() {
128	r.w.WriteString("\n")
129}
130
131func (r *Latex) Table(header []byte, body []byte, columnData []CellAlignFlags) {
132	r.w.WriteString("\n\\begin{tabular}{")
133	for _, elt := range columnData {
134		switch elt {
135		case TableAlignmentLeft:
136			r.w.WriteByte('l')
137		case TableAlignmentRight:
138			r.w.WriteByte('r')
139		default:
140			r.w.WriteByte('c')
141		}
142	}
143	r.w.WriteString("}\n")
144	r.w.Write(header)
145	r.w.WriteString(" \\\\\n\\hline\n")
146	r.w.Write(body)
147	r.w.WriteString("\n\\end{tabular}\n")
148}
149
150func (r *Latex) TableRow(text []byte) {
151	r.w.WriteString(" \\\\\n")
152	r.w.Write(text)
153}
154
155func (r *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align CellAlignFlags) {
156	if out.Len() > 0 {
157		out.WriteString(" & ")
158	}
159	out.Write(text)
160}
161
162func (r *Latex) TableCell(out *bytes.Buffer, text []byte, align CellAlignFlags) {
163	if out.Len() > 0 {
164		out.WriteString(" & ")
165	}
166	out.Write(text)
167}
168
169// TODO: this
170func (r *Latex) BeginFootnotes() {
171}
172
173// TODO: this
174func (r *Latex) EndFootnotes() {
175}
176
177func (r *Latex) FootnoteItem(name, text []byte, flags ListType) {
178
179}
180
181func (r *Latex) AutoLink(link []byte, kind LinkType) {
182	r.w.WriteString("\\href{")
183	if kind == LinkTypeEmail {
184		r.w.WriteString("mailto:")
185	}
186	r.w.Write(link)
187	r.w.WriteString("}{")
188	r.w.Write(link)
189	r.w.WriteString("}")
190}
191
192func (r *Latex) CodeSpan(text []byte) {
193	r.w.WriteString("\\texttt{")
194	r.escapeSpecialChars(text)
195	r.w.WriteString("}")
196}
197
198func (r *Latex) DoubleEmphasis(text []byte) {
199	r.w.WriteString("\\textbf{")
200	r.w.Write(text)
201	r.w.WriteString("}")
202}
203
204func (r *Latex) Emphasis(text []byte) {
205	r.w.WriteString("\\textit{")
206	r.w.Write(text)
207	r.w.WriteString("}")
208}
209
210func (r *Latex) Image(link []byte, title []byte, alt []byte) {
211	if bytes.HasPrefix(link, []byte("http://")) || bytes.HasPrefix(link, []byte("https://")) {
212		// treat it like a link
213		r.w.WriteString("\\href{")
214		r.w.Write(link)
215		r.w.WriteString("}{")
216		r.w.Write(alt)
217		r.w.WriteString("}")
218	} else {
219		r.w.WriteString("\\includegraphics{")
220		r.w.Write(link)
221		r.w.WriteString("}")
222	}
223}
224
225func (r *Latex) LineBreak() {
226	r.w.WriteString(" \\\\\n")
227}
228
229func (r *Latex) Link(link []byte, title []byte, content []byte) {
230	r.w.WriteString("\\href{")
231	r.w.Write(link)
232	r.w.WriteString("}{")
233	r.w.Write(content)
234	r.w.WriteString("}")
235}
236
237func (r *Latex) RawHtmlTag(tag []byte) {
238}
239
240func (r *Latex) TripleEmphasis(text []byte) {
241	r.w.WriteString("\\textbf{\\textit{")
242	r.w.Write(text)
243	r.w.WriteString("}}")
244}
245
246func (r *Latex) StrikeThrough(text []byte) {
247	r.w.WriteString("\\sout{")
248	r.w.Write(text)
249	r.w.WriteString("}")
250}
251
252// TODO: this
253func (r *Latex) FootnoteRef(ref []byte, id int) {
254}
255
256func needsBackslash(c byte) bool {
257	for _, r := range []byte("_{}%$&\\~#") {
258		if c == r {
259			return true
260		}
261	}
262	return false
263}
264
265func (r *Latex) escapeSpecialChars(text []byte) {
266	for i := 0; i < len(text); i++ {
267		// directly copy normal characters
268		org := i
269
270		for i < len(text) && !needsBackslash(text[i]) {
271			i++
272		}
273		if i > org {
274			r.w.Write(text[org:i])
275		}
276
277		// escape a character
278		if i >= len(text) {
279			break
280		}
281		r.w.WriteByte('\\')
282		r.w.WriteByte(text[i])
283	}
284}
285
286func (r *Latex) Entity(entity []byte) {
287	// TODO: convert this into a unicode character or something
288	r.w.Write(entity)
289}
290
291func (r *Latex) NormalText(text []byte) {
292	r.escapeSpecialChars(text)
293}
294
295// header and footer
296func (r *Latex) DocumentHeader() {
297	r.w.WriteString("\\documentclass{article}\n")
298	r.w.WriteString("\n")
299	r.w.WriteString("\\usepackage{graphicx}\n")
300	r.w.WriteString("\\usepackage{listings}\n")
301	r.w.WriteString("\\usepackage[margin=1in]{geometry}\n")
302	r.w.WriteString("\\usepackage[utf8]{inputenc}\n")
303	r.w.WriteString("\\usepackage{verbatim}\n")
304	r.w.WriteString("\\usepackage[normalem]{ulem}\n")
305	r.w.WriteString("\\usepackage{hyperref}\n")
306	r.w.WriteString("\n")
307	r.w.WriteString("\\hypersetup{colorlinks,%\n")
308	r.w.WriteString("  citecolor=black,%\n")
309	r.w.WriteString("  filecolor=black,%\n")
310	r.w.WriteString("  linkcolor=black,%\n")
311	r.w.WriteString("  urlcolor=black,%\n")
312	r.w.WriteString("  pdfstartview=FitH,%\n")
313	r.w.WriteString("  breaklinks=true,%\n")
314	r.w.WriteString("  pdfauthor={Blackfriday Markdown Processor v")
315	r.w.WriteString(VERSION)
316	r.w.WriteString("}}\n")
317	r.w.WriteString("\n")
318	r.w.WriteString("\\newcommand{\\HRule}{\\rule{\\linewidth}{0.5mm}}\n")
319	r.w.WriteString("\\addtolength{\\parskip}{0.5\\baselineskip}\n")
320	r.w.WriteString("\\parindent=0pt\n")
321	r.w.WriteString("\n")
322	r.w.WriteString("\\begin{document}\n")
323}
324
325func (r *Latex) DocumentFooter() {
326	r.w.WriteString("\n\\end{document}\n")
327}
328
329func (r *Latex) Render(ast *Node) []byte {
330	return nil
331}