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
 43func (r *Latex) GetFlags() HtmlFlags {
 44	return 0
 45}
 46
 47// render code chunks using verbatim, or listings if we have a language
 48func (r *Latex) BlockCode(text []byte, lang string) {
 49	if lang == "" {
 50		r.w.WriteString("\n\\begin{verbatim}\n")
 51	} else {
 52		r.w.WriteString("\n\\begin{lstlisting}[language=")
 53		r.w.WriteString(lang)
 54		r.w.WriteString("]\n")
 55	}
 56	r.w.Write(text)
 57	if lang == "" {
 58		r.w.WriteString("\n\\end{verbatim}\n")
 59	} else {
 60		r.w.WriteString("\n\\end{lstlisting}\n")
 61	}
 62}
 63
 64func (r *Latex) TitleBlock(text []byte) {
 65
 66}
 67
 68func (r *Latex) BlockQuote(text []byte) {
 69	r.w.WriteString("\n\\begin{quotation}\n")
 70	r.w.Write(text)
 71	r.w.WriteString("\n\\end{quotation}\n")
 72}
 73
 74func (r *Latex) BlockHtml(text []byte) {
 75	// a pretty lame thing to do...
 76	r.w.WriteString("\n\\begin{verbatim}\n")
 77	r.w.Write(text)
 78	r.w.WriteString("\n\\end{verbatim}\n")
 79}
 80
 81func (r *Latex) BeginHeader(level int, id string) {
 82	switch level {
 83	case 1:
 84		r.w.WriteString("\n\\section{")
 85	case 2:
 86		r.w.WriteString("\n\\subsection{")
 87	case 3:
 88		r.w.WriteString("\n\\subsubsection{")
 89	case 4:
 90		r.w.WriteString("\n\\paragraph{")
 91	case 5:
 92		r.w.WriteString("\n\\subparagraph{")
 93	case 6:
 94		r.w.WriteString("\n\\textbf{")
 95	}
 96}
 97
 98func (r *Latex) EndHeader(level int, id string, header []byte) {
 99	r.w.WriteString("}\n")
100}
101
102func (r *Latex) HRule() {
103	r.w.WriteString("\n\\HRule\n")
104}
105
106func (r *Latex) BeginList(flags ListType) {
107	if flags&ListTypeOrdered != 0 {
108		r.w.WriteString("\n\\begin{enumerate}\n")
109	} else {
110		r.w.WriteString("\n\\begin{itemize}\n")
111	}
112}
113
114func (r *Latex) EndList(flags ListType) {
115	if flags&ListTypeOrdered != 0 {
116		r.w.WriteString("\n\\end{enumerate}\n")
117	} else {
118		r.w.WriteString("\n\\end{itemize}\n")
119	}
120}
121
122func (r *Latex) ListItem(text []byte, flags ListType) {
123	r.w.WriteString("\n\\item ")
124	r.w.Write(text)
125}
126
127func (r *Latex) BeginParagraph() {
128	r.w.WriteString("\n")
129}
130
131func (r *Latex) EndParagraph() {
132	r.w.WriteString("\n")
133}
134
135func (r *Latex) Table(header []byte, body []byte, columnData []int) {
136	r.w.WriteString("\n\\begin{tabular}{")
137	for _, elt := range columnData {
138		switch elt {
139		case TableAlignmentLeft:
140			r.w.WriteByte('l')
141		case TableAlignmentRight:
142			r.w.WriteByte('r')
143		default:
144			r.w.WriteByte('c')
145		}
146	}
147	r.w.WriteString("}\n")
148	r.w.Write(header)
149	r.w.WriteString(" \\\\\n\\hline\n")
150	r.w.Write(body)
151	r.w.WriteString("\n\\end{tabular}\n")
152}
153
154func (r *Latex) TableRow(text []byte) {
155	r.w.WriteString(" \\\\\n")
156	r.w.Write(text)
157}
158
159func (r *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
160	if out.Len() > 0 {
161		out.WriteString(" & ")
162	}
163	out.Write(text)
164}
165
166func (r *Latex) TableCell(out *bytes.Buffer, text []byte, align int) {
167	if out.Len() > 0 {
168		out.WriteString(" & ")
169	}
170	out.Write(text)
171}
172
173// TODO: this
174func (r *Latex) BeginFootnotes() {
175}
176
177// TODO: this
178func (r *Latex) EndFootnotes() {
179}
180
181func (r *Latex) FootnoteItem(name, text []byte, flags ListType) {
182
183}
184
185func (r *Latex) AutoLink(link []byte, kind LinkType) {
186	r.w.WriteString("\\href{")
187	if kind == LinkTypeEmail {
188		r.w.WriteString("mailto:")
189	}
190	r.w.Write(link)
191	r.w.WriteString("}{")
192	r.w.Write(link)
193	r.w.WriteString("}")
194}
195
196func (r *Latex) CodeSpan(text []byte) {
197	r.w.WriteString("\\texttt{")
198	r.escapeSpecialChars(text)
199	r.w.WriteString("}")
200}
201
202func (r *Latex) DoubleEmphasis(text []byte) {
203	r.w.WriteString("\\textbf{")
204	r.w.Write(text)
205	r.w.WriteString("}")
206}
207
208func (r *Latex) Emphasis(text []byte) {
209	r.w.WriteString("\\textit{")
210	r.w.Write(text)
211	r.w.WriteString("}")
212}
213
214func (r *Latex) Image(link []byte, title []byte, alt []byte) {
215	if bytes.HasPrefix(link, []byte("http://")) || bytes.HasPrefix(link, []byte("https://")) {
216		// treat it like a link
217		r.w.WriteString("\\href{")
218		r.w.Write(link)
219		r.w.WriteString("}{")
220		r.w.Write(alt)
221		r.w.WriteString("}")
222	} else {
223		r.w.WriteString("\\includegraphics{")
224		r.w.Write(link)
225		r.w.WriteString("}")
226	}
227}
228
229func (r *Latex) LineBreak() {
230	r.w.WriteString(" \\\\\n")
231}
232
233func (r *Latex) Link(link []byte, title []byte, content []byte) {
234	r.w.WriteString("\\href{")
235	r.w.Write(link)
236	r.w.WriteString("}{")
237	r.w.Write(content)
238	r.w.WriteString("}")
239}
240
241func (r *Latex) RawHtmlTag(tag []byte) {
242}
243
244func (r *Latex) TripleEmphasis(text []byte) {
245	r.w.WriteString("\\textbf{\\textit{")
246	r.w.Write(text)
247	r.w.WriteString("}}")
248}
249
250func (r *Latex) StrikeThrough(text []byte) {
251	r.w.WriteString("\\sout{")
252	r.w.Write(text)
253	r.w.WriteString("}")
254}
255
256// TODO: this
257func (r *Latex) FootnoteRef(ref []byte, id int) {
258}
259
260func needsBackslash(c byte) bool {
261	for _, r := range []byte("_{}%$&\\~#") {
262		if c == r {
263			return true
264		}
265	}
266	return false
267}
268
269func (r *Latex) escapeSpecialChars(text []byte) {
270	for i := 0; i < len(text); i++ {
271		// directly copy normal characters
272		org := i
273
274		for i < len(text) && !needsBackslash(text[i]) {
275			i++
276		}
277		if i > org {
278			r.w.Write(text[org:i])
279		}
280
281		// escape a character
282		if i >= len(text) {
283			break
284		}
285		r.w.WriteByte('\\')
286		r.w.WriteByte(text[i])
287	}
288}
289
290func (r *Latex) Entity(entity []byte) {
291	// TODO: convert this into a unicode character or something
292	r.w.Write(entity)
293}
294
295func (r *Latex) NormalText(text []byte) {
296	r.escapeSpecialChars(text)
297}
298
299// header and footer
300func (r *Latex) DocumentHeader() {
301	r.w.WriteString("\\documentclass{article}\n")
302	r.w.WriteString("\n")
303	r.w.WriteString("\\usepackage{graphicx}\n")
304	r.w.WriteString("\\usepackage{listings}\n")
305	r.w.WriteString("\\usepackage[margin=1in]{geometry}\n")
306	r.w.WriteString("\\usepackage[utf8]{inputenc}\n")
307	r.w.WriteString("\\usepackage{verbatim}\n")
308	r.w.WriteString("\\usepackage[normalem]{ulem}\n")
309	r.w.WriteString("\\usepackage{hyperref}\n")
310	r.w.WriteString("\n")
311	r.w.WriteString("\\hypersetup{colorlinks,%\n")
312	r.w.WriteString("  citecolor=black,%\n")
313	r.w.WriteString("  filecolor=black,%\n")
314	r.w.WriteString("  linkcolor=black,%\n")
315	r.w.WriteString("  urlcolor=black,%\n")
316	r.w.WriteString("  pdfstartview=FitH,%\n")
317	r.w.WriteString("  breaklinks=true,%\n")
318	r.w.WriteString("  pdfauthor={Blackfriday Markdown Processor v")
319	r.w.WriteString(VERSION)
320	r.w.WriteString("}}\n")
321	r.w.WriteString("\n")
322	r.w.WriteString("\\newcommand{\\HRule}{\\rule{\\linewidth}{0.5mm}}\n")
323	r.w.WriteString("\\addtolength{\\parskip}{0.5\\baselineskip}\n")
324	r.w.WriteString("\\parindent=0pt\n")
325	r.w.WriteString("\n")
326	r.w.WriteString("\\begin{document}\n")
327}
328
329func (r *Latex) DocumentFooter() {
330	r.w.WriteString("\n\\end{document}\n")
331}
332
333func (r *Latex) Render(ast *Node) []byte {
334	return nil
335}