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 (
 19	"bytes"
 20)
 21
 22// Latex is a type that implements the Renderer interface for LaTeX output.
 23//
 24// Do not create this directly, instead use the LatexRenderer function.
 25type Latex struct {
 26}
 27
 28// LatexRenderer creates and configures a Latex object, which
 29// satisfies the Renderer interface.
 30//
 31// flags is a set of LATEX_* options ORed together (currently no such options
 32// are defined).
 33func LatexRenderer(flags int) Renderer {
 34	return &Latex{}
 35}
 36
 37func (options *Latex) GetFlags() int {
 38	return 0
 39}
 40
 41// render code chunks using verbatim, or listings if we have a language
 42func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, lang string) {
 43	if lang == "" {
 44		out.WriteString("\n\\begin{verbatim}\n")
 45	} else {
 46		out.WriteString("\n\\begin{lstlisting}[language=")
 47		out.WriteString(lang)
 48		out.WriteString("]\n")
 49	}
 50	out.Write(text)
 51	if lang == "" {
 52		out.WriteString("\n\\end{verbatim}\n")
 53	} else {
 54		out.WriteString("\n\\end{lstlisting}\n")
 55	}
 56}
 57
 58func (options *Latex) TitleBlock(out *bytes.Buffer, text []byte) {
 59
 60}
 61
 62func (options *Latex) BlockQuote(out *bytes.Buffer, text []byte) {
 63	out.WriteString("\n\\begin{quotation}\n")
 64	out.Write(text)
 65	out.WriteString("\n\\end{quotation}\n")
 66}
 67
 68func (options *Latex) BlockHtml(out *bytes.Buffer, text []byte) {
 69	// a pretty lame thing to do...
 70	out.WriteString("\n\\begin{verbatim}\n")
 71	out.Write(text)
 72	out.WriteString("\n\\end{verbatim}\n")
 73}
 74
 75func (options *Latex) Header(out *bytes.Buffer, text func() bool, level int, id string) {
 76	marker := out.Len()
 77
 78	switch level {
 79	case 1:
 80		out.WriteString("\n\\section{")
 81	case 2:
 82		out.WriteString("\n\\subsection{")
 83	case 3:
 84		out.WriteString("\n\\subsubsection{")
 85	case 4:
 86		out.WriteString("\n\\paragraph{")
 87	case 5:
 88		out.WriteString("\n\\subparagraph{")
 89	case 6:
 90		out.WriteString("\n\\textbf{")
 91	}
 92	if !text() {
 93		out.Truncate(marker)
 94		return
 95	}
 96	out.WriteString("}\n")
 97}
 98
 99func (options *Latex) HRule(out *bytes.Buffer) {
100	out.WriteString("\n\\HRule\n")
101}
102
103func (options *Latex) List(out *bytes.Buffer, text func() bool, flags int) {
104	marker := out.Len()
105	if flags&LIST_TYPE_ORDERED != 0 {
106		out.WriteString("\n\\begin{enumerate}\n")
107	} else {
108		out.WriteString("\n\\begin{itemize}\n")
109	}
110	if !text() {
111		out.Truncate(marker)
112		return
113	}
114	if flags&LIST_TYPE_ORDERED != 0 {
115		out.WriteString("\n\\end{enumerate}\n")
116	} else {
117		out.WriteString("\n\\end{itemize}\n")
118	}
119}
120
121func (options *Latex) ListItem(out *bytes.Buffer, text []byte, flags int) {
122	out.WriteString("\n\\item ")
123	out.Write(text)
124}
125
126func (options *Latex) Paragraph(out *bytes.Buffer, text func() bool) {
127	marker := out.Len()
128	out.WriteString("\n")
129	if !text() {
130		out.Truncate(marker)
131		return
132	}
133	out.WriteString("\n")
134}
135
136func (options *Latex) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int) {
137	out.WriteString("\n\\begin{tabular}{")
138	for _, elt := range columnData {
139		switch elt {
140		case TABLE_ALIGNMENT_LEFT:
141			out.WriteByte('l')
142		case TABLE_ALIGNMENT_RIGHT:
143			out.WriteByte('r')
144		default:
145			out.WriteByte('c')
146		}
147	}
148	out.WriteString("}\n")
149	out.Write(header)
150	out.WriteString(" \\\\\n\\hline\n")
151	out.Write(body)
152	out.WriteString("\n\\end{tabular}\n")
153}
154
155func (options *Latex) TableRow(out *bytes.Buffer, text []byte) {
156	if out.Len() > 0 {
157		out.WriteString(" \\\\\n")
158	}
159	out.Write(text)
160}
161
162func (options *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
163	if out.Len() > 0 {
164		out.WriteString(" & ")
165	}
166	out.Write(text)
167}
168
169func (options *Latex) TableCell(out *bytes.Buffer, text []byte, align int) {
170	if out.Len() > 0 {
171		out.WriteString(" & ")
172	}
173	out.Write(text)
174}
175
176// TODO: this
177func (options *Latex) Footnotes(out *bytes.Buffer, text func() bool) {
178
179}
180
181func (options *Latex) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int) {
182
183}
184
185func (options *Latex) AutoLink(out *bytes.Buffer, link []byte, kind int) {
186	out.WriteString("\\href{")
187	if kind == LINK_TYPE_EMAIL {
188		out.WriteString("mailto:")
189	}
190	out.Write(link)
191	out.WriteString("}{")
192	out.Write(link)
193	out.WriteString("}")
194}
195
196func (options *Latex) CodeSpan(out *bytes.Buffer, text []byte) {
197	out.WriteString("\\texttt{")
198	escapeSpecialChars(out, text)
199	out.WriteString("}")
200}
201
202func (options *Latex) DoubleEmphasis(out *bytes.Buffer, text []byte) {
203	out.WriteString("\\textbf{")
204	out.Write(text)
205	out.WriteString("}")
206}
207
208func (options *Latex) Emphasis(out *bytes.Buffer, text []byte) {
209	out.WriteString("\\textit{")
210	out.Write(text)
211	out.WriteString("}")
212}
213
214func (options *Latex) Image(out *bytes.Buffer, 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		out.WriteString("\\href{")
218		out.Write(link)
219		out.WriteString("}{")
220		out.Write(alt)
221		out.WriteString("}")
222	} else {
223		out.WriteString("\\includegraphics{")
224		out.Write(link)
225		out.WriteString("}")
226	}
227}
228
229func (options *Latex) LineBreak(out *bytes.Buffer) {
230	out.WriteString(" \\\\\n")
231}
232
233func (options *Latex) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
234	out.WriteString("\\href{")
235	out.Write(link)
236	out.WriteString("}{")
237	out.Write(content)
238	out.WriteString("}")
239}
240
241func (options *Latex) RawHtmlTag(out *bytes.Buffer, tag []byte) {
242}
243
244func (options *Latex) TripleEmphasis(out *bytes.Buffer, text []byte) {
245	out.WriteString("\\textbf{\\textit{")
246	out.Write(text)
247	out.WriteString("}}")
248}
249
250func (options *Latex) StrikeThrough(out *bytes.Buffer, text []byte) {
251	out.WriteString("\\sout{")
252	out.Write(text)
253	out.WriteString("}")
254}
255
256// TODO: this
257func (options *Latex) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
258
259}
260
261func needsBackslash(c byte) bool {
262	for _, r := range []byte("_{}%$&\\~") {
263		if c == r {
264			return true
265		}
266	}
267	return false
268}
269
270func escapeSpecialChars(out *bytes.Buffer, text []byte) {
271	for i := 0; i < len(text); i++ {
272		// directly copy normal characters
273		org := i
274
275		for i < len(text) && !needsBackslash(text[i]) {
276			i++
277		}
278		if i > org {
279			out.Write(text[org:i])
280		}
281
282		// escape a character
283		if i >= len(text) {
284			break
285		}
286		out.WriteByte('\\')
287		out.WriteByte(text[i])
288	}
289}
290
291func (options *Latex) Entity(out *bytes.Buffer, entity []byte) {
292	// TODO: convert this into a unicode character or something
293	out.Write(entity)
294}
295
296func (options *Latex) NormalText(out *bytes.Buffer, text []byte) {
297	escapeSpecialChars(out, text)
298}
299
300// header and footer
301func (options *Latex) DocumentHeader(out *bytes.Buffer) {
302	out.WriteString("\\documentclass{article}\n")
303	out.WriteString("\n")
304	out.WriteString("\\usepackage{graphicx}\n")
305	out.WriteString("\\usepackage{listings}\n")
306	out.WriteString("\\usepackage[margin=1in]{geometry}\n")
307	out.WriteString("\\usepackage[utf8]{inputenc}\n")
308	out.WriteString("\\usepackage{verbatim}\n")
309	out.WriteString("\\usepackage[normalem]{ulem}\n")
310	out.WriteString("\\usepackage{hyperref}\n")
311	out.WriteString("\n")
312	out.WriteString("\\hypersetup{colorlinks,%\n")
313	out.WriteString("  citecolor=black,%\n")
314	out.WriteString("  filecolor=black,%\n")
315	out.WriteString("  linkcolor=black,%\n")
316	out.WriteString("  urlcolor=black,%\n")
317	out.WriteString("  pdfstartview=FitH,%\n")
318	out.WriteString("  breaklinks=true,%\n")
319	out.WriteString("  pdfauthor={Blackfriday Markdown Processor v")
320	out.WriteString(VERSION)
321	out.WriteString("}}\n")
322	out.WriteString("\n")
323	out.WriteString("\\newcommand{\\HRule}{\\rule{\\linewidth}{0.5mm}}\n")
324	out.WriteString("\\addtolength{\\parskip}{0.5\\baselineskip}\n")
325	out.WriteString("\\parindent=0pt\n")
326	out.WriteString("\n")
327	out.WriteString("\\begin{document}\n")
328}
329
330func (options *Latex) DocumentFooter(out *bytes.Buffer) {
331	out.WriteString("\n\\end{document}\n")
332}