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	"strings"
21)
22
23// Latex is a type that implements the Renderer interface for LaTeX output.
24//
25// Do not create this directly, instead use the LatexRenderer function.
26type Latex struct {
27}
28
29// LatexRenderer creates and configures a Latex object, which
30// satisfies the Renderer interface.
31//
32// flags is a set of LATEX_* options ORed together (currently no such options
33// are defined).
34func LatexRenderer(flags int) Renderer {
35	return &Latex{}
36}
37
38func (options *Latex) GetFlags() int {
39	return 0
40}
41
42// render code chunks using verbatim, or listings if we have a language
43func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, info string) {
44	if info == "" {
45		out.WriteString("\n\\begin{verbatim}\n")
46	} else {
47		lang := strings.Fields(info)[0]
48		out.WriteString("\n\\begin{lstlisting}[language=")
49		out.WriteString(lang)
50		out.WriteString("]\n")
51	}
52	out.Write(text)
53	if info == "" {
54		out.WriteString("\n\\end{verbatim}\n")
55	} else {
56		out.WriteString("\n\\end{lstlisting}\n")
57	}
58}
59
60func (options *Latex) TitleBlock(out *bytes.Buffer, text []byte) {
61
62}
63
64func (options *Latex) BlockQuote(out *bytes.Buffer, text []byte) {
65	out.WriteString("\n\\begin{quotation}\n")
66	out.Write(text)
67	out.WriteString("\n\\end{quotation}\n")
68}
69
70func (options *Latex) BlockHtml(out *bytes.Buffer, text []byte) {
71	// a pretty lame thing to do...
72	out.WriteString("\n\\begin{verbatim}\n")
73	out.Write(text)
74	out.WriteString("\n\\end{verbatim}\n")
75}
76
77func (options *Latex) Header(out *bytes.Buffer, text func() bool, level int, id string) {
78	marker := out.Len()
79
80	switch level {
81	case 1:
82		out.WriteString("\n\\section{")
83	case 2:
84		out.WriteString("\n\\subsection{")
85	case 3:
86		out.WriteString("\n\\subsubsection{")
87	case 4:
88		out.WriteString("\n\\paragraph{")
89	case 5:
90		out.WriteString("\n\\subparagraph{")
91	case 6:
92		out.WriteString("\n\\textbf{")
93	}
94	if !text() {
95		out.Truncate(marker)
96		return
97	}
98	out.WriteString("}\n")
99}
100
101func (options *Latex) HRule(out *bytes.Buffer) {
102	out.WriteString("\n\\HRule\n")
103}
104
105func (options *Latex) List(out *bytes.Buffer, text func() bool, flags int) {
106	marker := out.Len()
107	if flags&LIST_TYPE_ORDERED != 0 {
108		out.WriteString("\n\\begin{enumerate}\n")
109	} else {
110		out.WriteString("\n\\begin{itemize}\n")
111	}
112	if !text() {
113		out.Truncate(marker)
114		return
115	}
116	if flags&LIST_TYPE_ORDERED != 0 {
117		out.WriteString("\n\\end{enumerate}\n")
118	} else {
119		out.WriteString("\n\\end{itemize}\n")
120	}
121}
122
123func (options *Latex) ListItem(out *bytes.Buffer, text []byte, flags int) {
124	out.WriteString("\n\\item ")
125	out.Write(text)
126}
127
128func (options *Latex) Paragraph(out *bytes.Buffer, text func() bool) {
129	marker := out.Len()
130	out.WriteString("\n")
131	if !text() {
132		out.Truncate(marker)
133		return
134	}
135	out.WriteString("\n")
136}
137
138func (options *Latex) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int) {
139	out.WriteString("\n\\begin{tabular}{")
140	for _, elt := range columnData {
141		switch elt {
142		case TABLE_ALIGNMENT_LEFT:
143			out.WriteByte('l')
144		case TABLE_ALIGNMENT_RIGHT:
145			out.WriteByte('r')
146		default:
147			out.WriteByte('c')
148		}
149	}
150	out.WriteString("}\n")
151	out.Write(header)
152	out.WriteString(" \\\\\n\\hline\n")
153	out.Write(body)
154	out.WriteString("\n\\end{tabular}\n")
155}
156
157func (options *Latex) TableRow(out *bytes.Buffer, text []byte) {
158	if out.Len() > 0 {
159		out.WriteString(" \\\\\n")
160	}
161	out.Write(text)
162}
163
164func (options *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
165	if out.Len() > 0 {
166		out.WriteString(" & ")
167	}
168	out.Write(text)
169}
170
171func (options *Latex) TableCell(out *bytes.Buffer, text []byte, align int) {
172	if out.Len() > 0 {
173		out.WriteString(" & ")
174	}
175	out.Write(text)
176}
177
178// TODO: this
179func (options *Latex) Footnotes(out *bytes.Buffer, text func() bool) {
180
181}
182
183func (options *Latex) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int) {
184
185}
186
187func (options *Latex) AutoLink(out *bytes.Buffer, link []byte, kind int) {
188	out.WriteString("\\href{")
189	if kind == LINK_TYPE_EMAIL {
190		out.WriteString("mailto:")
191	}
192	out.Write(link)
193	out.WriteString("}{")
194	out.Write(link)
195	out.WriteString("}")
196}
197
198func (options *Latex) CodeSpan(out *bytes.Buffer, text []byte) {
199	out.WriteString("\\texttt{")
200	escapeSpecialChars(out, text)
201	out.WriteString("}")
202}
203
204func (options *Latex) DoubleEmphasis(out *bytes.Buffer, text []byte) {
205	out.WriteString("\\textbf{")
206	out.Write(text)
207	out.WriteString("}")
208}
209
210func (options *Latex) Emphasis(out *bytes.Buffer, text []byte) {
211	out.WriteString("\\textit{")
212	out.Write(text)
213	out.WriteString("}")
214}
215
216func (options *Latex) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
217	if bytes.HasPrefix(link, []byte("http://")) || bytes.HasPrefix(link, []byte("https://")) {
218		// treat it like a link
219		out.WriteString("\\href{")
220		out.Write(link)
221		out.WriteString("}{")
222		out.Write(alt)
223		out.WriteString("}")
224	} else {
225		out.WriteString("\\includegraphics{")
226		out.Write(link)
227		out.WriteString("}")
228	}
229}
230
231func (options *Latex) LineBreak(out *bytes.Buffer) {
232	out.WriteString(" \\\\\n")
233}
234
235func (options *Latex) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
236	out.WriteString("\\href{")
237	out.Write(link)
238	out.WriteString("}{")
239	out.Write(content)
240	out.WriteString("}")
241}
242
243func (options *Latex) RawHtmlTag(out *bytes.Buffer, tag []byte) {
244}
245
246func (options *Latex) TripleEmphasis(out *bytes.Buffer, text []byte) {
247	out.WriteString("\\textbf{\\textit{")
248	out.Write(text)
249	out.WriteString("}}")
250}
251
252func (options *Latex) StrikeThrough(out *bytes.Buffer, text []byte) {
253	out.WriteString("\\sout{")
254	out.Write(text)
255	out.WriteString("}")
256}
257
258// TODO: this
259func (options *Latex) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
260
261}
262
263func needsBackslash(c byte) bool {
264	for _, r := range []byte("_{}%$&\\~#") {
265		if c == r {
266			return true
267		}
268	}
269	return false
270}
271
272func escapeSpecialChars(out *bytes.Buffer, text []byte) {
273	for i := 0; i < len(text); i++ {
274		// directly copy normal characters
275		org := i
276
277		for i < len(text) && !needsBackslash(text[i]) {
278			i++
279		}
280		if i > org {
281			out.Write(text[org:i])
282		}
283
284		// escape a character
285		if i >= len(text) {
286			break
287		}
288		out.WriteByte('\\')
289		out.WriteByte(text[i])
290	}
291}
292
293func (options *Latex) Entity(out *bytes.Buffer, entity []byte) {
294	// TODO: convert this into a unicode character or something
295	out.Write(entity)
296}
297
298func (options *Latex) NormalText(out *bytes.Buffer, text []byte) {
299	escapeSpecialChars(out, text)
300}
301
302// header and footer
303func (options *Latex) DocumentHeader(out *bytes.Buffer) {
304	out.WriteString("\\documentclass{article}\n")
305	out.WriteString("\n")
306	out.WriteString("\\usepackage{graphicx}\n")
307	out.WriteString("\\usepackage{listings}\n")
308	out.WriteString("\\usepackage[margin=1in]{geometry}\n")
309	out.WriteString("\\usepackage[utf8]{inputenc}\n")
310	out.WriteString("\\usepackage{verbatim}\n")
311	out.WriteString("\\usepackage[normalem]{ulem}\n")
312	out.WriteString("\\usepackage{hyperref}\n")
313	out.WriteString("\n")
314	out.WriteString("\\hypersetup{colorlinks,%\n")
315	out.WriteString("  citecolor=black,%\n")
316	out.WriteString("  filecolor=black,%\n")
317	out.WriteString("  linkcolor=black,%\n")
318	out.WriteString("  urlcolor=black,%\n")
319	out.WriteString("  pdfstartview=FitH,%\n")
320	out.WriteString("  breaklinks=true,%\n")
321	out.WriteString("  pdfauthor={Blackfriday Markdown Processor v")
322	out.WriteString(VERSION)
323	out.WriteString("}}\n")
324	out.WriteString("\n")
325	out.WriteString("\\newcommand{\\HRule}{\\rule{\\linewidth}{0.5mm}}\n")
326	out.WriteString("\\addtolength{\\parskip}{0.5\\baselineskip}\n")
327	out.WriteString("\\parindent=0pt\n")
328	out.WriteString("\n")
329	out.WriteString("\\begin{document}\n")
330}
331
332func (options *Latex) DocumentFooter(out *bytes.Buffer) {
333	out.WriteString("\n\\end{document}\n")
334}
335