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