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) 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}