anki/anki/latex.py

147 lines
4.8 KiB
Python

# -*- coding: utf-8 -*-
# Copyright: Ankitects Pty Ltd and contributors
# License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
import re, os, shutil, html
from anki.utils import checksum, call, namedtmp, tmpdir, isMac, stripHTML
from anki.hooks import addHook
from anki.lang import _
pngCommands = [
["latex", "-interaction=nonstopmode", "tmp.tex"],
["dvipng", "-D", "200", "-T", "tight", "tmp.dvi", "-o", "tmp.png"]
]
svgCommands = [
["latex", "-interaction=nonstopmode", "tmp.tex"],
["dvisvgm", "--no-fonts", "--exact", "-Z", "2", "tmp.dvi", "-o", "tmp.svg"]
]
build = True # if off, use existing media but don't create new
regexps = {
"standard": re.compile(r"\[latex\](.+?)\[/latex\]", re.DOTALL | re.IGNORECASE),
"expression": re.compile(r"\[\$\](.+?)\[/\$\]", re.DOTALL | re.IGNORECASE),
"math": re.compile(r"\[\$\$\](.+?)\[/\$\$\]", re.DOTALL | re.IGNORECASE),
}
# add standard tex install location to osx
if isMac:
os.environ['PATH'] += ":/usr/texbin:/Library/TeX/texbin"
def stripLatex(text):
for match in regexps['standard'].finditer(text):
text = text.replace(match.group(), "")
for match in regexps['expression'].finditer(text):
text = text.replace(match.group(), "")
for match in regexps['math'].finditer(text):
text = text.replace(match.group(), "")
return text
def mungeQA(html, type, fields, model, data, col):
"Convert TEXT with embedded latex tags to image links."
for match in regexps['standard'].finditer(html):
html = html.replace(match.group(), _imgLink(col, match.group(1), model))
for match in regexps['expression'].finditer(html):
html = html.replace(match.group(), _imgLink(
col, "$" + match.group(1) + "$", model))
for match in regexps['math'].finditer(html):
html = html.replace(match.group(), _imgLink(
col,
"\\begin{displaymath}" + match.group(1) + "\\end{displaymath}", model))
return html
def _imgLink(col, latex, model):
"Return an img link for LATEX, creating if necesssary."
txt = _latexFromHtml(col, latex)
if model.get("latexsvg", False):
ext = "svg"
else:
ext = "png"
# is there an existing file?
fname = "latex-%s.%s" % (checksum(txt.encode("utf8")), ext)
link = '<img class=latex src="%s">' % fname
if os.path.exists(fname):
return link
# building disabled?
if not build:
return "[latex]%s[/latex]" % latex
err = _buildImg(col, txt, fname, model)
if err:
return err
else:
return link
def _latexFromHtml(col, latex):
"Convert entities and fix newlines."
latex = re.sub("<br( /)?>|<div>", "\n", latex)
latex = stripHTML(latex)
return latex
def _buildImg(col, latex, fname, model):
# add header/footer
latex = (model["latexPre"] + "\n" +
latex + "\n" +
model["latexPost"])
# it's only really secure if run in a jail, but these are the most common
tmplatex = latex.replace("\\includegraphics", "")
for bad in ("\\write18", "\\readline", "\\input", "\\include",
"\\catcode", "\\openout", "\\write", "\\loop",
"\\def", "\\shipout"):
# don't mind if the sequence is only part of a command
bad_re = "\\" + bad + "[^a-zA-Z]"
if re.search(bad_re, tmplatex):
return _("""\
For security reasons, '%s' is not allowed on cards. You can still use \
it by placing the command in a different package, and importing that \
package in the LaTeX header instead.""") % bad
# commands to use?
if model.get("latexsvg", False):
latexCmds = svgCommands
ext = "svg"
else:
latexCmds = pngCommands
ext = "png"
# write into a temp file
log = open(namedtmp("latex_log.txt"), "w")
texpath = namedtmp("tmp.tex")
texfile = open(texpath, "w", encoding="utf8")
texfile.write(latex)
texfile.close()
mdir = col.media.dir()
oldcwd = os.getcwd()
png = namedtmp("tmp.%s" % ext)
try:
# generate png
os.chdir(tmpdir())
for latexCmd in latexCmds:
if call(latexCmd, stdout=log, stderr=log):
return _errMsg(latexCmd[0], texpath)
# add to media
shutil.copyfile(png, os.path.join(mdir, fname))
return
finally:
os.chdir(oldcwd)
log.close()
def _errMsg(type, texpath):
msg = (_("Error executing %s.") % type) + "<br>"
msg += (_("Generated file: %s") % texpath) + "<br>"
try:
with open(namedtmp("latex_log.txt", rm=False)) as f:
log = f.read()
if not log:
raise Exception()
msg += "<small><pre>" + html.escape(log) + "</pre></small>"
except:
msg += _("Have you installed latex and dvipng/dvisvgm?")
return msg
# setup q/a filter
addHook("mungeQA", mungeQA)