intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 237 insertions, 0 deletions

diff --git a/contrib/python/ipython/py3/IPython/lib/latextools.py b/contrib/python/ipython/py3/IPython/lib/latextools.py
new file mode 100644
index 0000000000..f976f2edb1
--- /dev/null
+++ b/contrib/python/ipython/py3/IPython/lib/latextools.py
@@ -0,0 +1,237 @@
+# -*- coding: utf-8 -*-
+"""Tools for handling LaTeX."""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+from io import BytesIO, open
+import os
+import tempfile
+import shutil
+import subprocess
+from base64 import encodebytes
+import textwrap
+
+from IPython.utils.process import find_cmd, FindCmdError
+from traitlets.config import get_config
+from traitlets.config.configurable import SingletonConfigurable
+from traitlets import List, Bool, Unicode
+from IPython.utils.py3compat import cast_unicode
+
+
+class LaTeXTool(SingletonConfigurable):
+    """An object to store configuration of the LaTeX tool."""
+    def _config_default(self):
+        return get_config()
+
+    backends = List(
+        Unicode(), ["matplotlib", "dvipng"],
+        help="Preferred backend to draw LaTeX math equations. "
+        "Backends in the list are checked one by one and the first "
+        "usable one is used.  Note that `matplotlib` backend "
+        "is usable only for inline style equations.  To draw  "
+        "display style equations, `dvipng` backend must be specified. ",
+        # It is a List instead of Enum, to make configuration more
+        # flexible.  For example, to use matplotlib mainly but dvipng
+        # for display style, the default ["matplotlib", "dvipng"] can
+        # be used.  To NOT use dvipng so that other repr such as
+        # unicode pretty printing is used, you can use ["matplotlib"].
+        ).tag(config=True)
+
+    use_breqn = Bool(
+        True,
+        help="Use breqn.sty to automatically break long equations. "
+        "This configuration takes effect only for dvipng backend.",
+        ).tag(config=True)
+
+    packages = List(
+        ['amsmath', 'amsthm', 'amssymb', 'bm'],
+        help="A list of packages to use for dvipng backend. "
+        "'breqn' will be automatically appended when use_breqn=True.",
+        ).tag(config=True)
+
+    preamble = Unicode(
+        help="Additional preamble to use when generating LaTeX source "
+        "for dvipng backend.",
+        ).tag(config=True)
+
+
+def latex_to_png(s, encode=False, backend=None, wrap=False, color='Black',
+                 scale=1.0):
+    """Render a LaTeX string to PNG.
+
+    Parameters
+    ----------
+    s : str
+        The raw string containing valid inline LaTeX.
+    encode : bool, optional
+        Should the PNG data base64 encoded to make it JSON'able.
+    backend : {matplotlib, dvipng}
+        Backend for producing PNG data.
+    wrap : bool
+        If true, Automatically wrap `s` as a LaTeX equation.
+    color : string
+        Foreground color name among dvipsnames, e.g. 'Maroon' or on hex RGB
+        format, e.g. '#AA20FA'.
+    scale : float
+        Scale factor for the resulting PNG.
+
+    None is returned when the backend cannot be used.
+
+    """
+    s = cast_unicode(s)
+    allowed_backends = LaTeXTool.instance().backends
+    if backend is None:
+        backend = allowed_backends[0]
+    if backend not in allowed_backends:
+        return None
+    if backend == 'matplotlib':
+        f = latex_to_png_mpl
+    elif backend == 'dvipng':
+        f = latex_to_png_dvipng
+        if color.startswith('#'):
+            # Convert hex RGB color to LaTeX RGB color.
+            if len(color) == 7:
+                try:
+                    color = "RGB {}".format(" ".join([str(int(x, 16)) for x in
+                                                      textwrap.wrap(color[1:], 2)]))
+                except ValueError:
+                    raise ValueError('Invalid color specification {}.'.format(color))
+            else:
+                raise ValueError('Invalid color specification {}.'.format(color))
+    else:
+        raise ValueError('No such backend {0}'.format(backend))
+    bin_data = f(s, wrap, color, scale)
+    if encode and bin_data:
+        bin_data = encodebytes(bin_data)
+    return bin_data
+
+
+def latex_to_png_mpl(s, wrap, color='Black', scale=1.0):
+    try:
+        from matplotlib import mathtext
+        from pyparsing import ParseFatalException
+    except ImportError:
+        return None
+
+    # mpl mathtext doesn't support display math, force inline
+    s = s.replace('$$', '$')
+    if wrap:
+        s = u'${0}$'.format(s)
+
+    try:
+        mt = mathtext.MathTextParser('bitmap')
+        f = BytesIO()
+        dpi = 120*scale
+        mt.to_png(f, s, fontsize=12, dpi=dpi, color=color)
+        return f.getvalue()
+    except (ValueError, RuntimeError, ParseFatalException):
+        return None
+
+
+def latex_to_png_dvipng(s, wrap, color='Black', scale=1.0):
+    try:
+        find_cmd('latex')
+        find_cmd('dvipng')
+    except FindCmdError:
+        return None
+    try:
+        workdir = tempfile.mkdtemp()
+        tmpfile = os.path.join(workdir, "tmp.tex")
+        dvifile = os.path.join(workdir, "tmp.dvi")
+        outfile = os.path.join(workdir, "tmp.png")
+
+        with open(tmpfile, "w", encoding='utf8') as f:
+            f.writelines(genelatex(s, wrap))
+
+        with open(os.devnull, 'wb') as devnull:
+            subprocess.check_call(
+                ["latex", "-halt-on-error", "-interaction", "batchmode", tmpfile],
+                cwd=workdir, stdout=devnull, stderr=devnull)
+
+            resolution = round(150*scale)
+            subprocess.check_call(
+                [
+                    "dvipng",
+                    "-T",
+                    "tight",
+                    "-D",
+                    str(resolution),
+                    "-z",
+                    "9",
+                    "-bg",
+                    "Transparent",
+                    "-o",
+                    outfile,
+                    dvifile,
+                    "-fg",
+                    color,
+                ],
+                cwd=workdir,
+                stdout=devnull,
+                stderr=devnull,
+            )
+
+        with open(outfile, "rb") as f:
+            return f.read()
+    except subprocess.CalledProcessError:
+        return None
+    finally:
+        shutil.rmtree(workdir)
+
+
+def kpsewhich(filename):
+    """Invoke kpsewhich command with an argument `filename`."""
+    try:
+        find_cmd("kpsewhich")
+        proc = subprocess.Popen(
+            ["kpsewhich", filename],
+            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        (stdout, stderr) = proc.communicate()
+        return stdout.strip().decode('utf8', 'replace')
+    except FindCmdError:
+        pass
+
+
+def genelatex(body, wrap):
+    """Generate LaTeX document for dvipng backend."""
+    lt = LaTeXTool.instance()
+    breqn = wrap and lt.use_breqn and kpsewhich("breqn.sty")
+    yield r'\documentclass{article}'
+    packages = lt.packages
+    if breqn:
+        packages = packages + ['breqn']
+    for pack in packages:
+        yield r'\usepackage{{{0}}}'.format(pack)
+    yield r'\pagestyle{empty}'
+    if lt.preamble:
+        yield lt.preamble
+    yield r'\begin{document}'
+    if breqn:
+        yield r'\begin{dmath*}'
+        yield body
+        yield r'\end{dmath*}'
+    elif wrap:
+        yield u'$${0}$$'.format(body)
+    else:
+        yield body
+    yield u'\\end{document}'
+
+
+_data_uri_template_png = u"""<img src="data:image/png;base64,%s" alt=%s />"""
+
+def latex_to_html(s, alt='image'):
+    """Render LaTeX to HTML with embedded PNG data using data URIs.
+
+    Parameters
+    ----------
+    s : str
+        The raw string containing valid inline LateX.
+    alt : str
+        The alt text to use for the HTML.
+    """
+    base64_data = latex_to_png(s, encode=True).decode('ascii')
+    if base64_data:
+        return _data_uri_template_png  % (base64_data, alt)
+
+