add a latex macro to convert Tex code to <img> tag using dataURI.

course/check.py

@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+
+from __future__ import division
+
+__copyright__ = "Copyright (C) 2016 Dong Zhuang, Andreas Kloeckner"
+
+__license__ = """
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+"""
+
+from django.core.checks import register, Tags as DjangoTags
+from django.conf import settings
+
+from course.latex.utils import get_all_indirect_subclasses
+from course.latex.converter import CommandBase
+
+
+class Tags(DjangoTags):
+    relate_course_tag = 'relate_course_tag'
+
+
+@register(Tags.relate_course_tag, deploy=True)
+def latex2image_bin_check(app_configs, **kwargs):
+    """
+    Check if all tex compiler and image converter
+    are correctly configured, if latex utility is
+    enabled.
+    """
+    if not getattr(settings, "RELATE_LATEX_TO_IMAGE_ENABLED", False):
+        return []
+    klass = get_all_indirect_subclasses(CommandBase)
+    instance_list = [cls() for cls in klass]
+    errors = []
+    for instance in instance_list:
+        error = instance.check()
+        if error:
+            errors.append(error)
+    return errors

course/content.py

@@ -781,8 +781,45 @@ def markup_to_html(course, repo, commit_sha, text, reverse_func=None,
     env = Environment(
             loader=GitTemplateLoader(repo, commit_sha),
             undefined=StrictUndefined)
+
+    # {{{ tex2img
+
+    from course.latex import tex_to_img_tag
+
+    def latex_not_enabled_warning(caller, *args, **kwargs):
+        return  "<div class='alert alert-danger'>%s</div>" % _(
+            "RELATE_LATEX_TO_IMAGE_ENABLED is set to False, "
+            "no image will be generated.")
+
+    def jinja_tex_to_img_tag(caller, *args, **kwargs):
+        from os.path import join
+        default_saving_folder = getattr(
+            settings, "RELATE_LATEX_IMAGE_SAVING_FOLDER_PATH",
+            join(settings.MEDIA_ROOT, "latex_image"))
+        kwargs["output_dir"] = default_saving_folder
+        return tex_to_img_tag(caller(), *args, **kwargs)
+
     template = env.from_string(text)
-    text = template.render(**jinja_env)
+    latex2image_enabled = getattr(
+        settings, "RELATE_LATEX_TO_IMAGE_ENABLED", False)
+    if latex2image_enabled:
+        try:
+            env.globals["latex"] = jinja_tex_to_img_tag
+            text = template.render(**jinja_env)
+        except:
+            if validate_only:
+                raise
+            else:
+                # fail silently
+                text = template.render(**jinja_env)
+    else:
+        if not validate_only:
+            env.globals["latex"] = latex_not_enabled_warning
+        else:
+            raise ImproperlyConfigured(_(
+            "RELATE_LATEX_TO_IMAGE_ENABLED is set to False, "
+            "no image will be generated."))
+        text = template.render(**jinja_env)
 
     # }}}
 

course/latex/__init__.py

@@ -0,0 +1,118 @@
+# -*- coding: utf-8 -*-
+
+from __future__ import division
+
+__copyright__ = "Copyright (C) 2016 Dong Zhuang, Andreas Kloeckner"
+
+__license__ = """
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+"""
+
+import six
+import re
+
+from django.utils.translation import ugettext as _
+
+from course.latex.converter import get_tex2img_class
+from course.latex.latex import TexDoc
+from course.latex.utils import (
+    replace_latex_space_seperator, strip_spaces)
+
+TIKZ_PGF_RE = re.compile(r"\\begin\{(?:tikzpicture|pgfpicture)\}")
+DEFAULT_IMG_HTML_CLASS = "img-responsive"
+
+
+def tex_to_img_tag(tex_source, *args, **kwargs):
+    '''Convert LaTex to IMG tag'''
+
+    compiler = kwargs.get("compiler", None)
+    if not compiler:
+        raise ValueError(_("'compiler' must be specified."))
+
+    image_format = kwargs.get("image_format", "")
+    if not image_format:
+        raise ValueError(_("'image_format' must be specified."))
+
+    output_dir = kwargs.get("output_dir")
+
+    tex_filename = kwargs.get("tex_filename", None)
+    tex_preamble = kwargs.get("tex_preamble", "")
+    tex_preamble_extra = kwargs.get("tex_preamble_extra", "")
+
+    force_regenerate = kwargs.get("force_regenerate", False)
+    html_class_extra = kwargs.get("html_class_extra", "")
+    empty_pagestyle = kwargs.get("empty_pagestyle", True)
+    alt = kwargs.get("alt", None)
+
+    # remove spaces added to latex code in jinja template.
+    tex_source = replace_latex_space_seperator(
+        strip_spaces(tex_source, allow_single_empty_line=True))
+    tex_preamble = replace_latex_space_seperator(
+        strip_spaces(tex_preamble, allow_single_empty_line=True))
+    tex_preamble_extra = replace_latex_space_seperator(
+        strip_spaces(tex_preamble_extra,
+                     allow_single_empty_line=True))
+
+    if html_class_extra:
+        if isinstance(html_class_extra, list):
+            html_class_extra = " ".join (html_class_extra)
+        elif not isinstance(html_class_extra, six.string_types):
+            raise ValueError(
+                _('"html_class_extra" must be a string or a list'))
+        html_class = "%s %s" %(DEFAULT_IMG_HTML_CLASS, html_class_extra)
+    else: html_class = DEFAULT_IMG_HTML_CLASS
+
+    texdoc = TexDoc(
+        tex_source, preamble=tex_preamble,
+        preamble_extra=tex_preamble_extra, empty_pagestyle=empty_pagestyle)
+
+    # empty document
+    if not texdoc.document.strip():
+        return ""
+
+    if (compiler == "latex"
+        and image_format == "png"
+        and re.search(TIKZ_PGF_RE, tex_source)):
+        image_format = "svg"
+
+    tex2img_class = get_tex2img_class(compiler, image_format)
+
+    if not alt:
+        alt = texdoc.document
+
+    if alt:
+        from django.utils.html import escape
+        alt = "alt='%s'" % alt.strip().replace("\n","")
+
+    latex2img = tex2img_class(
+        tex_source=texdoc.as_latex(),
+        tex_filename=tex_filename,
+        output_dir=output_dir
+        )
+
+    return (
+        "<img src='%(src)s' "
+        "class='%(html_class)s' %(alt)s>"
+        % {
+            "src": latex2img.get_data_uri_cached(force_regenerate),
+            "html_class": html_class,
+            "alt": alt,
+        })
+
+# vim: foldmethod=marker