Export tikz graphics as svg in html mode if `pdf2svg` is available

docutils_extended/_version.py

-__version_info__ = (0, 1, 6)
+__version_info__ = (0, 1, 7)
 __version__ = '.'.join(map(str, __version_info__))

docutils_extended/directives/tikz_directive.py

@@ -46,6 +46,8 @@ TMP_PDF_FILENAME = "tikz_picture.pdf"
 OUT_PDF_FILENAME = "_tikz_rendered{:04d}.pdf"
 TMP_PNG_FILENAME = "tikz_picture.png"
 OUT_PNG_FILENAME = "_tikz_rendered{:04d}.png"
+TMP_SVG_FILENAME = "tikz_picture.svg"
+OUT_SVG_FILENAME = "_tikz_rendered{:04d}.svg"
 
 
 VALID_OUTPUT_MODES = ("latex", "html")
@@ -77,7 +79,7 @@ class TemporaryDirectory(object):
         self.tmp_dir = None
 
 
-def render_tikz(tikz_code, options, output_png=False):
+def render_tikz(tikz_code, options, output_png=False, output_svg=False):
     self = render_tikz
     if not hasattr(self, "image_number"):
         self.image_number = 1
@@ -91,10 +93,12 @@ def render_tikz(tikz_code, options, output_png=False):
     latex_output = template.render(tikz_code=tikz_code, **options)
     out_pdf_filename = OUT_PDF_FILENAME.format(self.image_number)
     out_png_filename = OUT_PNG_FILENAME.format(self.image_number)
+    out_svg_filename = OUT_SVG_FILENAME.format(self.image_number)
     with TemporaryDirectory() as tmp_dir:
         tmp_latex_path = os.path.join(tmp_dir, TMP_LATEX_FILENAME)
         tmp_pdf_path = os.path.join(tmp_dir, TMP_PDF_FILENAME)
         tmp_png_path = os.path.join(tmp_dir, TMP_PNG_FILENAME)
+        tmp_svg_path = os.path.join(tmp_dir, TMP_SVG_FILENAME)
         with codecs.open(tmp_latex_path, "w", "utf-8") as f:
             f.write(latex_output)
         with open(os.devnull, "w") as devnull:
@@ -111,6 +115,15 @@ def render_tikz(tikz_code, options, output_png=False):
                 ) as f:
                     sys.stderr.write(f.read())
                 raise
+            if output_svg:
+                try:
+                    subprocess.check_call(
+                        ["pdf2svg", TMP_PDF_FILENAME, TMP_SVG_FILENAME], cwd=tmp_dir, stdout=devnull, stderr=devnull
+                    )
+                    output_png = False
+                except (OSError, subprocess.CalledProcessError):
+                    output_png = True
+                    output_svg = False
             if output_png:
                 for command in (["mudraw"], ["mutool", "draw"]):
                     try:
@@ -125,17 +138,27 @@ def render_tikz(tikz_code, options, output_png=False):
                         last_exception = e
                 else:
                     raise last_exception
-        if output_png:
+        if output_svg:
+            shutil.move(tmp_svg_path, out_svg_filename)
+            out_filename = out_svg_filename
+        elif output_png:
             shutil.move(tmp_png_path, out_png_filename)
+            out_filename = out_png_filename
         else:
             shutil.move(tmp_pdf_path, out_pdf_filename)
-    return out_png_filename if output_png else out_pdf_filename
+            out_filename = out_pdf_filename
+    return out_filename
 
 
-def convert_png_to_html_base64(png_filepath):
-    with open(png_filepath.encode(sys.getfilesystemencoding()), "rb") as image_file:
+def convert_image_to_html_base64(image_filepath):
+    filetype = os.path.splitext(image_filepath)[1].lower()
+    if filetype.startswith("."):
+        filetype = filetype[1:]
+    if filetype == "svg":
+        filetype = "svg+xml"
+    with open(image_filepath.encode(sys.getfilesystemencoding()), "rb") as image_file:
         encoded_string = base64.b64encode(image_file.read())
-    return "data:image/png;base64," + encoded_string
+    return "data:image/{format};base64,".format(format=filetype) + encoded_string
 
 
 class Tikz(Directive):
@@ -182,9 +205,9 @@ class Tikz(Directive):
                 content = f.read()
         else:
             content = self.content
-        rendered_tikz_filename = render_tikz("\n".join(content), self.options, output_png=is_output_mode_html)
+        rendered_tikz_filename = render_tikz("\n".join(content), self.options, output_svg=is_output_mode_html)
         if is_output_mode_html:
-            reference = directives.uri(convert_png_to_html_base64(rendered_tikz_filename))
+            reference = directives.uri(convert_image_to_html_base64(rendered_tikz_filename))
         else:
             reference = directives.uri(rendered_tikz_filename)
         self.options["uri"] = reference