1 files changed, 111 insertions, 0 deletions
diff --git a/sphinx/util/images.py b/sphinx/util/images.py
new file mode 100644
index 0000000..2def252
--- /dev/null
+++ b/sphinx/util/images.py
@@ -0,0 +1,111 @@
+"""Image utility functions for Sphinx."""
+
+import base64
+import imghdr
+from collections import OrderedDict
+from os import path
+from typing import IO, BinaryIO, NamedTuple, Optional, Tuple
+
+import imagesize
+
+try:
+    from PIL import Image
+except ImportError:
+    Image = None
+
+mime_suffixes = OrderedDict([
+    ('.gif', 'image/gif'),
+    ('.jpg', 'image/jpeg'),
+    ('.png', 'image/png'),
+    ('.pdf', 'application/pdf'),
+    ('.svg', 'image/svg+xml'),
+    ('.svgz', 'image/svg+xml'),
+    ('.ai', 'application/illustrator'),
+])
+
+
+class DataURI(NamedTuple):
+    mimetype: str
+    charset: str
+    data: bytes
+
+
+def get_image_size(filename: str) -> Optional[Tuple[int, int]]:
+    try:
+        size = imagesize.get(filename)
+        if size[0] == -1:
+            size = None
+        elif isinstance(size[0], float) or isinstance(size[1], float):
+            size = (int(size[0]), int(size[1]))
+
+        if size is None and Image:  # fallback to Pillow
+            with Image.open(filename) as im:
+                size = im.size
+
+        return size
+    except Exception:
+        return None
+
+
+def guess_mimetype_for_stream(stream: IO, default: Optional[str] = None) -> Optional[str]:
+    imgtype = imghdr.what(stream)
+    if imgtype:
+        return 'image/' + imgtype
+    else:
+        return default
+
+
+def guess_mimetype(filename: str = '', default: Optional[str] = None) -> Optional[str]:
+    _, ext = path.splitext(filename.lower())
+    if ext in mime_suffixes:
+        return mime_suffixes[ext]
+    elif path.exists(filename):
+        with open(filename, 'rb') as f:
+            return guess_mimetype_for_stream(f, default=default)
+
+    return default
+
+
+def get_image_extension(mimetype: str) -> Optional[str]:
+    for ext, _mimetype in mime_suffixes.items():
+        if mimetype == _mimetype:
+            return ext
+
+    return None
+
+
+def parse_data_uri(uri: str) -> Optional[DataURI]:
+    if not uri.startswith('data:'):
+        return None
+
+    # data:[<MIME-type>][;charset=<encoding>][;base64],<data>
+    mimetype = 'text/plain'
+    charset = 'US-ASCII'
+
+    properties, data = uri[5:].split(',', 1)
+    for prop in properties.split(';'):
+        if prop == 'base64':
+            pass  # skip
+        elif prop.startswith('charset='):
+            charset = prop[8:]
+        elif prop:
+            mimetype = prop
+
+    image_data = base64.b64decode(data)
+    return DataURI(mimetype, charset, image_data)
+
+
+def test_svg(h: bytes, f: Optional[BinaryIO]) -> Optional[str]:
+    """An additional imghdr library helper; test the header is SVG's or not."""
+    try:
+        if '<svg' in h.decode().lower():
+            return 'svg+xml'
+    except UnicodeDecodeError:
+        pass
+
+    return None
+
+
+# install test_svg() to imghdr
+# refs: https://docs.python.org/3.6/library/imghdr.html#imghdr.tests
+imghdr.tests.append(test_svg)