Add basic support for adding SVG pictures to docx files

See issues python-openxml#351, python-openxml#651, python-openxml#659.

Author: takis

src/docx/image/__init__.py

@@ -9,6 +9,7 @@
 from docx.image.jpeg import Exif, Jfif
 from docx.image.png import Png
 from docx.image.tiff import Tiff
+from docx.image.svg import Svg
 
 SIGNATURES = (
     # class, offset, signature_bytes
@@ -20,4 +21,5 @@
     (Tiff, 0, b"MM\x00*"),  # big-endian (Motorola) TIFF
     (Tiff, 0, b"II*\x00"),  # little-endian (Intel) TIFF
     (Bmp, 0, b"BM"),
+    (Svg, 0, b"<svg "),
 )

src/docx/image/constants.py

@@ -105,6 +105,7 @@ class MIME_TYPE:
     JPEG = "image/jpeg"
     PNG = "image/png"
     TIFF = "image/tiff"
+    SVG = "image/svg+xml"
 
 
 class PNG_CHUNK_TYPE:

src/docx/image/svg.py

@@ -0,0 +1,49 @@
+# encoding: utf-8
+
+from __future__ import absolute_import, division, print_function
+
+import xml.etree.ElementTree as ET
+
+from .constants import MIME_TYPE
+from .image import BaseImageHeader
+
+
+class Svg(BaseImageHeader):
+    """
+    Image header parser for SVG images.
+    """
+
+    @classmethod
+    def from_stream(cls, stream):
+        """
+        Return |Svg| instance having header properties parsed from SVG image
+        in *stream*.
+        """
+        px_width, px_height = cls._dimensions_from_stream(stream)
+        return cls(px_width, px_height, 72, 72)
+
+    @property
+    def content_type(self):
+        """
+        MIME content type for this image, unconditionally `image/svg+xml` for
+        SVG images.
+        """
+        return MIME_TYPE.SVG
+
+    @property
+    def default_ext(self):
+        """
+        Default filename extension, always 'svg' for SVG images.
+        """
+        return "svg"
+
+    @classmethod
+    def _dimensions_from_stream(cls, stream):
+        stream.seek(0)
+        data = stream.read()
+        root = ET.fromstring(data)
+        # FIXME: The width could be expressed as '4cm'
+        # See https://www.w3.org/TR/SVG11/struct.html#NewDocument
+        width = int(root.attrib["width"])
+        height = int(root.attrib["height"])
+        return width, height

src/docx/oxml/__init__.py

@@ -44,6 +44,8 @@
 
 register_element_cls("a:blip", CT_Blip)
 register_element_cls("a:ext", CT_PositiveSize2D)
+register_element_cls("a:extLst", CT_Transform2D)
+register_element_cls("asvg:svgBlip", CT_Transform2D)
 register_element_cls("a:graphic", CT_GraphicalObject)
 register_element_cls("a:graphicData", CT_GraphicalObjectData)
 register_element_cls("a:off", CT_Point2D)

src/docx/oxml/ns.py

@@ -21,6 +21,7 @@
     "wp": "http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing",
     "xml": "http://www.w3.org/XML/1998/namespace",
     "xsi": "http://www.w3.org/2001/XMLSchema-instance",
+    "asvg": "http://schemas.microsoft.com/office/drawing/2016/SVG/main",
 }
 
 pfxmap = {value: key for key, value in nsmap.items()}

src/docx/oxml/shape.py

@@ -40,6 +40,7 @@ class CT_Blip(BaseOxmlElement):
     link: str | None = OptionalAttribute(  # pyright: ignore[reportAssignmentType]
         "r:link", ST_RelationshipId
     )
+    extLst = ZeroOrOne("a:extLst")
 
 
 class CT_BlipFillProperties(BaseOxmlElement):
@@ -115,7 +116,7 @@ def _inline_xml(cls):
             "  <a:graphic>\n"
             '    <a:graphicData uri="URI not set"/>\n'
             "  </a:graphic>\n"
-            "</wp:inline>" % nsdecls("wp", "a", "pic", "r")
+            "</wp:inline>" % nsdecls("wp", "a", "pic", "r", "asvg")
         )
 
 
@@ -149,14 +150,48 @@ def new(cls, pic_id, filename, rId, cx, cy):
         """Return a new ``<pic:pic>`` element populated with the minimal contents
         required to define a viable picture element, based on the values passed as
         parameters."""
-        pic = parse_xml(cls._pic_xml())
+        if filename.endswith(".svg"):
+            pic = parse_xml(cls._pic_xml_svg())
+            pic.blipFill.blip.extLst.ext.svgBlip.embed = rId
+        else:
+            pic = parse_xml(cls._pic_xml())
+            pic.blipFill.blip.embed = rId
         pic.nvPicPr.cNvPr.id = pic_id
         pic.nvPicPr.cNvPr.name = filename
-        pic.blipFill.blip.embed = rId
         pic.spPr.cx = cx
         pic.spPr.cy = cy
         return pic
 
+    @classmethod
+    def _pic_xml_svg(cls):
+        return (
+            "<pic:pic %s>\n"
+            "  <pic:nvPicPr>\n"
+            '    <pic:cNvPr id="666" name="unnamed"/>\n'
+            "    <pic:cNvPicPr/>\n"
+            "  </pic:nvPicPr>\n"
+            "  <pic:blipFill>\n"
+            "    <a:blip>\n"
+            "      <a:extLst>\n"
+            '        <a:ext uri="{96DAC541-7B7A-43D3-8B79-37D633B846F1}">\n'
+            "          <asvg:svgBlip/>\n"
+            "        </a:ext>\n"
+            "      </a:extLst>\n"
+            "    </a:blip>\n"
+            "    <a:stretch>\n"
+            "      <a:fillRect/>\n"
+            "    </a:stretch>\n"
+            "  </pic:blipFill>\n"
+            "  <pic:spPr>\n"
+            "    <a:xfrm>\n"
+            '      <a:off x="0" y="0"/>\n'
+            '      <a:ext cx="914400" cy="914400"/>\n'
+            "    </a:xfrm>\n"
+            '    <a:prstGeom prst="rect"/>\n'
+            "  </pic:spPr>\n"
+            "</pic:pic>" % nsdecls("pic", "a", "r", "asvg")
+        )
+
     @classmethod
     def _pic_xml(cls):
         return (
@@ -178,7 +213,7 @@ def _pic_xml(cls):
             "    </a:xfrm>\n"
             '    <a:prstGeom prst="rect"/>\n'
             "  </pic:spPr>\n"
-            "</pic:pic>" % nsdecls("pic", "a", "r")
+            "</pic:pic>" % nsdecls("pic", "a", "r", "asvg")
         )
 
 
@@ -210,6 +245,7 @@ class CT_PositiveSize2D(BaseOxmlElement):
     cy: Length = RequiredAttribute(  # pyright: ignore[reportAssignmentType]
         "cy", ST_PositiveCoordinate
     )
+    svgBlip = ZeroOrOne("asvg:svgBlip")
 
 
 class CT_PresetGeometry2D(BaseOxmlElement):
@@ -276,6 +312,7 @@ class CT_Transform2D(BaseOxmlElement):
 
     off = ZeroOrOne("a:off", successors=("a:ext",))
     ext = ZeroOrOne("a:ext", successors=())
+    embed = OptionalAttribute("r:embed", ST_RelationshipId)
 
     @property
     def cx(self):