Add basic <symbol> support in SVG

CHANGELOG.md

@@ -19,6 +19,7 @@ This can also be enabled programmatically with `warnings.simplefilter('default',
 ## [2.8.8] - Not released yet
 ### Added
 * Punjabi (pa) tutorial translation - thanks to @Pawansingh3889
+* basic support for SVG `<symbol>` elements in the SVG parser
 * `resource_access_policy` and [Security considerations](https://py-pdf.github.io/fpdf2/Security.html) documentation
 ### Fixed
 * text rendering when the first text on a page starts with a fallback glyph - _cf._ [issue #1772](https://github.com/py-pdf/fpdf2/issues/1772)

fpdf/svg.py

@@ -1473,6 +1473,8 @@ def handle_defs(self, defs: "Element") -> None:
         for child in defs:
             if child.tag in xmlns_lookup("svg", "g"):
                 self.build_group(child)
+            elif child.tag in xmlns_lookup("svg", "symbol"):
+                self.build_symbol(child)
             elif child.tag in xmlns_lookup("svg", "a"):
                 # <a> tags aren't supported but we need to recurse into them to
                 # render nested elements.
@@ -1506,6 +1508,20 @@ def handle_defs(self, defs: "Element") -> None:
                     without_ns(child.tag),
                 )
 
+    @force_nodocument
+    def build_symbol(self, symbol: "Element") -> GraphicsContext:
+        """Parse <symbol> as reusable content, not rendered directly."""
+        group = self.build_group(symbol)
+        viewbox = symbol.attrib.get("viewBox")
+        if viewbox:
+            parts = viewbox.replace(",", " ").split()
+            if len(parts) >= 4:
+                vx, vy, vw, vh = (float(p) for p in parts[:4])
+                group.transform = Transform.scaling(
+                    x=1 / vw, y=1 / vh
+                ) @ Transform.translation(x=-vx, y=-vy)
+        return group
+
     # this assumes xrefs only reference already-defined ids.
     # I don't know if this is required by the SVG spec.
     @force_nodocument
@@ -1525,7 +1541,8 @@ def build_xref(self, xref: "Element") -> GraphicsContext:
             raise ValueError(f"use {xref} doesn't contain known xref attribute")
 
         try:
-            pdf_group.add_item(self.cross_references[ref])
+            target = self.cross_references[ref]
+            pdf_group.add_item(target)
         except KeyError:
             raise ValueError(
                 f"use {xref} references nonexistent ref id {ref}"
@@ -1536,7 +1553,20 @@ def build_xref(self, xref: "Element") -> GraphicsContext:
             # > The x and y properties define an additional transformation translate(x,y)
             x, y = float(xref.attrib.get("x", 0)), float(xref.attrib.get("y", 0))
             pdf_group.transform = Transform.translation(x=x, y=y)
-        # Note that we currently do not support "width" & "height" in <use>
+        # Note that we currently do not support "width" & "height" with % in <use>
+
+        if "width" in xref.attrib or "height" in xref.attrib:
+            w_str = xref.attrib.get("width", "")
+            h_str = xref.attrib.get("height", "")
+            if "%" not in w_str and "%" not in h_str:
+                w = float(w_str) if w_str else 1
+                h = float(h_str) if h_str else 1
+                if pdf_group.transform is None:
+                    pdf_group.transform = Transform.scaling(x=w, y=h)
+                else:
+                    pdf_group.transform = (
+                        Transform.scaling(x=w, y=h) @ pdf_group.transform
+                    )
 
         return pdf_group
 
@@ -1567,6 +1597,8 @@ def build_group(
             elif child.tag in xmlns_lookup("svg", "style"):
                 # Stylesheets already parsed globally.
                 continue
+            elif child.tag in xmlns_lookup("svg", "symbol"):
+                self.build_symbol(child)
             elif child.tag in xmlns_lookup("svg", "g"):
                 pdf_group.add_item(self.build_group(child, None, merged_style), False)
             elif child.tag in xmlns_lookup("svg", "a"):

test/svg/test_svg.py

@@ -246,6 +246,20 @@ def test_missing_xref(self):
         with pytest.raises(ValueError):
             fpdf.svg.SVGObject(svg_data)
 
+    def test_svg_symbol(self):
+        svg_data = (
+            '<svg xmlns="http://www.w3.org/2000/svg" '
+            'xmlns:xlink="http://www.w3.org/1999/xlink">'
+            "<defs>"
+            '<symbol id="rond" width="10" height="10" viewBox="0 0 2 2"><circle cx="1" cy="1" r="1" fill="red"/></symbol>'
+            "</defs>"
+            '<use href="#rond" x="10" y="10" width="40" height="40"/>'
+            "</svg>"
+        )
+        svg = fpdf.svg.SVGObject(svg_data)
+        assert svg is not None
+        assert "#rond" in svg.cross_references
+
     def test_svg_conversion_no_transparency(self, tmp_path):
         svg = fpdf.svg.SVGObject.from_file(parameters.svgfile("SVG_logo.svg"))