svgio: font-variation-settings is an inherited property

It is inherited per CSS Fonts, so the children of a group must inherit
it when set on the group.

Change-Id: I3a7f1c58b249e0d647c3b8a15f9e2043b7d6c891
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/209212
Reviewed-by: Khaled Hosny <khaled@libreoffice.org>
Tested-by: Jenkins

svgio/inc/svgstyleattributes.hxx

@@ -422,7 +422,7 @@ namespace svgio::svgreader
             void setFontWeight(const FontWeight aFontWeight) { maFontWeight = aFontWeight; }
 
             /// FontVariations content
-            const std::vector<vcl::font::Variation>& getFontVariations() const { return maFontVariations; }
+            const std::vector<vcl::font::Variation>& getFontVariations() const;
             void setFontVariations(std::vector<vcl::font::Variation>&& rFontVariations) { maFontVariations = std::move(rFontVariations); }
 
             /// FontDirection content

svgio/qa/cppunit/SvgImportTest.cxx

@@ -2293,6 +2293,21 @@ CPPUNIT_TEST_FIXTURE(Test, testFontVariationSettings)
     assertXPath(pDocument, "//textsimpleportion[7]", "font-variation-settings", u"\"wght\" 700");
 }
 
+CPPUNIT_TEST_FIXTURE(Test, testFontVariationSettingsInherit)
+{
+    // font-variation-settings is an inherited property.
+    xmlDocUniquePtr pDocument
+        = dumpAndParseSvg(u"/svgio/qa/cppunit/data/font-variation-settings-inherit.svg");
+
+    assertXPath(pDocument, "//textsimpleportion", 3);
+    // inherited from the group
+    assertXPath(pDocument, "//textsimpleportion[1]", "font-variation-settings", u"\"wght\" 300");
+    // the child's own list replaces the inherited one, it does not merge with it
+    assertXPath(pDocument, "//textsimpleportion[2]", "font-variation-settings", u"\"wght\" 700");
+    // the script of the text makes no difference
+    assertXPath(pDocument, "//textsimpleportion[3]", "font-variation-settings", u"\"wght\" 300");
+}
+
 CPPUNIT_PLUGIN_IMPLEMENT();
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

svgio/qa/cppunit/data/font-variation-settings-inherit.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <g font-family="Reem Kufi" font-variation-settings="'wght' 300">
+    <text y="1em">Inherited</text>
+    <text y="2em" style="font-variation-settings: 'wght' 700">Overridden</text>
+    <text y="3em" font-family="Noto Sans Arabic">مرحبا</text>
+  </g>
+</svg>

svgio/source/svgreader/svgstyleattributes.cxx

@@ -1367,7 +1367,7 @@ namespace svgio::svgreader
             maBaselineShift(BaselineShift::Baseline),
             maBaselineShiftNumber(0),
             maDominantBaseline(DominantBaseline::Auto),
-            maResolvingParent(36, 0),
+            maResolvingParent(37, 0),
             mbStrokeDasharraySet(false),
             mbUseFillFromContextFill(false),
             mbUseFillFromContextStroke(false),
@@ -2843,6 +2843,28 @@ namespace svgio::svgreader
             return FontStyle::normal;
         }
 
+        const std::vector<vcl::font::Variation>& SvgStyleAttributes::getFontVariations() const
+        {
+            if (!maFontVariations.empty())
+            {
+                return maFontVariations;
+            }
+
+            const SvgStyleAttributes* pSvgStyleAttributes = getCssStyleOrParentStyle();
+
+            if (pSvgStyleAttributes && maResolvingParent[36] < nStyleDepthLimit)
+            {
+                ++maResolvingParent[36];
+                const std::vector<vcl::font::Variation>& rInherited
+                    = pSvgStyleAttributes->getFontVariations();
+                --maResolvingParent[36];
+
+                return rInherited;
+            }
+
+            return maFontVariations;
+        }
+
         FontWeight SvgStyleAttributes::getFontWeight() const
         {
             if(maFontWeight != FontWeight::notset)