SVG import: add support for semi-transparent text

<tspan fill-opacity="..."> from SVG was ignored so far, only taking RGB
colors from the 'fill' attribute, but ignoring transparency.

The problem is that an SVG file is imported by mapping it to
drawinglayer primitives, but TextSimplePortionPrimitive2D takes a
basegfx::BColor as the font color, which doesn't handle transparency.

Fix the problem by rendering SVG similar to how commit
81b0d5393ca4cf2ff0954e53b05928cde047c2e0 (svx: add rendering for
semi-transparent shape text, 2019-11-20) did it for shape text: wrap the
text primitive in a UnifiedTransparencePrimitive2D when opacity is not
1.

Note that the drawinglayer primitive works with transparency and SVG
works with opacity, which is the opposite of each other, but both are
0..1 ranges.

Change-Id: If5c48613b70eac662b54b8c9da835cd0a966ba89
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/143429
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

4 files changed, 57 insertions, 3 deletions

diff --git a/svgio/inc/svgcharacternode.hxx b/svgio/inc/svgcharacternode.hxx
index 50ecda7e3a89..738ddf4d9e73 100644
--- a/svgio/inc/svgcharacternode.hxx
+++ b/svgio/inc/svgcharacternode.hxx
@@ -123,7 +123,7 @@ namespace svgio::svgreader
             OUString           maText;
 
             /// local helpers
-            rtl::Reference<drawinglayer::primitive2d::TextSimplePortionPrimitive2D> createSimpleTextPrimitive(
+            rtl::Reference<drawinglayer::primitive2d::BasePrimitive2D> createSimpleTextPrimitive(
                 SvgTextPosition& rSvgTextPosition,
                 const SvgStyleAttributes& rSvgStyleAttributes) const;
             void decomposeTextWithStyle(
diff --git a/svgio/qa/cppunit/SvgImportTest.cxx b/svgio/qa/cppunit/SvgImportTest.cxx
index 9d9fb93dc8c1..cf678964b996 100644
--- a/svgio/qa/cppunit/SvgImportTest.cxx
+++ b/svgio/qa/cppunit/SvgImportTest.cxx
@@ -84,6 +84,7 @@ class Test : public test::BootstrapFixture, public XmlTestTools
     void testTdf97663();
     void testTdf149880();
     void testCssClassRedefinition();
+    void testTspanFillOpacity();
 
     Primitive2DSequence parseSvg(std::u16string_view aSource);
 
@@ -134,6 +135,7 @@ public:
     CPPUNIT_TEST(testTdf97663);
     CPPUNIT_TEST(testTdf149880);
     CPPUNIT_TEST(testCssClassRedefinition);
+    CPPUNIT_TEST(testTspanFillOpacity);
     CPPUNIT_TEST_SUITE_END();
 };
 
@@ -1127,6 +1129,28 @@ void Test::testCssClassRedefinition()
         pDocument, "/primitive2D/transform/textsimpleportion[1]", "familyname", "Open Symbol");
 }
 
+void Test::testTspanFillOpacity()
+{
+    // Given an SVG file with <tspan fill-opacity="0.30">:
+    std::u16string_view aPath = u"/svgio/qa/cppunit/data/tspan-fill-opacity.svg";
+
+    // When rendering that SVG:
+    Primitive2DSequence aSequence = parseSvg(aPath);
+
+    // Then make sure that the text portion is wrapped in a transparency primitive with the correct
+    // transparency value:
+    drawinglayer::Primitive2dXmlDump aDumper;
+    xmlDocUniquePtr pDocument = aDumper.dumpAndParse(Primitive2DContainer(aSequence));
+    sal_Int32 nTransparence = getXPath(pDocument, "//textsimpleportion[@text='hello']/parent::unifiedtransparence", "transparence").toInt32();
+    // Without the accompanying fix in place, this test would have failed with:
+    // - Expected: 1
+    // - Actual  : 0
+    // - XPath '//textsimpleportion[@text='hello']/parent::unifiedtransparence' number of nodes is incorrect
+    // i.e. the relevant <textsimpleportion> had no <unifiedtransparence> parent, the text was not
+    // semi-transparent.
+    CPPUNIT_ASSERT_EQUAL(static_cast<sal_Int32>(70), nTransparence);
+}
+
 CPPUNIT_TEST_SUITE_REGISTRATION(Test);
 
 }
diff --git a/svgio/qa/cppunit/data/tspan-fill-opacity.svg b/svgio/qa/cppunit/data/tspan-fill-opacity.svg
new file mode 100644
index 000000000000..ef6d5352a8d2
--- /dev/null
+++ b/svgio/qa/cppunit/data/tspan-fill-opacity.svg
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.2" width="210mm" height="297mm" viewBox="0 0 21000 29700" preserveAspectRatio="xMidYMid" fill-rule="evenodd" stroke-width="28.222" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg" xmlns:presentation="http://sun.com/xmlns/staroffice/presentation" xmlns:smil="http://www.w3.org/2001/SMIL20/" xmlns:anim="urn:oasis:names:tc:opendocument:xmlns:animation:1.0" xmlns:svg="urn:oasis:names:tc:opendocument:xmlns:svg-compatible:1.0" xml:space="preserve">
+  <g class="ClosedBezierShape">
+    <rect stroke="none" fill="none" x="9737" y="6537" width="7527" height="3527"/>
+    <g style="opacity: 0.30">
+      <path fill="none" stroke="rgb(255,0,0)" stroke-width="25" stroke-linejoin="round" d="M 9875,6550 C 9806,6550 9750,6606 9750,6675 L 9750,9925 C 9750,9994 9806,10050 9875,10050 L 17125,10050 C 17194,10050 17250,9994 17250,9925 L 17250,6675 C 17250,6606 17194,6550 17125,6550 L 17000,6550 9875,6550 Z"/>
+    </g>
+  </g>
+  <g class="TextShape">
+    <rect stroke="none" fill="none" x="9825" y="6550" width="4076" height="955"/>
+    <text>
+      <tspan x="9825" y="7939" font-family="Arial Narrow, sans-serif" font-size="800px" fill-opacity="0.30" fill="rgb(255,0,0)" stroke="none">hello</tspan>
+    </text>
+  </g>
+</svg>
diff --git a/svgio/source/svgreader/svgcharacternode.cxx b/svgio/source/svgreader/svgcharacternode.cxx
index d2949d5a0630..4ca8a3468c02 100644
--- a/svgio/source/svgreader/svgcharacternode.cxx
+++ b/svgio/source/svgreader/svgcharacternode.cxx
@@ -24,6 +24,7 @@
 #include <drawinglayer/primitive2d/textlayoutdevice.hxx>
 #include <drawinglayer/primitive2d/textbreakuphelper.hxx>
 #include <drawinglayer/primitive2d/textdecoratedprimitive2d.hxx>
+#include <drawinglayer/primitive2d/unifiedtransparenceprimitive2d.hxx>
 #include <utility>
 #include <o3tl/string_view.hxx>
 #include <osl/diagnose.h>
@@ -208,12 +209,12 @@ namespace svgio::svgreader
             }
         }
 
-        rtl::Reference<TextSimplePortionPrimitive2D> SvgCharacterNode::createSimpleTextPrimitive(
+        rtl::Reference<BasePrimitive2D> SvgCharacterNode::createSimpleTextPrimitive(
             SvgTextPosition& rSvgTextPosition,
             const SvgStyleAttributes& rSvgStyleAttributes) const
         {
             // prepare retval, index and length
-            rtl::Reference<TextSimplePortionPrimitive2D> pRetval;
+            rtl::Reference<BasePrimitive2D> pRetval;
             sal_uInt32 nLength(getText().getLength());
 
             if(nLength)
@@ -412,6 +413,13 @@ namespace svgio::svgreader
                 if(rSvgStyleAttributes.getFill())
                     aFill = *rSvgStyleAttributes.getFill();
 
+                // get fill opacity
+                double fFillOpacity = 1.0;
+                if (rSvgStyleAttributes.getFillOpacity().isSet())
+                {
+                    fFillOpacity = rSvgStyleAttributes.getFillOpacity().getNumber();
+                }
+
                 // prepare TextTransformation
                 basegfx::B2DHomMatrix aTextTransform;
 
@@ -487,6 +495,13 @@ namespace svgio::svgreader
                         aFill);
                 }
 
+                if (fFillOpacity != 1.0)
+                {
+                    pRetval = new UnifiedTransparencePrimitive2D(
+                        drawinglayer::primitive2d::Primitive2DContainer{ pRetval },
+                        1.0 - fFillOpacity);
+                }
+
                 // advance current TextPosition
                 rSvgTextPosition.setPosition(rSvgTextPosition.getPosition() + basegfx::B2DVector(fTextWidth, 0.0));
             }