When an svg image has no viewbox tags, try to take the width/height

attribute as a fallback for these Allows the aspect ratio of svgs without a viewbox to be determined, resulting in correct rendering as svg markers (cherry picked from commit 0864e0a)
qgis · Sep 11, 2020 · ed47dd3 · ed47dd3
1 parent 5e6f5d9
commit ed47dd3
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diff --git a/src/core/symbology/qgssvgcache.cpp b/src/core/symbology/qgssvgcache.cpp
@@ -345,7 +345,31 @@ double QgsSvgCache::calcSizeScaleFactor( QgsSvgCacheEntry *entry, const QDomElem
 
   //could not find valid viewbox attribute
   if ( viewBox.isEmpty() )
+  {
+    // trying looking for width/height and use them as a fallback
+    if ( docElem.tagName() == QLatin1String( "svg" ) && docElem.hasAttribute( QStringLiteral( "width" ) ) )
+    {
+      const QString widthString = docElem.attribute( QStringLiteral( "width" ) );
+      const QRegularExpression measureRegEx( QStringLiteral( "([\\d\\.]+).*?$" ) );
+      const QRegularExpressionMatch widthMatch = measureRegEx.match( widthString );
+      if ( widthMatch.hasMatch() )
+      {
+        double width = widthMatch.captured( 1 ).toDouble();
+        const QString heightString = docElem.attribute( QStringLiteral( "height" ) );
+
+        const QRegularExpressionMatch heightMatch = measureRegEx.match( heightString );
+        if ( heightMatch.hasMatch() )
+        {
+          double height = heightMatch.captured( 1 ).toDouble();
+          viewboxSize = QSizeF( width, height );
+          return width / entry->size;
+        }
+      }
+    }
+
     return 1.0;
+  }
+
 
   //width should be 3rd element in a 4 part space delimited string
   QStringList parts = viewBox.split( ' ' );

diff --git a/tests/src/core/testqgssvgcache.cpp b/tests/src/core/testqgssvgcache.cpp
@@ -54,6 +54,7 @@ class TestQgsSvgCache : public QObject
     void base64();
     void replaceParams();
     void aspectRatio();
+    void noViewBox();
 
 };
 
@@ -332,6 +333,22 @@ void TestQgsSvgCache::aspectRatio()
   QVERIFY( imageCheck( QStringLiteral( "svgcache_aspect_ratio" ), img, 30 ) );
 }
 
+void TestQgsSvgCache::noViewBox()
+{
+  // if a source SVG has no viewbox but it does have width/height, use that as a backup so that
+  // we can correctly determine the svg's aspect ratio
+  const QString originalImage = TEST_DATA_DIR + QStringLiteral( "/svg/no_viewbox.svg" );
+  QgsSvgCache cache;
+  double size = 12;
+  const QColor fill = QColor( 0, 0, 0 );
+  const QColor stroke = QColor( 0, 0, 0 );
+  double strokeWidth = 1;
+  double widthScaleFactor = 1;
+  QSizeF viewBoxSize = cache.svgViewboxSize( originalImage, size, fill, stroke, strokeWidth, widthScaleFactor );
+  QGSCOMPARENEAR( viewBoxSize.width(), 1.329267, 0.0001 );
+  QGSCOMPARENEAR( viewBoxSize.height(), 6.358467, 0.0001 );
+}
+
 bool TestQgsSvgCache::imageCheck( const QString &testName, QImage &image, int mismatchCount )
 {
   //draw background

diff --git a/tests/testdata/svg/no_viewbox.svg b/tests/testdata/svg/no_viewbox.svg