Hardcode a DPI of 72 into GDAL GeoPDF composition file instead of

original layout DPI This fixes the incorrect page size reported by Acrobat reader for generated GeoPDF files. Unfortunately it comes with a side-effect of limiting the resolution at which GDAL will read the GeoPDF files as a raster layer, but of the two issues the page size issue is more critical. Fixes #33465
qgis · Oct 22, 2020 · 460bf8e · 460bf8e
1 parent f5c8739
commit 460bf8e
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/src/core/qgsabstractgeopdfexporter.cpp b/src/core/qgsabstractgeopdfexporter.cpp
@@ -408,9 +408,10 @@ QString QgsAbstractGeoPdfExporter::createCompositionXml( const QList<ComponentLa
   // pages
   QDomElement page = doc.createElement( QStringLiteral( "Page" ) );
   QDomElement dpi = doc.createElement( QStringLiteral( "DPI" ) );
-  dpi.appendChild( doc.createTextNode( qgsDoubleToString( details.dpi ) ) );
+  // hardcode DPI of 72 to get correct page sizes in outputs -- refs discussion in https://github.com/OSGeo/gdal/pull/2961
+  dpi.appendChild( doc.createTextNode( qgsDoubleToString( 72 ) ) );
   page.appendChild( dpi );
-  // assumes DPI of 72, which is an assumption on GDALs/PDF side. It's only related to the PDF coordinate space and doesn't affect the actual output DPI!
+  // assumes DPI of 72, as noted above.
   QDomElement width = doc.createElement( QStringLiteral( "Width" ) );
   const double pageWidthPdfUnits = std::ceil( details.pageSizeMm.width() / 25.4 * 72 );
   width.appendChild( doc.createTextNode( qgsDoubleToString( pageWidthPdfUnits ) ) );