diff --git a/cplusplus/Doxyfile.in b/cplusplus/Doxyfile.in
index b489896b..81ae6e67 100644
--- a/cplusplus/Doxyfile.in
+++ b/cplusplus/Doxyfile.in
@@ -2461,7 +2461,7 @@ DIRECTORY_GRAPH        = YES
 # The default value is: png.
 # This tag requires that the tag HAVE_DOT is set to YES.
 
-DOT_IMAGE_FORMAT       = png
+DOT_IMAGE_FORMAT       = svg
 
 # If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
 # enable generation of interactive SVG images that allow zooming and panning.