Support generating index-color PNG files

Based on the request http://stackoverflow.com/questions/27036474/how-do-make-doxygen-generate-index-color-png-files for index colored png files, this functionality will be included in the newer versions (2.39) of dot.
The functionality -Tpng:cairo:gd will automatically be used by doxygen, though the file extension would be wrong (.png:cairo:gd).
With this patch the :cairo:gd is stripped from the image extension, but not from the -T of the dot command.
In the doxywizard the different possibilities are supplied as well. Note however that the DOT_IMAGE_FORMAT name is not checked when read from the Doxyfile so it is possible to use other renderer / formats as well due to the generic solution with getDot ImageExtension.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/util.h b/src/util.h
index 937b222..b044d26 100644
--- a/src/util.h
+++ b/src/util.h
@@ -443,6 +443,8 @@ bool protectionLevelVisible(Protection prot);
 
 QCString stripIndentation(const QCString &s);
 
+QCString getDotImageExtension(void);
+
 bool fileVisibleInIndex(FileDef *fd,bool &genSourceFile);
 
 void addDocCrossReference(MemberDef *src,MemberDef *dst);