clang-uml diagrams can be easily added to the Doxygen documentation using the image tag, however Doxygen does not support the clang-uml specific commands, which will appear in the documentation unprocessed.

The best solution to this is to tell Doxygen to ignore them, by adding the following lines to the Doxygen config file:

ALIASES                += uml=""
ALIASES                += uml{1}=""
ALIASES                += uml{2}=""
ALIASES                += uml{3}=""

Furthermore, Doxygen adds images to HTML documentation as <img src=""/>, which disables interactive links in SVG diagrams. One way to go around it is to use a special command for these images, for instance:

ALIASES += embed{1}="\htmlonly <embed src=\"\1\"/> \endhtmlonly"

and then use the following in the source code comments:

/**
 * @brief Base class for all diagram models
 *
 * @embed{diagram_hierarchy_class.svg}
 */
class diagram {
public:
// ...

This directive in the configuration file will add the SVG diagrams using <embed> HTML tag, and enable the links in the diagram on most browsers.

Finally, to have clang-uml generate links from diagram elements such as classes or packages to Doxygen pages, it is only necessary to add the following configuration file option:

generate_links:
  link: "{% if existsIn(element, \"doxygen_link\") %}{{ element.doxygen_link }}{% endif %}"
  tooltip: "{% if existsIn(element, \"comment\") and existsIn(element.comment, \"brief\") %}{{ abbrv(trim(replace(element.comment.brief.0, \"\\n+\", \" \")), 256) }}{% else %}{{ element.name }}{% endif %}"

This option will tell clang-uml to generate a link to a local Doxygen documentation page, provided that it is possible to generate it. Currently, this only works for diagram elements, it will not work for instance for individual methods.