I have developed a internal site that genererates inline diagrams in HTML, but for doing this it requires a line separator such as the semicolon so it is visualy good.
I did this with intermedia DiagramGenerator that replaces the semicolon with the line separator.
The proposal is for plantuml to support an explicit line separator, that can be used as in the following example
<img src="http://pumlinline/redirect/
actor User;
User --> Wiki;
Wiki --> DiagramGenerator : Request;
;
DiagramGenerator --> GitRepository : GetFile;
DiagramGenerator --> PlantUml : GetRedirect;
DiagramGenerator --> Wiki : Redirect;
Wiki --> PlantUml : GetCachedImage;
" />
<!-- Please note that lines in the example are separated with semicolon -->
<!-- Blank lines are not supported-->