Single Comment

The page actually does produce a PNG image that can be uploaded to this website, when you hit the 'Draw' button. It also prints the URL for direct access to the renderer; this seemed useful for people that want to post a diagram on a site where they cannot upload stuff. I am not even sure that people who don't have contributed articles here can upload anything, e.g. for posting an image in a Comment.

The illustrations in the article can easily be replaced by uploaded images, and for some of those this would indeed be better. But it is very useful that a potential user can have some advance warning in the rare case that the rendering engine is off-line or unreachable, before he spends a lot of effort on composing a diagram that in the end will not render. Having an image on the page that directly samples the renderer seems a good way to do that. (Frankly, I do not know another way; browser security policies prevent probing another website in the background through JavaScript directly.)

Note that I do not want to keep the rendering engine on my website; I would be perfectly happy if it were on this website. It is just that there is no way for me to get it there, lacking ftp access.

The warning message is not really a technical problem; I can make it disappear through editing (the JavaScript embedded in) this page. So there is no need to build any special provision in the database for that. It is purely a policy matter whether it should be there and what it should say. When I first submitted the article I had in fact replaced it with a message explaining the purpose of the off-site images for the editors, but an editor commented that out of the script. That was fine with me; it meant he had seen it. For this occasion I temporarily re-instated the alternate warning.