[Font problems are enough to drive people crazy, let’s hope that does not happen here]
[Note, I am not encountering the problem of the cluster being to narrow. If anything, I am seeing cluster-too-wide.]
The Font FAQ (Font FAQ | Graphviz) will tell you lots about font problems.
Here are some possible solutions to this specific problem - choose one:
style=bold is not redundant, as this attribute is referring to the bounding box, not the font. Additionally, I only want part of the label to be bold, as I plan on adding additional detail to the label later.
I’ve confirmed that using svg:cairo fixes the issue, however I am not certain the extra overhead is worth it. Therefore, I think the only option left is for me to add additional spaces.
As Steve has alluded to, the problem is essentially that Graphviz’ native SVG renderer only does a limited estimation of text width. Answering “how wide is this text?” is a surprisingly complicated question. A full solution looks something like Cairo, which is why Graphviz has support for using that.