Some relation labels are omitted even when there is enough space to display them

[StephenF55]

The above behaviour is understandable in a 'busy' diagram with lots of relations that is fully zoomed out (i.e. it becomes difficult to distinguish what relation a label is associated with and/or closely spaced relation line labels end up sitting on top of one another, making them impossible to read.

This is the situation in my diagram. The issues I found are:

1. When I zoom in - by selecting a particular resource (thus hiding all irrelevant resources/relations) - labels that should appear in that much simpler layout are not displayed as expected. See attached screenshot, which has two relations with their label omitted (highlighted in yellow).

2. In the fully zoomed out diagram, 'labelless' relations should, at a minimum, produce a pop-up caption when moused over. I notice that this is the current behaviour where a relation's label text has been truncated to save space. However, the 'mouse over' seems to be restricted to hovering over the label text and not the line, which is a pity and also explains why this default behaviour doesn't help with my 'labelless' relation problem. As an aside, I feel that mousing over relation lines should highlight the current line by 'greying out' all other lines. This would neatly mirror the, extremely useful, current behaviour when a resource is moused over.

[billy-pilger]

Hi, thanks for this report. These are good points and I can see how the labels not appearing consistently would be frustrating. I'll take a look at that and the mouse-over suggestion for lines. It's a good idea if it is workable.

[StephenF55]

A couple of other comments...

1. If it helps, I can email you the YAML file to make it easier for you to see exactly the problem I'm trying to describe (I'd prefer to do that rather than post it on this public forum)
2. I've an idea for handling the 'too many arrows' problem that I'll hopefully get round to, but will post on a separate thread

[StephenF55]

Possible Fix Found

After reading your blog post on "Breaking up the master diagram", I decided to try and simplify my diagram by splitting into it two perspectives as follows:

• A 'Hi' perspective covering relations between 'parent' resources
• A 'Lo' perspective covering relations between 'child' resources

To explain, my diagram is C4 model-based that is structured as follows:

• A single container housing 2 'parent' components
• The 1st parent contains 16 child components with the following relation arrows:
  --> 41 'internal' arrows purely between sibling child components
  --> ~30 'external' arrows that output signals from some child components to child components in the 2nd parent (note that, due to label duplication, ilograph simplifies the actual arrow number down to ~20 arrows)
• The 2nd parent contains only 3 child components, which only receive the ~20 relation arrows from the 1st parent (i.e. have no 'internal' relation arrows going between them)

With the above arrangement in place - to separate 'internal' from 'external' concerns - I now find that, with careful selection of resources in the current perspective, all relation labels can be made visible.

Conclusion

The above approach solves the problem, as I'm now able to see all labels. This is important, as my particular use case requires that users are able to mouse over any label in the diagram of their choosing in order to reveal the associated 'description' caption containing a hyperlink to further important info.

Whilst ilograph is extremely well thought out and incredibly user-friendly, I still feel that the relation label management has a couple of rough edges: such as font size being reduced in some instances, but not others that seem equally in need of a size reduction. Also the wrapping of long label names means valuable real-estate causes nearby labels to be omitted (perhaps, when a congested network of arrows is detected, such long names could be truncated to put them on one line?).

However these are minor quibbles, as the workaround above achieves my original goal.

[billy-pilger]

Hi, thanks for this feedback. I think you're right that label display could be improved, especially when the labels have descriptions. I'll investigate more to see what can be done. In the meantime, yes, breaking up perspectives is by far the most common "workaround" when things get tight :)

Anyway, as of 2.2.3 (just released) the labels should appear more often, like in your original case.

[StephenF55]

Thanks, I can see the new 2.2.3 release does work in some cases e.g the leftmost arrow above does indeed now have a label.

However, as you say, the fix helps but isn't comprehensive. There are still a few 'missing label' examples in my diagram, which ideally would be populated with a label (as there's plenty of surrounding space). For example, the yellow-highlighted relation below:

Admittedly the above errant behaviour is restricted to my 'busiest' perspective, which is populated with all possible resources and all possible relations in the source C4 model. This behaviour is understandable, as I'm sure that, over a certain threshold, the complexity that the layout algorithm has to resolve rises exponentially with each additional resource/relation and so it ends up making the odd 'wrong' decision (as in the above image).

As I've said before, my simpler 'Hi' and 'Lo' perspectives that I later introduced don't suffer from this problem. As the same relation (as viewed via the 'Lo Level' perspective) illustrates below:

[billy-pilger]

Great, thanks for this follow-up. Eyeballing it I think I have a pretty good idea of what the issue might be. Look for a fix in the next release (if I'm right 🙏).