Unbundled bezier edge disappear or flip when nodes are close

[anthonyhtyao]

Environment info

• Cytoscape.js version : 3.30.0
• Browser/Node.js & version : firefox 126.0.1

Current (buggy) behaviour

Unbundled bezier edges disappear (2nd) or flip (3rd) when two nodes are next to each other or overlap as shown below

p.s. there is an ancient issue about the flip #411

Desired behaviour

The second and third edges should display similarly to the first one

Minimum steps to reproduce

Here is the js code to reproduce the image above

cytoscape({
    "container": document.getElementById("cy"),
     "elements": [
         {"data": {"id": 1}, "position": {"x": 0, "y": 0}},
         {"data": {"id": 2}, "position": {"x": 40, "y": 0}},
         {"data": {"id": 3}, "position": {"x": 0, "y": 40}},
         {"data": {"id": 4}, "position": {"x": 20, "y": 40}},
         {"data": {"id": 5}, "position": {"x": 0, "y": 80}},
         {"data": {"id": 6}, "position": {"x": 19, "y": 80}},
         {"data": {"source": 1, "target": 2}}, // normal
         {"data": {"source": 3, "target": 4}}, // disappear
         {"data": {"source": 5, "target": 6}}, // flip
    ],
    "style": [
         {"selector": "node", "style": {"width": 20, "height": 20}},
         {"selector": "edge", "style": {"curve-style": "unbundled-bezier", "control-point-weight": 0.5, "control-point-distance": 20}},
    ],
    "layout": {"name": "preset"},
})

For reviewers

Reviewers should ensure that the following tasks are carried out for incorporated issues:

• [ ] Ensure that the reporter has included a reproducible demo. They can easily fork this JSBin demo: http://jsbin.com/fiqugiq
• [ ] The issue has been associated with a corresponding milestone.
• [ ] The commits have been incorporated into the corresponding branches. Bug-fix patches go on
  • [ ] master,
  • [ ] unstable, and
  • [ ] the previous feature release branch (e.g. 1.1.x if the current release is 1.2).
• [ ] The issue has been labelled as a bug, if necessary.

[maxkfranz]

Great start to the issue. Let's get this in a demo so we can move forward, @anthonyhtyao

[maxkfranz]

Assigning to @anthonyhtyao until his demo is posted

[anthonyhtyao]

Hi, here is the demo

[AlexanderPico]

Thanks for the demo. While we look into fixing this for the automatic case, you might consider the manual control option for edge path in cases where you need a solution now.