When we change the layout of the diagram, draw.io fails to change the connection points of edges, which requires manual effort

[raindropsfromsky]

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Describe the bug
dra.io has a major bug: When I change the layout, all nodes are rearranged according to the new layout. But the app fails to switch the connection points of all nodes so that the edges can be re-routed properly toward the new direction.

To Reproduce
Steps to reproduce the behavior:

1. Create a simple TD diagram, as shown:

Note that this sample chart was generated in AI, and it uses simple connectors.
(In other words, I have NOT anchored the edges to special glue points.)

2. Change the layout to horizontal.
   In my theme, I click on the (+) button, and select Layout > Horizontal flow.

The app converts the diagram to this:

This is terrible! I have to drag the start and end points of all edges manually.
If this is a large diagram, the task is too tedious.

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Example-2:
Here, I have changed the edge type to "Horizontal", and manually dragged all connection points to North/South.

After changing the layout to Horizontal, the result is even worse:

Notice that the edges are no longer horizontal, and they look like squashed spiders.
In this example, I have to change the edge type also, apart from dragging the start+end points.

Expected behavior
Draw.io should automatically move the connection points of all edges toward the entry/exit direction (in this case, East-West).

It should automatically reset the edge types and also glue points.
(Both these attributes are for beautification of the graph, and not essential while we change the layout. Therefore, the original settings are irrelevant.)

Screenshots
(provided above)

draw.io version (In the Help->About menu of the draw.io editor):
v30.0.0 (Desktop version)

Desktop (please complete the following information):
Windows 11

Smartphone (please complete the following information):
N/A

I tested the problem in incognito/private mode with all browser extensions switched off, write "yes" below:
N/A

Additional context
Increasingly, users will copy Mermaid code from the AI engines and paste it in the draw.io to optimize/edit the diagram. In such case, they will invariably land in this trouble.

Therefore this solution is direly needed.

[draw-io-triage-bot]

👋 Thank you for opening this issue!

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Summary: The user requests that when applying a layout change (e.g., vertical to horizontal), draw.io should automatically update edge connection points (entry/exit positions), reset edge routing styles, and clear fixed glue points so that edges route cleanly in the new layout direction, rather than requiring manual adjustment of every edge.

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📝 Additional Information Needed

To help us investigate this more effectively, could you please provide:

• When you say 'change the layout', are you using the menu option Format → Layout → specific layout (e.g., Horizontal Tree, Vertical Tree), or are you manually rearranging nodes?
• Have you tried using 'Reset Connection Points' (Edit → Select Edges, then right-click → Edit Connection → Reset) or removing fixed connection points before applying the new layout?
• Have you tried using the 'Arrange' → 'Layout' options with the 'Reset Edge' style option, or removing the explicit entry/exit constraints from edges before applying the layout change?
• Could you attach the actual .drawio XML file so the developers can reproduce this exactly, rather than relying on screenshots?

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💬 A Note on Communication

draw.io is maintained by a small team, and while we try to address issues promptly, we prioritize based on severity and impact. Thank you for your patience.

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_{🤖 This is an automated response to help with initial triage. A human maintainer will review this issue. If you've provided all the requested information, no further action is needed - we'll get back to you soon!}

[raindropsfromsky]

Response to the points raised by the bot:

1. I have edited the description to state how I changed the layout.

2. There is no "reset" option in context menu after we select all edges (SHFT+CTRL+E). See the screenshot below:

3. When I change the layout to Horizontal flow, the app does not pop up a dialog. It directly changes the layout in one shot.

4. I checked the properties dialog also, to see whether I can remove the glue points or reset edge types.
   There is no such provision.

5. The xml file is attached.

When we change layout, the edges get jumbled up.drawio

[alderg]

Try Reset, Waypoints/Connection Points in the Arrange tab.

[raindropsfromsky]

When I selected the Reset the waypoints option, draw.io behaves as if I pressed ALT+SHFT+R.
The result is this:

Clearly, it does not help to select this option.

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Then I selected undo, and then selected the Reset connection points option.
The result is this:

This is much better, but not sufficient.

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Then I used both options together.
I experimented by changing the order, but both orders give this result:

This actually looks worse compared to the previous result (reset only the connection points).

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These options make the diagram technically better, but do not solve the problem entirely.
The diagram is still not presentable.

So I selected all edges (SHFT+CTRL+E) and carried out two steps:

1. Reset connection points
2. Changed the edge style to Vertical.

The result is much better, but still it needs tweaking, as the edges are not aligned perfectly in all places:

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CONCLUSION:

The triage bot actually suggested a good resolution: When we change the layout, Draw,io should pop up a dialog with these controls. Let the use accept that he is OK with resetting the connection points.

After that, draw.io should automatically select the default style for edges based on the selected layout:

1. If the new layout is horizontal or horizontal tree, the edge style should be vertical.
2. If the new layout is vertical, vertical tree, or organization chart, the edge style should be horizontal.
3. If the layout is Circle, circular or organic, the edge style should be straight.

The resultant drawing will be nearly perfect: Only few minor tweaking will be needed.

Of course, the user can set the edge style to curved, but that's his personal preference.
The default conversion would be near-perfect even without that correction.

[raindropsfromsky]

BTW I tried my last suggestion: After selecting the Reset waypoints and Reset connetion points, I changed the edge type to curved. The result is flawed, as shown below:

Notice that edges are running over nodes E and F. This should not happen.

The algorithm changed the connection points to top and bottom sides of B, C, D, and G nodes.
This was not warranted.

I tried to use the Reset connection points command once again, but the connection points do not move.

Finally, I moved the connection points manually.

This looks better, IMHO.

CONCLUSION:
If the edge type is changed to curved, draw.io should select the connection points appropriately.
The current algorithm for selecting the connection point needs to be improved.

[raindropsfromsky]

I had to move the B and C nodes to make their outgoing edges look symmetrical and to remove kinks in them.
Here is the result.

If this can be achieved algorithmically, it would be fantastic.

[davidjgraph]

Please test again with 30.2.2 on app.diagrams.net. The behaviour might have changed since 30.0.0

[raindropsfromsky]

I tried the same test on online draw.io.
I get the exact same problems.

[alderg]

Should be fixed in 30.2.5.