fix: asTRBL supported for flow elements

[abdul99ahad]

Related to bpmn-js: #2239

Proposed Changes

• Implemented support for handling TRBL coordinates in flow elements.
• Added test cases for TRBL handling, covering both shapes and connections.

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[abdul99ahad]

@barmac, all test cases are passing locally, but here it's encountering a single test failure in the CI environment.

[nikku]

Interesting, but is this the way we want to approach things? The utility clearly converts RECT|Point to TRBL, not a connection. I'd rather expose additional utilities to compute the TRBL from a connection.

[philippfromme]

As the parameter is documented as @param {Point|Rect} bounds I wouldn't expect to get a connection here. We should look into why a connection ends up getting passed to this function.

[abdul99ahad]

Interesting, but is this the way we want to approach things? The utility clearly converts RECT|Point to TRBL, not a connection. I'd rather expose additional utilities to compute the TRBL from a connection.

Completely agreed. The connection coordinates should be handled through separate method. I'll update it.

[nikku]

TRBL stands for "top, right, bottom, left. I don't think that this is what we want to accomplish here, right?

What do you want to accomplish? I assume you want to compute the bounding box (bounds, Rect) of a connection, and once you have it, you can feed that into asTRBL?

[nikku]

Or would you like to compute the "mid" of an element? This is available, too, so you just need a utility to compute the connection bounds, and chain things together.

[abdul99ahad]

Yes, that's what we want to accomplish. I wasn't aware that you can calculate bounding box for a connection, I thought it's just for element.

[abdul99ahad]

The issue is when you move the annotation from the flow that has label to it, and put on top of the label. The label should move downwards to the flow.

Currently, it's giving error cuz when annotation is moved some events emit to move label as well. A connection is passed in asTRBL and returns NaN since it's not designed to handle connections. What my approach was to handle asTRBL to support connections as well. If it's handled, then it can appropriately align the label to optimal position. The function of TRBL is just to return the current coordinates if it does, we are handling rest in bpmn-js.

[nikku]

Who exactly passes the connection into the asTRBL function (which is unsupported)?

[abdul99ahad]

AdaptiveLabelPositioningBehavior in bpmn-js passes the flow element to get TRBL to facilitate positioning of label.

[nikku]

@abdul99ahad Given what we discussed I don't see clearly what you see as the root cause for bpmn-io/bpmn-js#2241 and what solution approaches you considered.

Let's sync on your root cause analysis + solution approach along our ISSUE_PHASES docs.

[abdul99ahad]

Had a discussion with Nico, reached to the conclusion that it's not feasible to handle complex connection labels adjustment right now. It will be a feature request sometime in future.

Closing this PR!