plantuml/plantuml

[Packetdiag] fix `rotate`, allow `same_height` optional, ...

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#2530 opened on Feb 15, 2026

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 (3 comments) (0 reactions) (0 assignees)Java (9,118 stars) (847 forks)batch import
enhancementgood first issue

Description

Context

To follow:

Wanted feature

Here is a wanted feature in order to:

  • fix rotate
  • center vertically/horizontally all labels
  • allow same_height optional (same_height = true)

to be conform with the original form:

Not working Example

@startpacketdiag
{
  colwidth = 32
  node_height = 72

  0-15: Source Port
  16-31: Destination Port
  32-63: Sequence Number
  64-95: Acknowledgment Number
  96-99: Data Offset
  100-105: Reserved
  106: URG [rotate = 270]
  107: ACK [rotate = 270]
  108: PSH [rotate = 270]
  109: RST [rotate = 270]
  110: SYN [rotate = 270]
  111: FIN [rotate = 270]
  112-127: Window
  128-143: Checksum
  144-159: Urgent Pointer
  160-191: (Options and Padding)
  192-223: data [colheight = 3]
}
@endpacketdiag

(FYI @kolulu23) Regards, Th.

Contributor guide

Tech stack
java
Domain
backend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Basic knowledge of JavaUnderstanding of PlantUML's packetdiag syntax
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Examine existing packetdiag implementation in PlantUML source code, particularly the parsing and rendering of packet diagrams. Review linked PR #2529 and issues #2520 and #2529 for context on how rotate and same height are handled. The rotate attribute needs to be fixed for packetdiag, and same height should be made optional with a default value.