PlantUML Q&A - Recent questions in Question / help

Add pictures to participants in sequence diagramm

Thu, 07 May 2026 08:41:06 +0000

Hello all!

Is it possible to add a picture to the participant of a sequence diagram?

Many thanks in advance for your help.

Best regards,
J.B.

Why can't the old syntax for Activity-Diagram shapes no longer be supported?

Thu, 30 Apr 2026 08:12:34 +0000

We use a lot of activity Diagrams in our projects and need to change them from time to time. Now the old diagrams witch the syntax

 :FooBar>  
 :FooBar< 
 :FooBar|

etc. no longer work since they have instead to be written much longer using

:FooBar; <<StereoType>>

Is it realy such a big issue for the parser that it is not possible to stay compatible to previous versions?

I know the whole new actitivy syntax is marked as beta but it is such a long time already and people are using it - regardless of it being our fault to do so it would be nice if we had some kind of solution without needing to change all existing diagram sources...

How to get the calculated dates from gantt chart?

Wed, 22 Apr 2026 15:30:32 +0000

Hello,

When using the gantt chart, I set the project start date and add the tasks and its dependecies, so the plantuml engine calculates the end's date of these tasks.

How can I get or see these end's date tasks?

Thank you.

PlantUML activity grammar

Wed, 15 Apr 2026 19:14:22 +0000

I need to build ANTLR PlantUML activity diagram lexer and parser for my university project, is there any documentation with PlantUML grammar rules that I can refer to, or only this page https://plantuml.com/activity-diagram-beta?

Mutually exclusive tasks in Gantt Chart

Fri, 03 Apr 2026 05:14:43 +0000

G'Day,

I'm struggling with what I would have thought would be a simple thing in Gantt charts.

I have two [or more] tasks that are not dependent on each other, but require the same resource, so cannot be worked at the same time, exemplified by the following code:

@startgantt

Project starts 2026-04-06
Saturday are closed
Sunday are closed

[Task A] on {Me:100%} requires 5 days
[Task B] on {Me:100%} requires 3 days
[Task C] on {Me:100%} requires 2 days
[Task D] on {Me:100%} requires 5 days

[Task B] starts at [Task A]'s end
[Task C] starts at [Task A]'s end
[Task D] starts at [Task B]'s end
[Task D] starts at [Task C]'s end

@endgantt

This project could be completed by doing:

Task A, Task B, Task C, and Task D
Task A, Task C, Task B, and Task D
Task A, interleaving Tasks B and C, and Task D

Given that the order of tasks B and C doesn't matter, I'd be happy if the Gantt chart code picked option 1 as it's a valid solution.

What happens, however, is that I apparently clone myself and work both Task B and C concurrently for two days, completing the 15 days work in 13 elapsed days.

This produces the correct result:
[Task B] starts at [Task A]'s end
[Task C] starts at [Task A]'s end
[Task C] starts at [Task B]'s end with #FFFFFF00 link
[Task D] starts at [Task B]'s end
[Task D] starts at [Task C]'s end

Interestingly, this does not produce the correct result, scheduling Tasks C and D concurrently:
[Task B] starts at [Task A]'s end
[Task C] starts at [Task A]'s end
[Task D] starts at [Task B]'s end
[Task D] starts at [Task C]'s end
[Task C] starts at [Task B]'s end with #FFFFFF00 link

One extra invisible link isn't too much of an issue, but as a work-around it doesn't scale well.

Is there any way to enforce the resource constraint without adding extra dependencies?

Thanks,

Mark.

i want to make my external actor go to the right of the system boundary can u write a plant uml code in draw.io for me?

Mon, 16 Mar 2026 10:27:45 +0000

@startuml
skinparam actorStyle stickman
left to right direction

' --- Styling ---
skinparam usecase {
 BackgroundColor<<Hub>> #FFCC99
 BackgroundColor<<Technical>> #E1D5E7
 BackgroundColor<<Action>> #FFFFFF
 BackgroundColor<<External>> #F5F5F5
}

' --- Actors (Left Side) ---
actor Passenger
actor "System Administrator" as SysAdmin

' --- System Boundary ---
rectangle "LongThangNaiKorTorMor System" {

 (View Station Maps) as UC2
 (Check Train/Bus Schedule) as UC3
 (Top up Travel Card) as UC4
 (View Travel History) as UC5
 (Report Issue) as UC6
 (Generate Payment QR / NFC) as UC_Pay
 (Check Crowd Density) as UC_Crowd
 (Plan Multi-Modal Journey) as UC1

 (Deploy System Updates) as UC13
 (Generate System Reports) as UC7
 (Handle Feedbacks) as UC8
 (API Management) as UC12
 (Manage User Accounts) as UC9
 (Monitor System Health) as UC11
 (Configure GTFS Data) as UC_GTFS

 (Login to Passenger Account) as LoginP <<Hub>>
 (Verify Wallet Balance) as VerifyW <<Hub>>
 (Login to Admin Panel) as LoginS <<Hub>>

 (Update Transit Channels) as T1 <<Technical>>
 (Upload Map Media) as T2 <<Technical>>
 (Set Route Milestones) as T3 <<Technical>>
}

' --- Actors (Right Side) ---
' Defining these AFTER the rectangle forces them to the right
actor "Payment Scanner" as Scanner <<External>>
actor "Transit Operator API" as TransitAPI <<External>>

' --- Relationships (Left) ---
Passenger --> UC1
Passenger --> UC2
Passenger --> UC3
Passenger --> UC4
Passenger --> UC5
Passenger --> UC6
Passenger --> UC_Crowd
Passenger --> UC_Pay

SysAdmin --> UC7
SysAdmin --> UC8
SysAdmin --> UC9
SysAdmin --> UC_GTFS
SysAdmin --> UC11
SysAdmin --> UC12
SysAdmin --> UC13

' --- Internal Logic ---
UC_Pay ..> LoginP : <<include>>
UC_Pay ..> VerifyW : <<include>>
UC4 ..> LoginP : <<include>>
UC5 ..> LoginP : <<include>>
UC9 ..> LoginS : <<include>>
UC11 ..> LoginS : <<include>>
UC12 ..> LoginS : <<include>>

UC_GTFS <.. T1 : <<extend>>
UC_GTFS <.. T2 : <<extend>>
UC_GTFS <.. T3 : <<extend>>

' --- Relationships (Right) ---
' Using the syntax "UseCase -- Actor" pushes the actor to the right
UC_Crowd -- TransitAPI
UC1 -- TransitAPI
UC_Pay -- Scanner

@enduml

in class Diagram ,what does "#--"、“^--”、“x--”、“}--”、“+--” mean

Tue, 24 Feb 2026 07:48:38 +0000

How to simulate 0.5Hz clock in Timing-diagram

Sun, 15 Feb 2026 16:53:41 +0000

Hello,

how can I create cloack using floating numbers? For example a 0.5Hz clock.

clock clk with period 0.5

throws an error.

Faking a clock using a binary signal in the preprocessor is not working either as %string(...) can convert integers or strings to string form — but it cannot evaluate or stringify a non‑integer expression.
See the code below.

@startuml

binary "CLK" as CLK

!$t = 0
!$state = 0
!$max = 8

!while $t <= $max
@%string($t)
!if $state == 0
CLK is low
!$state = 1
!else
CLK is high
!$state = 0
!endif
!$t = $t + 1
!endwhile

@enduml

Mismatched and incompatible versions between online server and downloadable jar.

Thu, 12 Feb 2026 19:39:16 +0000

I noticed that the latest version of the plantuml jar I can download for local rendering is 1.2026.1, while the online server is running 1.2026.beta3.

When creating an activity diagram the non beta version wants this:
#green:Test;

The beta version wants this:
:Test;<<#lawngreen>>

Each of the server versions will not accept the alternative, beta3 produces a warning, 1.2026.1 creates an error.

I was trying to share a diagram with my team and saw unexpected output.

Could the version running on the online server be available for download to retain portability?

Problem with !include using relative paths in v1.2026.0?

Wed, 28 Jan 2026 15:14:43 +0000

I have just upgraded from v1.2025.10 to v1.2026.0 and all the punl files I have that us !include with a relative path now fail, for example:

@startuml 
!include ../../.theme/theme.puml

Is this a known issue, or a deliberate change?

Preferred use of qualified name (absolute vs. relative names)

Mon, 26 Jan 2026 09:37:36 +0000

Dear all, it seems that there are different ways to use qualified names (which are not well documented, unless I am mistaken). In the following simple example. I like to declare an association between the classes A and B which are in the packages p1 and p2, respectively.

PlantUML can create a duplicate of a referenced classifier, since it interprets a qualified name as a relative path unless it is prefixed with a dot or the first segment of the qualified name is already known. See below for an example. Is there a preference to use qualified names?

@startuml
' does not work: p2 is interpreted as subpackage of p1, B is duplicated
package p1 {
class A { }
A -- p2.B
}

package p2 {
class B { }
}
@enduml

@startuml
' forward declaration of p2, works
package p2 {}

package p1 {
class A { }
A -- p2.B
}

package p2 {
class B { }
}
@enduml

@startuml
' absolute qualified names using a preceding dot

package p1 {
class A { }
A -- .p2.B
}

package p2 {
class B { }
}
@enduml

@startuml
' enclosing with single root, works

package root {
package p1 {
class A { }
A -- root.p2.B
}

package p2 {
class B { }
}
}
@enduml

Uneven spacing between box items

Wed, 14 Jan 2026 06:12:26 +0000

How can I keep the spacing between box elements (Proxmox VE, Keycloak OIDC, and Okta SAML as seen in the attached sandbox) the same?

//www.plantuml.com/plantuml/png/ZP5DYzim48Rl-XM3hy4bRMy1btMpBPXksT2blIloa1NMXv76o-RVLwFQSXrQs9CJpQl7pxo-YoG3JTO8EP5taprZ477GRfH1MZZxruWZlD_lXI1D1g7wXbTbl1o0F7mCFPpI_IiyjTyVeBk7py4F62eXf28Vu6V403B2b9v291fKf-1VRVhnXE55Awm4m9WGMkbHEbhdlxvKV7DyGO6kPvCPK0GUk_iZTFtf5h5DPCgW_0tbSI09TVR-y6x_Jmn7SY0ZVFgtCfe6EgT9Iq9uy1Vlk8v5lMa4Bmpr9zQ7tUu0hL8Ouv8GV5odSOuTqZ56TCGaxU2h3tO3EAIo32g2pM9RI5qVu0VsEd2EV8aMKAg0JLPjPlnve-3PstGuMNHoGUr4pmpulqg95GftoJB5XLi6arrujc4LdUEpD0RT1Gk7dyo1exUZGSBR37Dcu6x7ujFPwhz9F5psuaoAy3TkOxfDshl8gotV8GVcsTnSFbvT-VI2VIfPt2NEPCrl

EDIT: Noticed I posted a PNG instead of a link to the sandbox. Here's the code:

@startuml
autonumber
title "Keycloak to 3rd Party SAML ID Broker"
actor User as user
box "Proxmox Service"
participant "Proxmox VE" as pve
end box
box "Keycloak OIDC IdP"
participant "Keycloak OIDC" as kco
end box
box "Okta - SAML2.0 IdP"
participant "Okta SAML" as okta
end box

== Initiate Logon to Proxmox ==
user -> pve ++: Access Proxmox
pve --> user : Present Login Form
user -> pve : Select Keycloak OIDC
pve --> user : Redirect to Keycloak
user -> kco ++: Initiate OIDC Login
kco --> user : Present Login Form
user -> kco : Select Okta Auth
kco --> user : Redirect to Okta Auth
user -> okta ++:Initiate SAML login
okta -> user : Present Challenge
user -> user ++: Complete Challenge
user -> okta --: Submit Challenge
okta -> kco --: Send Assertions
kco -> pve --: Assert Login
pve -> user --: Logged In
@enduml

Can I use UML notes (comments) notation in PlantUML according to the UML standard specification?

Sat, 10 Jan 2026 10:12:57 +0000

Hello! Happy new year!

I searched the forum for questions about UML notes but none seems to be related to mine.

PlantUML provides the ability to include notes in UML diagrams. Besides floating notes, notes can also be connected to elements as balloons. However, the balloon style apparently is not compatible with the UML Specification.

I managed to achieve the expected format in Class Diagrams, but I can't use such format in other diagrams. Currently I'm trying to do so in activity diagrams - and I'm not succeeding at all. :)

Please keep in mind that I'm not talking about drawing notes with dashed borders, but about the connection between notes and the corresponding elements (which can't be set in PlantUML for activity diagrams and others, AFAIK).

I brought the content of UML Specification to clarify my request. Here's how UML Specification defines the visual notation:

A Comment is shown as a rectangle with the upper right corner bent (this is also known as a “note symbol”). The rectangle contains the body of the Comment. The connection to each annotatedElement is shown by a separate dashed line. The dashed line connecting the note symbol to the annotated element(s) may be suppressed if it is clear from the context, or not important in this diagram.
Sources:
- UML 2.4.1 Infrastructure, Section 9.5.1 - Comment, pages 37-38
- UML 2.4.1 Infrastructure, Section 7.2.4 - Notation, page 22

Is it already implement and I'm missing something? Otherwise, would it be possible to include this in PlantUML? Maybe using <style>?

I believe this applies to all UML diagrams.

Thanks in advance!

How to increase heap size for plantuml-server running in container?

Tue, 06 Jan 2026 17:12:05 +0000

I am running plantuml-server (jetty) in a container, and I am getting OutofMemoryError: java.heap.space" for one larger diagram.

I tried increasing the heap by adding

```
environment:
- JAVA_OPTIONS=-Xmx512m

```

to my docker-compose file. But that does not seem to have any effect?

How does the new syntax of activity diagrams achieve the pointing of corresponding arrows?

Sat, 03 Jan 2026 15:51:15 +0000

The old syntax of activity diagrams achieves arrow conversion through keywords such as down, but the new syntax does not support the down keyword.

-down-> (default arrow)
-right-> or ->
-left->
-up->

As shown in the activity diagram of the new grammar below, how can the pointing of arrows be achieved：

@startuml
start
:"First Activity";
:"Second Activity;
:"Third Activity";
stop
@enduml

Avoid multiple PlantUML backwards arrows

Mon, 22 Dec 2025 13:21:41 +0000

The given activity schema :

@startuml
start
while (Work to do?) is (found)
if (Question 2 ?) then (yes)
if (Question 3 ?) then (yes)
if (Question 4 ?) then (yes)
if (Question 5 ?) then (yes)
:Success;
break;
else (no)
endif
else (no)
endif
else (no)
endif
else (no)
endif
endwhile (no more)
end
@enduml

Produces this diagram:

Is it possible to make all the "no" arrow to be one instead of these multiple squares?

Can I display diamond name in class diagram?

Thu, 18 Dec 2025 15:51:13 +0000

In class diagram diamonds are used to represent n-ary associations. In UML the association can be named and the name is displayed above or beside the diamond. Is it possible to do that in PlantUML? All my attempts to display diamond name failed.
All diamond examples I have seen name the diamond, but the name is not visible in the diagram.

Header one color, body different color

Thu, 04 Dec 2025 00:12:10 +0000

If I have a component such as

component NAME [
title
--
text
]

is there no way to have title be one background color, and text another background color?
It doesn't have to be a component either, anything that can be rendered as a rectangle parted in two by a horizontal line, with text above and below it, is good for me

In Network Diagrams (Nwdiag) is it possible to style the address default font background color, without using HTML tags?

Thu, 27 Nov 2025 15:20:58 +0000

Hi,

Is it possible to set the default background color of the text of "address", in order to avoid the overlapping of text and lines? I tried to set a style using :

<style>

nwdiagDiagram {

 arrow {

 ' FontXXX only for address

 BackGroundColor #plum

 }

}

</style>

But it does not seem to work. The alternative would be using HTML tags for every address:

nwdiag {

 network internal {
 address = "<back:plum>172.x.x.x/24";

 web01 [address = "<back:plum>172.x.x.1"];

 }

}

but I wonder if there is another way I'm not aware of.

Thank you in advance!

How to Set Default Zoom Level for Diagrams in PlantUML IDEA Plugin?

Thu, 27 Nov 2025 14:11:23 +0000

I am using the PlantUML plugin within IntelliJ IDEA. My computer screen has a 3840×2160 resolution (4K). Because of this, every time I open a sequence diagram, the image is displayed at a very small default zoom level, forcing me to zoom in manually each time to see it clearly.

My question is: Is there a way to configure the plugin to use a larger default zoom level when opening diagrams, so that they are easily readable from the start?

Thank you for your help.

Can resource allocation in a gantt chart be scaled on a weekly or monthly base?

Mon, 24 Nov 2025 14:23:29 +0000

I use a simple gantt chart with resources. Here a easy example from the website:

@startgantt
project starts 2025-10-01
printscale daily
[Task1] on {Alice} requires 30 days
[Task2] on {Bob:50%} requires 2 days
then [Task3] on {Alice:25%} requires 1 days
@endgantt

when I switch the printscale to weekly the resource calculation gives me the sum of the resources.

I know it's correct, but not intuitive to me. I would prefer a mean value for the week.

Is there a way to make this work?

Thanks!

Why this don't work.

Fri, 21 Nov 2025 20:07:05 +0000

File: govite_rpc_diagram.puml

@startuml
namespace rpc {
 class "API" << (S,Aquamarine) >> {
 + Namespace string
 + Version string
 + Service interface{}
 + Public bool

 }
 class "BatchElem" << (S,Aquamarine) >> {
 + Method string
 + Args []interface{}
 + Result interface{}
 + Error error

 }
 class "Client" << (S,Aquamarine) >> {
 - idCounter uint32
 - connectFunc func(context.Context) (net.Conn, error)
 - isHTTP bool
 - writeConn net.Conn
 - close chan struct{}
 - didQuit chan struct{}
 - reconnected chan net.Conn
 - readErr chan error
 - readResp chan []*jsonrpcMessage
 - requestOp chan *requestOp
 - sendDone chan error
 - respWait map[string]*requestOp
 - subs map[string]*ClientSubscription

 - nextID() json.RawMessage
 - newMessage(method string, paramsIn ...interface{}) (*jsonrpcMessage, error)
 - send(ctx context.Context, op *requestOp, msg interface{}) error
 - write(ctx context.Context, msg interface{}) error
 - reconnect(ctx context.Context) error
 - dispatch(conn net.Conn)
 - closeRequestOps(err error)
 - handleNotification(msg *jsonrpcMessage)
 - handleResponse(msg *jsonrpcMessage)
 - read(conn net.Conn) error
 - sendHTTP(ctx context.Context, op *requestOp, msg interface{}) error
 - sendBatchHTTP(ctx context.Context, op *requestOp, msgs []*jsonrpcMessage) error

 + SupportedModules() (map[string]string, error)
 + Close()
 + Call(result interface{}, method string, args ...interface{}) error
 + CallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error
 + BatchCall(b []BatchElem) error
 + BatchCallContext(ctx context.Context, b []BatchElem) error
 + EthSubscribe(ctx context.Context, channel interface{}, args ...interface{}) (*ClientSubscription, error)
 + ShhSubscribe(ctx context.Context, channel interface{}, args ...interface{}) (*ClientSubscription, error)
 + Subscribe(ctx context.Context, namespace string, channel interface{}, args ...interface{}) (*ClientSubscription, error)

 }
 class "ClientSubscription" << (S,Aquamarine) >> {
 - client *Client
 - etype reflect.Type
 - channel reflect.Value
 - namespace string
 - subid string
 - in chan json.RawMessage
 - quitOnce sync.Once
 - quit chan struct{}
 - errOnce sync.Once
 - err chan error

 - quitWithError(err error, unsubscribeServer bool)
 - deliver(result json.RawMessage) bool
 - start()
 - forward() (error, bool)
 - unmarshal(result json.RawMessage) (interface{}, error)
 - requestUnsubscribe() error

 + Err() chan error
 + Unsubscribe()

 }
 interface "Error" {
 + Error() string
 + ErrorCode() int

 }
 interface "ErrorWithId" {
 + Id() interface{}

 }
 class "StdIOConn" << (S,Aquamarine) >> {
 + Read(b []byte) (int, error)
 + Write(b []byte) (int, error)
 + Close() error
 + LocalAddr() net.Addr
 + RemoteAddr() net.Addr
 + SetDeadline(t time.Time) error
 + SetReadDeadline(t time.Time) error
 + SetWriteDeadline(t time.Time) error

 }
 class "Subscription" << (S,Aquamarine) >> {
 - namespace string
 - err chan error

 + ID ID

 + Err() chan error

 }
 class "WebSocketCli" << (S,Aquamarine) >> {
 - u *url.URL
 - c *websocket.Conn
 - srv *Server
 - closed chan struct{}
 - nextConnTime time.Time

 + Srv(c *websocket.Conn) error
 + Close()
 + Handle()

 }
 class "callback" << (S,Aquamarine) >> {
 - rcvr reflect.Value
 - method reflect.Method
 - argTypes []reflect.Type
 - hasCtx bool
 - errPos int
 - isSubscribe bool

 }
 class "callbackError" << (S,Aquamarine) >> {
 - message string

 + ErrorCode() int
 + Error() string

 }
 class "executePanicError" << (S,Aquamarine) >> {
 + ErrorCode() int
 + Error() string

 }
 class "httpConn" << (S,Aquamarine) >> {
 - client *http.Client
 - req *http.Request
 - closeOnce sync.Once
 - closed chan struct{}

 - doRequest(ctx context.Context, msg interface{}) (io.ReadCloser, error)

 + LocalAddr() net.Addr
 + RemoteAddr() net.Addr
 + SetReadDeadline( time.Time) error
 + SetWriteDeadline( time.Time) error
 + SetDeadline( time.Time) error
 + Write( []byte) (int, error)
 + Read(b []byte) (int, error)
 + Close() error

 }
 class "httpReadWriteNopCloser" << (S,Aquamarine) >> {
 + Close() error

 }
 class "invalidMessageError" << (S,Aquamarine) >> {
 - message string

 + ErrorCode() int
 + Error() string

 }
 class "invalidParamsError" << (S,Aquamarine) >> {
 - message string

 + ErrorCode() int
 + Error() string

 }
 class "invalidRequestError" << (S,Aquamarine) >> {
 - message string
 - id interface{}

 + ErrorCode() int
 + Error() string
 + Id() interface{}

 }
}
"__builtin__.int" #.. "rpc.CodecOption"
"__builtin__.string" #.. "rpc.ID"
"rpc.map[string]*callback" #.. "rpc.callbacks"
"rpc.map[string]*callback" #.. "rpc.subscriptions"
"rpc.map[string]*service" #.. "rpc.serviceRegistry"
"rpc.Error" *-- "rpc.ErrorWithId"
"io.Reader" *-- "rpc.httpReadWriteNopCloser"
"io.Writer" *-- "rpc.httpReadWriteNopCloser"

"rpc.Error" <|-- "rpc.callbackError"
"rpc.Error" <|-- "rpc.executePanicError"
"rpc.Error" <|-- "rpc.invalidMessageError"
"rpc.Error" <|-- "rpc.invalidParamsError"
"rpc.Error" <|-- "rpc.invalidRequestError"
"rpc.ErrorWithId" <|-- "rpc.invalidRequestError"
"rpc.ServerCodec" <|-- "rpc.jsonCodec"
"rpc.Error" <|-- "rpc.jsonError"
"rpc.Error" <|-- "rpc.methodNotFoundError"
"rpc.ErrorWithId" <|-- "rpc.methodNotFoundError"
"rpc.Error" <|-- "rpc.shutdownError"

@enduml

PS U:\UMLExperiment> java -Xmx2048m -jar G:\Tools\PlantUML\plantuml-mit-1.2025.10.jar govite_rpc_diagram.puml
Warning: no image in govite_rpc_diagram.puml
PS U:\UMLExperiment>

Hide the diagram code from readers of the document who do not have PlantUML ADD-in

Wed, 19 Nov 2025 09:46:35 +0000

After creating my diagrams with PlantUML, I hide the code using the "Hide PlantUML" button and save the document. However, when a reader who does not have PlantUML add-in opens the document, the code is still visible. I expected the code to be hidden and not readable. Is there a solution for this?

Class diagram: how to represent deprecated static method

Wed, 12 Nov 2025 16:53:10 +0000

I use strikethrough to represent deprecated fields and methods in a class diagram.

This renders nicely, _unless_ the method is also static.

For example:

class Test {
    +normalMethod(): void
    +--deprecatedMethod--(): void
    {static} +staticMethod(): void
    {static} +--deprecatedStaticMethod--(): void
}

Gets rendered as:

What is the recommended way to represent static deprecated methods?

create DOT diagrams

Fri, 07 Nov 2025 20:35:12 +0000

Unable to convert Ditaa diagram to png

Thu, 06 Nov 2025 15:39:18 +0000

Hi,

This is my version of Plantuml:

PlantUML version 1.2025.4 (Sat Jun 28 13:09:25 CEST 2025)

I'm trying to get a png from the following Ditaa diagram:

@startditaa
+-----------------+
| Things to do |
| cGRE |
| o Cut the grass |
| o Buy jam |
| o Fix car |
| o Make website |
+-----------------+
@endditaa

using plantuml.jar with this command:

java -jar /opt/plantuml/plantuml.jar mydiagram.puml

but I'm always getting this response:

Warning: no image in mydiagram.puml
No diagram found

I can however create png's from class diagrams (@startuml/@enduml) without problems.

Are Ditaa diagrams maybe not supported by this version of Plantuml? Thanks for your help,

Daniel.

Keep getting Error: 520

Wed, 05 Nov 2025 04:41:13 +0000

I'm having trouble with previewing PlantUML.

In the VSCode extension, I get a broken image symbol, and this error text:

Error: 520
GET https://www.plantuml.com/plantuml/svg/0/...
at ClientRequest.closeCallback (c:\Users\Matthew.Petty\.vscode\extensions\jebbs.plantuml-2.18.1\out\src\plantuml\renders\httpWrapper.js:78:27)
at ClientRequest.emit (node:events:519:28)
at TLSSocket.socketCloseListener (node:_http_client:481:9)
at TLSSocket.emit (node:events:531:35)
at node:net:346:12
at TCP.done (node:_tls_wrap:650:7)

I also tried using a local JAR instead of the online server, but that didn't seem to work

In the old online editor, it seems to work OK.

In the new online editor, I just get the broken image icon.

Can anyone help?

Participant - custom images

Mon, 03 Nov 2025 08:59:16 +0000

Hi Team. I need to do sequence diagrams, however, I wanted to use my own images on the participants. Can you please advise if it is possible, and how?

I am using VSCode, I tried to run the java -jar plantuml-1.2025.8-javadoc.jar or even to create a sprite of the image, but I am getting that Error: Invalid or corrupt jarfile plantuml-1.2025.8-javadoc.jar.

Can you please advise?

Thanks in advance.

Best,

Natacha

Link to pdf guide for older version

Tue, 28 Oct 2025 18:36:27 +0000

Are there links to older versions of the plantuml pdf guides? I'm trying to work with a Visual paradigm plugin to import/export plantuml, but it leverages the 1.2024.7 jar, so I'd like to know what format is. The 2024 jar files blows up on puml files the latest plantuml parses fine.

Make separate formatting for each `box` in Sequence_Diagram

Sun, 26 Oct 2025 09:08:20 +0000

Make separate formatting for each `box` in Sequence_Diagram

Make for `box "Lev-1"`
- the thickness of the lines is at your discretion;
- the color of the lines is red ;
- line type - solid;
- padding - at your discretion;
- marging - at your discretion;
- the `box` fill is blue;
- orientation on the `z` axis - 0;

Make for `box "Lev-2"`
- the thickness of the lines is at your discretion;
- the color of the lines is blue ;
- line type - dotted line;
- padding - at your discretion;
- marging - at your discretion;
- the `box` fill is blue;
- orientation on the `z` axis - 1;

If some property is not supported by PlantUML, then write "property is not supported";
If a property is specified inaccurately, then write the correct name of the property.;

I expect to see something like the diagram in the picture.

Does PlantUML online server no longer support `http:` image references?

Sat, 25 Oct 2025 16:21:38 +0000

The C4 Readme contains some samples with images referenced via `http:` instead of `https:`.
Previously, the old online server displayed these images without any problems.
The new/current online server reports a "Cannot decode: http://...." error. Is this intentional?

https://www.plantuml.com/plantuml/uml/bP91RzGm48Nl_XL3L45MsYP5XSkAe5PB1KWBMwL572itddKjENPaEvGLuhypjfTi3d3OKvonvvltddtb0tTXx3LxeKodHu7m5CBWLtNj-7CbLNWQ7qUFhhCce0bLP_jwqDp4ddCVX5QFzVhD-MqiVVkogNlk0pegFQofWok3hXeYdxtAfo7IVAg1m1qTyE07fm92aRQAevHtThTJ7TQfNXyRtpF6heLeKTzpMHP_zHHBE0luCwojjgufpgxRTllzORtTRDkufMdMVxQoWAPGlLn5_wjwCfaSQoljPJKO-SjtN6DpKLt-JaYKQCJToTslPzttfBWfA5zlDK9mIafqA8e5OxTas9eo6b_cT40wEmuWbAS9UnJmJ3S4_93Wt4hEaY1ikeYoowj4cwePaPG9u4P05pEYzNP0yvbQL3VdljnPBOYGhRojBfRfV2CTtyTnTtiVi2zz-j2S_7_GQK3rNE99aKTeY_gGmiIbKe9c8fG_58V0fLz4U5mqntUnc06c3EQCoQhvbzTawnEzbytDnvkl7ye5kq8Z2Fm7

The issue is related to PlantUML online server no longer(?) supports http: image references (replace with https:) · Issue #405 · plantuml-stdlib/C4-PlantUML

Thank you and best regards
Helmut

Timing Diagram participant/player title style color size

Wed, 15 Oct 2025 23:34:16 +0000

It doesn't seem that there is a way to change the font style, color or size for a Timing Diagram's concise, robust, and binary player participant's heading/title text on the left. I do understand that creole can be used, but that would have to be used for every single one.

If a CSS element exists for this, what is it? If not, please create one.

Two workers on one task starting at different times

Wed, 15 Oct 2025 16:17:51 +0000

I have a question similar to

https://forum.plantuml.net/18397/gantt-how-handle-resource-starts-terminates-specific-date

One worker is working on Job-1.

Once he finished that, he will start Job-2.

A second worker will start on Job-2 while worker one is still on Job-1.

@startgantt
project starts the 2025/10/01
saturday are closed
sunday are closed

[Job-1] as [J1] on {BKI} lasts 13 days
[Job-2] as [J2] lasts 9 days
[J2] on {BKI} starts after [J1]'s end
[J2] on {AKI} starts at 2025-10-15

@endgantt

I came up with the following, but it requires manual adjustment of the workload.

I'd rather prefer to start Job-2 on 2025-10-15 and add resource BKI once Job-1 is finished.

@startgantt
project starts the 2025/10/01
saturday are closed
sunday are closed

[Job-1]   as [J1] on {BKI} lasts 13 days
[Job-2]   as [J2a] lasts 3 days
[Job-2]   as [J2b] lasts 6 days
[J2a] on {BKI} starts after [J1]'s end
[J2b] on {AKI} starts at 2025-10-15

@endgantt

Grok3 building filez from scratch, with many "Type" errors to 2020 Pl. verzion. where are templates online? tkz

Mon, 13 Oct 2025 18:25:16 +0000

I am new here.
Grok3 supercomputer at @Xai is building PlantUML files from scratch, with many "Type" errors, even dated to 2020 Pl. version. Where are P.. templates online? thank ypu,
I am assuming that your recc'd templates are adapted to your current version or the PlantUML playground on-line server.. Building from scratch seems a difficult way to go up the mountain, even for a supercomputer without legs. But thanks again. D

Low quality render of scaled diagrams with transparent background using PlantUML online server

Fri, 03 Oct 2025 09:07:55 +0000

Hi, from few days I've been noticing a reduction of resolution of scaled images with transparent background generated by the PlantUML online server.

A a sample, using a test diagram:

@startuml
scale 3/4
hide empty members
skinparam backgroundcolor transparent

interface Test_Interface
class Test_Class
class Test_Module

Test_Interface <|.. Test_Class : <<implement>>
Test_Class .> Test_Module : <<use>>
@enduml

There is now a very big difference between local generated image using PlantUML.jar, and an image generated by the online server.
Please note that few days ago there both process generates the same (or very close) images.

Is this the expected behaviour of the server?
Is there a parameter to set locally to have the previous image quality quality?

Thanks in advances for any reply.

why %json_key_exists doesn't protect from missing keys?

Wed, 01 Oct 2025 09:04:13 +0000

I want to handle a case when a given key is not defined in a json object.

For some reason this works:

!if %json_key_exists($object, $key)

participant yes

!else

participant no

!endif

but this doesn't, and ends with "Data parsing error":

!if %json_key_exists($object, $key)

!if $object[$key]=="charm"

participant charm

!else

participant strange

!endif

!else

participant no

!endif

A more complete example:

https://www.plantuml.com/plantuml/uml/dP71Qe0m38RlVOeO72Xusd4W-1vZI6eZTDDMsWgJiNTVJOSNns3BnJ-_Ny8V7MAYaFPrKQgg3IM27ZuKv4B29y3PU-nAhyzUKq3rcU4j-8dD7XXgCgQf7QtSgihEyF0QlHlV-1ZvtSOK6zdRGK5arqOXsSbkv5AnWM8Hgk8bia3dbAR8Ty8PEylZ2d4BzFZ7H2ScxhEOBtqlfykxtnCBSgMMqdvtXiBn8odf_tscV6maRB_Lb9Kg1wCMLwJ9SiYJ-ST-0G00

I feel I'm missing something obvious. I wasn't able to find an answer though.

How do I use themes in the eclipse plugin

Tue, 23 Sep 2025 19:57:05 +0000

I have installed the eclipse plugin, how do i use themes with it?

Eclipse PlantUML view states "Cannot find style sysmic" in red text

Wed, 17 Sep 2025 17:21:01 +0000

I'm new to Eclipse. I have followed the instructions in the ReadME but when I select show view PlantUML I get a message this is an old version and a "Cannot find style sysmic". It was working until it came up with the error that it was 1229 days old, so I updated, and still get the error.

But now have in green on black image:

PlantUML 1.2024.5

This version of PlantUML is 479 days old, so you should

consider upgrading from https://plantUML.com/download

[From string (line 2) ]

@startuml

skin sysmic

Cannot find style sysmic

Preferences state PlantUML installation seems OK, File generation OK. Help!

Can I hide the closed days or move them behing the task in Gantt?

Wed, 17 Sep 2025 16:10:39 +0000

The closed days are shown on top of the tasks and cut it in a very ugly way, especially in bigger scales (monthly, quarterly, yearly).

Is there a way to move them behind the tasks (change the z-order)? Or maybe hide them in big project scales?

I thought I could export it as svg and bring the task to the front. But the task is really cut in smaller rectangles!

@startgantt

printscale quarterly zoom 5
saturday are closed
sunday are closed

project starts 2025-10-01

[Task1] lasts 55 days

[Task2] lasts 85 days and starts at [Task1]'s end

@endgantt

//www.plantuml.com/plantuml/png/NSwn2i8m4CRn_PxYsvmARI3Ws8Tm4uSZEKIDYUOkGtrwGsqNbnj-yFsvMOshNJcR4RtgBPi6Je9twomrBVYKyeGdPMiryWAkWf2AIYHj-Kzwejmb6DQimetE3zCuZ1FH-SJwc2v8hARm7dsh6xkTZpy6vxWtsB1D3mh9aMZkTttv2m00

Most of the images-links are not correct resolved

Thu, 11 Sep 2025 16:44:16 +0000

If I open ex. the README.md of the stdlib (plantuml-stdlib/README.md at master · plantuml/plantuml-stdlib) or the Themes.md of the C4-PlanrUML C4-PlantUML/Themes.md at master · plantuml-stdlib/C4-PlantUML then most of the images are not correct displayed or invisible (if I have no alternative text). In my extended brach I added an alternative text that all not correct resolved images are shown too C4-PlantUML/Themes.md at extended · kirchsth/C4-PlantUML

How can I avoid the broken links/images?

Thank you and best regards
Helmut

PS.: one alternative would be the PlantUML Editor Online - Free & Fast UML Diagram Tool | PlantText server, but this server does not have the last PlantUML release

Activity Diagram with swimlanes and fork: how to disable horizontal shift

Thu, 11 Sep 2025 14:36:04 +0000

Hi there,

I'm having trouble with the width of swimlanes and the horizontal positioning / vertical alignment of boxes therein. The activities should be vertically aligned and no space should be wasted. How could this be achieved?

Thanks for any hint.

@startuml
|P1|
|P2|
|P3|
|P4|
|P5|
|P1|
start
:Do1;
|P2|
:Do2-is-something-really-long;
|P5|
if (Cond1?) then (ok)
|P2|
:Do3-is-longer;
|P1|
:Do4;
floating note right
Comm1
end note
|P5|
:Do5-is-longer-too;
|P1|
:Do6;
:Do7;
fork
|P2|
:Do8-is-something;
:Do9-is-another-thing;
fork again
|P3|
:Do10;
:Do11;
fork again
|P5|
:Do12-leads-to-more-and-more-width;
end fork
|P4|
:Do13;
|P5|
:Do14;
else (not ok)
stop
endif
stop
@enduml

Is someone have experience about encode uml script with javscript or phyton code not in online server?

Sat, 30 Aug 2025 08:51:18 +0000

I am creating ai agent on n8n for generate script with ai and ecnode it with javascript or phyton code. But i got errors in this case. does someone have experience about it?

Other durations than days in Gantt

Fri, 29 Aug 2025 05:55:38 +0000

As topic, are there more options for duration definitions for Gantt diagrams?

It feels undynamic to specify all tasks to start at 1st of each month when they relate to another.

PlantUML AddIn for Word 365

Thu, 28 Aug 2025 07:07:34 +0000

I am trying to install PlantUML Word AddIn for Office 365 Word in Windows 11, but the Word does not open the PlantUML_Template_v35.dotm, which is meant for Word 2016 version.

Is it compatible with Office 365 Word? Is there some Word setting which I need to update.

I get this error message when opening Word: "Word cannot open this document template. (C:\Users\...\PlantUML_Template_v25.dotm)"

Vertical Alignment of States in State Diagram with a transition from bottom to top state

Tue, 26 Aug 2025 14:11:31 +0000

Hello,

I have this diagram (simplified example):

@startuml Example

state a
state b
state c
state d

a -d-> b
b -d-> c
c -d-> d

d --> a

@enduml

which produces this rendering:

Is there a way to force the states to be underneath each other, without floating to the left, and the arrow from d to a to curve around the right side?

Thank you very much for your input.

Force component port position

Fri, 01 Aug 2025 01:03:17 +0000

have a port like:

component DMA_in {

portout in0

portout in1

portout in2

portout in3

}

On its own it displays ok, but when wiring it with other components it sometimes renders the ports in different order, such as

in2

in1

in0

in3

is there a way to tell it to render the ports at a fixed position?

Installation on linux mint

Sun, 27 Jul 2025 20:28:29 +0000

Hi! I'm running Linux Mint on an older MacBook Pro and just installed PlantUML (version plantuml-1.2025.4.jar). It just installed as a zip file and I don't know what to do with it... I tried running 'sudo nano sequenceDiagram.txt' and creating the whole "Alice --> Ben or whatever" example file. But when I run 'java -jar plantuml.jar sequenceDiagram.txt', I get 'Error: Unable to access jarfile plantuml.jar'. How do I fix this or where do I find documentation how to properly install plantuml (I strongly assume that that's the problem, since the program is still a zip file...)? Thank you :))

Move package tab to the right

Thu, 24 Jul 2025 14:36:07 +0000

I have a component diagram rendered where lines go through the upper left text of the package. If the text tab would be on the right, the text would not be cut through by lines.

Is there a way to accomplish the package tab being on the right? I could not find such a thing with native styling, but maybe it can be done by modifying some underlying rendering code or introducing ones own component?

How can I style all children activities within a partition in an Activity diagram?

Mon, 21 Jul 2025 23:05:46 +0000

I'd like to be able to style all the children elements/activities under a specific partition while leaving those activities outside of the partition alone. I've tried the following but it doesn't end up selecting anything and has no effect. Is there another way to accomplish this without specifically tagging each activity I want to modify?

@startuml
<style>
partition {
activity {
BackgroundColor: blue;
}
}
</style>

start
partition "Partition1" {
:Activity1;
:Activity2;
}
:Activity3;
@enduml

how to change group header background color

Tue, 15 Jul 2025 09:28:23 +0000