Rel_Left/Right/Up/Down are not followed when using LAYOUT_LEFT_RIGHT.

[oliv3r]

With a simple graph like

@startuml

!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Context.puml

System(sysA, "System A", "System A")
System(sysB, "System B", "System B")

System_Boundary(sysbA, "System Boundary A") {
   Container(conA, "Container A", "Container A")
   Container(conB, "Container B", "Container B")

   Rel_Right(conA, conB, "Rel right")
}

Rel_Left(sysA, sysB, "Rel left")
Rel_Right(sysA, sysB, "Rel right")

@enduml

The behavior changes significantly (left becomes up) when using LAYOUT_LEFT_RIGHT.

@startuml

!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Context.puml

LAYOUT_LEFT_RIGHT()

System(sysA, "System A", "System A")
System(sysB, "System B", "System B")

System_Boundary(sysbA, "System Boundary A") {
   Container(conA, "Container A", "Container A")
   Container(conB, "Container B", "Container B")

   Rel_Right(conA, conB, "Rel right")
}

Rel_Left(sysA, sysB, "Rel left")
Rel_Right(sysA, sysB, "Rel right")

@enduml

And so to get the design right, one has to quirkingly use Up/Down to mean Left/Right.

@startuml

!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Context.puml

LAYOUT_LEFT_RIGHT()

System(sysA, "System A", "System A")
System(sysB, "System B", "System B")

System_Boundary(sysbA, "System Boundary A") {
   Container(conA, "Container A", "Container A")
   Container(conB, "Container B", "Container B")

   Rel_Up(conA, conB, "Rel right")
}

Rel_Down(sysA, sysB, "Rel left")
Rel_Up(sysA, sysB, "Rel right")

@enduml

[kirchsth]

Hi @oliv3r,

this is known PlantUML behavior which we cannot directly influence. We could only introduce a new LAYOUT_LEFT_RIGHT_KEEP_DIRECTIONS() macro and rotate it internally like below

@startuml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Context.puml

' possible (incomplete) extension start >>>>>>>>>>>>>>>>>>

!global $right_rotated=%false()

!procedure LAYOUT_LEFT_RIGHT_KEEP_DIRECTIONS() 
!global $right_rotated=%true()
left to right direction
!endprocedure

!unquoted procedure Rel_D($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-RIGHT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-DOWN->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure
!unquoted procedure Rel_Down($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-RIGHT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-DOWN->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure

!unquoted procedure Rel_U($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-LEFT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-UP->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure
!unquoted procedure Rel_Up($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-LEFT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-UP->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure

!unquoted procedure Rel_L($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-UP->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-LEFT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure
!unquoted procedure Rel_Left($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-UP->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-LEFT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure

!unquoted procedure Rel_R($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-DOWN->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-RIGHT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure
!unquoted procedure Rel_Right($from, $to, $label, $techn="", $descr="", $sprite="", $tags="", $link="")
!if ($right_rotated)
$getRel("-DOWN->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!else
$getRel("-RIGHT->>", $from, $to, $label, $techn, $descr, $sprite, $tags, $link)
!endif
!endprocedure

' possible extension end <<<<<<<<<<<<<<<<<<

' now it can be activated or not 
LAYOUT_LEFT_RIGHT_KEEP_DIRECTIONS()

System(sysA, "System A")
System(sysB, "System B")
System(sysC, "System C")

Rel(sysA, sysB, "Rel")
Rel(sysB, sysC, "Rel")

Person(P,"P")
Person(PU,"P Up")
Person(PD,"P Down")
Person(PL,"P Left")
Person(PR,"P Right")

Rel_Up(P, PU, "Up")
Rel_Down(P, PD, "Down")
Rel_Left(P, PL, "Left")
Rel_Right(P, PR, "Right")
@enduml

Without commented LAYOUT_LEFT_RIGHT_KEEP_DIRECTIONS() it looks like

With called LAYOUT_LEFT_RIGHT_KEEP_DIRECTIONS() it looks like

@Potherca: should we add an extension like this, or are our macros complex enough? What do you think?

Best regards
Helmut

[oliv3r]

@kirchsth I figured ;) but as a user of C4; I would expect this to 'just work'. So if this can be hidden in a macro, that sounds like a big pro to me?

[kirchsth]

@oliv3r: I think it is solved with PR #177. Can you please test it and add your comments?
Thank you and best regards
Hellmut