Lines in diagram to another rectangle all mangled, how to fix

Question

With the following UML, the lines into the Bus box all seem to attempt to join the left side of the bus box

@startuml
rectangle "System" as sys {
  rectangle "motherboard" as mboard {
     rectangle "CPU" as cpu {
       url of cpu is [[https://en.wikipedia.org/wiki/Central_processing_unit]]
     }
     rectangle "memory" as mem {
       url of mem is [[https://en.wikipedia.org/wiki/Computer_memory]]
     }
     rectangle "GPU" as gpu {
       url of gpu [[https://en.wikipedia.org/wiki/Graphics_processing_unit]]
     }
     rectangle "Disk" as disk {
       url of disk is [[https://en.wikipedia.org/wiki/Mass_storage]]
     }
     rectangle "keyboard" as kb {
       url of kb is [[https://en.wikipedia.org/wiki/Computer_keyboard]]
     }
  }
}

rectangle "Bus" as bus {
     rectangle "PCIe Bus" as pcie {
       url of pcie is [[https://en.wikipedia.org/wiki/PCI_Express]]
     }
     rectangle "USB" as usb {
       url of usb is [[https://en.wikipedia.org/wiki/USB]]
     }
}

cpu -- bus
mem -- bus
gpu -- bus
disk -- bus
kb -- bus
@enduml

But if I remove the pcie and usb then it looks fine, eg:

rectangle "Bus" as bus {

}

Then the lines are sort of spread out and it looks a lot nicer.  But I need the inner pcie and usb rectangles so can't remove those.

Answer 1

Hello A.,

That's seems due to the version of Graphviz.

From:

Here is a proposal (adding pseudo label and hidden arrow...) as:

@startuml
rectangle "System" as sys {
  rectangle "motherboard" as mboard {
     rectangle "CPU" as cpu {
       url of cpu is [[https://en.wikipedia.org/wiki/Central_processing_unit]]
     }
     rectangle "memory" as mem {
       url of mem is [[https://en.wikipedia.org/wiki/Computer_memory]]
     }
     rectangle "GPU" as gpu {
       url of gpu [[https://en.wikipedia.org/wiki/Graphics_processing_unit]]
     }
     rectangle "Disk" as disk {
       url of disk is [[https://en.wikipedia.org/wiki/Mass_storage]]
     }
     rectangle "keyboard" as kb {
       url of kb is [[https://en.wikipedia.org/wiki/Computer_keyboard]]
     }
  }
}

rectangle " " as b {
     label "Bus" as bus
     rectangle "PCIe Bus" as pcie {
       url of pcie is [[https://en.wikipedia.org/wiki/PCI_Express]]
     }
     rectangle "USB" as usb {
       url of usb is [[https://en.wikipedia.org/wiki/USB]]
     }
}
cpu --> bus
mem --> bus
gpu --> bus
disk --> bus
kb --> bus

bus -[hidden]- pcie
bus -[hidden]- usb
@enduml

If that can help,
Regards,
Th.

Comments

Hello A.,

Another workaround will be to use sub-diagram as:

@startuml
rectangle "System" as sys {
  rectangle "motherboard" as mboard {
     rectangle "CPU" as cpu {
       url of cpu is [[https://en.wikipedia.org/wiki/Central_processing_unit]]
     }
     rectangle "memory" as mem {
       url of mem is [[https://en.wikipedia.org/wiki/Computer_memory]]
     }
     rectangle "GPU" as gpu {
       url of gpu [[https://en.wikipedia.org/wiki/Graphics_processing_unit]]
     }
     rectangle "Disk" as disk {
       url of disk is [[https://en.wikipedia.org/wiki/Mass_storage]]
     }
     rectangle "keyboard" as kb {
       url of kb is [[https://en.wikipedia.org/wiki/Computer_keyboard]]
     }
  }
}

rectangle bus #white [{{
     title "Bus"
     rectangle "PCIe Bus" as pcie {
       url of pcie is [[https://en.wikipedia.org/wiki/PCI_Express]]
     }
     rectangle "USB" as usb {
       url of usb is [[https://en.wikipedia.org/wiki/USB]]
     }
}}]

cpu -- bus
mem -- bus
gpu -- bus
disk -- bus
kb -- bus
@enduml

Enjoy,
Regards,
Th.