Support transparency in Alt, Opt, Loop, Par ... insequence diagram

Question

In a sequence diagram, if I use boxes for readability, and one of the grouping feature (Alt, Opt, Loop, Par ..) the last ones hide completely the boxes. It could be nice if the background can be set as partially transparent:

https://www.plantuml.com/plantuml/png/XOunJyCm48Nd-5SykGkeGi8P6L2X4XCR8zCrFbAhYHDobugVpxaH843G38xqFljxRoDAayvz1sLHEBSRtk0Z7rF321whnzJkzRwRsLKZJPgQD59M-9J7MQ4a1myIZC5LaPHs90p_fCD4BP-81CSvmhpVtBMvxrvdwcbA-Poy_bDUVyeTTOhLm-dRNflZ1TiXnwHfo0ZGFMVlgkUhMzkAzHetq2crLXnGidh9n7GNfUlII5s856B0Mlc3Y97ogFpiKHmoBzTB69QGceEjPceq7KdPSiTTsL_EVvR8alqeN4Q6hpxyakVetCREkU_U0G00

Answer 1

it works with the color "transparent"

@startuml
box "device 1" #LightBlue
    participant "input task" as p1
    database "Storage" as s1
end box
box "device 2" #Aquamarine
    participant "input task" as p2
    database "Storage" as s2
end box

alt #transparent "if Condition 1 then"
    [-> p1 ++ : trig
    p1 -> p2 ++ : send(data)
    p2 -> s2 ++: store(data)
    s2 --> p2 -- : done
    p2 --> p1 -- : ack
    deactivate p1
else #blue "else"
    [-> p1 ++ : trig
    p1 -> s1 ++ : store(data)
    s1 -> p1 -- : done
    deactivate p1
end
@enduml

Answer 2

Hello all,

In fact it is good for SVG, but not for PNG...
The defect is for PNG output: @PlantUML team: Thank for a correction...

See comparison:

SVG : OK	PNG : KO

Regards,
Th.

Comments

Exactly what I was looking for. I hope it can be fixed with png.