#174 Add LAYOUT_LANDSCAPE()

[kirchsth]

This PR solves the #174 issue.

LAYOUT_LEFT_RIGHT() rotates the default flow direction and the directed relations rotates, e.g. Rel_Right() is displayed as relation from up to down, like below

@startuml
!include https://raw.githubusercontent.com/kirchsth/C4-PlantUML/extended/C4_Container.puml

LAYOUT_LEFT_RIGHT()

Person(admin, "Administrator")
System_Boundary(c1, 'Sample') {
    Container(web_app, "Web Application", "C#, ASP.NET Core 2.1 MVC", "Allows users to compare multiple Twitter timelines")
}
System(twitter, "Twitter")

Rel(admin, web_app, "Uses", "HTTPS")
Rel(web_app, twitter, "Gets tweets from", "HTTPS")

System(S,"S")
System(SU,"S Up")
System(SD,"S Down")
System(SL,"S Left")
System(SR,"S Right")

Rel_Up(S, SU, "Up")
Rel_Down(S, SD, "Down")
Rel_Left(S, SL, "Left")
Rel_Right(S, SR, "Right")

SHOW_LEGEND()
@enduml

The new LAYOUT_LANDSCAPE() rotates only the default flow direction and the directed relation are not rotated anymore, e.g. Rel_Right() remains a relation from left to right, like below

@startuml LAYOUT_LANDSCAPE Sample
!include https://raw.githubusercontent.com/kirchsth/C4-PlantUML/extended/C4_Container.puml

LAYOUT_LANDSCAPE()

Person(admin, "Administrator")
System_Boundary(c1, 'Sample') {
    Container(web_app, "Web Application", "C#, ASP.NET Core 2.1 MVC", "Allows users to compare multiple Twitter timelines")
}
System(twitter, "Twitter")

Rel(admin, web_app, "Uses", "HTTPS")
Rel(web_app, twitter, "Gets tweets from", "HTTPS")

System(S,"S")
System(SU,"S Up")
System(SD,"S Down")
System(SL,"S Left")
System(SR,"S Right")

Rel_Up(S, SU, "Up")
Rel_Down(S, SD, "Down")
Rel_Left(S, SL, "Left")
Rel_Right(S, SR, "Right")

SHOW_LEGEND()

@enduml

It can be tested with my extended branch.

@oliv3r: can you test it with your larger diagrams and add your comments?

Best regards
Helmut

[Potherca]

👍

[oliv3r]

Hey @kirchsth It seems to work for simple systems, but I noticed that for whatever reason 'up' is rendered as 'down' and vice versa on more complex systems. Actually in complex systems I see really odd things happening. I'll see if I can translate something to publish it ...

(Also, could it be you forgot Lay_[URDL]? :) Haven't checked those in depth yet though.