Cannot figure out alignment order - Help Needed

[AdrianSimionov]

With the below code, I am trying to figure out the following:

• what makes cluster 1 to be positioned lower?
• why Edge from B to D starts on TOP and not on the right side of B?
• why edge from D to F ends on the BOTTOM side of F instead of the left side of F?
• why B is down and C is up?

I personally believe there is not enough documentation to explain this behaviour, and I realised looking at older bug reports that it has to do with the way edge connections are defined.

from diagrams import Cluster, Diagram
from diagrams.aws.storage import S3

graph_attr = {
    "bgcolor": "transparent",
    "dpi": "192"
}

with Diagram("Infra", show=True, graph_attr=graph_attr):
    with Cluster("1"):
        A = S3("A")
        B = S3("B")
        C = S3("C")
    with Cluster("2"):
        D = S3("D")
        E = S3("E")
        F = S3("F")
    with Cluster("3"):
        G = S3("G")
        H = S3("H")

    A >> [B, C]
    [B, C] >> D
    D >> [E, F]
    E >> G
    F >> H

[clayms]

You need to change the "layout" engine to either "neato" or "fdp", then for each Node set the pin to "true" and set the pos (position) to the "x,y" you want.

see: https://graphviz.gitlab.io/doc/info/attrs.html#d:pos

Note: I also set "splines" to "spline" instead of the default "ortho".

from diagrams import Diagram, Edge, Node

graph_attr = {
    "splines":"spline",
    "layout":"neato",
    }

with Diagram("\n\nInfra", show=False, graph_attr=graph_attr) as diag:
    node_shape = "invtrapezium"
    label_loc = "c"

    with Cluster("1"):
        A = Node("A", shape=node_shape, labelloc=label_loc, pin="true", pos="0,1")
        B = Node("B", shape=node_shape, labelloc=label_loc, pin="true", pos="2,0")
        C = Node("C", shape=node_shape, labelloc=label_loc, pin="true", pos="2,2")
    with Cluster("2"):
        D = Node("D", shape=node_shape, labelloc=label_loc, pin="true", pos="4,1")
        E = Node("E", shape=node_shape, labelloc=label_loc, pin="true", pos="6,0")
        F = Node("F", shape=node_shape, labelloc=label_loc, pin="true", pos="6,2")
    with Cluster("3"):
        G = Node("G", shape=node_shape, labelloc=label_loc, pin="true", pos="8,0")
        H = Node("H", shape=node_shape, labelloc=label_loc, pin="true", pos="8,2")

    A >> [B, C]
    [B, C] >> D
    D >> [E, F]
    E >> G
    F >> H

diag

Output:

[clayms]

@AdrianSimionov
another simple solution is to nest the three Clusters in another Cluster.
You can set the "root" Cluster attributes independently to make invisible if you choose.

from diagrams import Diagram, Cluster
from diagrams.aws.storage import S3

graph_attr = {
    "bgcolor": "transparent",
    "dpi": "192"
}

root_clus_attr = {
    "bgcolor": "transparent",
    "pencolor":"transparent",
}

with Diagram("Infra", show=False, graph_attr=graph_attr) as diag:
    with Cluster("", graph_attr=root_clus_attr):
        with Cluster("1"):
            A = S3("A")
            B = S3("B")
            C = S3("C")
        with Cluster("2"):
            D = S3("D")
            E = S3("E")
            F = S3("F")
        with Cluster("3"):
            G = S3("G")
            H = S3("H")

    A >> [B, C]
    [B, C] >> D
    D >> [E, F]
    E >> G
    F >> H

diag