Graph Engine Overview (drawlib.graph)

drawlib.graph is a declarative pure coordinate and layout calculator powered by five specialized layout solvers (ArchitectureGraph, LayerGraph, TreeGraph, RadialGraph, and GridGraph).

Instead of manually computing (x, y) coordinates for every vertex and container when drafting a complex topology, you declare structural relationships—nodes, edges, and clusters—and call layout = g.get_layout(width=..., height=...) so Drawlib's pure-Python layout algorithms calculate clean coordinates, container bounding boxes, and orthogonal or radial edge routes automatically. You then render the solved coordinates using drawlib.diagrams or drawlib.shapes and drawlib.lines.

import math
from drawlib.canvas import save, setup
from drawlib.icons import phosphor
from drawlib.lines import line, lines
from drawlib.shapes import circle, rectangle
from drawlib.styles import Styles
from drawlib.text import text

setup(width=124, height=84)

# Row 1: 3 Cards (ArchitectureGraph, LayerGraph, TreeGraph)
row1_cards = [
    (22.5, 62.5, 37.0, "ArchitectureGraph", "5-Zone & Nested VPCs", phosphor.cloud, Styles.PrimaryFlat, Styles.WhiteBold, Styles.White),
    (62.0, 62.5, 37.0, "LayerGraph", "Sugiyama Ranked DAG", phosphor.git_merge, Styles.PrimaryNeutral, Styles.DarkBold, Styles.Primary),
    (101.5, 62.5, 37.0, "TreeGraph", "Balanced Hierarchy", phosphor.tree_structure, Styles.SecondaryNeutral, Styles.DarkBold, Styles.Secondary),
]

# Row 2: 2 Cards (RadialGraph, GridGraph)
row2_cards = [
    (32.25, 21.5, 56.5, "RadialGraph", "Concentric Orbit Rings", phosphor.circles_three_plus, Styles.PrimaryNeutral, Styles.DarkBold, Styles.Primary),
    (91.75, 21.5, 56.5, "GridGraph", "2D Matrix & Channel Routing", phosphor.grid_four, Styles.SecondaryNeutral, Styles.DarkBold, Styles.Secondary),
]

for cx, cy, cw, title, subtitle, icon_fn, hdr_style, hdr_text_style, ic_style in row1_cards + row2_cards:
    rectangle((cx, cy), width=cw, height=37.0, style=Styles.Neutral.patch(shape_r=2.5))
    rectangle((cx, cy + 13.0), width=cw - 2.4, height=8.2, style=hdr_style.patch(shape_r=1.5))
    icon_fn((cx - cw / 2.0 + 4.4, cy + 13.0), width=4.2, style=ic_style)
    text((cx + 2.0, cy + 13.0), title, style=hdr_text_style.patch(text_size=10.5))
    text((cx, cy + 6.2), subtitle, style=Styles.Dark.patch(text_size=10.0))

# 1. ArchitectureGraph miniature (cx=22.5, y=46..65)
rectangle((25.5, 54.0), width=22.0, height=13.5, style=Styles.MutedDashed.patch(shape_r=1.2))
line((10.5, 54.0), (19.5, 54.0), style=Styles.DarkBold)
line((19.5, 54.0), (31.0, 56.8), style=Styles.DarkBold)
line((19.5, 54.0), (31.0, 51.2), style=Styles.DarkBold)
rectangle((10.5, 54.0), width=7.5, height=5.8, style=Styles.White.patch(shape_r=0.8), text="Edge", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((19.5, 54.0), width=8.0, height=5.8, style=Styles.PrimaryFlat.patch(shape_r=0.8), text="API", text_style=Styles.WhiteBold.patch(text_size=10.0))
rectangle((31.0, 56.8), width=8.0, height=4.8, style=Styles.PrimaryNeutral.patch(shape_r=0.8), text="App", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((31.0, 51.2), width=8.0, height=4.8, style=Styles.SecondaryNeutral.patch(shape_r=0.8), text="DB", text_style=Styles.Dark.patch(text_size=10.0))

# 2. LayerGraph miniature (cx=62.0)
rectangle((62.0, 54.0), width=10.5, height=14.5, style=Styles.MutedDashed.patch(shape_r=1.2))
line((50.0, 56.8), (62.0, 56.8), style=Styles.DarkBold)
line((50.0, 51.2), (62.0, 51.2), style=Styles.DarkBold)
line((62.0, 56.8), (74.0, 54.0), style=Styles.DarkBold)
line((62.0, 51.2), (74.0, 54.0), style=Styles.DarkBold)
rectangle((50.0, 56.8), width=8.0, height=4.8, style=Styles.White.patch(shape_r=0.8), text="In1", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((50.0, 51.2), width=8.0, height=4.8, style=Styles.White.patch(shape_r=0.8), text="In2", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((62.0, 56.8), width=8.0, height=4.8, style=Styles.PrimaryNeutral.patch(shape_r=0.8), text="ETL", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((62.0, 51.2), width=8.0, height=4.8, style=Styles.PrimaryNeutral.patch(shape_r=0.8), text="Agg", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((74.0, 54.0), width=8.5, height=5.8, style=Styles.PrimaryFlat.patch(shape_r=0.8), text="Out", text_style=Styles.WhiteBold.patch(text_size=10.0))

# 3. TreeGraph miniature (cx=101.5)
lines([(101.5, 58.0), (101.5, 54.5), (92.5, 54.5), (92.5, 51.5)], style=Styles.DarkBold)
lines([(101.5, 58.0), (101.5, 54.5), (101.5, 51.5)], style=Styles.DarkBold)
lines([(101.5, 58.0), (101.5, 54.5), (110.5, 54.5), (110.5, 51.5)], style=Styles.DarkBold)
rectangle((101.5, 60.0), width=11.0, height=5.0, style=Styles.PrimaryFlat.patch(shape_r=0.8), text="Root", text_style=Styles.WhiteBold.patch(text_size=10.0))
rectangle((92.5, 49.5), width=8.2, height=5.0, style=Styles.PrimaryNeutral.patch(shape_r=0.8), text="C1", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((101.5, 49.5), width=8.2, height=5.0, style=Styles.SecondaryNeutral.patch(shape_r=0.8), text="C2", text_style=Styles.Dark.patch(text_size=10.0))
rectangle((110.5, 49.5), width=8.2, height=5.0, style=Styles.White.patch(shape_r=0.8), text="C3", text_style=Styles.Dark.patch(text_size=10.0))

# 4. RadialGraph miniature (cx=32.25, cy=13.2)
rcx, rcy = 32.25, 13.2
circle((rcx, rcy), radius=8.5, style=Styles.MutedDashed)
for deg, lbl, st in [(20, "S1", Styles.PrimaryNeutral), (160, "S2", Styles.SecondaryNeutral), (270, "S3", Styles.White)]:
    rad = math.radians(deg)
    x1, y1 = rcx + 12.0 * math.cos(rad), rcy + 7.2 * math.sin(rad)
    line((rcx, rcy), (x1, y1), style=Styles.DarkBold)
    rectangle((x1, y1), width=8.5, height=4.8, style=st.patch(shape_r=0.8), text=lbl, text_style=Styles.Dark.patch(text_size=10.0))
circle((rcx, rcy), radius=4.8, style=Styles.PrimaryFlat, text="Hub", text_style=Styles.WhiteBold.patch(text_size=10.0))

# 5. GridGraph miniature (cx=91.75)
g_cols = [76.5, 91.75, 107.0]
g_rows = [17.2, 9.2]
line((76.5, 17.2), (91.75, 17.2), style=Styles.DarkBold)
line((91.75, 17.2), (91.75, 9.2), style=Styles.DarkBold)
line((91.75, 9.2), (107.0, 9.2), style=Styles.DarkBold)
lines([(76.5, 14.5), (76.5, 13.2), (107.0, 13.2), (107.0, 11.8)], style=Styles.PrimaryBold)
for r_idx, gy in enumerate(g_rows):
    for c_idx, gx in enumerate(g_cols):
        is_hero = (r_idx == 0 and c_idx == 1)
        cell_st = Styles.PrimaryFlat if is_hero else (Styles.PrimaryNeutral if r_idx == 0 else Styles.White)
        txt_st = Styles.WhiteBold.patch(text_size=10.0) if is_hero else Styles.Dark.patch(text_size=10.0)
        rectangle((gx, gy), width=10.5, height=5.0, style=cell_st.patch(shape_r=0.8), text=f"{r_idx},{c_idx}", text_style=txt_st)

save()

1. Division of Responsibility: drawlib.graph + drawlib.diagrams

Drawlib cleanly separates topological coordinate calculation (drawlib.graph) from visual diagram rendering (drawlib.diagrams and drawlib.shapes).

1.1 Minimal Concept: Inspecting get_layout() and Connecting Circles

At its simplest, g.get_layout() takes your node/edge topology and returns a GraphLayout containing the solved (x, y) coordinates (nl.xy) for each node and the routed polyline points (e.points) for each edge. You can inspect these values with print(layout) and draw them with simple circle() and lines() calls:

from drawlib.canvas import save, setup
from drawlib.graph import LayerGraph
from drawlib.lines import lines
from drawlib.shapes import circle
from drawlib.styles import Styles

setup(width=100, height=52)

# Step 1: Declare topology & solve coordinates with get_layout()
g = LayerGraph(direction="LR", default_node_width=16.0, default_node_height=16.0)
g.edge("A", "B")
g.edge("A", "C")
g.edge("B", "D")
g.edge("C", "D")

layout = g.get_layout(margin=8.0)

# print(layout) outputs:
# GraphLayout(width=100.0, height=52.0)
# Nodes:
#   A : xy=(16.0, 26.0), bottom_left=(8.0, 18.0), size=(16.0, 16.0)
#   B : xy=(50.0, 36.0), bottom_left=(42.0, 28.0), size=(16.0, 16.0)
#   C : xy=(50.0, 16.0), bottom_left=(42.0, 8.0), size=(16.0, 16.0)
#   D : xy=(84.0, 26.0), bottom_left=(76.0, 18.0), size=(16.0, 16.0)
# Edges:
#   A -> B : points=[(24.0, 26.0), (33.0, 26.0), (33.0, 36.0), (42.0, 36.0)], mid_xy=(33.0, 31.0)
#   A -> C : points=[(24.0, 26.0), (33.0, 26.0), (33.0, 16.0), (42.0, 16.0)], mid_xy=(33.0, 21.0)
#   B -> D : points=[(58.0, 36.0), (67.0, 36.0), (67.0, 26.0), (76.0, 26.0)], mid_xy=(67.0, 31.0)
#   C -> D : points=[(58.0, 16.0), (67.0, 16.0), (67.0, 26.0), (76.0, 26.0)], mid_xy=(67.0, 21.0)

# Step 2: Connect circles with lines using the solved coordinates
for e in layout.edges:
    lines(e.points, arrow_head="->", style=Styles.DarkBold)

circle(layout["A"].xy, radius=8.0, style=Styles.PrimaryFlat, text="A\n(16, 26)", text_style=Styles.WhiteBold.patch(text_size=10.5))
circle(layout["B"].xy, radius=8.0, style=Styles.PrimaryNeutral, text="B\n(50, 36)", text_style=Styles.DarkBold.patch(text_size=10.5))
circle(layout["C"].xy, radius=8.0, style=Styles.PrimaryNeutral, text="C\n(50, 16)", text_style=Styles.DarkBold.patch(text_size=10.5))
circle(layout["D"].xy, radius=8.0, style=Styles.SecondaryNeutral, text="D\n(84, 26)", text_style=Styles.DarkBold.patch(text_size=10.5))

save()

1.2 Full Architecture Workflow: ArchitectureGraph + ArchitectureDiagram

For production architecture diagrams with nested VPCs, subnets, and cloud icons, pair ArchitectureGraph.get_layout() with ArchitectureDiagram:

from drawlib.canvas import save, setup
from drawlib.diagrams.architecture import ArchitectureDiagram, GcpIcon, Node, NodeGroup, PhosphorIcon
from drawlib.graph import ArchitectureGraph
from drawlib.styles import Styles

setup(width=118, height=96)

# Step 1: Declare topology & solve coordinates with ArchitectureGraph.get_layout()
g = ArchitectureGraph(
    direction="LR",
    container_sep=5.5,
    default_node_width=19.0,
    default_node_height=12.0,
)

g.cluster("clients", ["client"], pos="left", padding=3.5, header_height=4.5)
g.group("vpc", pos="center", padding=4.0, header_height=4.8)
g.cluster("app_tier", ["api", "worker"], parent="vpc", order=1, padding=4.0, header_height=4.5)
g.cluster("data_tier", ["db", "cache"], parent="vpc", order=2, padding=4.0, header_height=4.5)
g.cluster("obs", ["metrics"], pos="bottom", padding=3.5, header_height=4.2)

g.edge("client", "api")
g.edge("client", "worker")
g.edge("api", "db")
g.edge("worker", "cache")
g.edge("worker", "metrics")

layout = g.get_layout()

# Step 2: Render rich icon cards & boundaries using ArchitectureDiagram
d = ArchitectureDiagram(
    node_style=Styles.Primary,
    node_text_style=Styles.DarkBold.patch(text_size=10.0),
    edge_style=Styles.DarkBold,
    edge_text_style=Styles.Dark.patch(text_size=10.0),
    node_card_style=Styles.Neutral,
)
grp_hdr = Styles.DarkBold.patch(text_size=10.0, halign="left", valign="top")

c_cli = layout.clusters["clients"]
grp_cli = d.add(NodeGroup("External", width=c_cli.width, height=c_cli.height, text_style=grp_hdr), xy=c_cli.bottom_left)

c_vpc = layout.clusters["vpc"]
grp_vpc = d.add(NodeGroup("Production VPC", width=c_vpc.width, height=c_vpc.height, text_style=grp_hdr), xy=c_vpc.bottom_left)

c_app = layout.clusters["app_tier"]
grp_app = grp_vpc.add(
    NodeGroup("Compute Tier", width=c_app.width, height=c_app.height, style=Styles.PrimaryNeutral, text_style=grp_hdr),
    xy=c_app.local_bottom_left,
)

c_data = layout.clusters["data_tier"]
grp_data = grp_vpc.add(
    NodeGroup("Data Tier", width=c_data.width, height=c_data.height, style=Styles.SecondaryNeutral, text_style=grp_hdr),
    xy=c_data.local_bottom_left,
)

c_obs = layout.clusters["obs"]
grp_obs = d.add(NodeGroup("Telemetry", width=c_obs.width, height=c_obs.height, text_style=grp_hdr), xy=c_obs.bottom_left)

n_cli = grp_cli.add(Node("Client App", *layout["client"].size, icon=PhosphorIcon.LAPTOP, icon_size=5.0), xy=layout["client"].local_xy)
n_api = grp_app.add(
    Node(
        "API Gateway",
        *layout["api"].size,
        icon=GcpIcon.CLOUD_RUN,
        icon_size=5.5,
        style=Styles.White,
        text_style=Styles.WhiteBold.patch(text_size=10.0),
        card_style=Styles.PrimaryFlat,
    ),
    xy=layout["api"].local_xy,
)
n_wrk = grp_app.add(
    Node("Async Worker", *layout["worker"].size, icon=GcpIcon.GOOGLE_KUBERNETES_ENGINE, icon_size=5.5, card_style=Styles.White),
    xy=layout["worker"].local_xy,
)
n_db = grp_data.add(
    Node("Primary DB", *layout["db"].size, icon=GcpIcon.CLOUD_SQL, icon_size=5.5, card_style=Styles.White),
    xy=layout["db"].local_xy,
)
n_cache = grp_data.add(
    Node("Memorystore", *layout["cache"].size, icon=GcpIcon.MEMORYSTORE, icon_size=5.5, card_style=Styles.White),
    xy=layout["cache"].local_xy,
)
n_obs = grp_obs.add(
    Node("Monitoring", *layout["metrics"].size, icon=GcpIcon.CLOUD_MONITORING, icon_size=5.0),
    xy=layout["metrics"].local_xy,
)

d.connect(n_cli, n_api, label="HTTPS", padding=0.8)
d.connect(n_cli, n_wrk, label="Events", padding=0.8)
d.connect(n_api, n_db, label="SQL", padding=0.8)
d.connect(n_wrk, n_cache, label="Cache", padding=0.8)
d.connect(n_wrk, n_obs, style=Styles.MutedDashed, padding=0.8)

d.draw(xy=(-4.0, -5.0))
save()

2. The Five Specialized Layout Solvers

Rather than forcing every topology through a single generic heuristic, drawlib.graph provides five purpose-built coordinate solvers tailored to distinct structural patterns:

3. Shared Architecture (BaseGraph & GraphLayout)

All five solvers inherit from BaseGraph and share a unified, geometry-only API for registering topology elements and computing a GraphLayout:

from drawlib.graph import (
    ArchitectureGraph,
    BaseGraph,
    Cluster,
    ClusterLayout,
    Edge,
    EdgeLayout,
    GraphLayout,
    GridGraph,
    LayerGraph,
    Node,
    NodeLayout,
    RadialGraph,
    TreeGraph,
)

3.1. Building Topologies (node, edge, cluster, group)

BaseGraph(*, default_node_width=20.0, default_node_height=12.0)

Base constructor shared by all graph solvers, defining the default bounding box dimensions (default_node_width, default_node_height) assigned to nodes when explicit width or height is omitted.

g.node(...) -> Node

Registers a node in the graph and returns a Node dataclass instance carrying its structural and sizing metadata.

• Signature:

  g.node(
      id: str,
      *,
      width: float | None = None,
      height: float | None = None,
      ring: int | None = None,
      row: int | None = None,
      col: int | None = None,
      layer: int | None = None,
      group: str | None = None,
      subgroup: str | None = None,
  ) -> Node
  

g.edge(...) -> Edge

Registers a directed topological connection between src and dst (automatically registering undeclared endpoint nodes with default dimensions).

• Signature:

  g.edge(
      src: str,
      dst: str,
  ) -> Edge
  

g.cluster(...) -> Cluster and g.group(...) -> Cluster

Groups a list of nodes (or child clusters via parent=...) inside a container bounding box with configurable padding and top header_height clearance.

• Signatures:

  g.cluster(
      id: str,
      nodes: list[str] | None = None,
      *,
      padding: float = 4.0,
      header_height: float = 3.5,
      parent: str | None = None,
      order: int | None = None,
      pos: Literal["top", "bottom", "left", "right", "center"] | None = None,
  ) -> Cluster
  
  g.group(
      id: str,
      *,
      nodes: list[str] | None = None,
      padding: float = 4.0,
      header_height: float = 3.5,
      parent: str | None = None,
      order: int | None = None,
      pos: Literal["top", "bottom", "left", "right", "center"] | None = None,
  ) -> Cluster
  

3.2. The 2-Step Workflow (get_layout, print(layout), offset, and Render)

from drawlib.canvas import save, setup
from drawlib.icons import phosphor
from drawlib.lines import line, lines
from drawlib.shapes import rectangle
from drawlib.styles import Styles
from drawlib.text import text

setup(width=126, height=64)

# Top Header / Input Node
rectangle(
    (63, 53.5),
    width=118,
    height=13,
    style=Styles.PrimaryNeutral.patch(shape_r=2.5),
)
phosphor.tree_structure((14, 53.5), width=5.5, style=Styles.Primary)
text((66, 56.2), "Step 1: Declare Topology & Solve Layout", style=Styles.DarkBold.patch(text_size=11.5))
text((66, 50.6), "g.node()  ·  g.edge()  ·  g.cluster()   ──>   layout = g.get_layout(width=..., height=...)", style=Styles.Dark.patch(text_size=10.0))

# Orthogonal fan-out lines from top header into the 3 cards
line((63, 47.0), (63, 39.5), arrow_head="->", style=Styles.DarkBold)
lines([(63, 43.2), (22.5, 43.2), (22.5, 39.5)], arrow_head="->", style=Styles.DarkBold)
lines([(63, 43.2), (103.5, 43.2), (103.5, 39.5)], arrow_head="->", style=Styles.DarkBold)

# Card 1: Inspect Coordinates via print(layout)
rectangle((22.5, 21.5), width=37, height=35, style=Styles.Neutral.patch(shape_r=2.5))
phosphor.terminal_window((8.0, 33.5), width=4.4, style=Styles.Primary)
text((24.5, 33.5), "1a. Inspect Table", style=Styles.DarkBold.patch(text_size=10.5))
rectangle((22.5, 23.0), width=33, height=9.5, style=Styles.White.patch(shape_r=1.5))
text((22.5, 23.0), "print(layout)", style=Styles.PrimaryBold.patch(text_size=10.5))
text((22.5, 11.2), "View solved xy, size\n& local_xy summary", style=Styles.Dark.patch(text_size=10.0))

# Card 2: Access & Offset Coordinates (PrimaryFlat focal card)
rectangle((63, 21.5), width=39, height=35, style=Styles.PrimaryFlat.patch(shape_r=2.5))
phosphor.sliders_horizontal((47.5, 33.5), width=4.4, style=Styles.White)
text((65.0, 33.5), "1b. Query & Offset", style=Styles.WhiteBold.patch(text_size=10.5))
rectangle((63, 23.0), width=35, height=10.5, style=Styles.PrimaryNeutral.patch(shape_r=1.5))
text((63, 23.0), 'layout["id"].xy\nlayout.offset()', style=Styles.DarkBold.patch(text_size=10.0))
text((63, 11.0), "Direct lookup & post-\nlayout nudging", style=Styles.White.patch(text_size=10.0))

# Card 3: Step 2 Render with Diagrams or Shapes (SecondaryNeutral)
rectangle((103.5, 21.5), width=37, height=35, style=Styles.SecondaryNeutral.patch(shape_r=2.5))
phosphor.paint_brush_broad((88.5, 33.5), width=4.4, style=Styles.Secondary)
text((105.5, 33.5), "Step 2: Render", style=Styles.DarkBold.patch(text_size=10.5))
rectangle((103.5, 23.0), width=33, height=10.5, style=Styles.White.patch(shape_r=1.5))
text((103.5, 23.0), "drawlib.diagrams\ndrawlib.shapes", style=Styles.DarkBold.patch(text_size=10.0))
text((103.5, 11.2), "Draw rich cards,\nicons & connectors", style=Styles.Dark.patch(text_size=10.0))

save()

Step 1: Solve & Inspect Coordinates (layout = g.get_layout(*, width=None, height=None, margin=10.0) -> GraphLayout)

Calling g.get_layout() runs the layout solver and returns a GraphLayout object:

• print(layout) (GraphLayout.__str__()): Prints a formatted coordinate table of all solved clusters, nodes, and edges—ideal for inspecting coordinates during interactive development or copying exact numbers into a static diagram script:

  GraphLayout(width=120.0, height=80.0)
  Clusters:
    vpc : bottom_left=(18.0, 22.5), center=(38.0, 40.0), size=(40.0, 35.0)
    app : bottom_left=(22.0, 28.25), center=(38.0, 38.25), size=(32.0, 20.0), parent='vpc', local_bottom_left=(4.0, 5.75)
  Nodes:
    api    : xy=(38.0, 38.25), bottom_left=(26.0, 32.25), size=(24.0, 12.0), parent='app', local_xy=(16.0, 10.0)
    client : xy=(86.0, 38.25), bottom_left=(74.0, 32.25), size=(24.0, 12.0)
  Edges:
    client -> api : points=[(74.0, 38.25), (50.0, 38.25)], mid_xy=(62.0, 38.25)
  

• Direct Lookup (layout["id"]): Indexing layout[key] returns the corresponding NodeLayout or ClusterLayout directly (or access layout.nodes[id], layout.clusters[id], layout.edges, and layout.ring_radii).
• Post-Layout Fine-Tuning (layout.offset(node_id, dx=0.0, dy=0.0) -> Self): Shifts a specific node by (dx, dy) (updating both .xy and .local_xy) and automatically adjusts the attachment ports of all incident edges. Returns self for method chaining.

Step 2: Render with drawlib.diagrams or drawlib.shapes

Every geometry object in GraphLayout exposes convenience properties tailored for both drawlib.diagrams and drawlib.shapes:

from drawlib.canvas import save, setup
from drawlib.graph import LayerGraph
from drawlib.lines import lines
from drawlib.shapes import bubblespeech, rectangle
from drawlib.styles import Styles

setup(width=120, height=56)

# 1. Declare pipeline topology and calculate coordinates
g = LayerGraph(
    direction="LR",
    default_node_width=27.0,
    default_node_height=12.0,
)
g.node("ingest")
g.node("process")
g.node("store")

g.edge("ingest", "process")
g.edge("process", "store")

layout = g.get_layout(width=120.0, height=56.0, margin=8.0)

# 2. Fine-tune the middle node position downward
layout.offset("process", dy=-5.5)

# 3. Render edges and nodes using solved coordinates
for e in layout.edges:
    lines(e.points, arrow_head="->", style=Styles.DarkBold)

node_specs = [
    ("ingest", "Ingest", Styles.Neutral, Styles.DarkBold.patch(text_size=11.0)),
    ("process", "Stream Engine", Styles.PrimaryFlat, Styles.WhiteBold.patch(text_size=11.0)),
    ("store", "Data Lake", Styles.SecondaryNeutral, Styles.DarkBold.patch(text_size=11.0)),
]
for nid, label, box_style, txt_style in node_specs:
    n = layout.nodes[nid]
    rectangle(
        n.xy,
        width=n.width,
        height=n.height,
        style=box_style.patch(shape_r=1.5),
        text=label,
        text_style=txt_style,
    )

# 4. Overlay a custom speech callout anchored to the computed node coordinates
proc = layout.nodes["process"]
bubblespeech(
    (proc.x - 16.0, proc.top + 3.5),
    width=32.0,
    height=10.5,
    tail_edge="bottom",
    tail_start_ratio=0.4,
    tail_end_ratio=0.6,
    tail_vertex_xy=(proc.x, proc.top + 0.8),
    style=Styles.WarningNeutral,
    text="Auto-scaled x8",
    text_style=Styles.DarkBold.patch(text_size=10.5),
)

save()

4. Best Practices & 50%+ Neutral Baseline

1. Match Node Dimensions & header_height to Your Renderer:
   • Pass default_node_width and default_node_height to the graph constructor so the solver reserves the exact card dimensions you will render in ArchitectureDiagram, FlowDiagram, or rectangle() (or unpack *layout["id"].size directly into Node(title, *layout["id"].size, ...)).
   • When rendering clusters as NodeGroups in ArchitectureDiagram, set header_height=4.5 on g.cluster() / g.group() so the solver reserves extra vertical clearance at the top of each container for the group title.
2. Follow the 50%+ Neutral Baseline When Rendering:
   • Ground at least 50% of rendered nodes in calm neutral or tinted-neutral styles (Styles.Neutral, Styles.PrimaryNeutral, Styles.SecondaryNeutral), and reserve saturated fills (Styles.PrimaryFlat with Styles.WhiteBold) strictly for 1–2 primary focal nodes.
3. Use print(layout) or layout.offset() to Iterate Rapidly:
   • Start by passing layout["id"] coordinates directly into your rendering code. If a node or callout needs extra breathing room, chain layout.offset("node_id", dx=..., dy=...)—or call print(layout) to inspect and copy the solved coordinates.

5. Chapter Navigation

Explore each of the five graph solvers in detail:

• ArchitectureGraph: Multi-tier cloud topologies, nested VPC/subnet clusters, and 5-zone compass placement rendered with ArchitectureDiagram.
• LayerGraph: Sugiyama hierarchical DAGs, CI/CD pipelines, and explicit rank/tier pinning rendered with FlowDiagram and primitives.
• TreeGraph: Balanced parent-child trees (TB and LR) using the Reingold-Tilford / Buchheim algorithm.
• RadialGraph: Hub-and-spoke networks and multi-ring concentric dependency radars.
• GridGraph: 2D (row, col) matrix placement, row/column clusters, and smart channel routing.