drawlib.diagrams.flow

ISO 5807 / JIS X 0121 flowcharts and cross-functional swimlane workflows with semantic step shapes, decision branches, and orthogonal edge routing. Canonical import: from drawlib.diagrams.flow import Data, Decision, End, FlowDiagram, Process, Start.

from drawlib.canvas import save, setup
from drawlib.diagrams.flow import Data, Decision, End, FlowDiagram, Process, Start
from drawlib.styles import Colors, Styles

setup(width=120, height=68)

flow = FlowDiagram(
    node_style=Styles.Neutral.patch(text_size=10.5),
    edge_style=Styles.DarkBold,
    edge_text_style=Styles.DarkBold.patch(text_size=10.0),
    width=110,
    height=58,
    lane_orientation="vertical",
)

flow.add_lane(
    "Client",
    width=36,
    style=Styles.Neutral,
    header_style=Styles.PrimaryNeutral,
    text_style=Styles.DarkBold.patch(text_size=11.0),
)
flow.add_lane(
    "Gateway",
    width=38,
    style=Styles.Neutral,
    header_style=Styles.SecondaryNeutral,
    text_style=Styles.DarkBold.patch(text_size=11.0),
)
flow.add_lane(
    "Fulfillment",
    width=36,
    style=Styles.Neutral,
    header_style=Styles.PrimaryNeutral,
    text_style=Styles.DarkBold.patch(text_size=11.0),
)

start = flow.add(
    Start("Start", width=20, height=9, style=Styles.PrimaryFlat.patch(text_color=Colors.White, text_size=10.5)),
    xy=(18.0, 43.0),
)
submit = flow.add(Process("Submit Order", width=26, height=10), xy=(18.0, 27.5))
check = flow.add(
    Decision("Valid?", width=24, height=13, style=Styles.PrimaryNeutral.patch(text_size=10.5)),
    xy=(55.0, 27.5),
)
reject = flow.add(
    Data("Error Notice", width=26, height=9, style=Styles.SecondaryNeutral.patch(text_size=10.5)),
    xy=(55.0, 7.5),
)
ship = flow.add(
    Process("Dispatch", width=24, height=10, style=Styles.PrimaryNeutral.patch(text_size=10.5)),
    xy=(92.0, 35.5),
)
done = flow.add(
    End("Done", width=20, height=9, style=Styles.SecondaryNeutral.patch(text_size=10.5)),
    xy=(92.0, 12.0),
)

start.connect(submit, padding=0.8)
submit.connect(check, padding=0.8)
check.connect(ship, label="Yes", start_side="right", end_side="left", padding=0.8)
check.connect(reject, label="No", start_side="bottom", end_side="top", padding=0.8)
ship.connect(done, padding=0.8)

flow.draw(xy=(5.0, 5.0))
save()

typeArrowType#

Type alias specifying arrowhead markers on FlowEdge connections.

ArrowType = Literal["->", "<-", "<->", "-"] | str

• Coordinate Anchor: Applied to the start and/or end terminals of a FlowEdge.

typeConnectable#

Union type alias representing any flowchart element that can serve as the start or end endpoint of a FlowEdge.

Connectable = FlowNode | Junction

• Coordinate Anchor: Resolves to boundary port anchors on FlowNode (and subclasses Start, End, Process, Decision, Data) or exact (x, y) coordinates on Junction.

classData#

Flowchart I/O node rendered as a slanted parallelogram representing data input, output payloads, or external storage records. Subclass of FlowNode.

Data(
    text: str = "",
    width: float = 24.0,
    height: float = 12.0,
    style: Style | None = None,
    text_style: Style | None = None,
    show: bool = True,
) -> None

• Coordinate Anchor: Center (cx, cy) when registered via flow.add(node, xy=(cx, cy)).

Constructor Parameters#

Public Methods & Properties#

classDecision#

Flowchart conditional branching node rendered as a rhombus (diamond) with four vertex anchors. Subclass of FlowNode.

Decision(
    text: str = "",
    width: float = 22.0,
    height: float = 14.0,
    style: Style | None = None,
    text_style: Style | None = None,
    show: bool = True,
) -> None

• Coordinate Anchor: Center (cx, cy) when registered via flow.add(node, xy=(cx, cy)). Specify explicit start_side="right" / start_side="bottom" on .connect() calls to separate "Yes" and "No" outgoing branches cleanly.

Constructor Parameters#

Public Methods & Properties#

classEnd#

Flowchart terminal exit node rendered as a stadium (pill) shape. Subclass of FlowNode.

End(
    text: str = "End",
    width: float = 20.0,
    height: float = 10.0,
    style: Style | None = None,
    text_style: Style | None = None,
    show: bool = True,
) -> None

• Coordinate Anchor: Center (cx, cy) when registered via flow.add(node, xy=(cx, cy)).

Constructor Parameters#

Public Methods & Properties#

classFlowDiagram#

Top-level container for flowcharts and cross-functional swimlane workflow diagrams. All nodes share a unified global coordinate space across swimlanes.

FlowDiagram(
    *,
    node_style: Style,
    edge_style: Style,
    edge_text_style: Style,
    title: str = "",
    title_style: Style | None = None,
    width: float | None = None,
    height: float | None = None,
    style: Style | None = None,
    lane_orientation: Orientation = "vertical",
) -> None

• Coordinate Anchor: draw(xy=(0.0, 0.0), align="bottom_left") anchors the diagram's bottom-left (0.0, 0.0) corner at canvas coordinate xy (or centers the diagram at xy when align="center").

Constructor Parameters#

Public Methods & Properties#

classFlowEdge#

Connection line linking two Connectable elements in a FlowDiagram.

FlowEdge(
    start: Connectable,
    end: Connectable,
    label: str = "",
    arrow: ArrowType | None = None,
    routing: RoutingType = "orthogonal",
    start_side: Side = "auto",
    end_side: Side = "auto",
    style: Style | None = None,
    text_style: Style | None = None,
    padding: PaddingType = 0.0,
    show: bool = True,
) -> None

• Coordinate Anchor: Attaches to start_side on start and end_side on end; intermediate waypoints use diagram-local (x, y) coordinates.

Constructor Parameters#

Public Methods & Properties#

classFlowNode#

Base vertex class representing any flowchart shape ("process", "decision", "start", "end", or "data"). Concrete subclasses Start, End, Process, Decision, and Data pre-configure shape_type and standard dimensions.

FlowNode(
    text: str = "",
    width: float = 24.0,
    height: float = 12.0,
    style: Style | None = None,
    text_style: Style | None = None,
    shape_type: ShapeType = "process",
    show: bool = True,
) -> None

• Coordinate Anchor: Center (cx, cy) when registered via flow.add(node, xy=(cx, cy)).

Constructor Parameters#

Public Methods & Properties#

classJunction#

Zero-size connectable waypoint and branch/merge node in a FlowDiagram.

Junction(
    xy: tuple[float, float],
    *,
    show: bool = True,
) -> None

• Coordinate Anchor: Exact point (x, y) in diagram-local coordinates. Create via flow.junction(xy) or edge.add_point(xy).

Constructor Parameters#

Public Methods & Properties#

classLane#

Swimlane column (lane_orientation="vertical") or row (lane_orientation="horizontal") partitioning the background of a FlowDiagram. Typically created via flow.add_lane(...).

Lane(
    title: str,
    size: float,
    style: Style | None = None,
    text_style: Style | None = None,
    header_size: float = 6.0,
    header_style: Style | None = None,
    show: bool = True,
) -> None

• Coordinate Anchor: Automatically tiled sequentially (left-to-right for vertical columns; top-to-bottom for horizontal rows) across the diagram's (0, 0) global frame. For vertical lanes of widths $W_0, W_1, \dots$, column centerlines lie at $X_0 = W_0 / 2$, $X_1 = W_0 + W_1 / 2$, etc.

Constructor Parameters & Attributes#

typeOrientation#

Literal type controlling swimlane stacking direction on FlowDiagram.

Orientation = Literal["vertical", "horizontal"]

• Coordinate Anchor: Configures how Lane bands tile across the diagram background.

typePaddingType#

Union type alias specifying endpoint clearance gap distances on FlowEdge connections.

PaddingType = float | tuple[float, float]

• Coordinate Anchor: Offsets edge endpoints outward from start and end node boundaries.

classProcess#

Flowchart action, task, or operation step rendered as a rectangle. Subclass of FlowNode.

Process(
    text: str = "",
    width: float = 24.0,
    height: float = 12.0,
    style: Style | None = None,
    text_style: Style | None = None,
    show: bool = True,
) -> None

• Coordinate Anchor: Center (cx, cy) when registered via flow.add(node, xy=(cx, cy)).

Constructor Parameters#

Public Methods & Properties#

typeRoutingType#

Literal type controlling path geometry for FlowEdge connections.

RoutingType = Literal["orthogonal", "direct"]

• Coordinate Anchor: Governs segment interpolation between start and end port coordinates.

typeShapeType#

Literal type selecting the flowchart symbol geometry on FlowNode.

ShapeType = Literal["process", "decision", "start", "end", "data"]

• Coordinate Anchor: All shapes are centered around the node's (cx, cy) coordinate.

typeSide#

Literal type specifying boundary attachment ports on FlowNode shapes.

Side = Literal["left", "right", "top", "bottom", "auto"]

• Coordinate Anchor: Resolves to the midpoint (or vertex on Decision) of the corresponding node side, or selects the nearest facing side automatically when "auto".

classStart#

Flowchart entry terminal node rendered as a stadium (pill) shape. Subclass of FlowNode.

Start(
    text: str = "Start",
    width: float = 20.0,
    height: float = 10.0,
    style: Style | None = None,
    text_style: Style | None = None,
    show: bool = True,
) -> None

• Coordinate Anchor: Center (cx, cy) when registered via flow.add(node, xy=(cx, cy)).

Constructor Parameters#

Public Methods & Properties#