DFD (Data Flow Diagram) Family

DFD family: processes, data stores and external entities

Overview
Node Types
Connection Points
Connection Conventions
Usage Example

Overview

Base Control: DFDControl : MaterialControl
Namespace: Beep.Skia.DFD

The DFDControl is the root control for this diagram family. It inherits MaterialControl and provides shared port management, styling, and template methods for all nodes in the family.

This family contains 18 node types.

Node Types

Node Class	Shape	Description
`DFDProcess`	Circle	Standard process transforming data flows.
`DFDProcessCircle`	Circle	Simple circle notation process.
`DFDProcessGaneSarson`	Rounded rectangle	Gane-Sarson notation process with ID and location.
`DFDProcessOval`	Oval	Oval-shaped process variant.
`DFDProcessNumbered`	Rounded rectangle + number	Numbered process for decomposition.
`DFDProcessMultiIO`	Rectangle with multiple ports	Process with multiple input/output ports.
`DFDProcessGroupBoundary`	Dashed rectangle	Container grouping related processes.
`DFDDataStore`	Open-ended rectangle	Standard data store notation.
`DFDDataStoreCylinder`	Cylinder	Database-style data store.
`DFDDataStoreOpenEnded`	Rectangle open right	Yourdon-style open-ended store.
`DFDDataStoreParallel`	Double line rectangle	Parallel data store notation.
`DFDDataStoreShared`	Rectangle with label	Shared data store across systems.
`DFDExternalEntity`	Rectangle	External entity (source/sink of data).
`DFDExternalEntityGaneSarson`	Rectangle with shadow	Gane-Sarson external entity notation.
`DFDNote`	Rounded note	Annotation/comment node.
`DFDTrustBoundary`	Dashed enclosure	Trust/security boundary marking.
`DFDSubsystemContainer`	Rounded rectangle container	Container for decomposed subsystem.
`DFDControl`	Database container	Control and coordination process.

DFDProcess

Standard process transforming data flows.

Shape	Circle
Input Ports	2+ (any side)
Output Ports	2+ (any side)

DFDProcessCircle

Simple circle notation process.

Shape	Circle
Input Ports	2+
Output Ports	2+

DFDProcessGaneSarson

Gane-Sarson notation process with ID and location.

Shape	Rounded rectangle
Input Ports	2+
Output Ports	2+

DFDProcessOval

Oval-shaped process variant.

Shape	Oval
Input Ports	2+
Output Ports	2+

DFDProcessNumbered

Numbered process for decomposition.

Shape	Rounded rectangle + number
Input Ports	2+
Output Ports	2+

DFDProcessMultiIO

Process with multiple input/output ports.

Shape	Rectangle with multiple ports
Input Ports	4+
Output Ports	4+

DFDProcessGroupBoundary

Container grouping related processes.

Shape	Dashed rectangle
Input Ports	0
Output Ports	0

DFDDataStore

Standard data store notation.

Shape	Open-ended rectangle
Input Ports	2 (left/right)
Output Ports	2 (left/right)

DFDDataStoreCylinder

Database-style data store.

Shape	Cylinder
Input Ports	2
Output Ports	2

DFDDataStoreOpenEnded

Yourdon-style open-ended store.

Shape	Rectangle open right
Input Ports	2
Output Ports	2

DFDDataStoreParallel

Parallel data store notation.

Shape	Double line rectangle
Input Ports	2
Output Ports	2

DFDDataStoreShared

Shared data store across systems.

Shape	Rectangle with label
Input Ports	2
Output Ports	2

DFDExternalEntity

External entity (source/sink of data).

Shape	Rectangle
Input Ports	2
Output Ports	2

DFDExternalEntityGaneSarson

Gane-Sarson external entity notation.

Shape	Rectangle with shadow
Input Ports	2
Output Ports	2

DFDNote

Annotation/comment node.

Shape	Rounded note
Input Ports	0
Output Ports	0

DFDTrustBoundary

Trust/security boundary marking.

Shape	Dashed enclosure
Input Ports	0
Output Ports	0

DFDSubsystemContainer

Container for decomposed subsystem.

Shape	Rounded rectangle container
Input Ports	2+
Output Ports	2+

DFDControl

Control and coordination process.

Shape	Database container
Input Ports	2+
Output Ports	2+

Connection Points

Every node in this family exposes connection points (ports) for linking to other nodes. Port positions are computed lazily by LayoutPorts(), which runs when MarkPortsDirty() flags the layout as stale after a move or resize.

Node Class	Input Ports	Output Ports	Extra
`DFDProcess`	2+ (any side)	2+ (any side)	—
`DFDProcessCircle`	2+	2+	—
`DFDProcessGaneSarson`	2+	2+	—
`DFDProcessOval`	2+	2+	—
`DFDProcessNumbered`	2+	2+	—
`DFDProcessMultiIO`	4+	4+	—
`DFDProcessGroupBoundary`	0	0	—
`DFDDataStore`	2 (left/right)	2 (left/right)	—
`DFDDataStoreCylinder`	2	2	—
`DFDDataStoreOpenEnded`	2	2	—
`DFDDataStoreParallel`	2	2	—
`DFDDataStoreShared`	2	2	—
`DFDExternalEntity`	2	2	—
`DFDExternalEntityGaneSarson`	2	2	—
`DFDNote`	0	0	—
`DFDTrustBoundary`	0	0	—
`DFDSubsystemContainer`	2+	2+	—
`DFDControl`	2+	2+	—

Connection Conventions

When building diagrams with this family, follow these conventions:

Processes use consistent naming: 'Verb + Object'
Data flows are labeled with the data being transferred
External entities represent systems outside scope
Data stores use DB cylinder or open-ended rectangle shapes

Usage Example

Complete example showing creation, node placement, and connection:

C# Example

var dfd = new DFDControl
{
    X = 100, Y = 50,
    Width = 600, Height = 400
};
drawingManager.AddComponent(dfd);

var proc = new DFDProcess { X = 300, Y = 150, Text = "Process Order" };
var store = new DFDDataStore { X = 450, Y = 80, Text = "Orders DB" };
var ext = new DFDExternalEntity { X = 150, Y = 80, Text = "Customer" };

drawingManager.AddComponent(proc);
drawingManager.AddComponent(store);
drawingManager.AddComponent(ext);

drawingManager.ConnectComponents(ext.OutPoints[0], proc.InPoints[0]);
drawingManager.ConnectComponents(proc.OutPoints[0], store.InPoints[0]);

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