# Graphviz Syntax Reference Detailed syntax rules for advanced graph features. Load this when you need specific syntax details. --- ## Node Definition ### Basic Syntax ```dot digraph G { node_id [label="Display Name"]; "node with space" [label="Displayed"]; } ``` ### Node Attributes ```dot digraph G { node_id [ label="Display Name", shape=box, style=filled, fillcolor="#4A90E2", fontcolor=white, fontsize=12, width=2, height=1 ]; } ``` ### Record Nodes (Structured Data) ```dot digraph G { struct [shape=record, label="{name: string|age: int|email: string}"]; table [shape=record, label="{ id| name| value}"]; } ``` --- ## Edge Definition ### Basic Syntax ```dot digraph G { A -> B; // Simple edge A -> B [label="calls"]; // Labeled edge A -> {B; C; D}; // One to many } ``` ### Edge Attributes ```dot digraph G { A -> B [ label="relationship", style=dashed, color="#FF6B6B", penwidth=2, arrowhead=normal, arrowtail=none, dir=both ]; } ``` ### Edge Styles | Style | Description | |-------|-------------| | `solid` | Regular line (default) | | `dashed` | Dashed line | | `dotted` | Dotted line | | `bold` | Thick line | | `invis` | Invisible (for layout) | ### Arrow Heads | Type | Description | |------|-------------| | `normal` | Standard arrow (default) | | `open` | Open arrow tip | | `none` | No arrow | | `diamond` | Diamond end | | `odiamond` | Open diamond | | `dot` | Dot end | | `box` | Box end | | `crow` | Crow's foot (ER diagrams) | | `vee` | V-shaped | --- ## Layout Control ### Layout Directions ```dot digraph G { rankdir=TB; // Top to Bottom (default) // rankdir=LR; // Left to Right // rankdir=RL; // Right to Left // rankdir=BT; // Bottom to Top } ``` ### Node Ranking ```dot digraph G { {rank=same; A; B; C;} // Force same level {rank=min; StartNode;} // Force to top {rank=max; EndNode;} // Force to bottom {rank=source; Input;} // Absolutely first {rank=sink; Output;} // Absolutely last } ``` ### Spacing Control ```dot digraph G { graph [ nodesep=0.5, // Horizontal spacing between nodes ranksep=1.0, // Vertical spacing between ranks splines=ortho // Edge routing: ortho|polyline|curved|line ]; } ``` ### Edge Constraints ```dot digraph G { A -> B [constraint=false]; // Don't affect ranking A -> C [minlen=2]; // Minimum edge length } ``` --- ## Subgraph (Clustering) ```dot digraph G { subgraph cluster_backend { label="Backend Services"; style=filled; fillcolor="#F0F0F0"; color="#333333"; API [label="API Gateway"]; DB [label="Database", shape=cylinder]; API -> DB; } subgraph cluster_frontend { label="Frontend"; style=filled; fillcolor="#F5F5F5"; Client [label="Web Client"]; } Client -> API; } ``` **Note:** Cluster names must start with `cluster_` to render as boxes. --- ## Global Defaults ```dot digraph G { // Default for all nodes node [shape=box, style=filled, fillcolor="#3498DB", fontcolor=white]; // Default for all edges edge [color="#666666", arrowhead=vee]; // Graph attributes graph [rankdir=LR, bgcolor=white]; A -> B -> C; } ``` --- ## Color Palette | Color | Hex | Usage | |-------|-----|-------| | Green | `#2ECC71` | Success, completed | | Red | `#E74C3C` | Error, critical | | Orange | `#F39C12` | Warning, action | | Blue | `#3498DB` | Info, process | | Gray | `#95A5A6` | Neutral, disabled | | Purple | `#9B59B6` | Concept, idea | | Cyan | `#1ABC9C` | Secondary | | Yellow | `#F1C40F` | Highlight | --- ## Node Shapes ### Common Shapes | Shape | Description | Usage | |-------|-------------|-------| | `box` | Rectangle | Process, action | | `ellipse` | Ellipse (default) | General node | | `circle` | Circle | State, event | | `diamond` | Diamond | Decision | | `plaintext` | No border | Labels | | `record` | Structured | Data tables | | `cylinder` | Cylinder | Database | | `folder` | Folder | Directory | | `component` | UML component | Module | | `house` | House | Root | | `invhouse` | Inverted house | Leaf | ### HTML Labels ```dot digraph G { node [shape=plaintext]; A [label=<

Header

Content

>]; } ``` --- ## Undirected Graphs ```dot graph G { rankdir=LR; A -- B -- C; B -- D; } ``` Use `graph` instead of `digraph`, and `--` instead of `->`. --- ## Troubleshooting | Issue | Solution | |-------|----------| | Nodes not aligned | Use `rank=same` or invisible edges | | Edges crossing | Try different `splines` or `rankdir` | | Clusters not showing | Name must start with `cluster_` | | Labels too long | Use `\n` for line breaks | | Graph too wide | Switch to `rankdir=TB` | | Overlapping nodes | Increase `nodesep` or `ranksep` |